Plus Two

Teachers recommend solving Kerala Syllabus Plus Two Botany Previous Year Question Papers and Answers Pdf Board Model Paper 2023 to improve time management during exams.

Kerala Plus Two Botany Board Model Paper 2023 with Answers

I. Answer any 3 questions from 1 to 5. Each carries 1 score.

Question 1.
Choose the correct answer. The innermost wall layer of microsporangium that give nutrition to pollen grain is called _____.
(a) Epidermis
(b) Endothecium
(c) Tapetum
(d) Middle layer
Answer:
Tetum

Question 2.
Name the first transgenic cow that produces human protein enriched milk.
Answer:
Rosie

Question 3.
Fill in the blank:
The natural interconnection of different food chains is called ______ .
Answer:
Food web

Question 4.
Choose the correct answer.
Which of these enzymes removes nucleotides from the ends of a DNA?
(a) Exonuclease
(b) Endonuclease
(c) DNA Ligase
(d) DNA Polymerase
Answer:
Exonuclease

Question 5.
Fill in the blank:
The population interaction in which one species is harmed whereas the other is unaffected is known as
Answer:
Amensalism

II. Answer any 9 questions from 6 to 16. Each carries 2 scores.

Question 6.
Write two roles of Predators in ecosystem.
Answer:
1. They plays an important role in biological control and reduce the size ofprey populations.
2. Predators maintain species diversity in nature.

Question 7.
(a) What is emasculation?
Answer:
(a) Removal of anthers from the flower bud before dehiscence.
(b) It frevert self pollination

Question 8.
Bt-toxin does not kill Bacillus, but it kill insects. Write the reason.
Answer:
The Bt toxin is producéd by the bacteria as inactive protoxin. Due to alkaline PH of insect gut, insecticidal protein crystals are Solubilised and convert inactive protoxin into active toxin. Active Bt toxin binds to the midgut epithelial cells and make pores, then swelling, it causes lysis and leads to the death of insect.

Question 9.
(a) Write the name of the ecological pyramid given in the figure.
(b) This pyramid is always upright. Why?

Answer:
(a) Pyramid of energy.
(b) when energy flows from one trop hic level to the next some energy is lost as heat at each step
hence energy deceases in uccessive trophic levels.

Question 10.
How can we visualize DNA fragments in G el electrophoresis?
Answer:
Separated DNA fragmentcan bevisualised as orange coloured band under UV light exposure after staining with Ethydium Bromide.

Question 11.
(a) Expand ELISA.
(b) What is the principle of this process?
Answer:
(a) Enzyme linked immuno-sorbent assay
(b)Antigen-antibody interaction

Question 12.
Observe the figure of Monocot seed and label the parts marked as A, B, C & D

Answer:
A—Endosperm
B — Scutellum
C — Plumule
D — Radicle

Question 13.
Write the differnce between Gross Primary Productivity (GPP) and Net Primary Productivity (NPP).
Answer:
Gross primary productivity : The rate of production of total organic matter during photosynthesis.
Net primary productivity : Gross primary productivity minus respiration losses. GPP — R = NPP

Question 14.
N_t+1 = N_t + [(B + 1) – (D + E)] is the equation to find the population density at a given time. What does B, I, D and E stands for?
Answer:
B — Natality I Birth rate
I — Immigration
D — Mortality I Death rate
E — Emigration

Question 15.
(a) Which’enzymes are known as ‘molecular scissors’?
(b) What is the use of thse enzymes in Genetic engineering?
Answer:
(a) Restriction enzymes
(b) They are used to cut at specific nucleotide sequence of DNA

Question 16.
Match the following:

A	B
Fragmentation	Water soluble inorganic nutrients go down into the soil
Leaching	Breakdown of detritus into smaller particles
Catabolism	Formation of inorganic nutrients from humus
Mineralisation	Bacterial and fungal enzymes degrade detritus into simpler inorganic substances

Answer:

A	B
Fragmentation	Breakdown of detritus into smaller particles
Leaching	Water soluble inorganic nutrients go down into the soil
Catabolism	Bacterial and fungal enzymes degrade detritus into simpler inorganic substances.
Mineralisation	Formation of inorganic nutrients from humus

III. Answer any 3 questions from 17 to 20. Each carries 3 scores. (3 × 3 = 9)

Question 17.
(a) Observe the figure and write the name of two population growth curves marked as A & B.
(b) What does K and r stands for?

Answer:
(a) A— Exponential growth
B — Logistic growth.

(b) K — Carrng capacity
r — Intrinsic rate of natural increase

Question 18.
Write three adaptations of insect pollinated fldvers.
Answer:
Pollen grains are sticky. Flowers are large, brightly colou red. They have scent and rich in nectar. Small flowers present in cluster to make them conspicuous.

Question 19.
(a) Writethe name of the process given inthefigure.
(b) What is the purpose of this process in rDNA technology?
(c) What is the name of thermostabte DNA polymerase enzyme used in this technique?

Answer:
(a) Polymerase Chain Reaction
(b) Used for Amplification of DNA
(c) Taq Polymerase

Question 20.
Write three uses of Trangenic animals.
Answer:

1. Used to study the normal physiology and development.
2. Used to understand the role of a gene in the development of a disease.
3. Transgenic animals (mice) are used in testing the safety of vaccines and chemicals.

Reviewing Kerala Syllabus Plus Two Chemistry Previous Year Question Papers and Answers Pdf March 2022 helps in understanding answer patterns.

Kerala Plus Two Chemistry Previous Year Question Paper March 2022

Time: 2 Hours
Total Scores: 60

Part-I

A. Answer any 5 questions from 1 to 9. Each carries 1 score. (5 × 1 = 5)

Question 1.
Write an ionic compound which can exhibit both Schottky and Frenkel defect.
Answer:
AgBr (Silver Bromide)

Question 2.
Two solutions having same osmotic pressure at a given temperature are called ______________
Answer:
Isotonic Solution

Question 3.
The law that can be used to determine the limiting molar conductivity (λm°) of weak electrolytes is ______________
Answer:
Kohlrausch Law

Question 4.
The unit of rate constant of a first-order chemical reaction is ______________
(a) mol^-1 Ls^-1
(b) s^-1
(b) mol L^-1 s^-1
(d) mol^-2 L² s^-1
Answer:
(b) s^-1

Question 5.
What is the name of the colloidal system in which both the dispersed phase and dispersion medium are liquids?
(a) Emulsions
(b) Gel
(c) Sol
(d) Foam
Answer:
(a) Emulsions

Question 6.
The method used for the concentration of sulphide ores is
(a) Hydraulic washing
(b) Leaching
(c) Magnetic separation
(d) Froth flotation
Answer:
(d) Froth flotation

Question 7.
The reaction which converts benzene diazonium chloride to chlorobenzene using CuCl and HCl is known as ______________
(a) Swarts reaction
(b) Sandmeyer reaction
(c) Finkelstein reaction
(d) Kolbe’s reaction
Answer:
(b) Sandmeyers reaction

Question 8.
Give a reagent to distinguish 1°, 2°, and 3° alcohols.
Answer:
Lucas reagent [Conc. HCl & Anhydrous ZnCl₂]

Question 9.
The galvanic cells which are used to convert the energy of combustion of fuels like hydrogen, methane, etc. into electrical energy are generally called ______________
Answer:
Fuel Cell

B. Answer all questions from 10 to 13. Each carries 1 score. (4 × 1 = 4)

Question 10.
A white precipitate is obtained when aniline reacts with bromine water at room temperature. The chemical name of the precipitate is ______________
Answer:
2,4,6-Tribromoanilihe

Question 11.
Identify the peptide bond among the following:

Answer:
(c) -CO-NH-

Question 12.
Name the polymerization product formed by the condensation reaction between phenol and formaldehyde
(a) Bakelite
(b) Melamine formaldehyde
(c) Nylon
(d) Dacron
Answer:
(a) Bakelite

Question 13.
The artificial sweetener which is used in cold foods and soft drinks is
(a) BHT
(b) Aspartame
(c) Sodium benzoate
(d) Ranitidine
Answer:
(b) Aspartame

Part-II

A. Answer any 2 questions from 14 to 17. Each carries 2 scores. (2 × 2 = 4)

Question 14.
KCl crystals develop violet colour when heated in an atmosphere of potassium vapour. Explain.
Answer:
It is due to the presence of F-centre i.e., electron trapped anion vacancy.

Question 15.
State Henry’s law and mention any one of its applications.
Answer:
The amount of gas dissolved in a liquid is directly proportional to the pressure applied.
\(\frac{x}{m}\) ∝ P
\(\frac{x}{m}\) = K_HP

Application:

1. Soda bottles show a fizz sound while opening.
2. Scuba divers use little helium in oxygen cylinders.

Question 16.
(i) Write the Arrhenius equation. (1)
(ii) How will you obtain the value of activation energy (Ea) from a graphical plot using the Arrhenius equation? (1)
Answer:
(i) k = \(A \cdot e^{-E a / R T}\)

(ii) Activation energy is the product of the slope from the graph and R.

Question 17.
What is lanthanoid contraction? Mention any one of its consequences.
Answer:
The decrease is atomic and ionic size of lanthanides from La to Lu with an increase in atomic number is known as lanthanoid contraction.
Consequences:
1. Zr and Hf are similar
Nb and Ta are similar
or
2. Separation of lanthanoid mixture is difficult.
or
3. Basicity decreases from La(OH)₃ to Lu(OH)₃

B. Answer any 2 questions from 18 to 20. Each carries 2 scores. (2 × 2 = 4)

Question 18.
Why is Cr²⁺ reducing and Mn³⁺ oxidizing when both have a d⁴ configuration?
Answer:
₂₄Cr – 1s² 2s² 2p⁶ 3s² 3p⁶ 4s¹ 3d⁵
Cr²⁺ – 1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁴
₂₅Mn – 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d⁵
Mn³⁺ – 1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁴
Cr²⁺ easily loses one electron and becomes Cr³⁺ then the d⁴ configuration is changed to d³.
i.e. half-filled t2g oxidation occurs and Cr³⁺ acts as a reducing agent.
Mn³⁺ accepts one electron and becomes an Mn²⁺ – d⁵ half-filled orbital extra stable.
Here oxidation number decreases and reduction occurs and acts as an oxidizing agent.

Question 19.
Explain the carbylamine reaction with the equation.
Answer:
Primary amine treated with chloroform in the presence of alkali gives a foul-smelling gas. This is known as the carbonyl amine reaction.
Carbyl amine is methyl isocyanide

Question 20.
CH₃ – NH₂ is more basic than NH₃ while C₆H₅ – NH₂ is less basic than NH₃. Explain.
Answer:
Due to the presence of aromatic benzene ring where delocalization of electron occurs (+R effect).

Part-III

A. Answer any 3 questions from 21 to 24. Each carries 3 scores. (3 × 3 = 9)

Question 21.
Write any three differences between crystalline and amorphous solids. (3)
Answer:

Crystalline	Amorphous
1. Long-range order	1. Short-range order
2. Definite shape	2. no definite shape
3. Definite M.P.	3. M.P varies over a range
4. Anisotropic	4. Isotropic

Question 22.
18g of glucose, C₆H₁₂O₆, is dissolved in 1 kg of water in a saucepan. At what temperature will water boil at 1.013 bar? (3)
(K_b for water is 0.52 K kg mol^-1, boiling point of water = 373.15 K)
Answer:

Boiling point of the solution = 273.15 + 0.052 = 373.202 K

Question 23.
(i) Mention any two factors which influence the rate of a chemical reaction. (1)
(ii) Derive an expression for the half-life of a first-order reaction from its integrated rate equation. (2)
Answer:
(i) The important factors which affect the rate of a chemical reaction are:
Nature of the reactant, temperature, pressure, presence of catalyst, concentration.

Question 24.
(i) Write a suitable method to covert. (1)
CH₃ – CH₂ – Br to CH₃ – CH₂ – I
(ii) Suggest and explain a suitable mechanism for the nucleophilic substitution of tert-butyl bromide with NaOH. (2)
Answer:
(i) Finkelstein Reaction

(ii) S_N1 mechanism or Substitution Nucleophilic unimolecular mechanism. The reaction occurs in two steps:

Step I: Formation of carbocation

Step II: Addition of OH-

B. Answer any 2 questions from 25 to 27. Each carries 3 scores. (2 × 3 = 6)

Question 25.
(i) What are Grignard reagents? (1)
(ii) State the Saytzeff rule and illustrate it with an example. (2)
Answer:
(i) Grignard reagents -Alkyl magnesium halides or R-MgX
(ii) Saytzeff rule – More symmetrical products are favored.

Question 26.
(i) Alcohols and phenols have higher boiling points. Why? (1)
(ii) What is aspirin? How is it prepared from salicylic acid? (2)
Answer:
(i) Due to the presence of hydrogen bond (Intermolecular H-bond)
(ii) Salicylic acid is heated with acetic anhydride in the presence of mineral acid to give acetylsalicylic acid (Aspirin).

Question 27.
(i) Identify A and B in the following reaction

(ii) What is meant by hydroboration-oxidation reaction? Illustrate it with an example. (2)
Answer:
(i)

(ii) Hydroboration: Alkene is treated with diborane followed by oxidation with H₂O₂ in the presence of aqueous alkali to give alcohol. This occurs according to antimarkonikovs rule.

Part-IV

A. Answer any 3 questions from 28 to 31. Each carries 4 scores. (3 × 4 = 12)

Question 28.
(i) What are secondary batteries? (1)
(ii) Write the electrode reactions and the overall cell reaction happening in the tea storage battery when it is in use. (3)
Answer:
(i) Cells that can be recharged and reused are called secondary cells.
(ii) Anode:
Pb + \(\mathrm{SO}_4^{2-}\) → PbSO₄ + 2e^–
Cathode:
PbO₂ + \(\mathrm{SO}_4^{2-}\) + 4H⁺ + 2e^– → PbSO₄ + 2H₂O
Overall reaction:
Pb + PbO₂ + 2H₂SO₄ → 2PbSO₄ + 2H₂O

Question 29.
(i) Distinguish homogeneous and heterogeneous catalysis. (2)
(ii) Explain the Tyndal effect. Write any one practical application of this effect. (2)
Answer:
(i) Homogeneous Catalysis: Both the reactants and the catalyst are in the same phase.
Heterogeneous Catalysis: The reactants and catalysts are in different phases.
(ii) The  Tyndall effect is the scattering of light due to colloidal particles. The path of the light can be seen.
eg. Ultra microscope.

Question 30.
(i) Write chemical equations involved in the leaching of alumina from bauxite. (3)
(ii) What is the purpose of adding cryolite or CaF₂ into purified Al₂O₃ during the extraction of Al? (1)
Answer:
(i) Leaching of alumina from Bauxite: Powdered bauxite ore is treated with NaOH. Then sodium Aluminate is formed. To this solution, CO₂ gas is passed. Sod, Aluminate is precipitated as hydrated alumina. It is filleted and heated to get pure alumina.

(ii) To decrease the melting point of Alumina cryolite is mixed with it.

Question 31.
(i) What are oligosaccharides? Give an example. (2)
(ii) What is glycogen? (1)
(iii) Explain the chemical constitution of starch. (1)
Answer:
(i) Carbohydrates that give 3 to 10 minor saccharides on hydrolysis are known as Oligosaccharides.
eg. Sugar.
(ii) Carbohydrates stored in animal bodies are known as glycogen.
(iii) Starch contains two components – amylose and amylopectin.

B. Answer any 1 question from 32 to 33. Carries 4 scores. (1 × 4 = 4)

Question 32.
(i) Differentiate between thermoplastics and thermosetting plastics. (2)
(ii) Write the name and structure of the monomer of neoprene. (2)
Answer:
(i)

Thermoplastics	Thermosetting plastics
1. They can be reused.	1. They cannot be reused.
2. They can repeatedly soften on heating and harden on cooling.	2. Upon heating they undergo extensive cross-linking and become infusible.
3. They are linear or long-branched polymers.	3. They are cross-linked or heavily branched polymers.
4. Eg. Polythene	4. Eg. Bakelite

(ii) Neoprene – monomer is chloroprene 2-chiro 1, 3 butadiene

Question 33.
(i) Distinguish anionic detergents and cationic detergents with suitable examples. (3)
(ii) Name any one antioxidant used in food materials. (1)
Answer:
(i)

Anionic Detergents	Cationic Detergents
1. They contain Na salts of sulphonated long-chain alcohols or hydrocarbons.	1. They are quaternary ammonium salts of amines with acetates chlorides or bromides.
2. Anionic part is used in cleaning action.	2. The cationic part is the cause of the cleaning action.
3. Used in toothpaste.	3. Used in Hair conditioner.
4. Sodium Lauryl sulphate or Sod. Dodecyl benzene sulphonate.	4. Cetyl trimethyl ammonium bromide or quarternary ammonium compounds.

(ii) Butylated hydroxy toluene (BHT), Butylated hydroxy anisole (BHA).

Part-V

Answer any 2 questions from 34 to 36. Each carries 6 scores. (2 × 6 = 12)

Question 34.
(i) Write the chemical reaction when PCl₅ is strongly heated. (1)
(ii) What are interhalogen compounds? Give two examples. (2)
(iii) Explain the steps involved in the contact process to manufacture H₂SO₄. (3)
Answer:
(i) When strongly heated PCl₅ decomposes to form PCl₃ and Cl₂.
PCl₅ → PCl₃ + Cl₂
(ii) Two halogens combine to form interhalogen compounds.
eg. BrF₅, CIF₃
(iii) The contact process involves the following steps:
S + O₂ → SO₂
SO₂ + O₂ → SO₃
SO₃ + H₂SO₄ → H₂SO₂O₇ oleum
H₂SO₂O₇ + H₂O → 2H₂SO₄

Question 35.
(i) Draw the geometrical isomers of [Co(NH₃)₄Cl₂]⁺. (2)
(ii) Describe the four types of structural isomerism exhibited by coordination compounds. (4)
Answer:
(i)

(ii) (1) Ionisation isomerism – Due to the difference of ions in aqueous solution.
eg. [Co(NH₃)₅Br]SO₄ and [C0(NH₃)₅SO₄]Br
(2) Linkage isomerism – Due to the difference in linking atoms.
[CO(NH₃)₅NO₂]Cl₂ and [Co(NH₃)₅(ONO)]Cl₂
(3) Hydrate isomerism – Due to the difference in no. of H₂O molecules inside and outside of the coordination sphere.
[Cr(H₂O)₆]Cl₃ and [Cr(H₂O)₅Cl]Cl₂.H₂O
(4) Coordination isomerism – Due to the exchange of ligands between the central meta-atoms.
[Co(NH₃)₆][Cr(CN)₆] and [Co(CN)₆][Cr(NH₃)₆]

Question 36.
(i) Write the products of the following reaction: (2)

(ii) Expalin Hell -Volhard-Zelinsky (HVZ) reaction. (2)
(iii) Suggest a suitable method for the following conversion. (2)

Answer:
(i)

(ii) HVZ reaction: Carboxylic acids containing α-hydrogen atoms are heated with halogen and red phosphorous to form an α-halogenated carboxylic acid.

(iii) Etards reaction:

Teachers recommend solving Kerala Syllabus Plus Two Botany Previous Year Question Papers and Answers Pdf March 2020 to improve time management during exams.

Kerala Plus Two Botany Previous Year Question Paper March 2020

I. Answer any 3 questions from 1-5. Each carries 1 score. (3 × 1 = 3)

Question 1.
Which one of the following has the largest population in a food chain?
a) Products
b) Primary consumers
c) Secondary consumers
d) Tertiary consumers
Answer:
Producers or Primary consumers

Question 2.
Which among the fallowing is a selectable marker in pBR-322?
a) “Ori”
b) Hind III
c) amp^R
d) rop
Answer:
amp^R

Question 3.
____ is a better yielding semi dwarf variety of rice developed in India.
a) Sonalika
b) Kalyan Sona
c) IR-8
d) Jaya/iBco)
3. Jaya

Question 4.
What is a Clone?
Answer:
Morphologically and genetically similar offsprings are produced through asexual reproduction called as Clone

Question 5.
Fill up the blank suitably.
Mortality : No. of deaths in the population during a given period.
_________ : No. of births in the population during a given period.
Answer:
Natality or birth rate

II. Answer any9 questions from 6-16. Each carries 2 scores. (9 × 2 = 18)

Question 6.
What are the main consequences of Global warming?
Answer:
1. Melting of polar ice caps and Himalayan snow caps.
2. Rise in sea level and submerge many coastal areas.

Question 7.
What is the difference between hydrarch succession and xerarch succession.
Answer:
Xerarch succession : Succession that occurs in desert or xeric condition. The poineer community formed is Lichen.
Hydrarch : It is the ecological succession occur in the newly formed pond or lake . The poineer community formed is phytoplankton

Question 8.
Suggest any two methods for the disposal of solid wastes.
8. Two methods for the disposal of solid wastes
1. Sanitary landfills
2. Incineration

Question 9.
Match the columns A and B.

a) Rhizome	i) Agave
b) Bulbil	ii) Water hyacinth
c) Offset	iii) Ginger
d) Leaf buds	iv) BrvoDhvllum

Answer:

a) Rhizome	Ginger
b) Bulbil	Agave
c) Offset	Water hyacinth
d) Leaf buds	Bulbil

Question 10.
Identify the types of population growth noted in the graph as ‘A’ and ‘B’.

Answer:
a) J-shaped curve or Exponential growth
b) Sigmoid curve or Logistic growth

Question 11.
How does the inactive protoxin o£ Bacillus thurinaiensis gets converted into active toxin when an insect ingest it?
Answer:
Bt toxin protein exist as inactive protoxins but it is converted into an active form in the presence of the alkaline pH of insect gut.

Question 12.
Given below is a data showing number of individuals and dry weight of different trophic levels inva grassland ecosystem. Construct,
a) Pyramid of number
b) Pyramid of biomass
Answer:

Trophic Level	Number of individuals	Dry weight(Kg nr<sup>-2</sup>)
Primary Producer	5,842,000	809
Primary Consumer	7,08,000	37
Secondary Consumer	3,54,000	11
Tertiary Consumer	3	1.5

Answer:

Question 13.
How can you differentiate true fruits from false fruits?
Answer:
True fruits : Fruits develops only from the ovary eg. Mango
Fuse fruits : In this thalamus develops into fruit. eg. apple, strawberry, cashew, etc

Question 14.
What is biofortification? Write any two objectives of biofortification.
Answer:
biofortification
It is the breeding of crops with higher levels of vitamins minerals,proteins and healthierfats Objectives of improving nutritional quality
(i) Protein content and quality;
(ii) Oil content and quality

Question 15.
How can we make a host cell competent to receive a foreign gene or DNA?
Answer:
This is done by treating them with calcium ions and incubating the cells and recombinant DNA on ice, followed by placing them at 42°C Then putting them back on ice. This helps the bacteria to take up the recombinant DNA.

Question 16.
Early diagnosis is essential for the effective treatment of a disease. Write any two molecular diagnostic methods.
Answer:
Early diagnosis of disease is possible by:

1. Polymerase Chain Reaction (PCR) and
2.  Enzyme Linked Immuno-sorbent Assay (ELISA)

III. Answer any 3 questions from 17 – 20. Each carries 3 scores. (3 × 3 = 9)

Question 17.
Define the following terms:
a) Autogamy
b) Geitonogamy
c) Xenogamy
Answer:
(a) Auto gamy: It is the transfer of pollen grains from the anther to the stigma of the same flower.

(b) Geitonocjamy: Transfer of palIen grains from the anther to the stigma of anotherfiower of the same plant.

(C) Xen oaamy : Transfer of pollen grains from anther to the stigma of a different plant. This type of pollination occurs betwecn genetically different species.

Question 18.
Ozone depletion in stratosphere is a serious ; environmental issue.
a) What is good ozone?
b) How do CFCs degrade ozone molecule is stratosphere?
Answer:
a) Good’ ozone- This ozone is found in the upper part of the atmosphere (stratosphere), and it acts as a shield and absorbing ultraviolet radiation from the sun.

b) The CFC produced in the upper part of the atmosphere is degraded by the action of UV. If splits and release active dorme. This active dorme destroys ozone and makes holes.

Question 19.
The following are the. diagrams of two important processes used in rDNA technology.
a) Identify A and B
b) Write the uses of A and B in rDNA technology.

Answer:
a) A – Polymerase chain reaction
B – Gel electrophoresis

b) A-Polymerase Chain Reaction is helpful to produce multiple copies (1 billion conies) òf the
gene of interest.

B- Gel electrophoresis
The cut fragments of DNA are separated by this technique.

Question 20.
Given below are examplesfor some ecological! population interactions. Place them under sUitable columns provided below.
a) Abingdon tortoise and goat.
b) Cuscuta and host tree.
c) Fig tree and wasp.
d) Algae and fungi in Lichens
e) Belanus and Chathabalus bermacles
f) Lice on humans.

Competition	Parasitism	Mutualism

Answer:

Competition	Parasitism	Mutualism
Abingdon tortoise and goat.	Cuscuta and host tree.	Fig tree and wasp.
Belanus and  Chathamalus bernacles.	Lice on humans.	Algae and fungi in Lichens.

Reviewing Kerala Syllabus Plus Two Maths Previous Year Question Papers and Answers Pdf Board Model Paper 2022 helps in understanding answer patterns.

Kerala Plus Two Maths Board Model Paper 2022 with Answers

Time: 2 Hours
Total Score: 60 Marks

Part – I

A. Answer any five questions from 1 to 9. Each carries one score. (5 × 1 = 5)

Question 1.
The function f : R → R defined by f(x) = x.
Find for (x).
Answer:
Given f(x) = x
(fof)(x) = f(f(x))
= f(x) = x

Question 2.
Find the value of cos(sec^-1 x + cosec^-1 x), |x| ≥ 1.
Answer:
cos(sec^-1 x + cosec^-1 x)
= cos \(\frac{\pi}{2}\) = 0

Question 3.
Let Abe a square matrix of order 3 × 3, then which among the following is the value of |kA|?
(a) k²|A|
(b) k|A|
(c) k³|A|
(d) 3k|A|
Answer:
(c) k³|A|
(Hint : |kA| = kⁿ . |A|)

Question 4.
The rate of change of area of a circle with respect to its radius, when radius 6 cm is
(a) 10π
(b) 12π
(c) 8π
(d) 11π
Answer:
(b) 12π
[Hint : A = πr²
\(\frac{d A}{d r}\) = 2πr
\(\left.\frac{d A}{d r}\right]_{r=6}\) = 12π

Question 5.
Write the value of the definite integral \(\int_{-\pi / 2}^{\pi / 2} \sin x \mathrm{~d} x\).
Answer:
\(\int_{-\pi / 2}^{\pi / 2} \sin x \mathrm{~d} x\) = 0
(since sin x is an odd function)

Question 6.
Write degree of the differential equation \(\frac{d^2 y}{d x^2}\) + y = 0
Answer:
Degree = 1

Question 7.
If \(\vec{a}\) = 2î + ĵ + 3k̂ and \(\vec{b}\) = 8î + 4ĵ + 12k̂, then \(\vec{a}\) × \(\vec{b}\) is ___________ .
Answer:
\(\vec{a}\) × \(\vec{b}\) = \(\vec{0}\)
(since \(\vec{a}\) is parallel to \(\vec{a}\))

Question 8.
The Cartesian equation of a line is \(\frac{x}{2}\) = \(\frac{y}{4}\) = \(\frac{z}{2}\). Write the corresponding vector equation.
Answer:
\(\vec{a}\) =(0î + 0ĵ + 0k̂) + λ(2î + 4ĵ + 2k̂)

Question 9.
If A⊂B, then the value of P(B/A) is __________ .
Answer:
Since A⊂B, A∩B = A
∴ P(B/A) = \(\frac{P(A \cap B)}{P(A)}[latex] = [latex]\frac{P(A)}{P(A)}[latex] = 1

Answer all questions from 10 to 13. Each carries one score. (4 × 1 = 4)

Question 10.
Write the principal value of sin^-1([latex]\frac{x}{2}\)).
Answer:
sin^-1(\(\frac{1}{2}\) = \(\frac{\pi}{6}\)

Question 11.
If A is a singular matrix, then the value of |A| is __________ .
Answer:
|A| = 0

Question 12.
If y = e^{log x}, find \(\frac{d y}{d x}\).
Answer:
e^{log x} = x
∴ \(\frac{d y}{d x}\) = 1

Question 13.
If l, m, n are direction cosines of a line in space, then l² + m² + n² _____________ .
Answer:
l² + m² + n² = 1

Part – II

A. Answer any two questions from 14 to 17. Each carries two scores. (2 × 2 = 4)

Question 14.
Construct a 2 × 2 matrix A = [a_ij] whose elements are given by a_ij – 2i – j.
Answer:
A = \(\left[\begin{array}{ll}
a_{11} & a_{12} \\
a_{21} & a_{22}
\end{array}\right]\)
a_ij = 2i – j
a₁₁ = 1 a₁₂ = 0 a₂₁ = 3 a₂₂ = 2
∴ A = \(\left[\begin{array}{ll}
1 & 0 \\
3 & 2
\end{array}\right]\)

Question 15.
Find the intervals in which the function f given by f(x) = x² – 4x + 6 is strictly increasing.
Answer:
f(x) = x² – 4x + 6
f'(x) = 2x – 4
f'(x) = 0 ⇒ 2x – 4 = 0
2x = 4
x = 2

Intervals are (-∞, 2), (2, ∞)
In (-∞, 2), f'(x) < 0 In (2, ∞), f'(x) > 0
∴ f(x) is increasing in (2, ∞)

Question 16.
Find the equation of normal to the curve y = x³ at (1, 1)
Answer:
y = x³
\(\frac{d y}{d x}\) = 3x²
\(\left.\frac{d y}{d x}\right]_{(1,1)}\) = 3(1)² = 3
Eqn. of normal is
y – y₀ = \(\frac{-1}{f^{\prime}\left(x_0\right)}\) (x – x₀
y – 1 = \(\frac{-1}{3}\)(x – 1)
3y – 3 = – x + 1
x + 3 y – 4 = 0

Question 17.
From the differential equation corresponding to the family of straight lines y = mx where m is an arbitrary constant.
Answer:
Given y = mx ________ (1)
Diff: w.r.t x,
\(\frac{d y}{d x}\) = m
Sub. in (1)
y = \(\frac{d y}{d x}\) . x

B. Answer any two questions from ¡8 to 20. Each carries two scores. (2 × 2 = 4)

Question 18.
Find \(\frac{d y}{d x}\), if x – y = π.
Answer:
x – y = π
Diff: w.r.t x,
1 – \(\frac{d y}{d x}\) = 0
\(\frac{d y}{d x}\) = 1

Question 19.
Solve the differential equation \(\frac{d y}{d x}\) = \(\frac{x + y}{x}\)
Answer:
\(\frac{d y}{d x}\) = \(\frac{x + y}{x}\)
\(\frac{d y}{d x}\) = 1 + \(\frac{y}{x}\) ________ (1)
Which is homogeneous diff. eqn.
Put \(\frac{y}{x}\) = v
or y = vx
\(\frac{d y}{d x}\) = v + x\(\frac{d v}{d x}\)
Sub. these in (1)
v + x\(\frac{d v}{d x}\) = 1 + v
x\(\frac{d v}{d x}\) = 1
dv = \(\frac{d x}{x}\)
Which is variable separable
∴ Solution is ∫dv = ∫\(\frac{d x}{x}\)
v = log x + C
\(\frac{y}{x}\) = log x + C
or y = x(log x + C)

Question 20.
Show that the vectors \(\vec{a}\) = î – 2ĵ + 3k̂, \(\vec{b}\) = 2î + 3ĵ – 4k̂ and \(\vec{c}\) = î – 3ĵ + 5k̂ are coplanar.
Answer:
Given \(\vec{a}\) = î – 2ĵ + 3k̂,
\(\vec{b}\) = 2î + 3ĵ – 4k̂
\(\vec{c}\) = î – 3ĵ + 5k̂
[\(\vec{a}\)\(\vec{b}\)\(\vec{c}\)] = \(\left|\begin{array}{ccc}
1 & -2 & 3 \\
-2 & 3 & -4 \\
1, & -3 & 5
\end{array}\right|\)
= 1(3) + 2(-6) + 3(3)
= 3 – 12 + 9 = 0
∴ \(\vec{a}\), \(\vec{b}\), \(\vec{c}\) are coplanar.

Part – III

A. Answer any three questions from 21 to 24. Each carries three scores (3 × 3 = 9)

Question 21.
Show that the relation R in the set {1, 2, 3} given by R= {(1, 1), (2, 2), (3, 3), (1, 2), (2, 3)} is reflexive but neither symmetric nor transitive.
Answer:
Let A = {1, 2, 3}
R = {(1, 1), (2, 2), (3, 3), (1, 2), (2, 3)}
(a, a) ∈ R for all a ∈ A
∴ R is reflexive
(1, 2) ∈ R, but (2, 1) ∉ R
∴ R is not symmetric
(1, 2) ∈ R, (2, 3) ∈ R but (1, 3) ∉ R
∴ R is not transitive

Question 22.
If A = \(\left[\begin{array}{ll}
3 & -2 \\
4 & -2
\end{array}\right]\) and I = \(\left[\begin{array}{ll}
1 & 0 \\
0 & 1
\end{array}\right]\). Find K so that A² = KA – 2I.
Answer:

Question 23.
Find the, area of a parallelogram whose adjacent sides are given by the vectors:
\(\vec{a}\) = 3î + ĵ + 4k̂ and \(\vec{b}\) = î – ĵ + k̂
Answer:
\(\vec{a}\) = 3î + ĵ + 4k̂
\(\vec{b}\) = î – ĵ + k̂
\(\vec{a}\) × \(\vec{a}\) \(\left|\begin{array}{ccc}
\hat{i} & \hat{j} & \hat{k} \\
3 & 1 & 4 \\
1 & -1 & 1
\end{array}\right|\)
= î(5) – ĵ(-1) + k̂(-4)
= 5î + ĵ – 4k̂
Area of parallelogram = |\(\vec{a}\) × \(\vec{a}\)|
= \(\sqrt{25 + 1 + 16}\)
= \(\sqrt{42}\) sq. units

Question 24.
Probability of solving specific problem independently by A and B are \(\frac{1}{2}\) and \(\frac{1}{3}\) respectively. 1f both try to solve the problem independently. Find the prob
ability that exactly one of them solves the problem.
Answer:
Let P(A) = \(\frac{1}{2}\), P(B) = \(\frac{1}{3}\)
∴ P(A’) = \(\frac{1}{2}\), P'(B) = \(\frac{2}{3}\)
P(exactly one solves)
= P(A∩B’∪A’∩B)
= P(A∩B’) + P(A’∩B)
= P(A) . P(B’) + P(A’) . P(B)
= \(\frac{1}{2}\) . \(\frac{2}{3}\) + \(\frac{1}{2}\) . \(\frac{1}{3}\)
= \(\frac{2}{6}\) + \(\frac{1}{6}\) = \(\frac{3}{6}\) = \(\frac{1}{2}\)

B. Answer any two questions from 25 to 27. Each carries three scores. (2 × 3 = 6)

Question 25.
Consider the binary operation ∧ on the set {1, 2, 3, 4, 5} defined by a ∧ b = min {a, b}. Write the operation table of the operation ∧.
Answer:

Question 26.
By using elementary operations, find the inverse of the matrix A = \(\left[\begin{array}{cc}
1 & 2 \\
2 & -1
\end{array}\right]\)
Answer:

Question 27.
Find \(\int_0^2 x^2 d x\) as limit of a sum.
Answer:
a = 0, b = 2, nh = b – a = 2
f(x) = x²
f(a) = f(0) = 0
f(a + h) = f(0 + h) = (0 + h)² = h²
f(a + 2h) = f(0 + 2h) = (0 + 2h)² = 4h²
f(a + 3h) = f(0 + 3h) = (0 + 3h)² = 9h²
f(a + (n – 1)h = f(0 + (n – 1)h = (n – 1)²h²

Part – IV

A. Answer any three questions from 28 to 31. Each carries four scores. (3 × 4 = 12)

Question 28.
Show that:
(i) tan^-1(\(\frac{1}{2}\)) + tan^-1(\(\frac{2}{11}\)) =
tan^-1(\(\frac{3}{4}\))
(ii) cos^-1(4x³ – 3x) = 3cos^-1 x, x ∈ [\(\frac{1}{2}\), 1]
Answer:

(ii) Put x = cos θ ⇒ θ = cos^-1 x
LHS = cos^-1 (4 cos³ θ – 3 cos θ)
= cos^-1 (cos 3θ)
= 3θ = 3 cos^-1 x = RHS

Question 29.
Verify Mean Value Theorem for the function f(x) = x² in the interval [2, 4]
Answer:
Given f(x) = x²
Since f(x) is a polynomial function, it is continuous in [2, 4]
f'(x) = 2x
It is differentiable in (2, 4)
f(a) = f(2) = 4
f(b) = f(4) = 16
f'(c) = \(\frac{f(b)-f(a)}{b-a}\) = \(\frac{16 – 4}{2}\) = \(\frac{12}{2}\) = 6
2c = 6
c = 3 ∈ (2, 4)
Hence mean value theorem verified.

Question 30.
Find the area of the region bounded by the curve y² = x and the lines x = 1, x = 4 and the x-axis in the first quadrant.
Answer:
Given y² = x, x = 1, x = 4
Required area

Question 31.
Find the shortest distance between the lines whose vector equations are
\(\vec{r}\) = î + ĵ + λ̂,(2î – ĵ + k̂) and
\(\vec{r}\) = 2î + ĵ – k̂ + µ(3î – 5ĵ + 2k̂)
Answer:
Given \(\vec{r}\) = î + ĵ + λ̂,(2î – ĵ + k̂) and
\(\vec{r}\) = 2î + ĵ – k̂ + µ(3î – 5ĵ + 2k̂)
∴ \(\vec{a}\)₁ = î + ĵ,
\(\vec{b}\)₁ = 2î – ĵ + k̂
\(\vec{a}\)₂ = 2î + ĵ – k̂
\(\vec{b}\)₂ = 3î – 5ĵ + 2k̂
\(\vec{a}\)₂ – \(\vec{a}\)₁ = î – k̂
\(\vec{b}\)₁ × \(\vec{b}\)₂ = \(\left|\begin{array}{ccc}
\hat{i} & \hat{j} & \hat{k} \\
2 & -1 & 1 \\
3 & -5 & 2
\end{array}\right|\)
= î(3) – ĵ(1) + k̂(-7)
= 3î – ĵ – 7k̂
\(\vec{b}\)₁ × \(\vec{b}\)₂ = \(\sqrt{9 + 1 + 49}\)
= \(\sqrt{59}\)
(\(\vec{a}\)₂ – \(\vec{a}\)₁) . (\(\vec{b}\)₁ × \(\vec{b}\)₂) = 3 + 0 + 7 = 10
Shortest Distance = \(\left|\frac{\left(\bar{a}_2-\bar{a}_1\right) \cdot\left(\bar{b}_1 \times \bar{b}_2\right)}{\left|\bar{b}_1 \times \bar{b}_2\right|}\right|\)
= \(\frac{10}{\sqrt{59}}\) units

B. Answer any one question from 32 and 33. Carries four scores. (1 × 4 = 4)

Question 32.
Random variable Xhas following probability distribution.

(a) Find the value of k. (2)
(b) Find P (X < 3). (2)
Answer:
(a) 0.1 + k + 2k + 2k + k = 1
6k + 0.1 = 1
6k = 1 – 0.1 = 0.9
k = \(\frac{0.9}{6}\) = \(\frac{9}{60}\) = \(\frac{3}{20}\)

(b) p(x < 3) = p(0) + p(1) + p(2)
= 0.1 + k + 2k
= 0.1 + 3k
= \(\frac{1}{10}\) + \(\frac{9}{20}\)
= \(\frac{2}{20}\) + \(\frac{9}{20}\)
= \(\frac{11}{20}\)

Question 33.
Find the Cartesian and vector equation of the plane with intercepts 2, 3, 4 on the x, y, z axis respectively.
Answer:
a = 2, b = 3, c = 4
Eqn is
\(\frac{x}{a}\) + \(\frac{y}{b}\) + \(\frac{z}{c}\) = 1
\(\frac{x}{2}\) + \(\frac{y}{3}\) + \(\frac{z}{4}\) = 1
Multiplying throughout by 12
6x + 4y + 3z = 12
\(\vec{r}\).(6î + 4ĵ + 3k̂) = 12

Part – V

Answer any two questions from 34 to 36. Carries six scores. (2 × 6 = 12)

Question 34.
Solve the following system of equations by matrix method:
3x – 2y + 3z = 8
2x + y – z = 1
4x – 3y + 2z = 4
Answer:
Let A = \(\left[\begin{array}{ccc}
3 & -2 & 3 \\
2 & 1 & -1 \\
4 & -3 & 2
\end{array}\right]\), x = \(\left[\begin{array}{l}
x \\
y \\
z
\end{array}\right]\), B = \(\left[\begin{array}{l}
8 \\
1 \\
4
\end{array}\right]\)
∴ System of equations can be written as AX = B
|A| = 3(-1) + 2(8) + 3(-10)
= – 3 + 16 – 30
= -17 ≠ 0
∴ Unique solution is given by X = A^-1B
A₁₁ = -1 A₁₂ = -8 A₁₃ = -10
A₂₁ = -5 A₁₂ = -6 A₂₃ = 1
A₃₁ = -1 A₃₂ = 9 A₃₃ = 7

Question 35.
Solve the following linear programming problem graphically:
Maximize Z = 4x + y subject to the constraints x + y ≤ 50, 3x + y ≤ 90, x ≥ 0 , y ≥ 0
Answer:
x + y = 50

x	0	50
y	50	0

3x + y = 90

x	0	30
y	90	0

∴ z has maximum when x = 30, y = 0
Maxmimum value = 120

Question 36.
Find
(i) \(\int \frac{\sin \left(\tan ^{-1} x\right)}{1+x^2} d x\) (2)
(ii) \(\int_0^{\pi / 2} \frac{\sqrt{\sin x}}{\sqrt{\sin x}+\sqrt{\cos x}} d x\) (2)
(iii) \(\int \frac{d x}{x^2-16}\) (2)
Answer:

Teachers recommend solving Kerala Syllabus Plus Two Botany Previous Year Question Papers and Answers Pdf March 2021 to improve time management during exams.

Kerala Plus Two Botany Previous Year Question Paper March 2021

Answer the following questions from 1 to 31 upto a maximum score of 30.
I. Each questions from 1 to 7 carries 1 score.

Question 1.
Choose the correct answer
The plant which flowers only once in their life time:
(a) Mango
(c) Coconut
(b) Bamboo
(d) Jackfruit
Answer:
Bamboo

Fill in the blank:
Question 2.
During sexual reproduction, the process of syngamy results in the formation of a diploid cell called _____
Answer:
Zygote

Question 3.
Name the process of breeding crops for improved food quality.
Answer:
Biofortification

Question 4.
Choose the correctly mathced pair from the following:
(a) Gel electrophoresis – Used to produce biological products in large quantity.
(b) Bioreactors – Separation of DNA fragments.
(C) PCR – Amplification of gene
Answer:
PCR-Amplification of gene

Question 5.
Observe the relationship between the first two terms and fill in the blank.
Mycorrhizae : Mutualism
Lice on humans : _______
Answer:
Parasitism

Question 6.
Fill in the blank.
The portion of embryonal axis above the level of cotyledons in dicot embryo is known as ______ .
Answer:
Epicotyl

Question 7.
Which of the following is a curative method of ADA deficiency?
(a) ELISA
(b) Autoradiography
(c) PCR
(d) Bonemarrow transplantation
Answer:
Bone marrow transplantation

II. Each question from 8 to 26 carries 2 scores each. (19 × 2 = 38)

Question 8.
Differentiate monecious and dioecious plants with an example for both.
Answer:

Monecious plants	Dioecious plants
Male and female	Male and female
flowers present on the same plant.	flowers present on different plants.
Example – Coconut	Example – Papaya

Question 9.
EcoRI is an example of Restriction enzyme. List out the criteria for naming a Restriction enzyme.
Answer:
First capital letter represents the genus name of the bacteria(Ecoli). Second two letters represent the species name of the bacteria ‘R’ represents the strain of the bacteria. ‘I’ the roman number represents the order of isolation of enzyme from the bacteria.

Question 10.
Expand MOET. Write its significance.
Answer:
MOET – Multiple Ovulation Embryo Transfer Technology.
Significance
To improve successful production of hybrids.
Overcoming the problems of normal mating.

Question 11.
Different stages of development in a dicot embryo are given below. Arrange them in the correct sequential order. Heart shaped embryo, globular embryo, mature embryo, pro-embryo
Answer:
Pro-embryo → Globular embryo → Heart shaped embryo → Mature embryo

Question 12.
Observe the diagrams (a) and (b) given below. Identify the type of gametes. Explain the feature of gametes seen in diagram ‘b’.
Answer:

(a) Isogàmetes or Homogametes
(b) Heterogametes
Features of heterogametes
Morphologically distinct gametes i.e., male gamete is the antherozoid or sperm and Female gamete is egg or ovum.

Question 13.
The females of placental mammals exhibit cyclical changes in the activities of ovaries and accessory ducts during the reproductive phase. Specify two types of cyclical changes present in these organisms with appropriate examples.
Answer:

• Oestrus cycle
  1.  It is shown by Non-primate mammals eg. Cows, Tiger etc.
• Menstrual cycle
  1. It is shown by Primates eg. Man Monkey etc.

Question 14.
Write any two critical research areas of bio technology.
Answer:
(i) Providing the best catalyst in the form of improved organism usually a microbe or pure enzyme.
(ii) Creating optimal conditions through engineering for a catalyst to act.

Question 15.
What is biomagnification? Name any one chemical that causes biomagnification.
Answer:
Biomagnification It refers to increase in concentration of the toxicant at successive trophic level. Eg. DDT, Mercury etc.

Question 16.
List any four reasons for deforestation.
വനനശീകരണത്തിനുള്ള നാലു കാരണങ്ങൾ എഴുതുക.
Answer:

1. Conversion of forest to agricultural land so as to feed the growing human population.
2. Trees are axed for timber.
3. Trees are axed for firewood.
4. Slash and burn agriculture or Jhum cultivation.

Question 17.
Fill in the blanks with appropriate symbols (+, -, 0) or name of interaction.

Species A	Species B	Name of population interaction
(a)  _____	(b)  ____	Mutualism
+	(c) ____	Parasitism
+	0	(d)  _____

Answer:
(a) +
(b) +
(c) –
(d) Commensalism

Question 18.
What is the structural difference between proinsulin and mature functional insulin?
Answer:
Proinsulin

• Consists of three polypeptide chains: chain A and chain B and chain C.
• Non functional Mature Insulin
• Consists of two polypeptide chains: chain A and chain B linked together by disulphide bridges.

Question 19.
The diagram given below is E. coli cloning vector pBR322.

Identify the selectable markers present in it. Explain the significance of ‘ori’.
Answer:
amp^R and tet^R ori – Origin of replication or DNA sequence from where replication starts.

Question 20.
State the important steps in decomposition.
Answer:
Fragmentation, leaching, catabolism, Humification and mineralization.

Question 21.
Write four peculiarities of insect pollianted flowers.
Answer:

• Flowers are Large Colourful
• Fragrant With nectar
• Pollen grains sticky
• Small flowers are clustered into an inflorescence

Question 22.
Banana is a parthenocarpic fruit. What are partheno carpic fruits? How can be parthenocarpy induced?
Answer:
Parthenocarpic fruit is fruit formed without fertilization, they are Seedless fruits. Parthenocarpy can be induced by application of growth hormones.

Question 23.
Self incompatibility is an outbreeding mecahnism seen in plants. Explain self incompatibility.
Answer:
Self incompatibility means the inhibition of pollen germination on stigmatic surface of the same flower. It is the Genetic mechanism to prevent self pollination.

Question 24.
Based on the nature of the habitat, succession of plants may be hydrarch or xerarch.
(a) Which is the pioneer community in xerarch succession?
(b) Explain hydrarch succession.
Answer:
(a) Lichen
(b) Hydrarch succession is the transformation of hydric area into a mesic (medium water condition) area.

Question 25.
Organisms belonging to different trophic levels are listed below. Arrange the organisms under appropri- ate headings in the table provided. Man, phytoplankton, Fish, Zooplankton

First Trophic level	Second Trophic level	Third Trophic level	Fourth Trophic level

Answer:

1st trophic level	2nd trophic level	3rd trophic level	4th trophic level
Phytoplankton	Zooplankton	Fish	Man

Question 26.
Catalytic converters are fitted in automobiles for reducing emission of poisonous gases.
(a) Name the catalysts used in catalytic converters
(b) What happens to the automobile exhaust when it passes through catalytic converters?
Answer:
(a) Platinum, Palladium and Rhodium.
(b) When exhaust passes through the catalytic converter
1. Unburnt hydrocarbons are converted into carbon dioxide and water.
2. Carbon monoxide is converted into Carbon dioxide.
3. Nitric oxide is converted into Nitrogen gas.

III. Each questions 27 to 31 carries 3 scores. (5 × 3 = 15)

Question 27.
The four basic processes that affect the population density are given below. Natality, Mortality, Emigration, Immigration. Which of the two processes contribute to a decrease in population density and explain them.
Answer:
Mortality and Emigration

1. Mortality – It is the number of deaths in the population during a given period.
2. Emigration – It is is the number of individuals of the population who left the habitat.

Question 28.
Bt cotton is a transgenic plant with insecticidal protein named Bt toxin.
(a) Name the specific gene which produce Bt toxin.
(b) Name the organism from which this gene is isolated.
(c) Explain the mechanism behind the insect resistance in Bt cotton.
Answer:
(a) Cry gene

(b) Bacillus thuringiensis

(c) Cry gene produce insecticidal protein crystals that exists as inactive protoxins, Once an insect ingest the protoxin it is converted into an active toxin due to the alkaline pH of the gut, The activated toxin binds to the surface of midgut epithelial cells and create pores that cause cell swelling and lysis and eventually cause death of the insect.

Question 29.
A typical microsporangium is surrounded by four wall layers. Name the wall layers and state the function. of the innermost wall layer.
Answer:
Epidermis, Endothecium, middle layers & Tapetum Tapetum-Nourishes the developing pollen grains.

Question 30.
Different steps in rDNA technology are given below. Arrange them in correct sequential order.
(a) Ligation of DNA frament into a vector
(b) Culturing of host cells in a medium at large scale
(c) Isolation of DNA
(d) Transferring the rDNA into the host
(e) Fragmentation of DNA
(f) Isolation of desired DNA fragment
Answer:
(c) Isolation of DNA
(e) Fragmentation of DNA
(f) Isolation of desired DNA fragments
(a) Ligation of DNA fragment into a vector
(d) Transferring the rDNA into the host.
(b) Culturing of host cells in a medium at large scale

Question 31.
Dairying is the management of animals for milk and its products for human consumption. List out various management measures that should be undertaken for a successful management of dairy farm.
Answer:

1. Selection of good breeds having high yielding potential and resistance to diseases.
2. Provide adequate water.
3. Maintained disease free condition.
4. Feeding should be in a scientific manner (in the quality and quantity of fodder).
5. Regular visit of a veterinary doctor.

Reviewing Kerala Syllabus Plus Two Chemistry Previous Year Question Papers and Answers Pdf March 2023 helps in understanding answer patterns.

Kerala Plus Two Chemistry Previous Year Question Paper March 2023

Time: 2 Hours
Total Scores: 60

Answer any 4 questions from 1 to 5. Each carries 1 score. (4 × 1 = 4)

Question 1.
The unit of rate constant of a zero-order chemical reaction is _______________
Answer:
mol L^-1 s^-1

Question 2.
Among the following transition elements which one has a filled d orbital?
(a) Ag
(b) Ti
(c) Mo
(d) Ni
Answer:
(a) Ag

Question 3.
Give an example of a didentate ligand.
Answer:
Ethylene diamine (en), oxalate ion (\(\mathrm{C}_2 \mathrm{O}_4^{2-}\))

Question 4.

The name of this reaction is _______________
Answer:
Finkelstein Reaction

Question 5.
Identify the product ‘X’ in the chemical reaction given below:

Answer:
C₆H₅CHO benzaldehyde

Answer any 8 questions from 6-15. Each carries 2 scores. (8 × 2 = 16)

Question 6.
State Henry’s law. Write any one application of it.
Answer:
Henry’s Law: The solubility of a gas in a liquid is directly proportional to the pressure applied to it.
p = K_H.x
p = pressure
x = mole fraction of gas
Application:
When the soda bottle opens a fizz sound is produced. Anoxia and bends are also examples.

Question 7.
What are Ideal Solutions? Give one example.
Answer:
Ideal solutions are solutions which obey Raoults law.
P_A = \(\mathrm{P}_{\mathrm{A}}^0 \cdot x_{\mathrm{A}}\), ΔV_mix = 0, ΔH_mix = 0
Eg. n-hexane and n-heptane

Question 8.
\(\wedge_{\mathrm{m}}^0\) for NaCl, HCl and CH₃COONa are 126.4, 425.9 and 91.0 s cm² mol^-1 respectively. Calculate \(\wedge_{\mathrm{m}}^0\) for CH₃COOH.
Answer:
\(\lambda_{\mathrm{m}}^0\)CH₃COOH = \(\lambda_{\mathrm{m}}^0\)CH₃COONa + \(\lambda_{\mathrm{m}}^0\)HCl – \(\lambda_{\mathrm{m}}^0\)NaCl
= 91 + 425.9 – 126.4
= 390.5 S cm² mol^-1

Question 9.
(i) What are Pseudo first-order reactions? (1)
(ii) Write one example for a pseudo-first-order reaction. (1)
Answer:
(i) These are reactions that appear to follow a higher order but follow the first order.
(ii) Hydrolysis of ester

Question 10.
(i) Transition elements show variable oxidation state. Why? (1)
(ii) Identify the element in the 3d transition metal series that exhibits the maximum number of oxidation states. (1)
Answer:
(i) Because there is not much difference in the energy levels of 3d and 4s electrons, or there are partially filled (n-1)d orbital.
(ii) Manganese (Mn)

Question 11.
Write the IUPAC names of the following compounds:
(a) [Co(NH₃)₄(H₂O)Br]Br₂
(b) K₃[Al(C₂O₄)₃]
Answer:
(a) Tetraammineaquabromidocobalt (III) bromide
(b) Potassium trioxalatoaluminate (III)

Question 12.
Differentiate between S_N1 and S_N2 reactions.
Answer:

SN1	SN2
1. Takes place in 2 steps.	1. Through a single step.
2. Carbocation intermediate is formed.	2. No intermediate is formed.
3. Racemisation occur.	3. Inversion of configuration occurs.

Question 13.
How is phenol manufactured industrially? Write the chemical equation.
Answer:
Cumene is oxidized in the presence of air and then hydrolyzed in the presence of acid to get phenol.

Question 14.
Aniline does not undergo Friedelcraft’s reaction. Why?
Answer:
Aniline forms a salt with anhydrous aluminium chloride which is used as a catalyst in Friedel crafts reaction. So the catalyst is not available for the reaction and hence it does not undergo Friedel Crafts reaction.

Question 15.
What are oligosaccharides? Give any two examples.
Answer:
Oligosaccharides are carbohydrates that give two to ten monosaccharide units on hydrolysis.
E.g. Sucrose, maltose.

Answer any 8 questions from 16-26. Each carries 3 scores. (8 × 3 = 24)

Question 16.
(i) Define Molar Conductivity. (1)
(ii) Graphically represent the variation of molar conductivity with concentration for strong and weak electrolytes. (2)
Answer:
(i) Molar conductivity is the conductivity of 1 mole of an electrolytic solution kept between two electrodes of a conductivity cell with a unit area of cross section and at a distance of unit lengths.
(ii) λ_m = \(\frac{1000 \kappa}{m}\)

Question 17.
(i) A first-order reaction is found to have a rate constant, k = 6.8 × e 10^-14 s^-1. Find the half-life of the reaction. (1)
(ii) Write the integrated rate equation for a first-order reaction and explain the terms in it. (2)
Answer:

k – dissociation constant or rate constant
t – time
R₀ – initial concentration
R – final concentraton

Question 18.
Explain the effect of temperature and catalyst on the rate of chemical reaction.
Answer:
For every 10° rise in temperature rate constant doubles. Because with temperature rise, the number of molecules with energy equal to or greater than activation energy increases, and therefore rate constant also increases.
A catalyst increases or decreases the rate of a reaction by providing an alternate path for the reaction with low activation energy.

Question 19.
Write the preparation of K₂Cr₂O₇ from Chromite ore.
Answer:
1. Conversion of chromite ore to sodium chromate by fusing with sodium carbonate in the presence of air.
4FeCr₂O₄ + 8Na₂CO₃ + 7O₂ → 8Na₂CrO₄ + 2Fe₂O₃ + 8CO₂
2. Sodium chromate is acidified with sulphuric acid to form sodium dichromate.
2Na₂CrO₄ + 2H⁺ → Na₂Cr₂O₇ + 2Na⁺ + H₂O
3. Conversion of sodium dichromate to potassium dichromate by treating with potassium chloride.
Na₂Cr₂O₇ + 2KCl → K₂Cr₂O₇ + 2NaCl

Question 20.
(i) What is a Spectrochemical series? (1)
(ii) Draw a figure to show the splitting of d orbitals in an octahedral crystal field and label the diagram. (2)
Answer:
(i) It is a series in which the ligands are arranged in the increasing order of their field strength.
(ii)

Question 21.
Name the products formed when phenol is treated with the following reagents:
(i) Bromine water (1)
(ii) Zinc dust (1)
(iii) Conc. HNO₃ (1)
Answer:

Question 22.
Explain the following:
(i) Kolbe’s reaction (1½)
(ii) Reimer-Tiemann reaction (1½)
Answer:
(i) Kolbe’s Reaction: Sodium phenoxide reacts with CO₂ at 400 K and 4-7 atm sodium salt of salicylic acid is formed. This on acidification gives salicylic acid.

(ii) Reimer-Tiemann Reaction: Phenol reacts with chloroform in the presence of NaOH followed by acidification we get salicylaldehyde.

Question 23.
(i) Write any two nucleophilic addition reactions of aldehyde. (2)
(ii) Name the product formed when ethanal is reduced with LiAlH₄. (1)
Answer:

(ii) Ethanol OR, Ethyl alcohol (C₂H₅-OH OR, CH₃-CH₂-OH)

Question 24.
(i) Which one is more reactive among aldehydes and ketones? (1)
(ii) Describe any two tests to distinguish aldehydes from ketones. (2)
Answer:
(i) Aldehydes
(ii)

	Aldehyde	Ketone
Tollens Test	Gives silver mirror	No silver mirror is obtained
Fehling’s Test	The red precipitate of cuprous oxide	No red ppt.

Question 25.
(i) What is the Carbylamine reaction? (1)
(ii) Explain why aniline is less basic than ammonia. (2)
Answer:
(i) Primary amine reacts with chloroform in the presence of KOH to form isocyanides.
RNH₂ + CHCl₃ → RNC Carbylamine
(ii) In aniline the lone pair electron of N is in conjugation with the benzene ring. So it is not available for protonation. So it is less basic than NH₃.

Question 26.
(i) What are essential and non-essential amino acids? (1)
(ii) Explain the amphoteric behavior of amino acids. (2)
Answer:
(i) The amino acids which can be synthesized in the body are known as non-essential amino acids.
eg. Glycine, Alanine
The amino acid that cannot be synthesized in the body and get through diet is known as essential amino acid.
eg. Valine, Leucine

(ii) The same compound contains both +ve and -ve charges and hence shows an amphoteric nature.

Answer any 4 questions from 27 to 31. Each carries 4 scores. (4 × 4 = 16)

Question 27.
(i) What are Colligative properties? (1)
(ii) Write any two colligative properties. (1)
(iii) What is reverse osmosis? Mention one important practical utility of reverse osmosis. (2)
Answer:
(i) Properties that depend only on several particles.
(ii) 1. Relative lowering of vapour pressure
2. Depression at the freezing point
3. Elevation in boiling point
4. Osmosis
(ii) If a pressure higher than the osmotic pressure is applied to the solution side, the direction of osmosis gets reversed. This phenomenon is called reverse osmosis.
The application of reverse osmosis is the desalination of seawater.

Question 28.
Lead storage battery which is commonly used in automobiles is an example of a secondary cell.
(i) Write the name of the anode and cathode used in this cell. (1)
(ii) Write the reactions taking place in the anode and cathode of this cell. (2)
(iii) Explain how this cell can be recharged. (1)
Answer:
(i) Anode: Lead (Pb)
Cathode: A grid of lead packed with PbO₂
(ii) Anode reaction:
Pb + \(\mathrm{SO}_4^{2-}\) → PbSO₄ + 2e^–
Cathode reaction:
PbO₂ + \(\mathrm{SO}_4^{2-}\) + 4H⁺ + 2e^– → PbSO₄ + 2H₂O
(iii) The cell can be recharged by applying an external potential higher than the potential of the cell.

Question 29.
(i) Drew the structure of the geometrical isomers of the coordination compound [Co(NH₃)₄Cl₂]. (2)
(ii) Based on Valence Bond Theory (VBT) explain the structure and magnetic property of [Ni(CN)₄]^2-. (2)
Answer:
(i)

(ii) In [Ni(CN)₄]^2-, Ni in dsp² hybridisation. Square planar geometry.
Due to the absence of unpaired electrons, the complex is diamagnetic.

Question 30.
(i) Identify the major and minor products obtained by the reaction between 2-bromo butane and alcoholic KOH. (2)
(ii) Name and state the rule behind the formation of these products. (2)
Answer:
(i) Major product is But-2-ene (CH₃ – CH = CH – CH₃)
Minor product is But-1-ene (CH₃ – CH₂ – CH = CH₂)
(ii) Saytzeff’s rule: It states that in dehydrohalogenation reactions, the major product is alkene which contains a maximum number of alkyl groups around the C = C bond.

Question 31.
(i) Explain the Haloform reaction. (2)
(ii) How will you prepare benzaldehyde by the Gatterman-Koch reaction? (1)
(iii) Write the name of the reaction involved in the following conversion:

Answer:
(i) Haloform Reaction: Compounds with CH₃-CO or CH₃-CHOH-group, when treated with sodium hypohalite we get haloform (CHX₃).
R – CO – CH₃ → R – COONa + CHX₃
(ii) Benzene when treated with CO and HCl in the presence of anhydrous aluminium chloride or cuprous chloride we get benzaldehyde.

(iii) Clemmensen Reduction.

Teachers recommend solving Kerala Syllabus Plus Two Botany Previous Year Question Papers and Answers Pdf March 2022 to improve time management during exams.

Kerala Plus Two Botany Previous Year Question Paper March 2022

Part – I

A. Answer any 3 questions from 1 to 4. Each carries 1 score.
Choose the correct answer:

Question 1.
Innermost wall layer of Micro-sporangium is
(a) Middle layer
(b) Epidermis
(c) Tapetum
(d) Endothecium
Answer:
Tapetum

Question 2.
Fill in the blank.
The first restriction endonuclease enzyme isolated is ______ .
Answer:
Hindu

Question 3.
In polar seas, seals have a thick layer of fat. Name the fat layer seen below their skin.
Answer:
Blubber

Question 4.
Choose the correct answer:
The green plants in the ecosystem are the chief
(a) Decomposers
(c) Producers
(b) Consumers
(d) Herbivores
Answer:
Producers

B. Answer all questions from 5 to 6. Each carries 1 score.

Question 5.
Fill in the blank.
The time period from birth to the natural death of an organism is known as _____.
Answer:
Life span

Question 6.
Expand ELISA
Answer:
Enzyme Linked Immuno-sorbent Assay

Part-II

A. Answer any two questions from 7 to 9. Each carries 2 scores.

Question 7.
What are the four main objectives of Bio-fortification?
Answer:

1. Increased protein content and quality.
2. Increased oil content and quality
3. Increased vitamin content
4. Increased micronutrient and mineral content

Question 8.
Mention the functions of GEAC (Genetic Engineering Approval Committee)
Answer:
They take decisions regarding the validity of GM research and safety of introducing GM-organisms for public services.

Question 9.
Fill in the blanks with suitable terms:

Asexual Reproduction
Asexual Reproductive Structure	Examples
Zoospores	(a)
(b)	Penicillium
(c)	Hydra
Gemmules	(d)

Answer:

Asexual Reproductive Structures	Examples
Zoospoores	Chiamydomonas
Conidia	Penicillium
Buds	Hydra
Gemmules	Sponges

B. Answer any two questions from 10 to 13. Each carries 2 scores.

Question 10.
Comment on Self-incompatibility.
Answer:
Pollen from the same flower does not germinate in the stigma. This genetic mechanism helps to prevent self polination. Pollen from the same flower does not germinate in the stigma. This genetic mechanism helps to prevent self polination.

Question 11.
Introduction of semi-dwarf varieties increased production of rice and wheat. Complete the table with the names of any two semi-dwarf varieties of wheat and rice.

Rice	Wheat
–	–
–	–

Answer:
(i) Wheat – Sonalika and Kalyan Sona.
(ii) Rice – Jaya and Ratna

Question 12.
Fill in the blanks.

Population Interaction
Species – A	Species – B	Name of Interaction
(a)    _____	(b)	Competition
(c) _____	_____	Predation
_____	0	(d) ______

Answer:

Question 13.
Name the type of succession that occurs in wet area. What is the climax community in that succession?
Answer:
Hydrarch
Climax community – Forest

Part -III

A. Answer any three questions from 14 to 17. Each carries 3 scores.

Question 14.
Explain the method of genetically engineered human insulin production by ‘Eli Lilly’ in 1983.
Answer:
Eli Lilly Company prepared DNA sequences corresponding to A and B chain of insulin. A and B Chain’DNA were introduced into plasmids of E. coil to produce the Apoly peptide and B poly peptide chains, Chain A and B were extracted and combined by creating disulphide bonds.

Question 15.
List out some of the adaptations seen in desert plants.
Answer:

• They have a thick cuticle
• Leaf reduced to spine
• Sunken stomata to minimize water loss through transpiration.

Question 16.
What are the consequences of deforestation?
Answer:

• Increased carbon dioxide concentration
• Loss of Biodiversity.
• Disturbs hydrologic Cycle.
• Soil erosion.

Question 17.
The figure shows the pyramid of energy. Pyramid of energy is always upright. Why?

Answer:
When energy flows from one trophic level to the next level, some energy is lost as heat at each step a 10%.

B. Answer the following question. Carries 3 scores. (1 × 3 = 3)

Question 18.
CNG is widely used in vehicles in Delhi.
(a) Expand CNG.
(b) What are the advantages of using CNG than Diesel?
Answer:
(a) Compressed Natural Gas
(b) It burns efficiently

• It is cheaper than petrol or diesel
• It cannot be siphoned off by thieves.
• It cannot be adultered like petrol or diesel.

Part – IV

Answer any one question from 19 to 20. Carries 5 scores. (1 × 5 = 5)

Question 19.
Pollination is an important mechanism found in flowering plants.
(a) Define pollination
(b) Write short note on:
(1) Autogamy
(2) Geitonogamy
(3) Xenogamy
Answer:
(a) Transfer of pollen grains from the anther to the stigma of a pistil is termed as pollination.
(b)

1. Autogamy – Transfer of pollen grain from the anther to the stigma of the same flower.
2. Geitonogamy – The transfer of pollen grains from the anther to the stigma of different flowers of the same plant
3. Xenogamy – The transfer of pollen grains from the anther to the stigma of different plants of the same species.

Question 20.
Restriction enzymes are widely used in Biotechnolgoy.
(a) Name two kinds of restriction enzymes.
(b) Explain the naming procedure of restriction enzymes with one example.
Answer:
(a) Exonucleases & Endonucleases

(b) Eg:EcoRI – derivedfromEsche,ichiacoliRYl3
E – Genus (Escherichia)
co – Species (coli)
R – strain of bacteria
I – order in which enzyme is Isolated.

Reviewing Kerala Syllabus Plus Two Maths Previous Year Question Papers and Answers Pdf Board Model Paper 2023 helps in understanding answer patterns.

Kerala Plus Two Maths Board Model Paper 2023 with Answers

Time: 2 Hours
Total Score: 60 Marks

Answer any 6 questions from 1 to 8. Each carries 3 scores. (6 × 3 = 18)

Question 1.
Construct a 2 × 3 matrix whose elements are given by a_ij = 2i – 2j. (3)
Answer:
Given _ij = 2i – 2j
Let A = \(=\left[\begin{array}{lll}
a_{11} & a_{12} & a_{13} \\
a_{21} & a_{22} & a_{23}
\end{array}\right]\)
a₁₁ = 2 × 1 – 2 × 1 = 0
a₁₂ = 2 × 1 – 2 × 2 = 2 – 4 = -2
a₁₃ = 2 × 1 – 2 × 3 = 2 – 6 = -4
a₂₁ = 2 × 2 – 2 × 1 = 4 – 2 = 2
a₂₂ = 2 × 2 – 2 × 2 = 4 – 4 = 0
a₂₃ = 2 × 2 – 2 × 3 = 4 – 6 = -2
∴ A = \(\left[\begin{array}{rrr}
0 & -2 & -4 \\
2 & 0 & -2
\end{array}\right]\)

Question 2.
Examine the relation R in the set A = {1, 2, 3….13, 14} defined as R = {(x, y) : 3x – y = 0} is reflexive, symmetric and transitive. (3)
Answer:
Given A = {1, 2, 3….13,14}
R = {(x, y) : 3x – y = 0}
= {(1, 3), (2, 6), (3, 9), (4, 12)}
R is not reflexive, since (a, a) ∉ R for all a ∈ A
R is not symmetric, since (1, 3) ∈ R but (3, 1) ∉ R
R is not transitive, since (1, 3) ∈ R, (3, 9) ∈ R but (1, 9) ∉ R

Question 3.
If A = \(\left[\begin{array}{ll}
1 & 2 \\
4 & 2
\end{array}\right]\) then show that |2A| = 4|A|.
Answer:
Given A = \(\left[\begin{array}{ll}
1 & 2 \\
4 & 2
\end{array}\right]\)
2A = \(\left[\begin{array}{ll}
2 & 4 \\
8 & 4
\end{array}\right]\)
|2A| = \(\left[\begin{array}{ll}
2 & 4 \\
8 & 4
\end{array}\right]\) = 8 – 32 = -24
4|A| = 4\(\left[\begin{array}{ll}
1 & 2 \\
4 & 2
\end{array}\right]\) = 4(2 – 8) = 4 × -6 = -24
∴ |2A| = |4A|

Question 4.
Find the values of a and b such that the function defined by

is a continuous function. (3)
Answer:

At x = 2
LHL = RHL f(2)
2a + b = 5 ……………. (1)
At x =10
LHL = RHL = f(10)
10 a + b = 21
Solving (1) and (2)
a = 2 b = 1

Question 5.
Find the intervals in which the function f given by
f(x) = x² – 4x is increasing. (3)
Answer:
f(x) = x² – 4x
f'(x) = 0 ⇒ 2x – 4 = 0
x = 2

Intervals are (-∞, 2) (2, ∞)
At (-∞, 2), f'(0) = -4 < 0 At (2, ∞), f'(3) = 2 > 0
∴ f(x) is decreasing in (-∞, 2)
and increasing in (2, ∞)

Question 6.
Find the unit vector in the direction of the vector
\(\vec{a}\) = î + ĵ + 2k̂ (3)
Answer:
Given \(\vec{a}\) = î + ĵ + 2k̂
|\(\vec{a}\)|= \(\sqrt{(1)^2+(1)^2+(2)^2}\) = √6
Required unit vector = â = \(\frac{\vec{a}}{|\vec{a}|}\)
= \(\frac{\hat{\mathrm{i}}+\hat{\mathrm{j}}+2 \hat{\mathrm{k}}}{\sqrt{6}}\)
= \(\frac{1}{\sqrt{6}} \hat{\mathrm{i}}+\frac{1}{\sqrt{6}} \hat{\mathrm{j}}+\frac{2}{\sqrt{6}} \hat{\mathrm{k}}\)

Question 7.
Find the angle between the pair of lines given by
\(\vec{a}\) = 3î + 2ĵ – 4k̂ + λ(î + 2ĵ + 2k̂)
\(\vec{a}\) = 5î – 2ĵ + μ(3î + 2ĵ + 6k̂) (3)
Answer:
Let \(\vec{b}\)₁ = î + 2ĵ + 2k̂, \(\vec{b}\)₂ = 3î + 2ĵ + 6k̂
cos θ = \(\frac{\overline{\mathrm{b}}_1 \cdot \overline{\mathrm{~b}}_2}{\left|\mathrm{~b}_1\right|\left|\mathrm{b}_2\right|}\) = \(\frac{3+4+12}{\sqrt{9} \cdot \sqrt{49}}\) = \(\frac{19}{3 \times 7}\) = \(\frac{19}{21}\)
θ = cos^-1(\(\frac{19}{21}\))

Question 8.
Given two independent events A and B such that P(A) = 0.3, P(B) = 0.6
(i) P (A/B) = _________ . (1)
(ii) Find P (A and not B) (2)
Answer:
(i) P(A/B) = P(A) [∵ A and B are independant]
= 0.3

(ii) P(A and not B) = P(A∩B’)
= P(A).P(B’)
= 0.3 × 0.4
= 0.12

Answer any 6 questions from 9 to 16. Each carries 4 scores. (6 × 4 = 24)

Question 9.
(i) A function f : x → y is onto if and only if Range of f = ________ . (1)
(ii) If f : R → R defined by f(x) – 3 – 4x.
Check whether the function is bijective. (3)
Answer:
(i) Codomain of f

(ii) f(x) = 3 – 4x
f(x₁) = f(x₂) ⇒ 3 – 4x₁ = 3 – 4x₂
⇒ -4x₁ = -4x₂
x₁ = x₂
∴ f(x) is one – one (injective)
Let y = 3 – 4x
4x = 3 – y
x = \(\frac{3 – y}{4}\)
f(x) = f(\(\frac{3 – y}{4}\)) = 3 – 4(\(\frac{3 – y}{4}\))
= 3 – (3 – y) = y
∴ For every ‘y’ there exist x
such that f(x) = y
∴ f(x) is onto (surjective)
Hence f(x) is bijective

Question 10.
(i) If \(\frac{-\pi}{2}\) ≤ x ≤ \(\frac{\pi}{2}\) then sin^-1 (sin x) = _________ . (1)
(ii) Find the principal value of sin^-1(\(\frac{1}{\sqrt{2}}\)) (1)
(iii) Find the value of sin^-1(sin(\(\frac{13 \pi}{6}\)))
Answer:
(i) x

(ii) \(\frac{\pi}{4}\)

(iii) sin^-1(sin \(\frac{13 \pi}{6}\))
= sin^-1(sin 2π + \(\frac{\pi}{6}\)
= sin^-1(sin \(\frac{\pi}{6}\)) = \(\frac{\pi}{6}\).

Question 11.
Express the matrix \(\left[\begin{array}{ccc}
3 & 3 & -1 \\
-2 & -2 & 1 \\
-4 & -5 & 2
\end{array}\right]\) as the sum of a symmetric and skew-symmetric matrix. (4)
Answer:

\(\frac{\mathrm{A}+\mathrm{A}^{\mathrm{T}}}{2}\) + \(\frac{\mathrm{A}-\mathrm{A}^{\mathrm{T}}}{2}\) = A
where \(\frac{\mathrm{A}+\mathrm{A}^{\mathrm{T}}}{2}\) is a symmetric matrix and \(\frac{\mathrm{A}-\mathrm{A}^{\mathrm{T}}}{2}\) is a skew symmetric matrix.

Question 12.
Find the area enclosed by the circle x² + y² = a² (4)
Answer:
x² + y² = a²
y² = a² – x²
y = \(\sqrt{a^2-x^2}\)

Required area = 4 × area of shaded region.

Question 13.
F ind the general solution of the differential equation (4)
\(\frac{d y}{d x}\) + \(\frac{y}{x}\) = x²
Answer:
Given \(\frac{d y}{d x}\) + \(\frac{y}{x}\) = x²
which is of the form \(\frac{d y}{d x}\) + py = Q
where p = \(\frac{1}{x}\), Q = x²
Integrating factor (IF) = \(e^{\int P d x}=e^{\int \frac{1}{x} d x}\) = e^{log x} = x
∴ Solution is
y(IF) = ∫Q(IF)dx
yx² = ∫x². x dx
x²y = ∫x³dx + c
x²y = \(\frac{x^4}{4}\) + C

Question 14.
Find the area of a parallelogram whose adjacent sides are given by the vectors.
\(\vec{a}\) = 3î + ĵ + 4k̂
\(\vec{b}\) = î – ĵ + k̂ (4)
Answer:
\(\vec{a}\) = 3î + ĵ + 4k̂
\(\vec{b}\) = î – ĵ + k̂
\(\vec{a}\) × \(\vec{b}\) = \(\left|\begin{array}{ccc}
\hat{\mathbf{i}} & \hat{\mathbf{j}} & \hat{\mathbf{k}} \\
3 & 1 & 4 \\
1 & -1 & 1
\end{array}\right|\)
= î(5) – ĵ(-1) + k̂(-4)
= 5î + ĵ – 4k̂
Area of parallelogram = \(\vec{a}\) × \(\vec{b}\)
= \(\sqrt{25 + 1 + 16}\)
= \(\sqrt{42}\) sq.units

Question 15.
Find the shortest distance between the lines
\(\vec{r}\) = (î + 2ĵ + k̂) + λ(î – ĵ + k̂) and
\(\vec{r}\) = (2î + ĵ – k̂) + µ(2î + ĵ + 2k̂) (4)
Answer:
\(\vec{a}\)₁ = î + 2ĵ + k̂, \(\vec{b}\)₁ = î – ĵ + k̂
\(\vec{a}\)₂ = 2î – ĵ – k̂, \(\vec{b}\)₂ = 2î + ĵ + 2k̂
\(\vec{a}\)₂ – \(\vec{a}\)₁ = î – 3ĵ – 2k̂

Question 16.
A bag contains 4 red and 4 black balls, another bag contains 2 red and 6 black balls. One of the two bags is selected at random and a ball is drawn from the bag which is found to be black. Find the probability that the ball is drawn from the second bag.
Answer:

Answer any 3 questions from 17 to 20. Each carries 6 scores. (3 × 6 = 18)

Question 17.
Solve by matrix method
x – y + z = 4
2x + y – 3z = 0
x + y+ z = 2 (6)
Answer:
Let A = \(\left[\begin{array}{ccc}
1 & -1 & 1 \\
2 & 1 & -3 \\
1 & 1 & 1
\end{array}\right]\), X = \(\left[\begin{array}{l}
x \\
y \\
z
\end{array}\right]\), B = \(\left[\begin{array}{l}
4 \\
0 \\
2
\end{array}\right]\)
∴ System of equations can be written as AX = B
|A| = 1(1 + 3) + 1(2 + 3) + 1(2 – 1)
= 4 + 5 + 1 = 10 ≠ 0
∴ System is consistent and the unique solution is
X = A^-1B

Question 18.
(i) Find \(\frac{d y}{d x}\) if 4x – 5y = sin x (3)
(ii) Find the rate of change of the area of a circle , with respect to its radius r when r = 3 cm. (3)
Answer:
(i) 4x – 5y = sin x
Differentiating with respect to x
4 – 5 . \(\frac{d y}{d x}\) = cos x
-5 \(\frac{d y}{d x}\) = cos x – 4
\(\frac{d y}{d x}\) = \(\frac{\cos x-4}{-5}\) = \(\frac{4-\cos x}{5}\)

(ii) Let area A = πr²
\(\frac{d A}{d r}\) = π × 2r = 2πr
\(\left.\frac{\mathrm{dA}}{\mathrm{dr}}\right]_{\mathrm{r}=3}\) = 2π × 3 = 6π

Question 19.
(i) Find \(\int \frac{x d x}{(x+1)(x+2)}\) (3)
(ii) Evaluate \(\int \frac{x d x}{(x+1)(x+2)}\) (3)
Answer:
(i) \(\frac{x}{(x+1)(x+2)}\) = \(\) + \(\)
x = A(x + 2) + B(x + 1)
Put x = -1, -1 = A(1) ⇒ A = -1
x = -2, -2 = B(-1) ⇒ B = 2

Question 20.
Solve Linear Programming Problem (LPP) graphically.
Maximize Z = 17.5x + 7y (6)
Subject to constraints
3x + y ≤ 12
x + 3y ≤ 12
x ≥ 0
y ≥ 0
Answer:
3x + y = 12

x	0	4
y	12	0

x + 3y =12

x	0	12
y	4	0

∴ Z has maximum when x = 3, y = 3
Maximum value = 73.5

Reviewing Kerala Syllabus Plus Two Chemistry Previous Year Question Papers and Answers Pdf March 2024 helps in understanding answer patterns.

Kerala Plus Two Chemistry Previous Year Question Paper March 2024

Time: 2 Hours
Total Scores: 60

Answer any 4 questions from 1 to 5. Each carries 1 score. (4 × 1 = 4)

Question 1.
An electrochemical cell can behave like an electrolytic cell when ______________
(a) E_cell = 0
(b) E_cell > E_ext
(c) E_ext > E_cell
(d) E_cell = E_ext
Answer:
(c) E_ext > E_cell

Question 2.
Which of the following is the unit of rate constant for a first-order reaction?
(a) L mol^-1 s^-1
(b) s^-1
(c) L^-1 mol s^-1
(d) L² mol^-2 s^-1
Answer:
(b) s^-1

Question 3.
Coordination number of copper in [Cu(CN)₄]^3- is ______________
Answer:
Co-ordination number = 4, there are four cyanide ligands.

Question 4.
Write the name of the poisonous gas formed when chloroform is oxidized by air in the presence of light.
Answer:
Phosgene OR, Carbonyl Chloride OR, COCl₂

Question 5.
Name the linkage between two monosaccharide units in a disaccharide.
Answer:
Glycosidic linkage OR, C-O-C linkage.

Answer any 8 questions from 6 to 15. Each carries 2 scores. (8 × 2 = 16)

Question 6.
Write any two applications of Henry’s law.
Answer:
Applications of Henry’s law:

• In the preparation of soda water and Soft drinks.
• A medical condition known as Bends in Scuba divers.
• A medical condition known as Anoxia in people living at high altitudes or climbers.

Question 7.
Calculate the standard emf of the cell in which the following reaction takes place.
Zn(s) + Cu²⁺ (aq) → Zn²⁺ (aq) + Cu(s)
(E°CU²⁺ / Cu = 0.34 V & E°Zn²⁺ / Zn = -0.76V)
Answer:

Question 8.
Write any two differences between order and molecularity.
Answer:

Order	Molecularity
1. It is the sum of the powers of the concentration terms in the rate law expression.	1. It is the total number of reactant species that collide simultaneously in a chemical reaction.
2. It is an experimental quantity.	2. It is a theoretical quantity.
3. It can be zero or fractional.	3. It cannot be zero or fractional.
4. It applies to both elementary and complex reactions.	4. It applies only to elementary reactions.

Question 9.
What is the effect of temperature on the rate constant of a reaction? Write the equation used to determine the effect of temperature on the rate constant.
Answer:
When temperature increases, the rate constant of a reaction also increases; when the temperature is increased by 10°, the rate constant is nearly doubled.
k = \(\mathrm{A} \cdot \mathrm{e}^{-\mathrm{Ea} / \mathrm{RT}}\)
ln k = ln A – \(\frac{\mathrm{E}_{\mathrm{a}}}{\mathrm{RT}}\)
log k = log A – \(\frac{E_a}{2.303 R T}\)

Question 10.
Identify the products X and Y formed in the following reactions:
(i) CH₃CH₂OH + PCl₅ → X + POCl₃ + HCl (1)
(ii) CH₃ – Br + AgF → Y + AgBr (1)
Answer:
(i) X is CH₃-CH₂-Cl or, Chloroethane or, Ethyl chloride.
(ii) Y is CH₃-F or, Fluoromethane or, Methyl fluoride.

Question 11.
The reaction between free-butyl bromide and hydroxide ion yields tert-butyl alcohol following the SN1 mechanism. Write the mechanism.
Answer:
\(S_N{ }^1\) reaction between tert-butyl bromide and hydroxide ion occurs in two steps:
Step-I: The polarised C-Br bond undergoes slow cleavage to produce a carbocation (tert-butyl carbocation) and a bromide ion.

Step-II: The carbocation (tert-butyl carbocation) is then attacked by the nucleophile to form the product.

Question 12.
Write the name and statement of the law that helps to identify the major product in the β-elimination reactions of haloalkanes.
Answer:
Zaitsev rule [Saytzeff rule]:
The rule states that in dehydrohalogenation reactions, the major product is alkene, which has a greater number of alkyl groups attached to the doubly bonded carbon atoms.

Question 13.
Give a reason for the solubility of alcohols in water.
Answer:
Intermolecular hydrogen bonds, H bonds, or, alcohol can form intermolecular hydrogen bonds with water molecules. So they are soluble in water.

Question 14.
(i) What is Tollens’ reagent? (1)
(ii) Which among CH₃CHO and CH₃COCH₃ form a silver mirror on reaction with Tollens’ reagent? (1)
Answer:
(i) Tollen’s reagent is a freshly prepared ammoniacal silver nitrate (AgNO₃) solution or, [Ag(NH₃)₂]⁺OH^–
(ii) CH₃CHO

Question 15.
Among CH₃NH₂ and C₆H₅NH₂, which is more basic? Give reason.
Answer:
CH₃NH₂
Due to the electron releasing inductive (+1) effect of the -CH₃ group, or, less availability of lone pair of electrons on the nitrogen atom of aniline for protonation (resonance effect) results in a more basic nature of amine.

• due to the electron-withdrawing (-1) inductive effect of the phenyl group.
• due to the +R effect of the NH₂ group in aniline.
• due to the less stability of anilinium ion compared to aniline.

Answer any 8 questions from 16 to 26. Each carries 3 scores. (8 × 3 = 24)

Question 16.
Define ideal solutions by citing a suitable example. What are the values of ∆_mixH and ∆_mixV for such a solution?
Answer:
Ideal solutions are solutions that obey Raoult’s law at all concentrations.
E.g., a Mixture of n-hexane and n-heptane, a mixture of bromoethane and chloroethane, a mixture of benzene and toluene, etc…
For ideal solutions, ∆H_mix = 0 and ∆V_mix = 0.

Question 17.
(i) Define the molar conductivity of a solution. How does it vary with concentration? (2)
(ii) State the law that helps to determine the limiting molar conductivity of electrolytes. (1)
Answer:
(i) Molar conductivity of a solution at a given concentration is the conductance of the ‘V’ volume of a solution containing one mole of electrolyte kept between two electrodes with an area of cross-section A and distance of unit length.
or
Molar conductivity is the conductivity of a solution containing 1 mol of an electrolyte, placed in a conductivity cell having a unit distance between the electrodes.
Molar conductivity, ∧_m = k.V [k is the conductivity]
∧_m = k/c [c is the concentration]
Molar conductivity ∧_m = \(\frac{1000 \mathrm{k}}{\mathrm{M}}\) [M is the molarity of the solution]
The molar conductivity decreases with concentration (increases with dilution) for both strong and weak electrolytes.

(ii) The law that helps to determine the limiting molar conductivity of weak electrolytes is Kohirausch’s law. It states that the limiting molar conductivity of an electrolyte is the sum of the individual contributions of the anion and the cation of the electrolyte.

Question 18.
(i) What is meant by the half-life of a reaction? (1)
(ii) A first-order reaction is found to have a rate constant, k = 5.5 × 10^-14 s^-1. Find the half-life of the reaction. (2)
Answer:
(i) It is the time taken to reduce the concentration of a reactant to one-half of its initial concentration.
(ii) Here k = 5.5 × 10^-14 s^-1
\(t_{1 / 2}=\frac{0.693}{k}\)
k = \(\frac{0.693}{5.5 \times 10^{-14}}\) = 1.26 × 10¹³ s

Question 19.
(i) Some transition metal ions are given in the box below. Choose the ions that are colored. (2)
(Z for Sc, Ti, and Cr are 21, 22, and 24 respectively)
Sc³⁺, Ti⁴⁺, Ti³⁺, Cr³⁺
(ii) Give a reason for the formation of colored ions by transition metals. (1)
Answer:
(i) Coloured ions are Ti³⁺ and Cr³⁺
[Electronic configurations: Sc³⁺ – [Ar] 3d⁰, Ti⁴⁺ – [Ar] 3d⁰, Ti³⁺ – [Ar] 3d¹ and [Cr³⁺] – 3d³]
(ii) Colour is due to the d-d transition of electrons or due to the presence of partially filled d-orbitals. when light falls on a transition metal ion, electrons from lower d-orbitals are excited to higher d-levels. The energy required for this transition is absorbed from visible light, and hence, the metal ion exhibits the complementary color of the light absorbed.

Question 20.
What is lanthanoid contraction? What are the consequences of lanthanoid contraction?
Answer:
The regular decrease in the atomic and ionic radii along the lanthanoid series is known as lanthanoid contraction.
Consequences of lanthanoid contraction are:

• The 2nd and 3rd row transition series elements have similar radii [zirconium (Zr) and hafnium (Hf) have almost similar radii].
• Lanthanoids have similar physical properties/They occur together in nature/Their isolation is difficult.
• The basicity of hydroxides of lanthanoids decreases from lanthanum to lutetium. La(OH)₃ is more basiothan Lu(OH)₃.

Question 21.
Draw the hybridization scheme of [Co(NH₃)₆]³⁺ based on the Valence Bond Theory. Predict the geometry and magnetic behavior of the complex.
Answer:
In [Co(NH₃)₆]³⁺, the central atom cobalt is in a +3 oxidation state.
Co3+ – [Ar] 3d⁶ 4s⁰ 4p⁰
Orbitals of Co³⁺ ion

In the presence of the strong ligands NH₃, the electrons in the 3d level get paired. Now, two 3d orbitals, one 4s orbital, and three 4p orbitals undergo d²sp³ hybridization to form 6 new orbitals. Thus the shape of the molecule is octahedral. Due to the absence of unpaired electrons, the complex is diamagnetic.

Question 22.
(i) Write the formulae of the following coordination compounds:
(a) Pentaamminechloridocobalt(III) chloride (1)
(b) Potassiumhexacyanidoferrate(III) (1)
(ii) Which of the above is a heteroleptic complex? (1)
Answer:
(i) (a) [CO(NH₃)₅Cl] Cl₂
(b) K₃[Fe(CN₆)]
(ii) (a) [Co(NH₃)₅Cl] Cl₂ is the heteroleptic complex

Question 23.
(i) Identify the products P & Q in the following reaction:

(ii) What is the product obtained when phenol is treated with concentrated nitric acid? (1)
Answer:
(i) P is o-nitrophenol or, 2-nitrophenol
Or

Q is p-Nitrophenol or, 4-Nitrophenol,

(ii) 2,4,6-Trinitrophenol or, Picric acid
Or

Question 24.
(i) An organic compound A n reaction with CrO₂Cl₂ in CS₂ followed by acidification gives benzaldehyde as a product. Identify the compound A and also name the reaction. (2)
(ii) What is the product obtained when the above organic compound A undergoes side-chain oxidation with acidic potassium permanganate? (1)
Answer:
(i) Toluene or, Methyl Benzene or, The reaction is Etard reaction.

(ii) Benzoic acid or, Benzenecarboxylic acid or, C₆H₅-COOH OR

Question 25.
Describe the Hinsberg test to distinguish primary, secondary, and tertiary amines.
Answer:
Hinsberg Test: Benzenesulphonyl chloride (C₆H₅-SO₂Cl) is known as the Hinsberg reagent, which is used to distinguish the three types of amines. Primary amines react with the Hinsberg reagent to form a precipitate of N-alkylbenzene sulphonamide, which is soluble in alkali. Secondary amines react with Hinsberg reagent to give a precipitate of N, N-dialkylbenzenesulphonamide, which is insoluble in alkali. Tertiary amines do not react with the Hinsberg reagent or, chemical equations.

Question 26.
Write the classification of proteins based on their molecular shape by giving suitable examples.
Answer:
Based on molecular shape, proteins are classified into two – Fibrous protein and Globular protein.
Fibrous Proteins: They have fiber-like structures/They contain linear polypeptide chains/They are generally insoluble in water.
E.g. Keratin or myosin.
Globular proteins: They have a spherical shape/They contain polypeptide chains that are coiled around to give a spherical shape/ They are soluble in water.
E.g. Insulin or albumin.

Answer any 4 questions from 27 to 31. Each carries 4 scores. (4 × 4 = 16)

Question 27.
(i) What are colligative properties? (1)
(ii) The boiling point of benzene is 353.23 K. When 1.80 g of a non-volatile solute is dissolved in 90 g of benzene, the boiling point is raised to 354.11 K. Calculate the molar mass of the solute. K_b for benzene is 2.53 K kg mol^-1. (3)
Answer:
(i) These are properties of dilute solutions, which depend only on the relative number of solute particles and not on their nature. OR, these are properties that depend on the number of solute particles irrespective of their nature relative to the total number of particles present in the solution.
(ii) Here w₂ = 1.80 g, w₁ = 90 g
T_b = 354.11 K, \(\mathrm{T}_{\mathrm{b}}^0\) = 353.23 K and K_b = 2.53 K kg/mol.
ΔT_b = T_b – \(\mathrm{T}_{\mathrm{b}}^0\)
= 354.11 – 353.23
= 0.88 K
Molar mass, M₂ = \(\frac{1000 \mathrm{k}_{\mathrm{b}} \mathrm{w}_2}{\mathrm{w}_1 \Delta \mathrm{~T}_{\mathrm{b}}}\)
= \(\frac{1000 \times 2.53 \times 1.80}{90 \times 0.88}\)
= 57.5 g/mol

Question 28.
(i) Sketch the diagram of a H₂ – O₂ fuel cell. (1)
(ii) Write the chemical equations for electrode reactions in it. (2)
(iii) Write any two advantages of a fuel cell. (1)
Answer:
(i)

(ii) Anode reaction:
2H₂ (g) + 4OH^– (aq) → 4H₂O (l) + 4e^–
Cathode reaction:
O₂ (g) + 2H₂O (l) + 4e^– → 4OH^– (aq)
Net Reaction:
2H₂ (g) + O₂ (g) → 2H₂O (l)

(iii) Advantages of fuel cells are:

• It is highly efficient.
• It is eco-friendly (pollution-free).
• The cell works continuously as long as the reactants are supplied.
• Water obtained from the H₂ – O₂ fuel cell can be used for drinking.

Question 29.
Explain the different types of structural isomerism in coordination compounds with the help of suitable examples.
Answer:
Coordination compounds show four types of structural isomerism – Ionisation isomerism, Linkage isomerism, Coordination isomerism, and Solvate isomerism.
(i) Ionisation Isomerism: It arises due to the exchange of ions between the inside and outside of the coordination sphere/This type of isomerism arises when the counter ion in a complex can act as a ligand.
OR
E.g. [Co(NH₃)₅SO₄]Br and [Co(NH₃)₅Br]SO₄.
(ii) Linkage Isomerism: It arises in a coordination compound containing an ambidentate ligand, which can bond to the central atom through more than one donor atom.
OR
E.g. [Co(NH₃)₅(ONO)]Cl₂ and [Co(NH₃)₅(NO₂)]Cl₂
(iii) Coordination Isomerism: It arises due to the interchange of ligands between cationic and anionic coordination entities.
OR
E.g. [Co(NH₃)₆][Cr(CN)₆] and [Cr(NH₃)₆][Co(CN)₆]
(iv) Solvate Isomerism (Hydrate isomerism): It arises due to the difference in the no. of solvent molecules (water molecules) bonded to the metal ion as ligand.
OR
E.g. [Cr(H₂O)₆]Cl₃ and [Cr(H₂O)₅Cl]Cl₂.H₂O

Question 30.
(i) Describe the manufacture of ethanol from molasses. (2)
(ii) What is meant by denaturation of alcohol? (1)
(iii) Identify the product obtained when ethanol is treated with Conc. H₂SO₄ at 443 K. (1)
Answer:
(i) Ethanol is manufactured by the fermentation of molasses. The sugar in molasses is converted to glucose and fructose in the presence of an enzyme, invertase. Glucose and fructose are converted to ethanol and carbon dioxide by another enzyme, zymase. OR, the equations:

(ii) Commercial alcohol is made unfit for drinking by mixing it with copper sulphate and pyridine, This is known as denaturation of alcohol.
(iii) CH₂ = CH₂ OR, Ethene OR, Ethylene.

Question 31.
Describe the following reactions:
(i) Cannizaro reaction. (2)
(ii) Stephen reaction (2)
Answer:
(i) Cannizzaro Reaction: Aldehydes having no α-hydrogen atom, when treated with cone, alkali, undergo self-oxidation and reduction (disproportionation) to form alcohol and carboxylic acid salt. This reaction is called the Cannizzaro reaction.

(ii) Stephen Reaction: Nitriles are reduced to imine with stannous chloride in the presence of HCl, which on hydrolysis gives aldehyde. This reaction is known as Stephen’s reaction.

Teachers recommend solving Kerala Syllabus Plus Two Botany Previous Year Question Papers and Answers Pdf March 2023 to improve time management during exams.

Kerala Plus Two Botany Previous Year Question Paper March 2023

Answer any 3 questions from 1 to 5. Each carries 1 score.

Choose the correct answer:
Question 1.
The residual persistent nucellus is called _____. (Pericarp, Tapetum, Scutellum, Perisperm)
Answer:
Perisperm

Question 2.
Fill in the blank :
The process of breaking down of detritus into smaller particles is called _____.
Answer:
Fragmentation

Question 3.
Name the technique used to separate the fragments of DNA.
Answer:
Gel electrophoresis

Question 4.
Fill in the blanks:
Interaction between sea anemone and clown fish is an example for _____ interaction.
Answer:
Commensalism

Question 5.
Name the ‘cry’ gene that control corn borer insects.
Answer:
crylAb

II. Answer any 9 questions from 6 to 16. Each carries 2 scores. (9 × 2 = 18)

Question 6.
Differentiate between grazing food chain and detritus food chain.
Answer:
Grazing Food Chain
It starts with producer belongs to first trophic level

Detritus Food Chain
It starts with dead organic matter belongs to first trophic level.

Question 7.
List out any two devices in plants, which help to discourage self-pollination and to encourage cross pollination.
Answer:

1. Pollen release and stigma receptivity are not synchronized.
2. Anther and stigma are placed at different position.

Question 8.
How can we make bacterial cell competent for trans- formation with recombinant DNA?
Answer:
Bacterial cells are treated with divalent cation such as Ca²⁺ to increase cell permeability. Then these cells are treated with recombinant DNA on ice. The cells and rDNA in ice are allowed to heat at 42°C Then return back to ice bath. Repeat this process.

Question 9.
Observe the given figure of ovule and label the parts (a), (b), (c) and (d).

Answer:
(a) Funicle
(b) Micropyle
(c) Embryo sac / Female gametophyte
(d) Chalaza

Question 10.
(a) Which is the thermostable enzyme used in PCR?
Answer:
Taq polymerase

(b) Name the bacterium from which the enzyme isolated.
Answer:
Thermus aquaticus.

Question 11.
Define productivity. What are the factors affecting primary productivity?
Answer:
The rate of biomass production is called productivity. Factors affecting primary productivity.

1. Environmental factors.
2. Availability of nutrients.

Question 12.
Explain the mechanism of insect resistance in Bt. cotton.
Answer:
Due to cry gene expression, insecticidal protein crystals are produced. In the Alkaline pH of insect
gut convert inactive protoxin into active toxin. Active Bt toxin binds to the midgut epithelium and causes cell lysis leading to death of insect.

Question 13.
Different types of population interaction has been observed in population. Write the type of interaction observed among the following species:

Species A	Species B	Type of Interaction
Orchid ophrys	Bees	(a)  _______
Ticks	Dogs	(b) _______
Barnacles	Whale	(e) _______
Fungus	Photosynthetic Algae	(d) _______

Answer:
(a) Mutualism
(b) Parasitism
(c) Commensalism
(d) Mutualism

Question 14.
The figure given below shows pyramid of energy. Pyramid of energy is always upright, can never be inverted. Give reason.

Answer:
When energy flow from one trophic level to the next level some energy is lost as heat at each step as 10%.

Question 15.
What are Genetically Modified Organisms(GMO)? Mention any one merit of GM plants.
Answer:
An organism whose genetic material is altered is called Genetically Modified Organism.
Made crops tolerant to abiotic stress.

Question 16.
The following graph shows two types of population growth curves.
(a) Name the growth curves (a)& (b)
Answer:
(a) (a)- Exponential growth
(b) Logistic growth

(b) What does ‘K’ stand for?

Answer:
K – Carrying capacity

III. Answer any 3 questions from 17 to 20. Each carries 3 scores.

Question 17.
Explain how Eli Lilly company produced genetically engineered insulin.
Answer:
Eli Lilly Company isolated DNA sequences corresponding to A and B chain of insulin. A and B Chain DNA were introduced in plasmids of E.coli to produce the polypeptide A and B chains: Polypeptide chain A and B were extracted. and combined by creating disulphide bonds to form genetically engineered insulin.

Question 18.
Wind pollinated flowers have many peculiarities. Write down any three such peculiarities.
Answer:
Flowers with well exposed stamens. Large feathery stigma to trap air-borne pollen grains. Flowers contain single ovule in one ovary and numerous flowers packed into an inflorescence e.g. corn cob.

Question 19.
Given below is a schematic representation which shows the factors influencing population density:

(i) Label (a) and (b)
Answer:
(a) – Mortality
(b) – Emigration

(ii) Which are the factors that contribute to an in crease in population density?
Answer:
Natality and Immigration

(iii) Define Natality.
Answer:
Natality – The number of births during a given period.

Question 20.
EcoRI is isolated from Escheritia coli RY 13. Explain the naming procedure of EcoRI.
Answer:
(E) – First letter represent genus of the bacteria.
(co) – First two letters represent the species of the organism.
(R) – Represent strain of bacteria.
Roman number (I) – Order in which enzyme is isolated.