Bhagya

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

Kerala Plus Two Zoology Question Paper March 2021 with Answers

Answer the following questions from 1 to 31 upto a maximum score of 30. (7 × 1 = 7)
I. Each question from 1 to 7 carries 1 score.

Question 1.
Name the oral contraceptive for female developed by CDRI.
Answer:
Saheli

Question 2.
Name the genetic’disorder in which a blood clotting protein is affected leading to non-stop bleeding even through a simple wound.
Answer:
Haemophilia

Question 3.
Under microscope, chromatin is seen as ‘beads-on-string’ like structure. Here, ‘beads’ represent the structures called.
Answer:
Nucleosome

Question 4.
During luteal phase of menstrual cycle, Graafian follicle transforms into
Answer:
Corpus luteum

Question 5.
Organic pollutants in sewage water is measured as
(a) GMO
(b) MPT
(c) BOD
(d) HGP
Answer:
BOD

Question 6.
Select an example for homologous organs.
(a) Eyes of octopus and mammals
(b) Forelimbs of Whales and Bats
(c) Flippers of Penguins and Dolphins
(d) Wings of Birds and Butterflies
Answer:
Forelimbs of Whales and bats

Question 7.
Enzyme used in detergents for removing oily stains from laundry is _____.
(a) Lipase
(b) Protease
(c) Amylase
(d) Pectinase
Answer:
Lipase

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

Question 8.
‘In a cell, euchromatin and Heterochromatin can be observed under microscope’. Distinguish between euchromatin and Heterochromatin.
Answer:

Euchromatin	Heterochromatin
i) It is loosely packed.	It is densely packed.
ii) It is Trascriptionally active.	It is Transcriptionally Inactive.

Question 9.
Presence of an additional copy of chromosome 21 was observed in a person during diagnosis.
(a) Identify the genetic disorder
(b) Write the characteristic features of this disorder.
Answer:
(a) Down’s Syndrome

(b) 1. Short stature and small round head,
2. Furrowed tongue and partially open mouth

Question 10.
Fill in the blanks to complete the table:

Micro-organism	Use of Micro-organism
i. (a) _____	Curding of Milk
ii. Bacillus thuringiensis	(b) ______
iii. Aspergillus niger	(c) ______
iv. (d) ______	Production of butyric acid

Answer:
(a) Lactic acid bacteria
(b) Control butterfly catterpillars
(c) Citric acid
(d) Clostridium butylicum

Question 11.
If a father is with ‘O’ blood group and mother is with ‘B’ blood group, write the possible blood groups of their children.
Answer:
‘B’ group and ‘O’ roup

Question 12.
Observe the figure

(a) Identify the molecular strucuture given in the figure.
(b) Name the regions labelled as A, B and C.
Answer:
(a) Antibody or Immunoglo’bulins
(b) A – Antigen binding site
B – Light chain
C – Heavy chain

Question 13.
In eukaryotes, gene expression can be regulated at several levels. Write diffèrent levels at which gene expression can be regulated.
Answer:
(i) Transcriptional level
(ii) Translational level

Question 14.
Expand the following terms related with Assisted Reproductive Technologies:
Answer:
(a) Intra Cytoplasmic Sperm Injection
(b) Gamete Intra Fallopian Transfer

Question 15.
Fill in the blanks to complete the schematic repre sentation.

Answer:
(a) Lippes loop
(b) Multiloäd 375
(c) LNG-20
(d) Progestasert

Question 16.
Write any four objectives of Reproductive and Child Health Care (RCH) programmes.
Answer:

1. Creating awareness among people about various reproduction related aspects.
2. Providing facilities and support for building up a reproductively healthy society.
3. Provide right information to the young so as to discourage children from believing in myths and
   having misconceptions about sex-related aspects.
4. Proper information about reproductive organs, adolescence and related changes, safe and hygienic sexual practices, sexually transmitted diseases.

Question 17.
‘Now-a-days, the world is facing a problem of increased rate of species extinction due to huma
activities’. Write major causes of biodiversity losses.
Answer:

1. Habitat loss and fragmentation
2. Over-exploitation
3. Alien špecies invasion
4. Co-extinctions

Question 18.
Drug/Alcohol abuse results in immediate and far reaching effects. Write some effects you have studied.
Answer:

1. Use of alcohol causes stomach ulcer and pancreatitis.
2. Causes lack of interest in personal hygiene, isolation, depression, aggressiveness etc.
3. Causes deteriorating relationship with family and friends change in eating and sleeping habit.
4. The excess usage of alcohol causes liver cirrhosis and damage to nervous system.

Question 19.
Evolution of Darwin finches in an example for ‘Adaptive radiation’.
(a) What is meant by ‘Adaptive radiation’?
(b) Give two other example for organisms those exhibitAdaptive radiation.
Answer:
(a) The process of evolution of different species in a given geographical area starting from a point and literally radiating to other areas of habitat is called adaptive radiations.

(b) Marsupia[ mammal in Australia & Placental mammals.

Question 20.
Write any four differences between Spermatogenesis and Oogenesis.
Answer:

Spermatogenesis	Oogenesis
1. Four sperms from one primary from spermatocyte.	1. It is the process of formation of ovum oregg.
2. It is the process of formation of sperms.	2. It take place in ovary.
3. It take place in male.	3. It take place in female.
4. It take place in testis.	4. Starts in embryonic stage.

Question 21.
Micrograph of Red blood cells of two persons (A) and (B) are shown below. Person B is affected with
a specific genetic disorder.
(i) Identify the genetic disorder.
(ii) Write reason for this disorder.

Answer:
(i) Sickle-cell anemia
(ii) The defect is due to substitution of glutamic acid (Glu) by valine (Val) at sixth position of beta globulin chain of haemoglobin.

Question 22.
In women, some hormones are secreted only durng pregnancy. Name any such hormones.
Answer:

1. Human chorionic gonadotropin (hCG)
2. Human placental lactogen (hPL)

Question 23.
Match following:

A	B
i. L.H. Surge	Fertilisation
ii. Leydig cells	Nutrition to
iii. Ampullary-isthmic junction	Spermatids
iv. Sertoli cells	Ovulation

Answer:

A	B
i. L.H. Surge	Ovulation
ii. Leydig cells	Androgens
iii. Ampullary-isthmic junction	Fertilisation
iv. Sertoli cells	Nutrition to Spermatids

Question 24.
“Species diversity is greater in tropical regions than in temperate regions.” Give reasons.
Answer:
Tropical environment are more constant and predictable. Solar energy is more in tropical area than temperate area.

Question 25.
Vaccines are given to children at various stages of their development.
(a) What is meant by ‘vaccine’?
(b) Write the principle of vaccination.
Answer:
(a) Vaccines are preparation of antigenic proteins of pathogen or inactivated or weakened pathogen
(b) Property of memory of the immune system

Question 26.
Match following:
Answer:

1. 1^st month – Heart sound is noticed using stethescope.
2. 2^nd month – Limbs and digits are developed in foetus
3. 5^th month – First movement of foetus is observed
4. 6^th month – Eye lids are separated and eye lashes are formed

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

Question 27.
(a) Identify the equation related with genetic equilib rium given below:
p² + 2pq + q² = 1
(b) Write the factors affecting genetic equilibrium resulting in evolution.
Answer:
(a) Hardy Weinberg Equilibrium
(b) Gene flow ,Genetic drift, Mutation and Natural selection

Question 28.
LH and FSH play significant role in spermatogenesis.
(a) Write the funchons of LH and FSH in spermato genesis.
(b) Write a single term used to denote LH and FSH together.
Answer:
(a) LH – Act on the Leydig cell and stimulate t he production of and rogens
FSH – Acton Sertoli cells and stimulates some factors which help in spermatogenesis.

(b) Gonadotropins

Question 29.
Figure of ‘lac operon’ in the absence of lactose (inducer) is given below. Draw the diagram of ‘lacoperon’ in the presence of lactose and label it.

Answer:

Question 30.
SexuallyTransmitted Diseases (STDs) are seen to be high among people with age group 15 -24 yrs.
(a) Write the names of any 4 STDs
Answer:
(a)

1. AIDS
2. Genital Herpes
3. Genital Warts
4. Trichomoniasis

(b)

1. Avoid sex with unknown partner
2. Always use condoms during coitus
3. In case of doubt consult a doctor for diagnosis and treatment

Question 31.
‘Incomplete Dominance’ is an example for deviation from Mendelian Inheritance. Illustrate with example.
Answer:
It is the inheritance in which the heterozygous offspring show intermediate character between two parents. Cross given below shows the genotypic and phenbtypic ratio in F₁ and F₂ generation.

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

Kerala Plus Two Zoology Question Paper March 2022 with Answers

A. Answer any three questions from 1 to 4. Each carries 1 score. (3 × 1 = 3)

Question 1.
Homologous organ: Divergent evolution:: Analogous organ:
Answer:
Convergent evolution

Question 2.
Expand the term ZlFT.
Answer:
Zygote Intra Fallopian Transfer

Question 3.
Mitotic division of zfgote results in the formation of blastomeres is called
Answer:
Cleavage

Question 4.
Name the enzyme that joins the DNA fragments in dis-contthuous strand during replication.
Answer:
DNA Ligase

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

Question 5.
The term ‘Biodiversity’ was popularised by the scientist ______
Answer:
Edward Wilson

Question 6.
The first antibiotic discovered was ______
Answer:
Penicillin

Part-II

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

Question 7.
‘Codon AUG is known as initiator codon.
(a) Name the amino acid coded by AUG.
(b) Write any two stop codons
Answer:
(a) Methionine
(b) U, UAG

Question 8.
Write the functions of the following
(a) Leydig cells
(b) Corpus luteum
Answer:
(a) Secrete testicular hormones called androgens or Testosterone.
(b) Secretes progesterone

Question 9.
Match the following:

(A)	(B)
i) Trtchoderma	a. Citric acid
ii) Monascus purpureus	b. Ethanol
iii) Saccharomyces cerevisiae	c. Cyclosponn A
iv) Aspergillus niger	d. Statin

Answer:

A	B
Trichoderma polysporum	a. Cyclosporin A
Monascus purpureus	b. Statin
Sacoharomyces cervisiae	c. Ethanol
Aspergillus niger	d. Citric acid

B. Answer any two questions from 10 to 13. Each carries 2 scores. (2 × 2 = 4)

Question 10.
Choose the correct terms from the bracket to fill in the blanks and complete the table: (Bigbang theory, Miller’s experiment, Lamarkism, Darwinism)

(A)	(B)
i) Natural selection	a ____
ii) Chemical evolution	b ____
iii) Origin of Universe	c ____
iv) Use and Disuse of organs	d ____

Answer:

(A)	(B)
i) Natural selection	Darwinism
ii) Chemical evolution	Miller’s experiment
iii) Origin of Universe	Bigbang theory
iv) Use and Disuse of organs	Lamarkism

Question 11.
Write any four ill-effects of Drug/Alcohol abuse.
Answer:

1. Causes heart failure and hypertension.
2. Use of alcohol causes stomach ulcer and pancreatitis.
3. Causes lack of interest in personal hygiene,solation, depression , aggressiveness etc.
4. Causes deteriorating relationship with famil y and friends change in eating and sleeping habit etc.

Question 12.
(a) Name the cap-like structure present in sperm head.
(b) Write its function.
Answer:
(a) Acrosome

(b) Acrosome is filled with lytic enzyme that helps in the penetration of sperm in wall iayers of ovum  that leads to fertilisation

Question 13.
(a) Distinguish between Male heterogamety and Female heterogamey.
(b) Write one example for each.
Answer:

Male heterogamety	Female heterogamery
Here males are heterozygous (XY/XO)	Here females are heterozygous (ZW)
Mates produce two types of gamete	Females produce two types of gamete
Type of male gamete/sperm will determine the sex of the progeny	The type of female gamete/egg will determine the sex of the baby
This type of mechanism seen in	This type of mechanism seen in
. Human male	. Birds
. Grass hopper

(b) Male heterogamety – Different type of chromo some constitution in Male.
Eg :- Human or Drosophila
Female heterogamety -Different type of chromo some constitution in female
Eg :- Birds

Part – III

A. Answer any three questions from 14 to 17. Each carries 3 scores. (3 × 3 = 9)

Question 14.
“Allele frequencies in a population are stable and is constant from generation to generation.”
(a) Name the principle
(b) Mention any four factors those affect this principle.
Answer:
(a) Hardy Weinberg Principle
(b) Gene flow mutation genetic recombination natural selection

Question 15.
“Sex of a child is determined by father”. Substantiate the statement.
(b) Name any four STDs.
Answer:
In human, the male produce two types of gametes i.e. one with X chromosome and other with Y chromosome. During fertilisation, Sperm with X chromosome fuses with egg to produce female child while sperm with Y chromosome fuses with eg to produce male child.

Question 16.
incidents of STDs are very high among the age group of 15-24 years.
(a) What is STD?
(b) Name any four STDs.
Answer:
(a) Sexually Transmitted Diseases
(b) Gonorrhoea, syphilis, genital herpes, hepatitis B,& AIDS

Question 17.
(a) Write four major causes of Biodiversity loss.
(b) Give one example for in-situ conservation and ex-situ conservation of Biodiversity.
Answer:
(a)

1. Habitat loss and fragmentation
2. Over-exploitation,
3. Alien species invasions
4. Co-extinctions

(b) In situ conservation
Eg :- Biosphere Reserves or National Park
Ex situ Conservation
Eg :- Botanical Gardens or Zoological Park

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

Question 18.
(a) Expand the term DNA. Who proposed double helical model of DNA?
(b) List out the nitrogen bases in DNA.
Answer:
(a) Deoxyribo Nucleic Acid James Watson & Francis Crick
(b) Adenine, Thyrnine, Guanine, Cytosine

Part – IV

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

Question 19.
(a) Expand thetermAlDS. Mention the name of virus that causes AIDS.
(b) Name the widely used diagnostic test for AIDS.
(c) List out any four practices for the prevention of AIDS.
Answer:
(a) Acquired Immuno Deficiency Syndrome

(b) ELISA Test

(c)

1. Use disposable syringe and needles.
2. Checking of blood before blood transfusion.
3. Use condom for male or female during intercourse.
4. Avoid intercourse with unknown partner.

Question 20.
Schematic diagram of a transcription unit is given below:

(a) Identify the pans A and B.
(b) What is transcription?
(c) Write the complementary DNA strand by observing the strand given below:
Answer:
(a) A – Promoter gene
B – Template strand

(b) It is the process of formation of mRNA from DNA

(c) 3 – TACGTACGTA-5

Teachers recommend solving Kerala Syllabus Plus Two Zoology Previous Year Question Papers and Answers Pdf March 2024 to improve time management during exams.

Kerala Plus Two Zoology Question Paper March 2024 with Answers

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

Question 1.
Genes which code for a pair of contrasting traits are known as _____.
Answer:
Alleles

Question 2.
The process of copying genetic information from one strand of the DNA into RNA.
Answer:
Transcription

Question 3.
Name an. oral contraceptive for females developed by scientists at Central Drug Research Institute.
Answer:
Saheli

Question 4.
The enlarged end of penis called the glans penis is covered by a loose fold of skin called _____.
Answer:
Foreskin

Question 5.
Biodiversity is the term popularized by the sociobiologist to describe the combined diversity at all the levels of biological organization.
Answer:
Edward Wilson

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

Question 6.
Differentiate between analogous organs and homologous organs and mention one example each.
Answer:

Homologous organs	Analogous organs
. Organs that have similar structure but having differentfunction	. The organs that are having similar function but differ in structure and ongins are calLed analogous organs
. Homology indioetes common ancestry.	. Analogous organ represents the convergent evolution.
. Homologous organ represents the divergent evolution.
Examples:	Examples:
. Fore limbs of whale, bat, human and cheetah.	. Wings of Butterfly and Birds.
. Hearts of Vertebrates	. Eye of Octopus and Mammals.
. Brain of Vertebrates	. Fhppers of Penguins and Dolphins
. Tendril in Cucurbits & Thom in Bougainvillea	. Tuber of Potato and Sweet Potato.

Question 7.
Observe the given diagram of male reproductive system, and identify the parts labelled as A, B, C and D.

Answer:
A – Vas deferens
B – Urethra
C – Epididymis
D – Rete testis

Question 8.
Infections or diseases which are transmitted through sexual intercourse are collectively called sexually transmitted infections.
(a) NameanytwoSTis.
(b) Suggest any two methods to prevent STIs.
Answer:
(a) Gonorrhoea
• Syphilis

(b) • Avoid sex with unknown partners
• Always use condoms during coitus.

Question 9.
Complete the following table:

Chromosomal Disorder	Karyotype	Symptoms
(A) _______	Trisomy 21	Palm is broad, Short statued
(B) _______	(C)  _______	Gynaecomastia
Turner’s Syndrome	44 + Xo	D

Answer:
A – Down’s Syndrome
B – Kllnefelter’s Syndrome
C – 47 with XXY / 44A + XXY
D – Sterile female

Question 10.
Innate immunity is non-specific type of defence, that is present at the time of birth. Which are the four types of barriers involved in innate immunity and mention one example for each.
Answer:

1. Physical Barriers
   • It includes’ the anatomical barriers like skin.
2. Physiological Barder
   • It indude body temperature Cellular Barriers
   • Phagocytic cells in our bod y such as Polymorpho-nuclear leucocytes (PMNLe neutrophils)
3. Cytokine Barriers
   • Interferons. (My one example in each)

Question 11.
Complete the following flow chart which shows the origin and evolution of man.

Answer:
A – Ram apithecus
B – Homo habilis
C – Homo erectus
D – Homo sapiens

Question 12.
A wide range of contraceptive methods are presently available.
(a) Name two surgKal methods advised for male and female partner as a terminal method to prevent any more pregnancies. (1)
(b) Give two examples for copper releasing IUDS. (1)
Answer:
(a) Male – Vasectomy.
Female – Tubectomy.
(b) CuT, Cu7 and Multiload 375 (Any two exam pies)

Question 13.
In a cross between true breeding red-flowered (RR) and true breeding white-flowered (rr) plants, the F₁ (Rr) was pink coloured.
(a) Name the inheritance pattern mentioned here. (1,4)
(b) F₁ was self-pollinated and F₂ was obtained. What is the genotypic ratio and phenotypic ratio of F₂. (1)
(c) Mention a plant which shows this inheritance. (1/2)
Answer:
(a) Incomplete dom inanc
(b) Phenotypic ratio = 1 : 2 : 1
Genotypic ratio = 1 : 2 : 1
(c) Dog flower plant or Snapdragon or Antirrhinum

Question 14.
The following diagram shows central dogma in molecular biology. Write the name of process represented asAand B.

Answer:
A – Transcription
B – Translation

Question 15.
Match the following:

A	B
Clostridium butylicum	Acetic acid
Aspergillus niger	Lactic acid
Acetobacter aceti	Butyric acid
Lactobacillus	Citric acid

Answer:

A	B
Clostridium butylicum	Butyric acid
Aspergillus niger	Citric acid
Acetobacier aceti	Acetic acid
Lactobacillus	Lactic acid

Question 16.
In a debate conducted in school, your friend said that AIDS can be transmitted through touch or physical contact.
(a) Do you agree with that statement? (1/2)
(b) Name theeclinical test used to diagnose AIDS. (1/2)
(c) How do HIV infect human body? (1)
Answer:
(a) No.

(b) ELISA- Enzyme Linked Immuno-Sorbent Assay.

(c)

1. HIV enters body and infect the Macrophages
2. RNA genome replicates to form viral DNA by Reverse transcriptase.
3. Viral DNA incorporates into host cell’s DNA.
4. Infected cells produce more and more viral particles.
5. Enters Helper T Lymphocytes (TH).
6. Replicates and produce progeny virus.
7. Attack other T cells so that T cells count decreases.
8. Immunity weakens.

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

Question 17.
Observe the diagrammatic presentation of various events during a menstrual cycle.

(a) Identify ‘A’ and ‘B’ in graph. (1)
(b) Name two different methods of biodiversity conservation. (1)
(c) What is so special about tropics that might account for their greater biological diversity? (1)
Answer:
(a) A – Estrogen; B – Progesterone.

(b) C – Corpus luteum. It secretes a large amount of progesterone, which maintain the endometrium of uterus.

(c) Luteinizing hormone.

Question 18.
Pedigree analysis of two Mendelian disorders are shown below:
Answer:

1. Isolation of DNA
2. Digestion of DNA by restriction endonuclease enzyme
3. Separation of DNA fragments by electrophoresis
4. Blotting of separated DNA fragments into synthetic nylon or nitrocellulose membrane.
5. Hybridisation using labelled VNTR (Variable Number of Tandem Repeats) pcobe.
6. Detection of hybridised DNA fragment by autoradÍography.

Question 19.
Answer:
(a)

1. Habitat loss and fragmentation,
2. Over-exploitation,
3. Alien species invasions,
4. Co-extinctions

(b) In Situ Conservat ion – Ex Situ Conservation

1. Speciation is generally a function of time.
2. Tropical latitudes have remained relatively undisturbed for millions of years and thus had a long evolutionary time for species diversification.

Question 20.
Pedigree analysis of two Mendelian disorders are shown below:

(a) Identify the trait represented asAand B.(1)
(b) Which is the symbol for consanguineous mating used in pedigree analysis? (1)
(c) What do you mean by pedigree analysis?(1)
Answer:
(a) A – Autosomal dominant trait/ Myotonic dystrophy
B – Autosomal recessive trait I Sickle cell anaemia

(b)

(c) Analysis of a genetic trait in a several generations of a family is called pedigree analysis.

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

Kerala Plus Two Zoology Question Paper March 2023 with Answers

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

Question 1.
Select the odd one. Justify your selection. (Rete testis, Vasa efferentia, Fallopian tube, Vas deferens)
Answer:
Fallopian tube.

Question 2.
Write the Central dogma in Molecular biology.
Answer:
Genetic information flows from DNA-» mRNA —» Protein

Question 3.
Which microbe is called baker’s yeast?
(A) Propionibacterium sharmanii
(B) Lacto bacillus
(C) Saccharomyces cerevisiae
(D) Aspergillus niger
Answer:
Saccharomyces cerevisiae

Question 4.
Pick out the correct pair of disease and its pathogen:
(A) Filaria – Rhino virus
(B) Typhoid – Streptococcus
(C) Malaria – Plasmodium
(D) Ascariasis – Entamoeba
Answer:
Malaria-Plasmodium.

Question 5.
Identify two ex-situ conservation approaches of or-ganisms from the following list:(Zoological Park, Biosphere Reserve, National Park, Botanical Garden)
Answer:
Zoological Park, Botanical Garden.

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

Question 6.
Placenta also act as an endocrine tissue and produce several hormones.
(A) Name any two placental hormones.
(B) Write two functions of Placenta, (other than endocrine function)
Answer:
(A) 1. Human chorionic gonadotropin
2. Human placental lactogen

(B) It facilitates the supply of oxygen and nutrients to the embryo.
• It helps to remove CO₂ and excretory wastes produced by the embryo.

Question 7.
The graph given below shows the ovarian events and ovarian hormone levels during menstrual cycle

(i) Name hormones A and B.
(ii) Write the ovarian events during luteal phase.
Answer:
(i) A-Progesterone
B – Estrogen.

(ii) The remaining parts of the Graafian follicle transform as the corpus luteum.
• It secretes large amounts of progesterone essential for maintenance of endometrium.

Question 8.
What are lUDs? Name one copper releasing and one hormone releasing lUDs.
Answer:
lUD’s (Intra Uterine Devices) :-These devices that are inserted by doctor or expert nurse into the uterus through vagina.

• Copper releasing lUDs .
Eg CuT, Cu7 & Multiload 375

• Hormone releasing lUDs.
Eg Progestasert, LNG -20 (Any one example in each)

Question 9.
Match the following:

Genetic Disorders	Genetic Reasons
Klinefelter’s syndrome	21st Trisomy
Down’s syndrome	Lack of one ‘X’ chromosome in females(XO)
Turner’s syndrome	Due to autosomal recessive trait
Phenylketonuria	Presence of an extra X chromosome in males (XXY)

Answer:

Genetic Disorders	Genetic Reasons
Klinefelter’s Syndrome	Presence of an extra X chromosome in males (XXY)
Down’s Syndrome	21st Trisomy.
Turner’s Syndrome	Lack of one ‘X’ chromosome in female (XO).
Phenylketonuria	Due to autosomal recessive trait.

(i) A-Terminator gene B – Coding strand
(ii) It determines the base sequence in mRNA

Question 10.
Schematic representation of a transcription unit is given;

(i) Fill up the missing parts A and B.
(ii) Write the role of template strand in transcription.
Answer:
(A) The organs that are having similar function but differ in structure and origins.
(B) Eyes of octopus and mammals, Wings of butterfly and birds

Question 11.
(A) Define Analogous organs.
(B) Identify analogous organs from the given ex-amples :
(i) Eyes of octopus and mammals
(ii) Vertebrate hearts
(iii) Wings of butterfly and bird
(iv) Forelimbs of Cheetah and Human
Answer:
(A) The organs that are having similar function but differ in structure and origins.
(B) Eyes of octopus and mammals, Wings of butterfly and birds

Question 12.
Using the given terms in brackets, complete the following evolutionary stages of man :
(Homo sapiens, Homo habilis, Homo erectus, Australopithecines)

A – Australopithecines
B – Homo habilis
C- Homo erectus
D – Homo sapiens

Question 13.
Differentiate between Active immunity and Passive immunity.
Answer:

• Active Immunity
  1. Antibodies are produced in the host body when pathogen is entered into body.
  2. It shows the property of memory.
• Passive Immunity
  1. Ready-made anti-bodies are directly injected into the body.
  2. Memory property is absent.

Question 14.

Write some important measures that would be use-ful for the prevention and control of alcohol and drug abuse among adolescents.(Write relevant four points)
Answer:

1. Avoid undue pressure in adolescence
2. Proper education and counselling
3. Providing help from parents
4. Peer group looking for the danger sign

Question 15.
Two bioactive molecules are given :
(i) Cyclosporin-A
(ii) Streptokinase
(A) Name the microbe,which produces these bioactive molecules.
(B) Write its use.
Answer:
(A) Trichoderma polysporum. Used as Immunosuppressive agent.
(B) Streptococcus. Used as clot buster (Removing the clot)

Question 16.
A figure showing the global biodiversity of inverte-brates and vertebrates are given.

(A) Identify the most diverse groups of vertebrates and invertebrates.
(B) What are the three important levels of biodiversity?
Answer:
(A) Vertebrates – Fishes Invertebrates – Insects
(B) Genetic Diversity, Species diversity, Ecological diversity

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

Question 17.
(A) What are STIs?
(B) Give two examples!
(C) Write any two preventive measures of STIs.
Answer:
(A) Sexually Transmitted Infections
(B) Gonorrhoea and Syphilis.
(C) Avoid sex with unknown partners. Always use condoms during coitus.

Question 18.
Cross between Red flower (RR) and white flower (rr) bearing plants of Snapdragon produced all plants with pink flowers in F₁ generation.
(A) Name the genetic phenomenon of this cross.
(B) Illustrate F2 generation of this cross using Punnet square.
Answer:
(A) Incomplete Dominance
(b)

Question 19.
The given illustration shows ‘Evil Quartet’ of biodiversity loss :

(i) Fill up A’ and ‘B.
(ii) Explain Co-extinction and Alien species invasion with suitable examples.
Answer:
(i) A-Habitat loss and fragmentation B – Over-exploitation.

(ii) Co-extinction – When a species becomes extinct, the plant and animal species associated with it also become extinct.
Eg plant and its pollinator, Host and its parasites.

Alien species invasion – New species introducing into a geographical region is called alien species. It cause decline or extinction of indigenous species.

Eg : – Nile Perch introduced into Lake Victoria in East Africa lead to extinction of Cichlid fish in the lake.

Question 20.
Explain the transformation experiments performed by Frederick Griffith with bacteria Streptococcus
Pneumoniae.
Answer:
Streptococcus pneumonia bacterium has two strains S strain cause Pneumonia. R strain did not cause Pneumonia.

Steps in Griffith’s experiment

S-strain Injected into mouse → Mouse dies of pneumonia.

R-strain → Injected into mouse → Mouse lives Heat killed S-strain → Injected into mouse → Mouse lives.
Heat killed S-strain + Live R-strain → Injected into mouse Mouse → dies

Griffith’s postulated that some ‘transforming principle’ transferred from the heat- killed S-strain to R-strain and make them virulent.

Teachers recommend solving Kerala Syllabus Plus Two Botany Previous Year Question Papers and Answers Pdf March 2024 to improve time management during exams.

Kerala Plus Two Botany Previous Year Question Paper March 2024

I. Answer any 3 questions from 1-4. Each carries 1 score. (3 × 1 = 3)

Question 1.
Choose the correct answer and fill up the blanks. In grasses the monocot embryo contains single cotyledons named. (Plumule, Radicle, Scutellum, Coleorhiza)
Answer:
Scutellum.

Question 2.
In Recombinant DNAtechnology, precipitated DNA can be separated by ______.
Answer:
Spooling

Question 3.
A single stranded DNA or RNA tagged with radioactive molecule is called
(a) Plasmid
(b) Probe
(c) Clone
(d) Vector
Answer:
b) Probe.

Question 4.
Sun is the only source of energy for all ecosystem on earth. But one exception. What is that?
Answer:
Deep sea hydro-thermal ecosystem I Deep Sea.

II. Answer any 9 questions from 5-15. Each carries 2 scores. (9 × 2 = 18)

Question 5.
Observe the diagram of Pollen grain given below and answer the questions.

(a) Identify the cell ‘A’ and ‘B’.
(b) Write the two features of ‘A’.
Answer:
(a) A – Vegetative cell
B – Generative cell

(b) Vegetative cell is bigger / has abundant food reserve I has large irregularly shaped nucleus. (Any two features)

Question 6.
Name the special cellular thickening present in the synergid at micropylar end. Write its function.
Answer:
Filiform apparatus. It plays an important role in guiding the entry of pollen túbe into the synergids.

Question 7.
What are the two core techniques that enabled the birth of modern biotechnology?
Answer:
Genetic engineering. Bioprocess engineenng I Chemical engineering processes.

Question 8.
Explain any two methods by which recombinant DNA can be directly introduced into the host cell.
Answer:
Microinjection : Direct injection of recombinant DNA (rDNA) into the nucleus of an animal cell is called microinjection  It is the rDNA transfer method for animal cell.

Biolistics : Bombardment of plant cell with high velocity micro particle of gold or tungsten coated with DNA is called biolistics I It is the rDNA transfer method for plant cell.

Question 9.
The first trarisgenic cow p roduced human protein enriched milk. Name the cow and the
protein found in milk.
Answer:
The first transgenic cow is Rosie. The protein is aipha-lactalbumin I Human protein.

Question 10.
Match the following

A	B
1. Biopiracy	A. ADA deficiency
2. Gene Therapy	B. Basmathi Rice
3. RNA Interference	C. Cry gene
4. Bacillus thuringiensis	D. Melodegynae incognita

Answer:

A	B
1.Biopiracy	Basmati Rice
2. Gene Therapy	ADA deficiency
3. RNA Interference	Meloidogyne incognitia
4. Bacillus thurengiensis	Cry gene

Question 11.
the following graph shows two types of population growth curves.

(1) Name the growth curve ‘a’ and ‘b’.
(2) What does ‘K’ stands for?
Answer:
(1) a) Exponential growth I J shaped curve I Geometric growth model.
b) Logistic growth / Verhulst-Pearf Logistic Growth I Sigmoid Growth I S-shaped curve.

(2) K – Carrying capacity.

Question 12.
Parasites evolved special adaptations to live on host. What are they?
Answer:

• The loss of unnecessary sense organs
• presence of adhesive organs or suckers to cling on to the host
• loss of digestive system
• high reproductive capacity.

Question 13.

The figure depicts pyramid of energy.
(a) Pyramid of energy is always upright, can never be inverted. Justify
(b) Which are the other two ecological pyramids?
Answer:
(a) When energy flow from a particular trophic level to the next level some energy is lost as heat at each step. Only 10% of the energy is transferred to each trophic level from the lower trophic level according to law of 10%.

(b) Pyramid of numbers, Pyramid of biomass.

Question 14.
A list of different organism in an ecosystem are given below. Arrange them in 1^st, 2^nd and 3^rd and 4^th trophic level. (Phytoplankton, Man, Fish, Zooplankton)
Answer:
Phytoplankton → Zooplankton → Fish → Man

Question 15.
Rate of Biomass production in an ecosystem is called productivity. Productivity are divided into two, GPP and NPP.
(a) Expand GPP & NPP.
(b) Write the equation relating GPP with NPP.
Answer:
(a) GPP — Gross Primary ProductMty
NPP – Net Primary Productivity
b) GPP-R=NPR

III. Answer any 3 questions from 16 to 19. Each carries 3 scores. (3 × 3 = 9)

Question 16.
Observe the diagram and answer the following questions:

(1) Label‘a’,‘b’,‘c’and”d’.
(2) Name the diploid cell found in embryo sac.
Answer:
(1) a — Antipodals
b — polar nuclei
c — Synergids
d — Egg I Female gamete

(2) Central cell.

Question 17.
The genes of organism can be altered by Manipulation. Such organisms are called Genetically Modified Organism (GMO). List any 3 merits of G.M. Plants.
Answer:
Merits of G.M. Plants includes:

• Made crops tolerant to abiotic stress (cold, drought, salt & temperature)
• Develop pest resistance
• Helped to reduce post-harvest losses

Question 18.
Observe the figure given below:
(1) Fill in the blanks a, b, and c in the figure.
(2) Write the name of this process.
(3) What is the name of thermostable DNA polymerase enzyme used in this techniques?

Answer:
(1) a. Denaturation
b. Annealing
c. Extension.

(2) Polymerase Chain Reaction

(3) Taq Polym erase (from the bacteria Therm us aquaticus).

Question 19.
Given below are examples of some population interactions. Identify and define the interaction.
(a) Cattle egret and grazing cattle
(b) Fig tree and wasp
(c) Cuscuta growing on hedge plants.
Answer:
(a) Commensalism: It is +, O interaction In this interaction one species is benefitted and the other is neither behefitted nor harmed.

(b) Mutualism : It is +, + interaction In this interaction both the species are benefrited.

(c) Parasitism: It is +, – interaction I in this interaction only one species is benefited and the interaction is detrimental to the other species Interaction between host and parasite.

Reviewing Kerala Syllabus Plus Two Physics Previous Year Question Papers and Answers Pdf March 2021 helps in understanding answer patterns.

Kerala Plus Two Physics Previous Year Question Paper March 2021

Answer the following questions from 1 to 45 upto a maximum score of 60.

I. Questions 1 to 8 carry 1 score each. (8 × 1 = 8)

Question 1.
Fill in the blanks:
” The force between two point charges is directly proportional to the product ……… of and inversely proportional to the ………. of the distance between them”.
Answer:
charges, square

Question 2.
The expression ΣB.AS = 0 is
(i) Gauss Law in Electrostatics
(ii) Gauss Law in Magnetism
(iii) Ampere’s circuital law ‘
(iv) Lenz’s law
Answer:
(ii) Gauss Law in Magnetism

Question 3.
The electromagnetic waves used in LASIK eye surgery is
(i) microwaves
(ii) ultraviolet rays
(iii) infra-red waves
(iv) gamma rays
Answer:
(ii) ultraviolet rays

Question 4.
Write Lens maker’s formula:
Answer:
\(\frac{1}{f}\) = (n-1) [\(\frac{1}{R_1}\) – \(\frac{1}{R_2}\)]

Question 5.
Name the property of light that proves its transverse nature.
Answer:
Polarisation

Question 6.
Write the equation for the wavelength of de Broglie wave associated with a moving particle.
Answer:
Wave length λ = \(\frac{h}{mV}\)

Question 7.
Energy of electron in the n^th orbit of hydrogen atom is E_n =\(\frac{13.6}{n^2}\) eV. What is the energy required to make electron free from first orbit of hydrogen atom?
Answer:
+ 13.6 eV

Question 8.
If radius of first electron orbit of hydrogen is a₀, radius of second electron orbit of hydrogen is ……… .
Answer:
a = 4a₀ [a = n²a₀; n = 2]

Questions from 9 to 22 carry 2 scores eqch. (14 × 2 = 28)

Question 9.
Calculate the electric potential at a point 9.0 cm away from a point charge of 4 × 10^-7 C.
Answer:
V = \(\frac{1}{4 \pi \varepsilon_0}\) \(\frac{q}{r}\)
= 9 × 10⁺⁹ × \(\frac{4 \times 10^{-7}}{9 \times 10^{-2}}\) = 4 × 10⁴ V

Question 10.
State Biot – Savart law and express it mathematically.
Answer:
dB = \(\frac{\mu_0}{4 \pi}\) \(\frac{\mathrm{Id} \ell \sin \theta}{\mathrm{r}^2}\)

Question 11.
Draw Wheatstone’s bridge and write its balancing condition.
Answer:

When bridge is balanced, \(\frac{P}{Q}\) = \(\frac{R}{S}\)

Question 12.
Determine the value of resistance R in the figure, assuming that the current through the galvanometer (G) is zero.

Answer:
When galvanometer current is zero,
We can write \(\frac{P}{Q}\) = \(\frac{R}{S}\)
\(\frac{R}{3}\) = \(\frac{40}{60}\)
R = 3 × \(\frac{40}{60}\) = 2 Ω

Question 13.
Write any two properties of nuclear force.
Answer:
(i) N uclear force is indepentant of charge
(ii) It is a short range force

Question 14.
Define half life of a radioactive sample. Write the equation that connects half life with disintegration constant.
Answer:
Half life is the time taken to reduce half of initial value of sample.
T_1/2 = \(\frac{0.693}{λ}\)

Question 15.
An air cored solenoid has 1000 turns per metre and carries a current of 2A. Calculate the magnetic intensity (H).
Answer:
n = 1000, I = 2 A
H = 1000 × 2 = 2000 Alm³

Question 16.
The behaviour of magnetic filed lines near two magnetic substances P and Q are shown below.

(a) From the figure identify paramagnetic substance.
Answer:
Substance Q

(b) Susceptibility of substance P is ………….. (positive /negative).
Answer:
Negative

Question 17.
Current in a curcuit fall from 5.0 A to 0.0 A in 0.1 s. If an average emf of 200 V is induced. Calculate the self inductance of the curcuit.
Answer:
ε = L \(\frac{dI}{dt}\) dI = 5 – 0
200 = L \(\frac{5 – 0}{0.1}\) dt = 0.1 ; ε = 200
L = \(\frac{200 \times 0.1}{5}\) = 4 H

Question 18.
Using a suitable ray diagram prove that the radius of curvature of a spherical mirror is twice its focal length.
Answer:

Consider a ray AB parallel to principal axis incident on a cpncave mirror at point B and is reflected along BF. The line CB is normal to the mirror as shown in the figure.
Let θ be angle of incidence and reflection.
Draw BD ⊥ CP,
In right angled ∆ BCD,
Tanθ = \(\frac{BD}{CD}\) ……….(1)
In right angled ∆ BFD,
Tan2θ = \(\frac{BD}{FD}\) ……….(2)
Dividing (1) and(2)
\(\frac{Tanθ}{Tan2θ}\) = \(\frac{CD}{FD}\) ………(3)
If θ is very small, then tanθ ≈ θ and tan2θ ≈ 2θ
The pointB lies very close to P. Hence CD ≈ CP and FD ≈ FP From (3) we get
\(\frac{2θ}{θ}\) = \(\frac{PC}{PF}\) = \(\frac{R}{f}\)
R = 2f

Question 19.
A light bulb of resistance 484 Ω is connected with 200 V ac supply. Find peak value of current through the bulb.
Answer:
R = 484 Ω
V = 220 V
I_rms = \(\frac{V}{R}\) = \(\frac{220}{484}\) = 0.45 A
I_rms = \(\frac{I_0}{\sqrt{2}}\)
I₀ = \(\sqrt{2} \times I_{m s}\)
= √2 × 0.45 = 0.64 A

Question 20.
Write any two postulates of Bohr model of hydrogen atom.
Answer:
1. Electrons revolve round the positively charged nucleus in circular orbits.
2. The electron which remains in a privileged path cannot radiate its energy.
3. The orbital angular momentum of the electron is an integral multiple of h/2π.
4. Emission or Absorption of energy takes place when an electron jumps from one orbit to another.

Question 21.
The symbol of a logic gate is given below. Identify the gate and write its truth table.

Answer:
OR gate
Tablee

Question 22.
When bulk pieces of conductors are subjected to changing magnetic flux, currents are induced in them.
(a) Write the name of this induced current.
Answer:
Eddy current

(b) Write any two practical applications of this current.
Answer:
(i) Magnetic breaking
(ii) Induction furnance

Questions from 23 to 34 carry 3 scores each. (12 × 3 = 36)

Question 23.
(a) Define electric dipole moment. (1)
Answer:
Electric dipole moment is product of magnitude of charge of dipole and its length.

(b) A system has two charges 2.5 × 10^-7 C and 2.5 × 10^-7 C located at points (0, 0, -15 cm) and (0,0, +15 cm), respectively.
Determine the magnitude and direction of electric dipole moment of the system. (2)
Answer:
q = 2.5 × 10^-7 C
2a = 2 × 15 = 30 cm
P = q × 2a = 2.5 × 10^-7 × 30 × 10^-2
= 75 × 10^-9 Cm
direction → -q to +q

Question 24.
(a) Write any two properties of electric field lines. (2)
Answer:
(i) Electric field lines never intercept each other.
(ii) Electric field lines are originated from positive charge and terminated at negative charge.

(b) Observe the figure and write the signs of the charges q₁ and q₂.

Answer:
q₁ is positive and q₂ is negative.

Question 25.
Derive an expression for the energy stored in a ca-pacitor in terms of capacitance and potential differ-ence across the capacitor.
Answer:
Energy of a capacitor is the work done in charging it. Consider a capacitor of capacitance ‘C’. Let ‘q’ be the charge at any instant and ‘V’ be the potential. If we supply a charge ‘dq’ to the capacitor, then work done can be written as,
dw = Vdq
dw = \(\frac{q}{C}\)dq (Since V = \(\frac{q}{C}\))
∴ total work done to change the capacitor (from 0 to Q) is
W = \(\int_0^Q \frac{q}{C} d q\)
W = \(\frac{1\left[q^2\right]_0^Q}{\mathrm{C} 2}\)
W = \(\frac{1}{C} \frac{Q^2}{2}\)
but Q = CV
W = \(\frac{1}{2}\) CV²
This work done is stored in the capacitor as electric potential energy.
Energy stored in the capacitor is,
U = \(\frac{1}{2}\) CV²

Question 26.
Write any one difference between polar and non-polar molecule: Give one example each for polar and non-polar molecule.
Answer:
In polar molecule, positive centre and negative centre does not coincide each other. But in non polar molecule, positive centre and negative centre coin-cide each other.
Example:
Polar molecule – H₂O, HCl
Non polar molecule – H₂, O₂

Question 27.
(a) Define angle of dip. (1)
Answer:
The angle between earths magnetic field with its horizontal is called dip.

(b) At a particular place the horizontal and vertical components of earth’s magnetic field are found to be equal. What is the value of dip at this place? (2)
Answer:
B_H = B_V
B cosθ = B sinθ
cosθ = sinθ
∴ θ = 45°

Question 28.
In the figure shown below
(a) Which are the resistors Connected in parallel? (1)
Answer:
6Ω and 3Ω

(b) Calculate the current drawn from the cell. (2)

Answer:
6Ω and 3Ω resistors are’connected in parallel. Hence effecting resistance
R = \(\frac{6 \times 3}{6+3}\) = \(\frac{18}{9}\) = 2Ω
This 2Ω connected 8Ω in series.
.-. Total resistance = 8 + 2 = 10Ω
Current I = \(\frac{\text { Total voltage }}{\text { Total resistance }}\)
I = \(\frac{24}{10}\) = 2.4 A

Question 29.
Using Ampere’s circuital law show that the intensity of magnetic field at an axial point near the centre of a current carrying solenoid is B = μ₀n I.
Answer:

Consider a solenoid having radius ‘r’. Let ‘n’ be the number of turns per unit length and I be the current flowing through it.
In order to find the magnetic field (inside the solenoid ) consider an Amperian loop PQRS. Let ‘e ‘ be the length and ‘b’ the breadth.
Applying Amperes law, we can write

(since RS is completely out side the solenoid, for which B = 0)
Substituting the above values in eq (1 ),we get
Bl = μ₀ I_ene …….(2)
But I_ene = n l I
where ‘nl’ is the total number of turns that carries current I (inside the loop PQRS)
∴ eq (2) can be written as
Bl = μ₀ nI l
B = μ₀ nI
If core of solenoid is filled with a medium of relative permittivity nr then
B = μ₀μ_rnl

Question 30.
Write a circuit diagram explain how a moving coil galvanometer can be converted to an ammeter.
Answer:
A galvanometer can be converted into an ammeter by a low resistance (shunt) connected parallel to it.
Theory: Let G be the resistance of the galvanometer, giving full deflection for a current I_g.
To convert it into an ammeter, a suitable shunt resistance ‘S’ is connected in parallel. In thisoafirange- ment Ig current flows through Galvanometer and remaining (I-Ig) current flows through shunt resistance.
Since G and S are parallel
P.d Across G = p.d across S
Ig × G = (I-Ig)S

Question 31.
Prove that when an alternating voltage is applied to an inductor, the current thrcjugh it lags behind voltage by an angle \(\frac{\phi}{2}\).
Answer:

Consider a circuit containing an inductor of inductance ‘L’ connected to an alternating voltage.

Let the applied voltage be
V = V₀ sin ωt ………(1)
Due to the flow of alternating current through coil, an emf, L\(\frac{dI}{dt}\) is produced in the coil. This induced emf is equaland opposite to the applied emf (in the case of ideal inductor)
ie. L\(\frac{dI}{dt}\) = V₀ sin ωt
dI = \(\frac{dI}{dt}\) sin ωt dt
Integrating, we get
I = \(\frac{V_0}{L \omega}\) cos ωt
I = \(\frac{V_0}{L \omega}\) Sin (ωt – \(\frac{\phi}{2}\))
I = I₀ Sin (ωt – \(\frac{\phi}{2}\)) ………(2)
Where I₀ = \(\frac{V_0}{L \omega}\)
The term Lω is called inductive reactance. Comparing eq(1) and eq(2), we can understand that, the current lags behind the voltage by an angle 90°.

Question 32.
(a) The current due to time varying electric field is called ……… (1)
Answer:
displacement current

(b) An electromagneticjwave travels in free space with a velocity of 3 × 10⁸ m/s. At a particular point in space and timte, magnitude of intensity of electric field is 6.3 V/m. What is magnitude of magnetic field at this point? (2)
Answer:
C = \(\frac{E}{B}\)
3 × 10⁸ = \(\frac{63}{B}\)
Magnetic field, B = \(\frac{63}{3 × 10^8}\) = 2.1 × 10^-8 T

Question 33.
Using Huygens wave theory prove that angle of incidence is equal tojangle of reflection.
Answer:
Reflection of plane wave by a plane surface.

AB is the incident wavefront and CD is the reflected wavefront, ‘i’ is the angle of incidence and ‘r’ is the angle of reflection. Let c₁ be the velocity of light in the medium. Let PO be the incident ray and OQ be the reflected ray.
The time taken for the ray to travel from P to Q is
t = \(\frac{\mathrm{PO}}{\mathrm{C}_1}+\frac{\mathrm{OQ}}{\mathrm{C}_1}\) …….(1)
t = \(\frac{A O \sin i}{C_1}+\frac{O D \sin r}{C_1}\)

O is an arbitrary point. Hence AO is a variable. But the time to travel for a wave front from AB to CD is a constant. So eq.(2) should be independent of AO. i.e., the term containing AO in eq.(2) should be zero.

\(\frac{A O}{C_1}\) (sin i – sin r) = 0
sin i – sin r = 0
sin i = sinr i = r

Question 34.
(a) Write Einstein’s photoelectric equation.
Answer:
hυ = hυ₀ + \(\frac{1}{2}\)mv²

(b) Using this equation show that, “photoelectric emission is not possible if the frequency of incident radiation is less than threshold – frequency”. (2)
Answer:
hυ = hυ₀ + \(\frac{1}{2}\)mv²
If incident frequency is less than threshold frequence (υ < υ₀), kinetic energy of photoelectron becomes negative, which means that no photo emission takes place.

Reviewing Kerala Syllabus Plus Two Physics Previous Year Question Papers and Answers Pdf March 2021 helps in understanding answer patterns.

Kerala Plus Two Physics Previous Year Question Paper March 2020

Time : 2 1/2 Hours
Maximum : 80 scores

I. Answer all questions from 1 to 6. Each carries 1 Score. (6 × 1 = 6)

Question 1.
How capacitance changes if the distance between the plates of a parallel plate capacitor is halved?
a) Does not change
b) Becomes half
c) Doubled
d) Becomes one fourth
Answer:
c) Doubled

Initial capaciatatance C₀ = \(\frac{A \varepsilon_0}{d}\)
New capaciatatance C₁ = \(=\frac{A \varepsilon_0}{d / 2}\) = \(\frac{2 A \varepsilon_0}{d}\)
C₁ = 2 C₀

Question 2.
The path of a charged particle entering parallel to uniform magnetic field will be
a) Circular
b) helical
c) Straight line
d) None of these
Answer
c) Straight line

Force acting on the charge F = q(\(\vec{υ} \times \vec{B}\))
= qυB
in this case θ = 0, Hence F = 0
No force acting on the partical, hence partical continues its path.

Question 3.
Coefficient of mutual inductance of two coils is 1H. Current in one of the coils is increased from 4 to 5 A in 1ms. What average emf will bw induced in the other coil?
a) 100V
b) 2000V
c) 100V
d) 200V
Answer:
a) 100V

Induced emf ε = M \(\frac{\mathrm{dI}}{\mathrm{dt}}\)
M = 1 H,dI = 5 – 4, dt = 1 × 10^-3
ε = \(=1 \times \frac{(5-4)}{1 \times 10^{-3}}\) = \(\frac{1}{10^-3}\)
= 10³
= 1000 V

Question 4.
Total internal reflection may be observed if
a) Light ray is travelling from denser medium to rarer medim
b) Light ray is travelling from rarer medium to denser medium
c) light ray is travelling from any medium to another medium
Answer:
a) Light ray is travelling from denser medium to rarer medim

Question 5.
Optical fibres make use of the phenomenon of ……….
a) refraction
b) total internal reflection
c) interference
d) diffraction
Answer:
b) total internal reflection

Question 6.
The size of the atom in Thomson’s model is ……… the atomic size in Rutherford’s model.
a) much greater than
b) not different from
c) much less than
Answer:
a) much greater than

Question 7.
A Permanent electric dipole of dipole moment P is placed in a uniform external electric field E, as shown in Figure.

(a) Redraw the figure and show the magnitude and direction of force actng on the charges.
Answer:

(b) Write an expresson of the torque acting on this dipole in vector form.
Answer:
Torque acting on the dipole τ = \(\overrightarrow{\mathbf{P}} \times \overrightarrow{\mathbf{E}}\)

Question 8.
Ampere’s theorem helps to find the magnetic field in a region around a current carrying conductor.
a) Write the expression of Ampere’s theorem.
Answer:
\(\oint \overrightarrow{\mathrm{B}} \cdot \overrightarrow{\mathrm{~d} \ell}=\gamma_0 \mathrm{I}\)

b) Draw a graph showing the variation of intensity of magnetic field with the distance from the axis of a current carrying conductor.
Answer:

Question 9.
A magnetised needle in uniform magnetic field experiences a torque but no net force. An iron nail near a bar magnet, however experiences a force of attraction in addition to a torque. Why?
Answer:
A bar magnet produces non – uniform field. Hence iron nail experiences a force of attraction in addition to a torque.

Question 10.
What is the magnitude of the equatorial and axial fields due to a bar magnet of length 5.0 cm at a distance of 50cm from its mid-point? The magnetic moment of the bar magnet is 0.40 Am².
Answer:
If magnet is short,
Magnetic field along the equatorial line
B_E = \(\frac{\mu_0}{4 \pi} \frac{M}{r^3}\)
\(\frac{\mu_0}{4 K} \) = 10^-7, M = 0.40 Am², r = 50 cm = 0.5 cm
∴ B_E = 10^-7 × \(\frac{0.40}{(0.5)^3}\)
B_E = 3.2 × 10^-7 T
Magnetic field along the axial line
B_axial = \(\frac{\mu_0}{4 \pi} \frac{2 M}{2 r^3}\)
B_axial = 2 B_E
= 2 × 3.2 × 10^-7 T
= 6.4 × 10^-7 T

Question 11.
A magician during a show makes a glass lens with n = 1.47 disappear in a liquid.
a) What is the refractive index of the liquid?
Answer:
1.47

b) Could the liquid be water?
Answer:
No, the reflactive index of the water is 1.33

Question 12.
Explain why the bluish colour predominates in a clear sky.
Answer:
Blue colour undergoes for more scattering.

Question 13.
Match the following:
Tablee 1
Answer:
Tablee 2

Question 14.
Diodes are cone of the building elements of electronic circuits. Some type of diodes are shown in the figure.

a) Identify rectifier diode from the figure.
Answer:
(iii)

b) Draw the circuit diagram of a forward biased rectifier diodes are shown in the figure.
Answer:

Question 15.
The given figure shows the various propagation modes of e.m. waves in communication.

a) Write the names of propagation modes in A, B, C.
Answer:
A – ground wave
B – sky wave
C – space wave

b) Why transmission of TV signals via sky wave is not possible?
Answer:
The frequencies below 40 MHz is reflected by ionosphere. Tv signals have frequences above 54 MHz. Hence sky wave propagation;is not possible in Tv transmission.

Answer any 6 questions from 16 to 23. Each carries 3 scores. (6 × 3 = 18)

Question 16.
An infinitely long straight wire with uniform linear charge density is shown in figure.

a) Draw a Gaussian surface in order to calculate the electric field at P and mark direction of electric field at this point.
Answer:

b) Derive an expression to calculate electric field at this point P.
Answer:

Consider a thin infinitely long straight rod
conductor having charge density λ. [ λ = \(\frac{q}{l}\)]
To find the electric field at P ,we imagine a Gaussian surface passing through P.
Then according to Gauss’s law we can write,
\(\int \overrightarrow{\mathrm{E}} \cdot \mathrm{~d} \overrightarrow{\mathrm{~s}}\) = \(\frac{1}{\varepsilon_0}\) q
\(\int E d s \cos \theta\)= \(\frac{1}{\varepsilon_0}\) q (θ = 0°)
\(E \int d s\)= \(\frac{\lambda I}{\varepsilon_0}\) q (since q = λ.I)
Integrating over the Gaussian surface, we get (we need not integrate the upper and lower surface because, electric lines do not pass through these surfaces.)

Question 17.
Three resistors R₁, R₂, R₃ are to be combined as shown in the figures.

a) Identify the series and parallel combinations,
Answer:
Fig 1 – parallel combination
Fig 2 – series combination

b) Which combination has lowest effective resistance?
Answer:
Parallel combination

c) Arrive at the expression for the effective resistance of parallel combination.
Answer:
Consider three resistors R₁, R₂ and R₃ connected in parallel across a pd of V volt. Since all the resistors are connected across same terminals, pd across all the resistors are equal.
Img 18
As the value of resistors are different current will be different in each resistor and is given by Ohm’s law
Current through the first resistor
I₁ = \(\frac{V}{R_1}\)
Current through the second resistor
I₂ = \(\frac{V}{R_2}\)
Current through the third resistor
I₃ = \(\frac{V}{R_3}\)

Total current through the combination is I = \(\frac{V}{R}\), where R is the effective resistance of parallel combination.
Total current through the combination = the sum of current through each resistor
I = I₁ + I₂ + I₃
Substituting the values of current we get
\(\frac{V}{R}\) = \(\frac{V}{R_1}\) + \(\frac{V}{R_2}\) + \(\frac{V}{R_3}\)
Eliminating V from all terms on both sides of the equations, we get
\(\frac{1}{R}\) = \(\frac{1}{R_1}\) + \(\frac{1}{R_2}\) + \(\frac{1}{R_3}\)

Question 18.
a) State Faraday’s law of electomagnetic induction.
Answer:
Faraday’s Law of induction
Faraday’s law of electromagnetic induction states that the magnitude of the induced emf in a circuit is equal to the time rate of change of magnetic flux through the circuit.
Mathematically, the induced emf is given by
\(\epsilon=\frac{d \phi}{d t}\)
If the coil contain N turns, the total induced emf is given by
\(\epsilon=N \frac{d \phi}{d t}\)

b) How does the magnetic energy stored in an inductor and electrostatic energy stored in a capacitor related to their respective field strengths?
Answer:
In capacitor energy is stored in electronic field
E = \(\frac{1}{2}\) cv²
In inductor energy is stored in magnetic field
E = \(\frac{1}{2}\)LI²

Question 19.
A typical plane electromagnetic wave propagating along the Z direction is shown in figure.

a) Write the equation for electric and magnetic fields.
Answer:
This em wave is travelling in z direction and direction of oscillation of electric field is along x. Hence equation for electric field
E_x = E₀ Sin(Kz-wt)
The direction of oscillation of magnetic field is along the y direction, hence
B_y = B₀ Sin (Kz-wt)

b) Write the methods of production of radio waves and microwaves. Write any one use of these waves. (1+2)
Answer:
Radio wave: Rapid accelartion and deacceleration of electrons in aerials. These are used in radio and televisiion communication systems.

Microwaves: Microwaves are produced by special vaccum tubes. Microwaves ovens are domestic applica¬tion of those waves.

Question 20.
The figure shows the image formation of an object in simple microscope.

a) Find out the object distance and image distance from the figure.
Answer:
OQ is the object distance.
OQ₁ is the image distance.

b) Derive an equation for magnifying power of the simple microscope.
Answer:
A simple microscope is a converging lens of small focal length.

Working: The object to be magnified is placed very close to the lens and the eye is positioned close to the lens on the other side. Depending upon the position of object, the position of image is changed.
If the image is formed at ‘D’, (D = 25 cm) we can take u = -D. Hence the lens formula can be written as
\(\frac{1}{v}\) – \(\frac{1}{u}\) = \(\frac{1}{f}\)
1 – \(\frac{v}{u}\) = \(\frac{v}{f}\)
\(\frac{v}{u}\) = 1 – \(\frac{v}{f}\)
m = 1 – \(\frac{v}{f}\)
The image is formed at D, ie. v = -D
m = 1 – \(\frac{-D}{f}\)
m = 1 + \(\frac{D}{f}\)

Question 21.
The atomic line spectra of hydrogen atom is shown in figure.

Answer:
A – Lyman series
B – Balmor series
C – Paschen series

Question 22.
Spontaneous and continuous disinflation of a nucleus of a heavy element with the emission of certain types of radiation is known as radioactivity,
a) The radioactive isotope ‘D’ decays according to the sequence.

If the mass number and atomic number of D₂ are 172 and 71 respectively, what are the (i) Mass number, (ii) atomic number of D.
Answer:

When an α (₂He⁴) emitted, mass number 4 and atomic number 2 is reduced from the parent nucleus. Hence pamet nucleus,
D₁ = ₇₃Y¹⁷⁶
When is emitted, atomic number of daughter nuclei increases by 1 unit and mass numbers constant
Hence D = ₇₂Z¹⁷⁶

atomic number of D is 72, and mass number is 176.

b) State radioactive decay law.
Answer:
The number of nuclei undergoing decay per unit time is proportional to number of nuclei in the sample at that time.

c) Write he relation connecting half-life and mean life of radioactive element.
Answer:
T_1/2 = 0.693 τ
T_1/2 is the half life
τ is the mean life

Question 23.
In the broadcast of communication, modulation is necesary.
a) What do you mean by modulation?
Answer:
Modulation is the process of superprosing a low ferquency signal on a high frequency carrier wave.

b) Explain any two reason why modulation is necessary?
Answer:
i) Size of the antenna can be reduced.
ii) Effectiven power radiated from the source can be increased.

Answer any 2 questions from 24 to 26, Each carries 4 scores. (2 × 4 = 8)

Question 24.
Three capacitors of capacitances 2 pF, 3pF are connected in parallel.
a) Write the SI unit of capacitance.
Answer:
Farad

b) Calculate the effective capacitance of the combination.
Answer:
C = C₁ + C₂ + C₃
C = (2+3+4) PF
C = 9 PF

c) Determine the charge on each capacitor if the combination is connected to a 100V supply
Q = CV
Q₁ = C₁V
= 2 PF × 100 = 2 × 10^-10 C
Q₂ = C₂V = 3 PF × 100 = 3 × 10^-10 C
Q₃ = C₃V = 4 PF × 100 = 4 × 10^-10 C

Question 25.
A rectangular loop o ara A and carrying a steady current I is placed in a uniform magnetic field.
a) Derive the expression of torque, acting on the loop.
Answer:
Torque on a rectangular current loop in uniform magnetic filed

Consider a rectangular coil PQRS of N turns which is suspended in a magnetic field, so that it can rotate (about yy1). Let l be the length (PQ) and ‘b’ be the breadth (QR).
When a current ‘l’ flows in the coil, each side produces a force. The forces on the QR and PS will not produce torque. But the forces on PQ and RS will produce a Torque.
Which can be written as
τ = Force × ⊥ distance …….(1)
But, force = BIl ……..(2) [since θ = 90°]
And from AQTR, we get
⊥ distance (QT) = b sin θ ………..(3)
Substituting the vales of eq (2) and eq (3) in eq(1)
we get
τ = BIl b sin θ
= BIA sin θ [since lb = A (area)]
τ = IAB sin θ
τ = m B sin θ [since m = IA]
If there are N turns in the coil, then
τ = NIAB sin θ

b) Increasing the current sensitivity may not necessarily increase the voltage sensitivity, of a galvanometer. Justify.
Answer:
Current sensitivtity can be increased by incraesing number of turns. When number of turns doubble, the resistance of the wire will also be doubbled. Hence the voltage sensitivity does not change.

Question 26.
The work function of caesium metal is 2.14eV. When light of frequency 6 × 10¹⁴ Hz is incident On the metal surface, photoemission of electrons occurs. (h = 6.6 × 10¹⁴)
a) Define work function
Answer:
Work function is the amount of energy required fora electron tojust escape from a metal surface.

b) Calculate the maximum kinetic energy of the emitted electrons.
Answer:
hυ = ϕ₀ + KE
6.6 × 10³⁴ × 6 × 10^-20 = 2.14 × 1.6 × 10^-19 + KE
39.6 × 10^-20 = 3.424 × 10^-19 + KE
KE = 5.36 × 10^-19 J
KE = 3.35 ev
KE = ev₀
3.35 ev = ev₀
v₀ = 3.35 v

Answer any 3 questions from 27 to 30, Each carries 5 scores. (3×5 = 15)

Question 27.
A Wheatstone bridge is shown in figure.

a) Derive a relation connecting the four resistors for the galvanometer to give zero or null deflection.
Answer:
Four resistances P,Q,R and S are connected as shown in figure. Voltage ‘V’ is applied in between A and C. Let I, I₁,I₂,I₃ and I₄ be the four currents passing through P,R,Q and S respectively.

Working :
The voltage across R
When key is closed, current flows in different branches as shown in figure. Under this situation
The voltage across P, V_AB = I₁P
The voltage across Q, V_BC = I₃Q ……….(1)
The voltage across R, V_AD = I₂R
The voltage across S, V_DC = I₄S
The value of R is adjusted to get zero deflection in galvanometer. Under this condition,
I₁ = I₃ and I₂ = I₄ ………(2)
Using KirchofFs second law in loop ABDA and BCDB, weget
V_AB = V_AD ………(3)
and V_BC = V_DC —-(4)
Substituting the values from eq(1) into (3) and (4), weget
I₁P = I₂R …….(5)
I₃Q = I₄S …….(6)
Dividing Eq(5)byEq(6)
\(\frac{\mathrm{I}_1 P}{\mathrm{I}_3 Q}\) = \(\frac{I_2 R}{I_4 S}\)
\(\frac{P}{Q}\) = \(\frac{R}{S}\)
This is called Wheatstone condition,

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

Kerala Plus Two Botany Board Model Paper 2020 with Answers

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

Question 1.
Choose the correct answer and fill in the blank.
_______ is the female gametophyte of angiosperms.
a) Embryo sac
b) Nuceluus
c) Integument
d) Pollen grain
Answer:
Embryosac

Question 2.
Choose the correct answer. Natural aging of a lake by nutrient enrichment of its water is called
a) Biomagnification
b) Algal bloom
c) Succession
d) Eutrophication
Answer:
Eutrophication

Question 3.
Fill in the blank :
The wheat variety having high protein content used as donor in bio-fortification is ______
Answer:
Atlas 66

Question 4.
Name the type interaction between an orchid plant and Mango tree.
Answer:
Commensalism

Question 5.
Find the odd one.
Hilsa, Sardine, Rohu, Mackerel
Answer:
Rohu

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

Question 6.
The innermost wall layer of Microsporangium is Tapetum.
a) What is it is function?
b) Features of Tapetal cells.
Answer:
a) It nourishes the pollen grain
b) It has dense cytoplasm, It posses prominent nucleus

Question 7.
Match the following:

A	B
Chlamydomonas	Gemmule
Conidia	Zoospore
Sponage	Bulbil
Hydra	Pencillium
	Buds

Answer:

A	B
Chlamydomonas	Zoospore
Conidia	Penicillium
Sponage	Gemmule
Hydra	Buds

Question 8.
Explain the terms:
a) Micro propagation
b) Totipotency
Answer:
a) It is the production of large number of plants within short time in tissue culture,
b) The ability of a cell to form whole plant.

Question 9.
Explain the separation of DNA fragments using gel electrophoresis.
Answer:
In Gel electrophoresis, negatively charged DNA fragments are separated by forcing them to move towards the anode under an electric field through a agarose matrix. The DNA fragments separate according to their sizd in agarose gel.

Question 10.
Write notes on:
a) Micro injection
b) Biolistics
Answer:
a) Micro-injection Recombinant DNA is directly injected into the nucleus of an animal cel.,

b) Biolistics – Cells are bombarded with high velocity micro-particles of gold or tungsten coated with DNA. It is suitable for plants.

Question 11.
Amplification of gene of interest is done using PCR.
a) Expand PCR
b) Mention the three steps of this process.
Answer:
a) Polymerase chain reaction

b) 1. Denaturation
2. Annealing
3. Extension

Question 12.
Observe the diagram and answer A and B.

Answer:
a) Pro-insulin
b) Mature insulin

Question 13.
a) Define transgenic animals.
b) Write any two uses of transgenic animals.
Answer:
a) Animals that possess manipulated gene (genetically modified) and express foreign gene are called as transgenic animals.
b) Transgenic animals are used in the field of

1. Biological products
2. Study of disease and
3. Normal physiology and development

Question 14.
Humification and Mineralisation occur during decomposition in the soil. Write the difference between these two processes.
Answer:
Humification
It is process by which simplified detritus is changed into dark coloured amorphous substance called humus. It is the reservoir of nutrients.

Minerilisation
It invoves the release of inorganic subtances (Water, CO₂, etc.) and other nutrients (NH₂⁺, Ca⁺⁺, Mg⁺⁺, K₊, etc.) in the soil.

Question 15.
a) Construct a grazing food chain using the following organisms: Bird, Grass, Grasshopper
b) Write the trophic level of grasshopper.
Answer:
a) Grass → GrasshopperBird
b) Second trophic level or primary consumer

Question 16.
Why is CNG better than diesel or petrol?
Answer:

1. CNG is better than diesel.
2. It burns most efficiently.
3. CNG is cheaper than petrol or diesel.
4. It cannot be adulterated like petrol or diesel.

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

Question 17.
Briefly describe the adaptations of desert plants.
Answer:

1. Thick cuticle on their leaf surfaces .
2. Stomata arranged in deep pits to minimise water loss.
3. They show CAM pathway (they open stomata during night and closed during daytime).
4. Leaves are reduced to spines and the flattened stems do photosynthesis.

Question 18.
Density of a population fluctuates due to changes in four basic processes.
a) Complete the diagram by adding the points ABC and D.
b) Explain A and D.

Answer:
a)

1. Natality
2. Mortality
3. Immigration
4. Emigration

b) A-lmmigration-Movement of individuals into the population.
D-Emigration- Movement of individuals out of the population.

Question 19.
Air pollution is a serious environmental issue. Give three harmful effects of air pollution.
Mention the out-breeding devices in plants to prevent self pollination, (any 3 points).
Answer:

1. Reduce the growth and yield of crops.
2. It cause premature death of plants.
3. Affect respiratory system of animals and humans!

Question 20.
Mention the out-breeding devices in plants to prevent self pollination. (any 3 points)
Answer:

1. Pollen release and stigma receptivity are not at the same time.
2. Anther and stigma are placed at different positions.
3. Self-incompatibility.
4. Production of unisexual flowers

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

Kerala Plus Two Botany Board Model Paper 2021 with Answers

Answer the following questions from 1 to 31 upto a maximum score of 30.
1. Questions 1 to 7 carry 1 score each.

Question 1.
Which among the following is a vegetative propagule?
(a) Rhizome
(b) Gemmules
(c) Zoospores
(d) Conidia
Answer:
Rhizome

Fill in the blank :
Question 2.
The protective wall layer of fruit is known as ____.
Answer:
Pericarp

Question 3.
Fruit which develop from any part of the flower other than ovary is called ____.
Answer:
False fruit

Question 4.
Name any two products obtained through Beekeeping.
Answer:
Honey and bee wax

Question 5.
Fill in the blank:
The restriction enzyme EcoRI isolated from the bac-terium _____.
Answer:
Escherichia coli RY 13

Question 6.
In recombinant DNAtechnology, DNAfragments are joined by the help of the enzyme.
(a) DNA ligase
(b) DNA polymerase
(c) Restriction enzyme
(d) Taq polymerase
Answer:
DNA ligase

Question 7.
Select the non-parasitic organism from the list given below:
(a) Lice
(b) Cuscuta
(c) Epiphytic orchid.
(d) Ticks
Answer:
Epiphytic orchid

II. Questions 8 to 26 carry 2 scores each.

Question 8.
In some organisms, female gamete undergoes de-velopment to form new organisms without fertiliza-tion. Name the phenomenon. Give an example.
Answer:
Parthenogenesis
eg. Honeybee and rotifers

Question 9.
Chromosome number in meiocytes and gametes of some organisms are given in the table. Fill in the blanks.

Name of organism	Chromosome number in meiocytes	Chromosome number in qametes
a. Rice	–	12
b. Onion	–	8
c. Apple	34	–
d. Maize	20	–

Answer:

Name of organism	Chromosome number in meiocytes	Chromosome number in qametes
a. Rice	24	12
b. Onion	16	8
c. Apple	34	17
d. Maize	20	10

Question 10.
There are two types of cyclic events that happens in the reproductive phase of female organismsamong placental mammals. Which are the cyclic events and give one example for each.
Answer:
Menstrual cycle-Primates eg. monkeys, apes Oesrous cycle – Non primates eg. cow, sheep

Question 11.
The outer layer of pollengrains is made up of’ sporopollenin. What is the importance of sporopollenin?
Answer:
It is one of the most resistant organic material which can withstand high temperature strong acid and al-kali. So the pollen grains are well preserved as fos-sils.

Question 12.
Differentiate between Autogamy and Xenogamy.
Answer:
Atutogamy: It is the transfer of pollen grains from the anther to the stigma of the same flower.
Xenogamy: Transfer of pollen grains from anther to the stigma of a different plant. This type of pollina-tion occurs between genetically different species.

Question 13.
If the female parent produces bisexual flowers, emas-culation is necessary in artificial hybridization.
(a) What is emasculation?
(b) Write down the importance of emasculation.
Answer:
(a) Anthers are removed before the dehiscence of bisexual flowers.

(b) It is helpful to avoid self pollination and fertilisation.

Question 14.
Fusion of polar nuclei with male gamete in double fertilisation result in formation of endosperm.
(a) Write down the function of endosperm.
(b) Write briefly about the endosperm development in coconut.
Answer:
(a) It gives nutrition to the developing embryo.

(b) PEN undergo successive nuclear divisions to give rise to free nuclei. This stage of endosperm v development is called free nuclear endosperm. Later cell wall formation occurs and the endosperm becomes cellular.

Question 15.
‘Hisardale’ is a new breed of sheep developed in Punjab.
(a) Identify the method by which the breed is devel-oped.
(b) Name the parental breeds of’Hisardale’.
Answer:
(a) Crossbreeding
(b) Bikaneriewes and Marino rams

Question 16.
In r-DNA technology, amplification of gene is done by a process called PCR.
(a) Expand PCR
(b) What are the three main steps involved in PCR?
Answer:
(a) Polymerase chain reaction
(b) Denaturation, Annealing and extension.

Question 17.
Observe the picture given below:
(a) Identify the instrument in the figure.
(b) Write any one use of this instrument.

Answer:
(a) Bioreactor

(b) It is the large culture vesel for large Scale production of Recombinant protein, enzyme etc.

Question 18.
List any two uses of GMO (Genétically Modified Or ganism) in agriculture.
Answer:
(i) Made crops more tolerant to abiotic stresses (cold, drought, salt, heat).
(ii) Reduced reliance on chemical pesticides (pest-resistant crops).

Question 19.
Expand GEAC. Mention its function.
Answer:
GEAC-Genetic Engineering Approval Committee. They take decisions regarding the validity of GM research and the safety of introducing GM organisms for public services.

Question 20.
Comment on Brood Parasitism with an example.
Answer:
In Brood parasitism parasitic bird lays its eggs in the nest of its host and the host incubate them. The eggs of the parasitic bird resemble the host’s egg in size and colour. So the host bird keep up it in their nest. Example of brood parasitism are cuckoo (koel) and the crow.

Question 21.
The figure shows simplified model of phosphorus cycle. Analyse the figure and fill up the blanks.

Answer:
a) Rock Minerals
(b) Producers

Question 22.
The figure given below indicates a pyramid of energy. Why pyramid of energy is always upright in
position?

Answer:
Pyramid of energy is always upright because when energy flows from a particular tropic level to the next tropic level. Some energy is always lost as heat at each step.

Question 23.
What is ecological succession? Differentiate Hydrarch succession and Xerarch succession?
Answer:
Ecological succession-It is the successive replace- – ment of plant communities in an area over a p eriod of time. Hydrarch – It involves the ecological succession in the newly formed pond or lake. Pioneer communi ty’- Phytoplanktons. Xerarch – It involves the ecological succession on bare rock surfaces. Pioneer community – Lichen.

Question 24.
‘Jhum’ cultivatjon/Slah and bum agriculture is an agricultural practice in north esatern states of India. How this practice enhances deforestation?
Answer:
In slash and burn agriculture, the farmers cut down the trees of the forest and burn the plant remains. The ash is used as a fertiliser and theland is then used for farming or cattle grazing. After cultivation, the area is left for several years so as to allow its recovery. The farmers then move on to other areas and repeat this process.

Question 25.
Write any four measures for controlling Global Warming.
Answer:

1. Cutting down use of fossil fuel.
2. Improving efficiency of energy usage.
3. Preventing deforestation and planting trees.
4. Slowing down the growth

Question 26.
In 1980 Government of India introduced a management programme, JFM.
(a) Expand JFM
(b) What is its significance?
Answer:
(a) Joint Forest Managment(JFM)

(b) This is helpful to local communities for getting
benefit of various forest products for the return of services and thus the forest can be conserved in a sustainable manner.

III. Questions 27 to 31 carey 3 scores each.

Question 27.
Pollination is the transfer of pollengrams from anther to stigma of pistil. Write any three adaptations seen in wind pollinated plants.
Answer:

1. Pollen grains are light and no-sticky.
2. Flowers have a single ovule in each ovary.
3. They possess well-exposed stamens and feathery stigma.

Question 28.
Different steps of plant breeding is given below;
(1) Testing, release and commercialization of new cultivais.
(2) Cross hybridization among the selected parents.
(3) Evaluation and selection of parents.
(4) Collection of variability
(5) Selection and testing of superior recombinants.
Create a flow chart of plant breeding from the above steps in sequential manner.

Answer:
(a) Evaluation and selection of parents.
(b) Cross hybridization among the selected parents.
(c) Selection and testing of superior recombinants.

Question 29.
Given diagram shows a technique used in r-DNA technology.

(a) Identify the process
(b) What is the purpose of this technique in r-DNA technokgy?
(c) Name the stain used in this technique for visualizing DNA under UV-light.
Answer:
(a) Gel electrophoresis
(b) In this cut fragments of DNA are separated.
(c) Ethidium bromide

Question 30.
Bt-cotton is a transgenic plant
(a) What does ‘Bt’ stands for?
(b) Explain the mechanism of insect resistance in Bt-cotton
Answer:
(a) Bacillus thuringiensis
(b) Bt toxin protein exist as inactive protoxins but it is converted into an active of form in the presence of the alkaline pH of insect gut. The activated toxin binds to the surface of midgut epithelial cells and create pores that cause cell swelling and lysis atid results in the death of insect.

Question 31.
Opuntia is a plant well adapted to desert conditions. Write down the various adaptation found in desert
plants.
Answer:
Desert plants have a thick cuticle on their leaf surfaces and stomata arranged in deep pits to minimise water loss through transpiration. They also have CAM pathway in which they open stomata during night and closed during time.

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

Kerala Plus Two Botany Board Model Paper Model 2022 with Answers

Part – I

A. Answer any 3 questions from 1 to 4. Each carries 1 score. (3 × 1 = 3)

Question 1.
Observe the relationship of the first pair and fill in the blank.
Restriction enzyme: Cutting of DNA
_______ : Joining of DNA fragments.
Answer:
DNA Ligase

Question 2.
Choose the correct answer and fill up the blank. The single cotyledon of monocotyledons are called
(plumule, radicle, scutellum, coleorrhiza)
Answer:
Scutellum

Question 3.
Name the association between fungi and roots of higher plants.
Answer:
Mycorrhiza

Question 4.
Which among the following equation is related with net primary productivity?
(a) GPP + R = NPP
(b) NPP-R = GPP
(c) GPP + NPP = R
(d) GPP-R = NPP
Answer:
GPP – R = NPP

B. Answer all questions from 5 to 6. Each carries 1 score. (2 × 1 = 2)

Question 5.
Fill in the blank.
Animals that have their DNA altered and express a foreign gene are known as ____.
Answer:
Transgenic animals

Question 6.
Choose the correct answer.
The protective, outer thick wall of the fruits in angiosperms. (Perisperm, Endosperm, pericarp, Integument)
Answer:
Pericarp

Part – II

Answer any two questions from 7 to 9. Each carries 2 scores. (2 × 2 = 4)

Question 7.
Observe the given diagram showing the process of maturation of insulin.

(a) Explain the structure of Proinsulin.
(b) What are the change that occur in Proinsulin when it becomes mature insulin?
Answer:
(a) Proinsulin composed of polypeptide chains A and B are connected with an extra stretch-called the C peptide.
(b) C peptide is removed during maturation.

Question 8.
Match the following:

Asexual Reproductive Structures	Organisms
(a) Zoospores	Hydra
(b) Buds	Penicillium
(c) Conidia	Sponges
(d) Gemmules	Chlamydomonas

Answer:

Asexual Reproductive Structures	Organisms
(a) Zoospores	Chlamydomonas
(b) Buds	Hydra
(c) Conidia	Penicillium
(d) Gemmules	Sponges

Question 9.
MOET is an advanced animal breeding technique for herd improvement. Expand MOET. Which hormone is used for superovulation?
Answer:
Multiple Ovulation Embryo Transfer Technology. FSH (Follicle stimulating hormone)

B. Answer any two questions from 10 to 13. Each carries 2 scores. (2 × 2 = 4)

Question 10.
Distinguish euryhaline and stenohaline organisms.
Answer:
Euryhaline organisms :- They can tolerate wide range of salinity.
Stenohaline organisms :- They can tolerate narrow range of salinity.

Question 11.
In many plants more than one embryo is seen in one seed. Name the phenomenon with an example,
Answer:
Polyembryony : Example Seeds of orange or citrus

Question 12.
Write any two points that are important for successful poultry farm management.
Answer:

• Selection of good breeds
• Provide proper food & water

Question 13.
Given below are the different stages of hydrarch succession. Forest, marshmeadow, phytoplankton, Reed swamp, submerged free floating stage, scrub, submerged plant stage. Write down the pioneer species and climax community. Arrange the stages in correct sequential order.
Answer:
Pioneer species – Phytoplankton.
Climax community – Forest.
Phytoplankton → Submerged plant stage → Submerged freefloating plant stage → Reed → swamp → Marsh- Meadow → Scrub → Forest stage.

Part – III

Answer any three questions from 14to 17. Each carries 2 scores. (3 × 3 = 9)

Question 14.
The equation of population density is given below.N_t+1 = N_t + [(BB + I) – (D + E)]
(a) What does D and E stand for?
(b) Write two factors which increase the population density.
Answer:
(a) D – Mortality
E – Emigration

(b) Natality & Immigration

Question 15.
Increase in the level of green house gases lead to overheating of earths atmosphere.
(a) Name the phenomenon.
(b) State any two consequences of this phenomenon.
Answer:
(a) Global warming
(b) Affects weather & climate ( El Nino effect), Melting of polar ice caps & Himalayan snow caps that leads to rise in sea level.

Question 16.
Observe the given ecological pyramid in an aquatic ecosystem.

Identify the type of pyramid and reason out why the pyramid is inverted.
Answer:
Pyramid of biomass Here biomass of primary producers (phytoplanktons) is much less than primary consumers (zooplanktons)

Question 17.
Bt-cotton is an example of genetically engineered plant. Name the gene responsible for Bt-toxin production. Explain how Bt-toxin kill the insect.
Answer:
Cry gene
When an insect ingest the inactive insecticidal protein crystals, it is converted into an active toxin due to the alkaline pH of the gut which solubilise the crystals. The activated toxin binds to the surface of midgut epithelial cells and create pores that cause cell swelling and lysis and eventually leads to death of the insect.

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

Question 18.
Vehicular emission is the major cause of air pollution.
(a) Write four steps taken by Delhi Government for reducing vehicular pollution.
(b) What is CNG?
Answer:
(a)

1. Use of low-sulphur petrol & diesel,
2. Use of catalytic converter
3. Use of CNG & Use of unleaded petrol etc.

(b) Compressed Natural Gas

Part – IV

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

Question 19.
The given diagram depicts the separation of DNA fragments.

(a) Identify the technique.
(b) How can you visualize the separated DNA fragments in this technique?
(c) What is elution?
Answer:
(a) Gel electrophoresis
(b) Separated DNA fragments can be visualised after staining with Ethidium bromide followed by exposure to UV light.
(c) Separated bands of DNA are cut out from the agarose gel and extracted from gel piece.

Question 20.
Given below is the diagram of a mature embryosac in angiosperm.

Label the parts a,b, c and d.
What is double fertilization? Mention the ploidy of zygote and PEN.
Answer:
a – Synergids
b – Secondary nucleus or Polar nuclei
c – Antipodals
d – Filiform apparatus

Two types of fusion like syngamy and triple fusion are together known as Double fertilization Zygote – Diploid (2n), PEN – Triploid (3n)