Kerala Plus One Botany Board Model Paper 2020 with Answers

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

Kerala Plus One Botany Board Model Paper 2020 with Answers

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

Question 1.
Which among the following produce biogas from the dung of ruminant animals?
a) Thermiacidophiles
b) Cyanobacteria
c) Methanogens
d) Halophiles
Answer:
c) Methanogens

Question 2.
The stage between Meiosis I and Meiosis II is called
a) Diakinesis
b) Interkinesis
c) Pachytene
d) Diplotene
Answer:
b) Interkinesis

Question 3.
Choose the only growth inhibiting plant hormone among the following options:
a) ABA
b) NAA
c) IAA
d) 2,4-D
Answer:
a) ABA

Question 4.
The process of conversion of molecular nitrogen to ammonia is termed as _____.
Answer:
Nitrogen Fixation

Question 5.
Observe the relation, and fill up the blank Trypanosoma: Flagellated Protozoan : Ciliated protozoan
Answer:
Paramecium

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

Question 6.
Write any two economic uses of bryophytes.
Answer:
1) They Provide food for herbaceous mammals, birds and other animals
2) Peat moss(spagnum) is used as fuel and Packing material for trans-shipment of living materials

Question 7.
Observe the diagram and label the parts noted as A, B, C and D.

Answer:
A) Region of Maturation
B) Region of Elongation
C) Region of meristematic activity
D) Root cap’

Question 8.
What is the role of fungus in mycorrhiza?
Answer:
1) Fungal hyphae have large surface area, so it helps to absorb mineral ions and water from soil.
2) Pinus seeds cannot germinate and establish without the presence of micorrhizae.

Question 9.
Column A represents chromosomal behaviour during different sub-stages of Propose I of Meiosis I. Fill up the blanks in Column B.

Chromosomal behaviour (A)	Sub-stages (B)
a) Crossing over occurs	i)
b) Formation of Chiasmata	ii)
c) Pairing of homologous chromosomes	iii)
d) Chromosoems visible under light microscope	iv) Leptotene
e) Terminalisation of Chiasmata	v)

Answer:

Chromosomal behaviour (A)	Sub-stages (B)
a) Crossing over occurs	i) Pachytene
b) Formation of Chiasmata	ii) Diplotene
c) Pairing of homologous chromosomes	iii) Zygotene
d) Chromosoems visible under light microscope	iv) Leptotene
e) Terminalisation of Chiasmata	v) Diakinesis

Question 10.
The behaviour of plant cells with regard to water movement depends on the surrounding solution. Explain the changes occur in cells A and B.

Answer:
A) In hypotonic solution water diffuses into the cell causing the cytoplasm to build up turgor pressure against the cell wall and Cell become turgid

B) In hypertonic solution water moves out of the cell and protoplast withdraws from cell wall and shrinks. Due to this the Cell become Plasmolysed.

Question 11.
Plants that are adapted to dry tropical regions have the C4 pathway. Write any two advantages of C4 plants :
Answer:
1) They lacks Photorespiration
2) Photosynthetic yield or Productivity is high

Question 12.
Differentiate lactic acid fermentation from alcohol fermentation.
Answer:

Lactic acid fermentation	Alcohol fermentation.
The product is Lactic acid	The products are Ethanol and CO2
Lactate dehydrogenase is the enzyme involved	Pyruvic acid decarboxylase and alcohol dehydrogenase are the enzymes involved

Question 13.
Ethylene is one of the most widely used Plant Growth Regulator in Agriculture. Write any two agricultural applications of ethylene.
Answer:

1. Ethylene is a gaseous hormone promotes senescence and ripening of fruits.
2. It promotes horizontal growth of seedlings, swelling of the axis and apical hook formation in dicot seedlings

Question 14.
In glycolysis, ATP is utilized at two steps only. Write down these two steps.
Answer:

1. Glucose → Glucose 6 phosphate
2. Fructose 6 phosphate  → Fructose 1,6 biphosphate

Question 15.
Define, “The law of limiting factors”. Write any two external factors which directly affect the rate of photosynthesis.
Answer:
Blackman’s Law of Limiting Factors If a chemical process is affected by more than one factor, then its rate will be determined by the factor which is nearest to its minimal value

1. Light
2. Temperature

Question 16.
What is the difference between nitrification and denitrification in Nitrogen cycle?
Answer:
Nitrification is the formation of Nitrates from Ammonia by Nitrosomonas and Nitrobacter.
Denitrification is conversion of Nitrate in the soil to Nitrogen by Pseudomonas and Thiobacillus.

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

Question 17.
C₄ plants have large cells around the vascular bundles of leaves called bundle sheath cells.
a) What is this anatomy called?
b) Write any two features of bundle sheath cells.
Answer:
a) Kranz anatomy
b) They are Large cells
They are arranged in several layers around vascular tissue

Question 18.
A and B are floral diagrams of two angiosperm families.
Answer:
a) A)Solanaceae
B) Liliaceae

b) A) Ovary is bicarpellary, syncarpous, superior, bilocular with axile placentation.
B) Ovary is tricarpellary, Syncarpous, Superior with axile placentation.

Question 19.
Following are the diagrams showing primary structure of dicot stem (A) and monocot stem (B). Write any three differences between them.

Answer:

A) Dicot Stem	B) Monocot Stem
Ground tissue is differentiated into cortex, endodermis, pericycle and pith	Undifferentiated Ground tissue
Collenchymatous hypodermis	Sclerenchymatous hypodermis
Vascular bundle is conjoint, open and endarch	Vascular bundles are conjoint and closed

Question 20.
Given below is the diagram of a cell organelle.
a) Identify the organelle.
b) Write any two functions of this organelle.

Answer:
a) Golgi apparatus

b) It helps in the Packaging of materials.
It is the site of synthesis of Glycoproteins and Glycolipids