Category: Class 11 Biology Objective Questions

Zoology Interview Questions and Answers on “Animals Structural Organisations – Earthworm – 2”.

1. The body wall of the earthworm is externally covered by ______
a) mucous
b) capsule
c) epidermis
d) cuticle
Answer: d
Clarification: The body wall of the earthworm is externally covered by the cuticle. It is thin and non-cellular. The epidermis lies below the cuticle. It also contains two layers of muscles and an inner coelomic epithelium.

2. The epidermis of earthworm is made of ______
a) squamous epithelial cells
b) cuboidal epithelial cells
c) columnar epithelial cells
d) multi-layered squamous epithelial cells
Answer: c
Clarification: The epidermis is made of columnar epithelial cells. They are present in a single layer. The epidermis lies below the cuticle. There are two layers of muscles present below the epidermis. Human skin is made of squamous epithelium.

3. The buccal cavity of the earthworm leads to the _____
a) gizzard
b) esophagus
c) pharynx
d) anus
Answer: c
Clarification: The buccal cavity is present from the 1^st to 3^rd segment. It is the mouth part of the body of the earthworm. The buccal cavity opens up into the pharynx. The pharynx is made of muscular tissue.

4. Identify the correct pathway of food ingested by an earthworm.
a) Mouth→Pharynx→Esophagus→Gizzard
b) Mouth→Esophagus→Pharynx→Gizzard
c) Mouth→Esophagus→Gizzard→Pharynx
d) Mouth→Pharynx→Gizzard→Esophagus
Answer: a
Clarification: Food is ingested by the earthworm through the mouth. The mouth part opens up into the muscular pharynx. This is followed by a narrow esophagus followed by the gizzard where food is broken down by the process of grinding.

5. What is the function of gizzard in earthworm?
a) Secretion of digestive enzymes
b) Grinding soil particles and leaves
c) Absorption of water
d) It is a respiratory structure
Answer: b
Clarification: The gizzard has the principal role of grinding soil particles and decaying leaves. It does not secrete digestive enzymes nor does it play a role in water absorption. It is not a respiratory structure and only helps in the mechanical breakdown of food.

6. Where are the calciferous glands of the earthworm present?
a) Esophagus
b) Gizzard
c) Stomach
d) Intestine
Answer: c
Clarification: The calciferous glands of the earthworm are present in the stomach. The food of the earthworm contains soil particles and humus. The calciferous glands neutralize the humic acid which is present in the humus.

7. Which segments of the earthworm contain the stomach?
a) 9^th to 14^th
b) 23^rd to 25^th
c) 16^th to 18^th
d) 5^th to 8^th
Answer: a
Clarification: The stomach of the earthworm extends from the 9^th to 14^th segments. It is present after the gizzard, where the ingested food is mechanically grinded before being passed through to the stomach.

8. Which segment of the earthworm contains the intestinal caecum?
a) 25^th
b) 23^rd
c) 24^th
d) 26^th
Answer: d
Clarification: The 26^th segment of the body of the earthworm contains intestinal caeca. It projects out from the wall of the intestine. The intestine of the earthworm starts at the 15^th segment and continues till the last segment.

9. What is the function of typhlosole in earthworm?
a) Mechanical breakdown of food
b) Secretes digestive enzymes
c) Increases the surface area for absorption
d) Excretes waste products
Answer: c
Clarification: Typhlosole is present in the intestine after the 26^th segment. It arises from the median fold of the dorsal wall. It increases the surface area of absorption of nutrients from the digested food material.

10. Open blood vascular system is present in Pheretima.
a) True
b) False
Answer: b
Clarification: Pheretima has a closed blood vascular system. This implies that its blood is confined to the components of the vascular system only. The components of this vascular system are heart, blood vessels and capillaries. In closed type of vascular system, the circulating blood travels in one direction only.

11. Which segments of the earthworm contain the blood glands?
a) 9^th to 12^th
b) 16^th to 18^th
c) 23^rd to 25^th
d) 4^th to 6^th
Answer: d
Clarification: The 4^th, 5^th and 6^th segments of the body of the earthworm contain the blood glands. The function of these glands is to produce blood cells and hemoglobin. These components of blood are dissolved in the blood plasma.

12. Respiratory exchange in earthworms takes place through ______
a) gills
b) mouth
c) body surface
d) lungs
Answer: c
Clarification: Respiratory exchange in earthworms takes place via the body surface. Since earthworm is an annelid, it lacks gills and lungs. The mouth of the earthworm is responsible for uptake of food only.

13. What is the excretory organ in earthworm known as?
a) Gizzard
b) Typhlosole
c) Nephridium
d) Setae
Answer: c
Clarification: Nephridium is the excretory organ in earthworm. Nephridia occur as coiled tubules arranged segmentally. Typhlosole and gizzard are involved in digestion of food while setae help in locomotion.

14. Which of the following is not a type of nephridia present in earthworm?
a) Intestinal
b) Septal
c) Integumentary
d) Pharyngeal
Answer: a
Clarification: The nephridia in earthworm are of three types – septal nephridia, integumentary nephridia and pharyngeal nephridia. All three types are similar in structure. Intestinal nephridia is not present.

15. Which of the following is not true about nephridia in earthworm?
a) They are excretory organs
b) They do not regulate the composition of body fluids
c) They are of three types
d) They regulate the volume of body fluids
Answer: b
Clarification: Nephridia regulate both the volume as well as the composition of body fluids. They are the excretory organs of the earthworm. They are of three types – septal, integumentary and pharyngeal.

To practice Zoology Interview Questions and Answers,

Biology Problems for Class 11 on “Eukaryotic Cells and it’s Organelles – 4”.

1. Which of these organelles possess a single circular DNA molecule?
a) Golgi apparatus
b) Peroxisome
c) Lysosome
d) Mitochondria
Answer: d
Clarification: Apart from the genomic DNA present inside the nucleus, the mitochondria possesses its own genetic material in the form of a single circular DNA molecule. This DNA codes for some mitochondrial proteins.

2. Where is 70S ribosome found in the animal cell?
a) Inside the nucleus
b) Surface of rough endoplasmic reticulum
c) Inside mitochondria
d) In the cytoplasm
Answer: c
Clarification: Apart from the genomic DNA present inside the nucleus, the mitochondria possesses its own genetic material in the form of a single circular DNA molecule. It also possesses 70S (prokaryotic) ribosomes.

3. Which of these plastids store proteins?
a) Amyloplasts
b) Elaioplasts
c) Aleuroplasts
d) Chromoplasts
Answer: c
Clarification: Chromoplasts impart colours to the different cells of a plant such as yellow colour of a flower or a fruit. Elaioplasts store oils and fats, amyloplasts store starch and aleuroplasts store proteins.

4. How many chloroplasts are present in each cell of Chlamydomonas?
a) 1
b) 2
c) 3
d) 4
Answer: a
Clarification: Chloroplasts are plastids containing the green pigment chlorophyll, which is necessary to trap sunlight to carry out the process of photosynthesis. Chlamydomonas has only one chloroplast per cell.

5. Identify the part of the chloroplast.

a) Inner membrane
b) Thylakoid
c) Stroma
d) Lamella
Answer: b
Clarification: Chloroplasts are plastids which contain the green pigment chlorophyll. The structure of the chloroplast shown in the diagram is the thylakoid, which is present on the stroma, stacked on top of each other.

6. Which structure of the chloroplast contains enzymes required for the synthesis of carbohydrates?
a) Lamellae
b) Grana
c) Stroma
d) Inner membrane
Answer: c
Clarification: Chloroplasts are plastids which contain the green pigment chlorophyll. The stroma is the ground substance of the chloroplast. It contains enzymes which are required for the synthesis of carbohydrates and proteins.

7. Which of these statements is not true about ribosomes?
a) They are bound by a single membrane
b) They are composed of RNA and proteins
c) They were first observed by George Palade
d) The small subunit of the prokaryotic ribosome is 30S
Answer: a
Clarification: Ribosomes are not bound by a membrane. They are made of RNA and proteins. Ribosomes were first observed by George Palade. The small subunit of the prokaryotic ribosome is 30S.

8. The eukaryotic ribosome is 80S. what does this ‘S’ denote?
a) Supernatant coefficient
b) Segregation coefficient
c) Solidification coefficient
d) Sedimentation coefficient
Answer: d
Clarification: The ‘S’ in 80S ribosome, or Svedberg’s Unit, stands for sedimentation coefficient. The sedimentation coefficient (S) of a particle characterizes the rate of sedimentation during centrifugation.

9. Which of these is not a part of the cytoskeleton?
a) Microtubules
b) Microfilaments
c) Axoneme
d) Intermediate filaments
Answer: c
Clarification: The cytoskeleton is comprised of microtubules, microfilaments and intermediate filaments. It is a network of these filamentous proteins. Axoneme is present in flagella and cilia.

10. Cytoskeleton does not provide motility. True or false?
a) True
b) False
Answer: b
Clarification: The cytoskeleton is comprised of microtubules, microfilaments and intermediate filaments. It is a network of these filamentous proteins. The cytoskeleton provides mechanical support and motility.

11. The flagellar core is known as the _____
a) filament
b) hook
c) basal body
d) axoneme
Answer: d
Clarification: which are responsible for the movement of cells. The flagellar core is called the axoneme which has microtubules running parallel to the long axis.

12. How many microtubules does the axoneme contain?
a) 6 + 5
b) 8 + 3
c) 9 + 2
d) 7 + 4
Answer: c
Clarification: Flagella are thin long hair – like growths of the cell membrane. The flagellar core is called the axoneme which has microtubules running parallel to the long axis. It contains 9 + 2 axonemal microtubules.

13. What is the shape of a centriole?
a) Irregular
b) Spherical
c) Cylindrical
d) Cuboidal
Answer: c
Clarification: Centrosome is a cell organelle containing two structures cylindrical in shape, called centrioles. Centrioles lie perpendicular to each other. The centrioles are composed of tubulin protein.

14. Which protein is the centriole made of?
a) Tubulin
b) Actin
c) Myosin
d) Keratin
Answer: a
Clarification: Centrosome is a cell organelle containing two structures cylindrical in shape, called centrioles. Centrioles lie perpendicular to each other. The centrioles are composed of tubulin protein.

15. What forms the basal body of flagella?
a) Axoneme
b) Centrioles
c) Keratin
d) Calcium carbonate
Answer: b
Clarification: Centrosome is a cell organelle containing two structures cylindrical in shape, called centrioles. Centrioles lie perpendicular to each other. They also form the basal body of cilia and flagella.

To practice Biology Problems for Class 11,

Biology Multiple Choice Questions on “Biomolecules – Structure of Proteins-1”.

1. Proteins are heteropolymers of ______
a) lipids
b) monosaccharides
c) peptides
d) amino acids
Answer: d
Clarification: Proteins are heteropolymers made of amino acid monomers. There are 21 amino acids. Various numbers and combinations of amino acids in a sequence or chain forms different types of proteins.

2. Structure of molecules in inorganic chemistry refers to the ______
a) three-dimensional structure
b) two-dimensional structure
c) molecular formula
d) primary structure
Answer: c
Clarification: Structure of molecules in inorganic chemistry refers to the molecular formula of the compound. In organic chemistry it refers to the two-dimensional structure while in physics it refers to the three-dimensional structure.

3. Structure of molecules in physics refers to the ______
a) primary structure
b) two-dimensional structure
c) three-dimensional structure
d) molecular formula
Answer: c
Clarification: In physics, the structure of molecules refers to the three-dimensional structure of the molecule. In inorganic chemistry it refers to the molecular formula of the compound. In organic chemistry it refers to the two-dimensional structure.

4. How many levels of organization do proteins have?
a) 4
b) 3
c) 2
d) 5
Answer: a
Clarification: There are four levels of structural organization of proteins. These are the primary structure, secondary structure, tertiary structure and the quaternary structure. The level affects the function of the protein.

5. What is the configuration of proteins in the primary structure?
a) Helix
b) Line
c) Sheet
d) Globule
Answer: b
Clarification: In the primary structure of proteins, the proteins are imagined to be arranged in a linear fashion such as a line. Helix and sheets are the configuration of proteins for the secondary structure.

6. What makes up the primary structure of proteins?
a) Peptides
b) Peptones
c) Amino acids
d) Polypeptides
Answer: c
Clarification: The primary structure of amino acids is made of monomers of amino acids. The amino acids are linked together by peptide bonds between the amino group of one amino acid and the carboxyl group of the adjacent one.

7. What is the left end of the primary structure of proteins represented by?
a) First amino acid
b) Last amino acid
c) Cofactor
d) Methyl group
Answer: a
Clarification: The primary structure of amino acids is made of monomers of amino acids. Hence, cofactors are absent. The left end of the primary or linear structure of proteins is represented by the first amino acid.

8. What is the right end of the primary structure of proteins represented by?
a) Methyl group
b) Cofactor
c) First amino acid
d) Last amino acid
Answer: d
Clarification: The primary structure of amino acids is made of monomers of amino acids. Hence, cofactors are absent. The right end of the primary or linear structure of proteins is represented by the last amino acid.

9. What is the first amino acid of the primary structure known as?
a) A-terminal amino acid
b) C-terminal amino acid
c) N-terminal amino acid
d) L-terminal amino acid
Answer: c
Clarification: The left end of the primary or linear structure of proteins is represented by the first amino acid. The left end of the first amino acid contains the amino group and is hence called the N-terminal.

10. A protein thread exists as an extended rigid rod. True or false?
a) True
b) False
Answer: b
Clarification: It is false as a protein thread cannot exist as an extended rigid rod conformation. It undergoes folding in the form of helices or sheets with the help of various interactions. This represents the secondary structure.

11. What is the last amino acid of the primary structure known as?
a) N-terminal amino acid
b) L-terminal amino acid
c) S-terminal amino acid
d) C-terminal amino acid
Answer: d
Clarification: The right end of the primary or linear structure of proteins is represented by the last amino acid. The right end of the first amino acid contains the carboxyl group and is hence called the C-terminal.

12. Identify the labeled portion of the peptide.

a) N-terminal amino acid
b) C-terminal amino acid
c) L-terminal amino acid
d) S-terminal amino acid
Answer: a
Clarification: The diagram represents a primary structure or linear structure. The amino acid on the left represents the first amino acid. The left end of the first amino acid contains the amino group and is hence called the N-terminal.

13. Identify the labeled portion of the peptide.

a) I-terminal amino acid
b) N-terminal amino acid
c) C-terminal amino acid
d) L-terminal amino acid
Answer: c
Clarification: The diagram represents a primary structure or linear structure. The amino acid on the right represents the last amino acid. The right end of the last amino acid contains the carboxyl group and is hence called the C-terminal.

14. Which of these bonds is present in the primary structure of protein?
a) Peptide bond
b) Glycosidic bond
c) Hydrogen bond
d) Disulfide bonds
Answer: a
Clarification: The primary structure of amino acids is made of monomers of amino acids. The amino acids are linked together by peptide bonds between the amino group of one amino acid and the carboxyl group of the adjacent one.

15. Which of these is a type of secondary structure of proteins?
a) Line
b) Sheet
c) Globule
d) Spherical
Answer: b
Clarification: The secondary structure of proteins is formed by the folding of the primary or linear structure. The linear chain of amino acids may be folded into a helix or a sheet. These are the secondary structures.

Biology Multiple Choice Questions on “Transpiration”.

1. Isobilateral leaf has equal number of stomata on both surfaces of the leaf.
a) True
b) False
Answer: a
Clarification: Isobilateral leaf is found in monocotyledonous plants and it contains equal number of stomata on both sides of the leaf. Dorsiventral leaf is found in dicotyledonous plants and it has been more stomata on the lower surface of the leaf.

2. Which of the following is not a function of stomata?
a) Regulation of turgidity of guard cells
b) Loss of water vapor
c) Loss due to guttation
d) Exchange of O₂ and CO₂
Answer: c
Clarification: Loss due to guttation is not a function of stomata. Regulation of entry and exit of water into the guard cells, loss of water by transpiration and exchange of O₂ and CO₂ are among the major functions of the stomata.

3. Statement A: C3 plants are twice efficient as C4 plants in terms of fixing carbon dioxide.
Statement B: C4 plant loses twice the amount of water as C3 plant for same amount of CO₂ fixed.
a) Both the statements are true
b) Both the statements are false
c) Statement A is true but Statement B is false
d) Statement B is true but Statement A is false
Answer: b
Clarification: C4 plants are twice efficient than C3 plants in terms of fixing CO₂. C4 plants lose half the amount of water than C3 plants for same amount of CO₂ fixed. C4 plants have properties to maximize the availability of CO₂.

4. In the figure given below, guard cells are shown by?

a) By region of color
b) By region of color
c) By region of color
d) By region of color
Answer: b
Clarification: A: Epidermal cell
B: Guard cell
C: Stomatal aperture
D: Cell wall.

5. Which among the following is an external factor affecting transpiration?
a) Light
b) Number of stomata
c) Canopy structure
d) Water status of plant
Answer: a
Clarification: Light and temperature are among the most important factors affecting transpiration externally. Number of stomata, canopy structure and water status of plant are internal factors regulating transpiration.

6. Which among the following is an internal factor affecting transpiration?
a) Temperature
b) Humidity
c) % open stomata
d) Wind speed
Answer: c
Clarification: % open stoma is an important determinant of the loss due to transpiration. If less number of stomata is open, less transpirative loss will occur. Temperature, humidity and wind speed affect transpiration externally.

7. Transpirative loss is studied through girdling experiment.
a) True
b) False
Answer: b
Clarification: Transpirative loss is studied through cobalt chloride test. The color changes when water is absorbed. Girdling experiment is used to test that phloem tissue is responsible for translocation of food. When a ring of bark is removed up to the depth of the phloem layer and in the absence of downward movement of food, the portion of the bark above the ring of the stem is swollen after a few weeks.

8. The small diameter of the tracheary elements increases ___________
a) adhesion
b) cohesion
c) tensile strength
d) capillarity
Answer: d
Clarification: In plants, capillarity is aided by the small diameter of the xylem elements, i.e., the tracheids and vessel elements. Capillarity is the ability to rise in thin tubes. Cohesion is mutual attraction between molecules of H2O. Adhesion is attraction of water molecules to the surfaces of tracheary elements. Tensile strength is ability to resist a pulling force. Adhesion, cohesion and tensile strength are properties of xylem which enables the ascent of xylem sap.

9. Statement A: Inner wall is pushed outwards
Statement B: Outer wall is pulled outwards
a) Both the statements are true
b) Both the statements are false
c) Statement A is true but Statement B is false
d) Statement B is true but Statement A is false
Answer: d
Clarification: Thin outer wall bulges out due to change in turgidity of guard cells during the shift from night to day. This leads to thick inner wall being pulled outside by the outer wall, thereby forming crescent shape.

10. Statement A: Transpiration creates pressure in xylem sufficient enough to transport water up to 130 m high.
Statement B: Transpiration creates a pushing force.
a) Both the statements are true
b) Both the statements are false
c) Statement A is true but Statement B is false
d) Statement B is true but Statement A is false
Answer: c
Clarification: Transpiration is the loss of water in the gaseous phase from the leaves. It is a necessary evil. It might be a major cause of loss of water but it is the driving force for ascent of xylem sap, therefore, conduction of water and minerals. It creates pressure in xylem which can allow water conduction up to 130m height. Transpiration is a pulling force while root pressure is a pushing force.

Botany Aptitude Test on “Higher Plants Photosynthesis – ATP and NADPH-2”.

1. Which of these is not a stage of the Calvin cycle?
a) Carboxylation
b) Reduction
c) Regeneration
d) Oxidation
Answer: d
Clarification: The Calvin cycle is a pathway of light independent reactions of photosynthesis. It depends on the energy carriers ATP and NADPH and hence, Calvin cycle indirectly depends upon light.

2. Which is the most crucial step of the Calvin cycle?
a) Oxidation
b) Reduction
c) Carboxylation
d) Regeneration
Answer: c
Clarification: The Calvin cycle is a pathway of light independent reactions of photosynthesis. The most crucial step of the Calvin cycle is carboxylation, where carbon dioxide is fixated into a stable organic intermediate.

3. Which of these undergoes carboxylation during Calvin cycle?
a) NADPH
b) ATP
c) RuBP
d) PGA
Answer: c
Clarification: The most crucial step of the Calvin cycle is carboxylation, where carbon dioxide is fixated into a stable organic intermediate. This organic intermediate is RuBP or ribulose bisphosphate.

4. Which of these substances catalyse carboxylation?
a) RuBP carboxylase
b) Pyruvate carboxylase
c) Propionyl-CoA carboxylase
d) Acetyl-CoA carboxylase
Answer: a
Clarification: The most crucial step of the Calvin cycle is carboxylation, where carbon dioxide is fixated into a stable organic intermediate, known as ribulose bisphosphate. RuBP carboxylase catalyses carboxylation.

5. What is the product of carboxylation?
a) 2-PGA
b) 3-PGA
c) RuBP
d) Rubisco
Answer: b
Clarification: 3-PGA or 3-phosphoglyceric acid is the product of carboxylation. It is a 3-carbon organic acid. RuBP or ribulose bisphosphate is the primary carbon dioxide acceptor which undergoes carboxylation.

6. How many molecules of PGA are produced on carboxylation?
a) 3
b) 1
c) 2
d) 4
Answer: c
Clarification: 3-PGA or 3-phosphoglyceric acid is the product of carboxylation. It is a 3-carbon organic acid. RuBP or ribulose bisphosphate undergoes carboxylation to produce two molecules of 3-PGA or 3-phosphoglyceric acid.

7. Which of these statements is false about reduction in the Calvin cycle?
a) It is the third step of the cycle
b) It leads to the formation of glucose
c) It utilizes NADPH for reduction
d) It utilizes ATP for phosphorylation
Answer: a
Clarification: Reduction is the second step of the Calvin cycle. It results in the formation of glucose. Reduction utilizes NADPH for reduction and ATP for phosphorylation which results in the production of glucose.

8. How many turns of the Calvin cycle are required for the formation of 3 glucose molecules?
a) 15
b) 16
c) 12
d) 18
Answer: d
Clarification: The formation of one molecule of glucose requires the fixation of 6 carbon dioxide molecules and hence six turns of the Calvin cycle. Hence, 3 glucose molecules will require 18 turns of the cycle.

9. Which of these molecules is regenerated during the Calvin cycle?
a) NADPH
b) ATP
c) RuBP
d) CO₂
Answer: c
Clarification: Regeneration is the third and final step of the Calvin cycle. In this step, the CO₂ acceptor molecule RuBP or ribulose bisphosphate is regenerated. The regenerated RuBP is again used for the next Calvin cycle.

10. Regeneration during the Calvin cycle requires 3 ATP molecules. True or false?
a) True
b) False
Answer: b
Clarification: Regeneration is the third and final step of the Calvin cycle. In this step, the CO₂ acceptor molecule RuBP is regenerated. Regeneration requires 1 ATP molecule for the purpose of phosphorylation.

11. How many molecules of NADPH are required for each Calvin cycle?
a) 3
b) 1
c) 4
d) 2
Answer: d
Clarification: For every carbon dioxide molecule used up in the Calvin cycle, 2 molecules of NADPH are required. Six cycles are required to produce one glucose molecule; hence 12 NADPH molecules are required to produce one molecule of glucose.

12. How many molecules of ATP are required for each Calvin cycle?
a) 1
b) 2
c) 3
d) 4
Answer: c
Clarification: For every carbon dioxide molecule used up in the Calvin cycle, 3 molecules of ATP are required. Six cycles are required to produce one glucose molecule; hence 18 ATP molecules are required to produce one molecule of glucose.

13. How many molecules of NADP are produced as a result of six Calvin cycles?
a) 9
b) 18
c) 12
d) 24
Answer: c
Clarification: For every carbon dioxide molecule used up in the Calvin cycle, 2 molecules of NADPH are required. Hence, 2 molecules of NADP are produced. For six Calvin cycles, 12 molecules of NADP are produced.

14. How many molecules of ADP are produced as a result of six Calvin cycles?
a) 18
b) 24
c) 12
d) 32
Answer: a
Clarification: For every carbon dioxide molecule used up in the Calvin cycle, 3 molecules of ATP are required. Hence, 3 molecules of ADP are produced. For six Calvin cycles, 18 molecules of ADP are produced.

15. How many molecules of carbon dioxide are required in the Calvin cycle to produce 3 molecules of glucose?
a) 9
b) 18
c) 6
d) 15
Answer: b
Clarification: To make one molecule of glucose six molecules of carbon dioxide are required. Hence, six cycles of the Calvin cycle are required. To make three molecules of glucose, 18 molecules of carbon dioxide are required.

To practice Botany Aptitude Test,

Biology Multiple Choice Questions on “Plant Growth and Development – Photoperiodism and Vernalisation”.

1. Which of the crops doesn’t show vernalisation?
a) Wheat
b) Barley
c) Rice
d) Rye
Answer: c
Clarification: Rice doesn’t show vernalisation. Other crops such as Wheat, Barley and rye which are have two varieties: spring and winter require cold treatment to stimulate photoperiodic response of plants.

2. Plants are able to measure the duration of exposure to light.
a) True
b) False
Answer: a
Clarification: Flowering in plants depends upon the period of exposure of light to the plant. Plants are able to measure the duration of sunlight received through leaves. A hypothetical hormone Florigen is said to be responsible for flowering.

3. Statement A: Critical duration is different for different plants.
Statement B: The plants which are dependent on critical duration are called day-neutral plants.
a) Both the statements are true
b) Both the statements are false
c) Statement A is true but Statement B is false
d) Statement B is true but Statement A is false
Answer: c
Clarification: Critical duration is a well-defined period of exposure of plant to light and dark conditions for initiation of flowering in plants. It is different for different plants. Some require exposure less than critical duration such as short day plants. Some plants require exposure more than the critical duration such as long day plants. Also there are plants which are independent of the critical duration. They are called as day-neutral plants.

4. Which of the following plants is a polycarpic plant?
a) Sugarbeet
b) Cabbage
c) Carrots
d) Apple
Answer: d
Clarification: Polycarpic plants are plants that set seeds numerous times before senescence. Apple is a polycarpic plant. Sugarbeet, Cabbage & Carrots are some of the common biennials. Biennials are plants that take 2 seasons to complete their lifecycle.

5. Statement A: Short day plants required more exposure to light than the critical duration.
Statement B: Long day plants required less exposure to light than the critical duration.
a) Both the statements are true
b) Both the statements are false
c) Statement A is true but Statement B is false
d) Statement B is true but Statement A is false
Answer: b
Clarification: A well-defined exposure to light and dark conditions are pre-requisite for initiation of flowering in plants. Short day plants required less exposure to light than the critical duration. Long day plants required greater exposure to light than the critical duration.

6. Statement A: Vernalisation prevents precocious reproductive development.
Statement B: Vernalisation promotes flowering by cold treatment.
a) Both the statements are true
b) Both the statements are false
c) Statement A is true but Statement B is false
d) Statement B is true but Statement A is false
Answer: a
Clarification: Vernalisation is the process which improves qualitative and quantitative flowering in plants by exposure to cold conditions. It has dual functions. It allows the plants to attain full maturity. It also stimulates early flowering of plants by providing the desired conditions.

7. Duration of light period is more important than the duration of dark period.
a) True
b) False
Answer: b
Clarification: Both the durations of light and dark are equally important. The critical duration of the periods is essential for the proper functioning of phytochromes present in the plant.

8. Statement A: Response of plants to low temperature is regulated by a hypothetical hormone.
Statement B: Response of plants to different periods of light is also regulated by a hypothetical hormone.
a) Both the statements are true
b) Both the statements are false
c) Statement A is true but Statement B is false
d) Statement B is true but Statement A is false
Answer: a
Clarification: Vernalisation is the process which improves qualitative and quantitative flowering in plants by exposure to cold conditions. Response of plants to low temperature is regulated by a hypothetical hormone, Vernalin. Photoperiodism is the response of plants to duration of exposure to light and dark conditions. It is also regulated by a hypothetical hormone, Florigen.

9. Which is the site for perception of light/dark duration?
a) Leaves
b) Stem
c) Roots
d) Apical bud
Answer: a
Clarification: Leaves are the site for perception of light/dark duration. Florigen is responsible for flowering. Shoot apices are modified to flowering apices prior to flowering. The hormone further migrates to stem and roots.

10. The hormone responsible for flowering is ________
a) vernalin
b) cytokinin
c) ABA
d) florigen
Answer: d
Clarification: The hypothetical hormone florigen is said to be responsible for flowering in plants. Vernalin is promotes early maturity leading to flowering. ABA is majorly an inhibitor and functions in stressful conditions. Cytokinin stimulates shoots development.