Category: Class 11 Biology Objective Questions

Biology Assessment Questions for Class 11 on “Eukaryotic Cells and it’s Organelles – 2”.

1. Which of these structures is non-living?
a) Nucleus
b) Cell membrane
c) Lysosome
d) Cell wall
Answer: d
Clarification: The cell wall covering the cell of fungi and plants is a non-living structure. The cell membrane covering the cell and the various organelles of the cell such as the nucleus and the lysosomes are living.

2. Which of these is not a function of the cell wall?
a) Cell-to-cell interaction
b) Provides cell shape
c) Synthesis of Rubisco
d) Protection from infection
Answer: c
Clarification: The cell wall covers the cell membrane of the plant and fungal cell. It provides many functions including cell-to-cell interaction, cell shape and protection from infection but it does not synthesize rubisco.

3. Which of these statements is not true regarding the cell wall?
a) It is present in fungi
b) It is a rigid structure
c) It is living
d) It protects the cell from infections
Answer: c
Clarification: The cell wall is a non-living rigid structure that covers the cells of fungi and plants. It also provides functions like protection from infection and mechanical stresses, and cell to cell interactions.

4. Which of these is not present in algal cell wall?
a) Pectin
b) Mannan
c) Galactan
d) Cellulose
Answer: a
Clarification: The algal cell wall contains cellulose, galactans, mannans and minerals like calcium carbonate. However, it does not contain pectin. The plant cell wall contains cellulose, hemicellulose, pectins and proteins.

5. Which of these is not present in a plant cell wall?
a) Pectin
b) Calcium carbonate
c) Hemicellulose
d) Cellulose
Answer: b
Clarification: The algal cell wall contains cellulose, galactans, mannans and minerals like calcium carbonate. However, the plant cell wall contains cellulose, hemicellulose, pectins and proteins.

6. Which of these statements is not true regarding the cell wall?
a) The cell wall of a young plant can grow
b) The primary wall of the cell wall can grow
c) The secondary wall accelerates the growth of the cell wall
d) the secondary wall is formed on the inner side of the cell
Answer: c
Clarification: The cell wall of a young plant cell can grow because of the growth of the primary wall of the cell wall. However, as the plant gets bigger, the secondary wall which is formed towards the cell membrane diminishes this growth.

7. Which of these is a common component of both algal and plant cell wall?
a) Cellulose
b) Pectin
c) Galactan
d) Mannan
Answer: a
Clarification: The algal cell wall contains cellulose, galactans, mannans and minerals like calcium carbonate. The plant cell wall contains cellulose, hemicellulose, pectins and proteins. Hence, cellulose is the common component.

8. Which of these is the main component of the middle lamella?
a) Calcium phosphate
b) Calcium silicate
c) Calcium carbonate
d) Calcium pectate
Answer: d
Clarification: The middle lamella is a layer present between two plant cells which joins the cell walls of both the cells. It is the first layer which is formed and deposited during cytokinesis. It mainly contains calcium pectate.

9. What is the main role of the middle lamella?
a) It performs photosynthesis
b) It helps in the transport of sodium ions
c) It connects adjacent plant cells
d) It provides calcium to the plant cells
Answer: c
Clarification: The middle lamella is a layer present between two plant cells which joins the cell walls of both the cells. It mainly contains calcium pectate. It is the first layer which is formed and deposited during cytokinesis.

10. The secondary wall of the cell wall faces the adjacent plant cell. True or false?
a) True
b) False
Answer: b
Clarification: The secondary wall of the cell wall does not face the adjacent plant cell. It grows inwards, hence facing the cell membrane of the same cell. It diminishes the growth of the cell wall of young cells.

11. Which of these structures connect the cytoplasm of adjacent plant cells?
a) Trichome
b) Vacuole
c) Middle lamellae
d) Plasmodesmata
Answer: d
Clarification: Adjacent plant cells adhere to each other due to the presence of the middle lamella. However, the plasmodesmata pass through the middle lamella and connect the cytoplasm of the two cells.

12. What is the function of plasmodesmata in plants?
a) Protecting the cells from mechanical stresses
b) Providing shape to the cells
c) Connecting the cytoplasm of adjacent cells
d) Joining two adjacent plant cell walls
Answer: c
Clarification: The plasmodesmata pass through the cell wall and the middle lamella and connect the cytoplasm of the two cells. Adjacent plant cells adhere to each other due to the presence of the middle lamella.

13. Which of these structures is not a part of the endomembrane system?
a) Vacuoles
b) Golgi bodies
c) Peroxisomes
d) Lysosomes
Answer: c
Clarification: The functions of the endoplasmic reticulum (ER), Golgi bodies, vacuoles and lysosomes are coordinated. Hence, they form an endomembrane system. Peroxisomes are not a part of the endomembrane system.

14. Which of these organelles do not have coordinated functions with the others?
a) Peroxisomes
b) Lysosomes
c) Golgi bodies
d) Vacuoles
Answer: a
Clarification: The functions of the endoplasmic reticulum (ER), Golgi bodies, vacuoles and lysosomes are coordinated. Hence, they form an endomembrane system. Peroxisomes are not a part of the endomembrane system.

15. Which of these organelles is a part of the endomembrane system?
a) Mitochondria
b) Lysosomes
c) Peroxisomes
d) Chloroplasts
Answer: b
Clarification: The endoplasmic reticulum (ER), Golgi bodies, vacuoles and lysosomes form the endomembrane system. Organelles such as mitochondria, chloroplasts and peroxisomes are not a part of the endomembrane system.

To practice Biology Assessment Questions for Class 11,

Biology Online Test for Medical Entrance Exams on “Biomolecules – Polysaccharides – 2”.

1. Identify the structure.

a) Hydrogen bond
b) Ether formation
c) Ketone formation
d) Glycosidic bond
Answer: d
Clarification: The structure shown contains two glucose molecules linked to each other. The bond between them is known as a glycosidic bond. It is a covalent bond which is formed between a hemiacetal or hemiketal group of a sugar and the hydroxyl group of some compound.

2. Which of these is a branched polysaccharide?
a) Sucrose
b) Cellulose
c) Glycogen
d) Chitin
Answer: c
Clarification: Glycogen is a homopolymer of glucose monomers. It is highly branched. Sucrose is a disaccharide. Cellulose and chitin are both polysaccharides but they are unbranched or linear in structure.

3. What is the shape of the secondary structure of starch?
a) Spherical
b) Linear
c) Helical
d) Branched
Answer: c
Clarification: Starch is a polymer made of glucose monomers. It is a polysaccharide. The secondary structures of starch have a helical structure. Starch is the main energy storing polysaccharide in plants.

4. Which molecule can starch hold in its helix?
a) Iodine
b) DNA
c) Amylopectin
d) Cellulose
Answer: a
Clarification: Starch can hold iodine molecules in its helix. The secondary structure of starch is in the form of a helix. Starch is a polysaccharide made of glucose monomers. It is an energy storing polysaccharide in plants.

5. In which part of the starch chain is iodine incorporated?
a) Left non-reducing end
b) Right reducing end
c) Helix
d) Branched portion
Answer: c
Clarification: Iodine is incorporated into the helix of the starch chain. Starch is a polysaccharide made of glucose monomers. The secondary structure of starch is in the form of a helix, where iodine molecules are incorporated.

6. What color is the starch-iodine complex?
a) Yellow
b) Brick red
c) Blue
d) Black
Answer: c
Clarification: The starch-iodine complex has a characteristic blue color. This presence of color serves as a test for the detection of starch in a sample. On addition of iodine solution, if the sample turns blue then the presence of starch is confirmed.

7. Which of these molecules can hold iodine molecules?
a) Starch
b) Cellulose
c) Chitin
d) Sucrose
Answer: a
Clarification: The secondary structure of starch is helical and can hold iodine molecules in its structure. Cellulose and chitin do not have helices and hence cannot hold iodine. Sucrose is a disaccharide.

8. The absence of which structure in cellulose does not allow it to hold iodine molecules?
a) Branches
b) Left non-reducing end
c) Right reducing end
d) Helix
Answer: d
Clarification: Iodine molecules are held in helices of polysaccharide structures such as starch. The secondary structure of starch is helical and can hence hold starch. Cellulose has a linear structure and thus, cannot hold iodine molecules.

9. What is the main component of the plant cell wall?
a) Lipids
b) Glycogen
c) Cellulose
d) Peptidoglycan
Answer: c
Clarification: The plant cell wall is made of cellulose. It is not digestible by humans. Glycogen is a storage carbohydrate in animals. Lipids make up cell membranes. Peptidoglycan is found in the covering of bacteria.

10. Cotton fiber is made of cellulose. True or false?
a) True
b) False
Answer: a
Clarification: Cotton fibers are long threads of the polysaccharide cellulose. Cellulose is the most abundant organic polymer in the world. It also makes up the cell wall of plant cells. It is a linear polymer.

11. Which of these structures do not contain cellulose as its major constituent?
a) Cotton fibers
b) Plant cell wall
c) Jute
d) Fungal cell wall
Answer: d
Clarification: Cellulose is a homopolymer made of glucose monomers. Cotton fibers, the cell walls of plants and jute are all primarily made of cellulose. However, the fungal cell wall is made of the polysaccharide chitin.

12. Chitin is a _____
a) monomer
b) heteropolymer
c) homopolymer
d) dimer
Answer: c
Clarification: Chitin is a polysaccharide made of monomers of N-acetyl glucosamine, which is a modified sugar. It is the main component of the cell walls of fungi and the exoskeleton of arthropods.

13. Which of these is a complex polysaccharide?
a) Glycogen
b) Inulin
c) Chitin
d) Starch
Answer: c
Clarification: The polysaccharides glycogen, inulin and starch are simple polysaccharides. Chitin is a complex polysaccharide. Chitin is a homopolymer made of repeating monomers of N-acetyl glucosamine, which is a modified sugar.

14. What is the main constituent of the exoskeleton of arthropods?
a) Chitin
b) Cellulose
c) Glycogen
d) Starch
Answer: a
Clarification: Chitin is the main constituent of the exoskeleton of arthropods and also of fungal cell walls. It is a complex polysaccharide. Cellulose makes up plant cell walls, glycogen is a storage polysaccharide in animals while starch is the storage polysaccharide in plants.

15. Which of these statements is not true regarding polysaccharides?
a) Inulin is a polysaccharide made of fructose
b) Chitin is a heteropolymer
c) Glycogen is a highly branched polysaccharide
d) Cellulose makes up cotton fibers
Answer: b
Clarification: Inulin is a homopolymer of repeating units of the monomer fructose. Glycogen is highly branched. Cellulose is the major component of cotton fibers. However, chitin is a homopolymer of N-acetyl glucosamine units.

To practice Biology Online Test for Medical Entrance Exams,

Botany Written Test Questions and Answers on “Plant-Water Relations-2”.

1. At atmospheric pressure, the water potential is equal to_________
a) Gravitational potential
b) Pressure potential
c) Solute potential
d) Matrix potential
Answer: c
Clarification: For a solution at atmospheric pressure, the water potential is equal to solute potential. Gravitational potential and matrix potential are of negligible importance. Pressure potential is responsible for creating tension in the xylem which leads to water transport up a stem.

2. The pressure built up against the cell wall of a plant cell due to diffusion of water causes the cell to become _________
a) flaccid
b) turgid
c) plasmolysed
d) imbibed
Answer: b
Clarification: In hypotonic solution, water enters into the resulting in pressure being developed against the wall and the cell becomes turgid. The cell becomes flaccid in isotonic solution, plasmolysed in hypertonic solution and imbibed when imbibition takes place which is also a kind of hypotonic solution activity.

3. Affinity between the absorbent and the liquid is pre-requisite condition for imbibition.
a) True
b) False
Answer: a
Clarification: For imbibition to take place, there should be water potential gradient between the absorbent and the liquid imbibed. Also, for any substance to carry out imbibition with any other liquid, there must be potential attraction between the absorbent and the liquid.

4. Pressure potential is ________
a) constant
b) zero
c) positive
d) negative
Answer: c
Clarification: Pressure potential is usually positive but it causes negative potential in the xylem in order to enable water transport up the stem. Water potential of pure water is zero. Solute potential is negative. Gravitational and matrix potential remains relatively constant.

5. The space between the cell wall and the shrunken protoplast in a plasmolysed cell is occupied by ________
a) hypotonic solution
b) hypertonic solution
c) isotonic solution
d) water
Answer: b
Clarification: The protoplast shrinks in presence of hypertonic solution, swells in presence of hypotonic solution and becomes flaccid in isotonic condition. Water is helpful in dilution or in bringing isotonic condition.

6. Which of the following is a reversible phenomenon?
a) Plasmolysis
b) Turgidity
c) Flaccidity
d) Imbibition
Answer: a
Clarification: Only plasmolysis is a reversible phenomenon as the cell can become normal when shifted to hypotonic solution. When the cell is already in hypotonic solution it swells and bursts, therefore, cannot be reversed. Flaccid cell is an ideal cell where there is continuous flow of water in and out of the cell. Imbibition aids in germination which is again a non-reversible process.

7. Seedlings emerge out of the soil into open surroundings due to imbibition.
a) True
b) False
Answer: a
Clarification: Imbibition is a special type of diffusion which helps solids absorb moisture resulting in increase in volume. In the same way, it provides the required pressure for emergence out of the soil to the tiny seedlings.

8. Imbibition is commonly seen in _____
a) liquids
b) gases
c) suspension
d) colloids
Answer: d
Clarification: Imbibition is usually found in colloids which can absorb other substances. Liquids and gases are fluids which are absorbed. Suspension is formed in centrifugation.

9. Which of the following is not an important determinant of the movement of molecules in or out of the cell?
a) Cell membrane
b) Thickness of membrane
c) Tonoplast
d) Membrane of vacuole
Answer: b
Clarification: Thickness of membrane has no role to play in the movement of molecules from one region to another. The cell membrane, tonoplast and membrane of the vacuole must be permeable to the substances, hence, are important determinants of the transportation of molecules.

10. Statement A: Osmotic pressure is negative.
Statement B: Osmotic potential is also negative.
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: Osmotic pressure is the pressure required to prevent diffusion of water in and out of the membrane. Osmotic potential is the energy required to carry out the process of osmosis. Both are numerically same but osmotic pressure is positive while osmotic potential is negative. They depend on the solute concentration.

To practice Botany Written Test Questions and Answers,

Biology Multiple Choice Questions on “Higher Plants Photosynthesis – Electron Transport”.

1. The electron transport system occurs in _____
a) Thylakoid membrane
b) Stroma
c) Cytosol
d) Mitochondria
Answer: a
Clarification: It is in the thylakoid membrane, in which the electron transport system occurs. Each thylakoid membrane is a closed compartment that gets protons from stroma by the b₆ or f complex. Also, thylakoid membrane is impermeable to protons.

2. The first electron acceptor in photosystem 1 is _____
a) Plastoquinone
b) Cytochrome b
c) A Fe-S protein
d) Water
Answer: c
Clarification: The first electron acceptor in photosystem 1 is a Fe-S protein. It is a stable complex of iron and sulfur atoms bonded to a protein. It primarily accepts the electrons and passes onto NADP⁺.

3. Water produces electrons for the reduction reactions of photosynthesis.
a) True
b) False
Answer: a
Clarification: It is a true statement. The photolysis of water (2 molecules) produces four electrons that are required for the reduction reactions of photosynthesis which is needed for non-phosphorylation.

4. How much hydrogen protons are released by twelve water molecules?
a) 48
b) 6
c) 12
d) 24
Answer: d
Clarification: By understanding the photolysis equation, one water molecule gives 2 hydrogen protons. So, 12 water molecules will give 24 hydrogen protons.

5. The name of the scheme given to the transport of electrons is called as _______
a) Z scheme
b) W scheme
c) Y scheme
d) E scheme
Answer: a
Clarification: The scheme is called Z-scheme. This name was given due to the shape of the sequence. The transfer of electrons from PS II to NADP⁺ produces this scheme when the carries are placed in the order of the redox potential scale.

6. _____ is the only product in cyclic photophosphorylation.
a) ADP
b) ATP
c) Hydrogen
d) Oxygen
Answer: b
Clarification: ATP is the only product in cyclic photophosphorylation. PS II is not involved in this process. So, there will be no creation of reducing power i.e. NADPH + H⁺. And the only source of energy is ATP in cyclic photophosphorylation.

7. In PS II, the last electron acceptor is ______
a) Plastocyanin
b) Ferredoxin
c) Cytochrome b₆
d) Cytochrome b₁₂
Answer: a
Clarification: Plastocyanin, which is a Cu protein is the last electron acceptor in PS II. It receives the electrons from cytochrome f and passes onto PS I. This is all based on non-cyclic photophosphorylation reaction.

8. _______ accepts the electrons from Pheophytin.
a) Cytochrome f
b) Cytochrome d
c) Plastoquinone
d) Ferredoxin
Answer: c
Clarification: Plastoquinone (PQ) is an electron carrier. It accepts the electrons from pheophytin. PQ gets 2 electrons and passes these to cytochrome b₆. It also plays a major role in light-dependent reactions.

9. The electrons produced in the photolysis of water enters ______
a) Fe-S protein
b) PS II
c) Plastocyanin
d) Cytochrome a
Answer: b
Clarification: During the photolysis of water, two electrons are produced. These electrons enter into PS II and it transfers the electron to Pheophytin (the primary electron acceptor). These electrons mainly help during reduction reactions.

10. The process by which the pH gradient across the membrane provides energy for the synthesis of ATP is called as ______
a) Phosphorylation
b) Transfusion
c) Diffusion
d) Chemiosmosis
Answer: d
Clarification: There is a pH gradient across the thylakoid membrane, which provides a proton motive force. This creates chemical potential energy for the production of ATP from ADP and inorganic phosphate is called chemiosmosis. Peter Mitchell proposed this theory.

11. In which process does carbon dioxide join photosynthesis?
a) Oxidation
b) PS I
c) Dark reaction
d) Reduction
Answer: c
Clarification: Carbon dioxide is entering the photosynthetic pathway through dark reaction. RuBP reacts with CO₂ to form the first unstable carbon compound. So, here 6 molecules of CO₂ are required to start dark reaction.

Biology Multiple Choice Questions on “Growth Regulators in Plants – 1”.

1. Who isolated the hormone auxin?
a) Darwin
b) Skoog
c) Went
d) Miller
Answer: c
Clarification: F.W. Went isolated hormone auxin. Charles and Francis Darwin had discovered auxin. Skoog and Miller identified and crystallized cytokinesis promoting substance and named it kinetin.

2. Movement of auxin is centripetal.
a) True
b) False
Answer: b
Clarification: Auxin is a hormone which is produced by growing apices of the plant. It is transported to other growing region in both acropetal as well as basipetal succession.

3. The hormone responsible for apical dominance is________
a) IAA
b) ABA
c) GA
d) Kinetin
Answer: a
Clarification: Indole-3-acetic acid (IAA) is the hormone responsible for apical dominance. ABA promotes abscission of older parts. GA delays senescence. Kinetin helps in removing apical dominance and aiding lateral growth.

4. Phototropic and geotropic movements are linked to________
a) ethylene
b) ABA
c) GA
d) Auxin
Answer: d
Clarification: Auxin is associated with different movement of plant stem including phototropic and geotropic movements. GA promotes early maturity of plants. ABA prevents death of plant in stressful conditions. Ethylene increases respiratory rate of plants.

5. The concentration of auxin is highest in _______
a) leaves
b) stem
c) growing tips
d) vascular bundles
Answer: c
Clarification: The concentration of auxin is found to be highest in growing tips as they are the source of the hormone. It further spreads to leaves & stem. Vascular bundles have no role in the activity of PGRs.

6. The hormone which can replace vernalization is _______
a) IAA
b) ABA
c) GA
d) Kinetin
Answer: c
Clarification: Gibberellic acid is the hormone which can be function similar to vernalisation treatment. IAA initiates rooting in stem cuttings. ABA is functional in unfavorable conditions. Kinetin is responsible for formation of new leaves, lateral shoot growth and adventitious shoot formation.

7. Foolish seeding disease of rice led to discovery of Cytokinins.
a) True
b) False
Answer: b
Clarification: Foolish seeding disease of rice was found to be caused by a fungal pathogen Gibberalla fujikori. It was reported in 1926 by Japanese scientist Eiichi Kurosawa after observing symptoms in uninfected seedlings of rice after treatment with sterile filtrates of the fungus which resulted in the discovery of Gibberellic acid (GA₃).

8. Which of the following is a terpene derivative?
a) Ethylene
b) ABA
c) Auxin
d) GA
Answer: d
Clarification: GA is a terpene derivative. Ethylene is a volatile gaseous hormone. ABA is a derivative of carotenoids. Auxin is an indole compound.

9. Which of the following hormone promotes bolting?
a) GA
b) Ethylene
c) Auxin
d) Kinetin
Answer: a
Clarification: Bolting is the elongation of internode just prior to flowering. It is seen in plants with rosette habit. GA promotes the action of bolting. Ethylene helps rapid internode elongation in deep-water seedlings of rice. Auxin promotes rooting in stems. Kinetin promotes shooting in stems.

10. The hormone responsible for speeding up of malting process in brewing industry is ________
a) Auxin
b) GA₃
c) Ethylene
d) Kinetin
Answer: b
Clarification: GA₃ is the hormone responsible for speeding up of malting process in brewing industry. Auxin is useful to prepare weed free lawns. Ethylene is responsible for quick initiation of flowering in fruit plants. Kinetin is naturally present in meristematic regions of the plant.