The ratio of photosynthesis to respiration in a plant is represented by:

The correct answer is D: Apparent photosynthesis. Apparent photosynthesis (net photosynthesis) represents the actual photosynthesis minus respiration measured as the gaseous exchange in the plant.

The bulliform cells found in monocot leaves are primarily involved in

The correct answer is C: Leaf rolling and unrolling in response to water stress. Bulliform cells are large, vacuolated cells on the adaxial surface of monocot leaves that control leaf rolling to reduce water loss during drought.

Which of the following is NOT a characteristic of Kingdom Plantae?

The correct answer is C: Heterotrophic nutrition. Plants are autotrophic and perform photosynthesis. Heterotrophic nutrition is characteristic of animals and fungi, not plants.

The grana in chloroplasts are composed of:

The correct answer is A: Stacked thylakoids. Grana are stacks of thylakoids arranged vertically, while stroma lamellae are unstacked thylakoids connecting different grana.

The bulliform cells found in monocot leaves, particularly in grasses, function to:

The correct answer is A: Regulate leaf rolling and unrolling based on water status. Bulliform cells are large, colorless epidermal cells that absorb water and swell, causing the leaf to unfold; they lose water and collapse during drought, causing leaf rolling to reduce transpiration.

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NEET Botany

Botany questions for NEET UG — Plant Anatomy, Physiology, Reproduction, Ecology.

139 Q 3 Topics Take Mock Test

Difficulty: All Easy Medium Hard 1–10 of 139

Topics in NEET Botany

All Plant Kingdom 100 Plant Anatomy 100 Plant Physiology 76

Q.1 Medium Plant Physiology

Which of the following is a characteristic feature of bundle sheath cells in C4 plants?

A Rich in chloroplasts with well-developed grana

B Absence of starch grains

C Tightly packed with few intercellular spaces

D Directly exposed to stomata

Correct Answer: A. Rich in chloroplasts with well-developed grana

EXPLANATION

Bundle sheath cells in C4 plants contain large chloroplasts with well-developed grana for the Calvin cycle, unlike mesophyll cells.

Test

Q.2 Medium Plant Physiology

In C4 plants, the first stable product of CO2 fixation is:

A 3-Phosphoglycerate

B Oxaloacetate

C Malate

D Phosphoenolpyruvate

Correct Answer: B. Oxaloacetate

EXPLANATION

In the Hatch-Slack pathway, PEP carboxylase catalyzes formation of oxaloacetate (4-carbon compound) in mesophyll cells.

Test

Q.3 Medium Plant Physiology

At saturating light intensity, photosynthesis is primarily limited by:

A Light wavelength

B Photosynthetic pigments

C CO2 concentration

D Chloroplast number

Correct Answer: C. CO2 concentration

EXPLANATION

When light is saturating, CO2 becomes the limiting factor as RuBisCO activity depends on substrate availability.

Test

Q.4 Medium Plant Physiology

Which organelle is responsible for amino acid synthesis in plants?

A Ribosome

B Chloroplast

C Peroxisome

D Endoplasmic reticulum

Correct Answer: B. Chloroplast

EXPLANATION

Chloroplasts synthesize amino acids using carbon skeletons from the Calvin cycle and nitrogen from nitrite reduction.

Test

Q.5 Medium Plant Physiology

In photorespiration, the primary substrate is:

A 3-Phosphoglycerate

B Ribulose-1,5-bisphosphate

C Glyceraldehyde-3-phosphate

D Phosphoenolpyruvate

Correct Answer: B. Ribulose-1,5-bisphosphate

EXPLANATION

RuBisCO catalyzes oxygenation of RuBP instead of carboxylation under high O2/CO2 ratios, initiating the photorespiratory pathway.

Test

Q.6 Medium Plant Physiology

Which of the following factors does NOT directly affect photosynthesis?

A Chlorophyll concentration

B Soil pH

C CO2 concentration

D Light wavelength

Correct Answer: B. Soil pH

EXPLANATION

While soil pH affects nutrient availability, it does not directly affect the photosynthetic process itself. Chlorophyll, CO2, and light wavelength directly influence photosynthesis.

Test

Q.7 Medium Plant Physiology

In the electron transport chain, which complex pumps the most protons across the inner mitochondrial membrane?

A Complex I

B Complex II

C Complex III

D Complex IV

Correct Answer: A. Complex I

EXPLANATION

Complex I (NADH dehydrogenase) pumps 4 protons, Complex III pumps 4, Complex IV pumps 2, making Complex I the most significant proton pump.

Test

Q.8 Medium Plant Physiology

Which statement about transpiration is INCORRECT?

A Cuticular transpiration accounts for 5-10% of total water loss in most plants

B Stomatal transpiration is the major pathway of water loss in mesophytes

C Transpiration is independent of atmospheric humidity

D Transpiration cools the plant through evaporative cooling

Correct Answer: C. Transpiration is independent of atmospheric humidity

EXPLANATION

Transpiration is highly dependent on atmospheric humidity. Lower humidity increases transpiration rate due to greater water vapor gradient.

Test

Q.9 Medium Plant Physiology

Which of the following statements about respiration is correct?

A Aerobic respiration yields 38 ATP per glucose molecule

B The Krebs cycle directly produces the maximum ATP in cellular respiration

C Anaerobic respiration in plants produces ethanol and CO2 through fermentation

D Glycolysis is an aerobic process occurring in the mitochondrial matrix

Correct Answer: C. Anaerobic respiration in plants produces ethanol and CO2 through fermentation

EXPLANATION

In plants, anaerobic conditions lead to fermentation producing ethanol and CO2. Aerobic respiration yields ~30-32 ATP; Krebs cycle produces limited ATP directly; Glycolysis is cytoplasmic.

Test

Q.10 Medium Plant Physiology

At what light intensity does compensation point occur in a typical C3 plant?

A 50-100 μmol/m²/s

B 500-1000 μmol/m²/s

C 1000-2000 μmol/m²/s

D 2000-3000 μmol/m²/s

Correct Answer: A. 50-100 μmol/m²/s

EXPLANATION

The light compensation point for C3 plants typically occurs at 50-100 μmol/m²/s where photosynthesis equals respiration rate.

Test

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