Home Subjects NEET Botany

NEET Botany

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

116 Q 7 Topics Take Mock Test
Advertisement
Difficulty: All Easy Medium Hard 41–50 of 116
Topics in NEET Botany
A desert plant maintains stomata closure during the day and opens them at night, fixing CO2 into malic acid. This adaptation is characteristic of which photosynthetic pathway?
A C3 photosynthesis
B C4 photosynthesis
C CAM photosynthesis
D Hatch-Slack pathway
Correct Answer:  C. CAM photosynthesis
EXPLANATION

CAM (Crassulacean Acid Metabolism) plants fix CO2 at night into malate and release it during the day for photosynthesis, reducing water loss in arid environments.

Test
Which of the following enzyme complexes in the thylakoid membrane is responsible for water splitting and oxygen evolution?
A Photosystem I
B Photosystem II (Oxygen Evolving Complex)
C Cytochrome b6f complex
D ATP synthase
Correct Answer:  B. Photosystem II (Oxygen Evolving Complex)
EXPLANATION

Photosystem II contains the oxygen-evolving complex (OEC) with a manganese cluster that catalyzes water splitting, releasing O2, H+, and electrons.

Test
The phenomenon where plants lose water in liquid form through hydathodes is called:
A Transpiration
B Guttation
C Exudation
D Imbibition
Correct Answer:  B. Guttation
EXPLANATION

Guttation occurs when root pressure forces water out through hydathodes (water pores) as liquid water droplets, typically at night.

Test
The grana in chloroplasts are composed of:
A Stacked thylakoids
B Unstacked thylakoids
C Stroma lamellae
D Cristae
Correct Answer:  A. Stacked thylakoids
EXPLANATION

Grana are stacks of thylakoids arranged vertically, while stroma lamellae are unstacked thylakoids connecting different grana.

Test
The Q10 value for enzyme-catalyzed reactions is typically:
A 1.0-2.0
B 2.0-3.0
C 3.0-4.0
D 4.0-5.0
Correct Answer:  B. 2.0-3.0
EXPLANATION

Q10 of 2.0-3.0 indicates that enzyme activity doubles or triples with every 10°C increase in temperature, typical for biological systems.

Test
In the Calvin cycle, which enzyme catalyzes the fixation of CO2?
A Ribulose-1,5-bisphosphate carboxylase (RuBisCO)
B Phosphofructokinase
C Aldolase
D Transketolase
Correct Answer:  A. Ribulose-1,5-bisphosphate carboxylase (RuBisCO)
EXPLANATION

RuBisCO is the most abundant enzyme on Earth and catalyzes the carboxylation of RuBP with CO2 in the dark reactions.

Test
During photosynthesis, the splitting of water molecules occurs in which compartment of the chloroplast?
A Stroma
B Thylakoid lumen
C Outer membrane
D Inner membrane
Correct Answer:  B. Thylakoid lumen
EXPLANATION

Water photolysis (photosystem II) occurs in the thylakoid lumen where oxygen is released as a byproduct.

Test
A student observes that a plant kept in a completely dark room still shows some gas exchange. This can be attributed to:
A Photorespiration
B Aerobic respiration
C Fermentation
D Chemosynthesis
Correct Answer:  B. Aerobic respiration
EXPLANATION

In darkness, photosynthesis stops, but aerobic respiration continues, consuming O2 and releasing CO2, resulting in measurable gas exchange.

Test
Which hormone is primarily responsible for closing stomata under water stress conditions?
A Gibberellin
B Abscisic acid (ABA)
C Auxin
D Cytokinin
Correct Answer:  B. Abscisic acid (ABA)
EXPLANATION

ABA accumulates in guard cells during water stress and causes stomatal closure by reducing turgor pressure in guard cells.

Test
In C4 photosynthesis, the primary CO2 acceptor molecule is:
A Oxaloacetate
B Phosphoenolpyruvate (PEP)
C 3-Phosphoglycerate
D Ribulose-1,5-bisphosphate
Correct Answer:  B. Phosphoenolpyruvate (PEP)
EXPLANATION

In C4 plants, CO2 first combines with PEP (3-carbon molecule) to form oxaloacetate (4-carbon), which is why it's called C4 photosynthesis.

Test
IGET
IGET AI
Online · Exam prep assistant
Hi! 👋 I'm your iget AI assistant.

Ask me anything about exam prep, MCQ solutions, study tips, or strategies! 🎯
UPSC strategy SSC CGL syllabus Improve aptitude NEET Biology tips