Grade 11 : Biology - Photosynthesis (Set 2)

Question 1

A student isolates intact organelles from green plant cells to observe carbohydrate synthesis.

Which specialized organelle is primarily responsible for performing photosynthesis in plant cells?

Accepted Answer

B) Chloroplast

Answer

A) Mitochondrion

Answer

C) Peroxisome

Answer

D) Endoplasmic Reticulum

Question 2

In which specific region of the chloroplast do the light-dependent reactions of photosynthesis take place?

Accepted Answer

A) Thylakoid membranes

Answer

B) Stroma matrix

Answer

C) Outer membrane

Answer

D) Intermembrane space

Question 3

Which fluid-filled compartment inside the chloroplast is the site for the Calvin cycle (light-independent reactions)?

Accepted Answer

C) Stroma

Answer

A) Lumen

Answer

B) Cristae

Answer

D) Matrix

Question 4

During an experiment tracing oxygen isotopes in photosynthetic aquatic plants, isotopic oxygen ($^{18}O$) is detected in the evolved oxygen gas.

What is the direct source of the oxygen gas ($O_2$) liberated during photosynthesis?

Accepted Answer

D) Water ($H_2O$)

Answer

A) Carbon dioxide ($CO_2$)

Answer

B) Glucose ($C_6H_{12}O_6$)

Answer

C) ATP

Question 5

Which primary photosynthetic pigment absorbs light predominantly in the blue and red wavelengths of the visible spectrum?

Accepted Answer

B) Chlorophyll a

Answer

A) Carotenoid

Answer

C) Anthocyanin

Answer

D) Phycobilin

Question 6

What reaction center reaction peak wavelength characterizes Photosystem II (PS II)?

Accepted Answer

A) P680

Answer

B) P700

Answer

C) P650

Answer

D) P730

Question 7

What peak absorption wavelength is associated with the reaction center of Photosystem I (PS I)?

Accepted Answer

C) P700

Answer

A) P600

Answer

B) P680

Answer

D) P750

Question 8

Which two main products synthesized during the light-dependent reactions are directly consumed by the Calvin cycle?

Accepted Answer

B) ATP and NADPH

Answer

A) $O_2$ and Glucose

Answer

C) $CO_2$ and $H_2O$

Answer

D) ADP and $NADP^+$

Question 9

What is the key enzyme responsible for catalyzing the initial fixation of $CO_2$ onto Ribulose-1,5-bisphosphate in $C_3$ plants?

Accepted Answer

D) RuBisCO

Answer

A) PEP carboxylase

Answer

B) ATP synthase

Answer

C) Amylase

Question 10

What is the first stable 3-carbon intermediate compound produced after $CO_2$ fixation in $C_3$ plants?

Accepted Answer

A) 3-Phosphoglycerate (3-PGA)

Answer

B) Oxaloacetic acid (OAA)

Answer

C) Glyceraldehyde-3-phosphate (G3P)

Answer

D) Pyruvate

Question 11

Leaf Anatomy Diagram:
Outer Layer: Epidermis with Stomata
Concentric Rings around Bundle Sheath: Kranz Arrangement

What anatomical feature characterizes leaves of $C_4$ plants such as maize and sugarcane?

Accepted Answer

C) Kranz anatomy

Answer

A) Mesophyll-only structure

Answer

B) Sunken stomata only

Answer

D) Secondary cambium

Question 12

In $C_4$ plants, what is the primary $CO_2$ acceptor present in the mesophyll cells?

Accepted Answer

B) Phosphoenolpyruvate (PEP)

Answer

A) Ribulose-1,5-bisphosphate (RuBP)

Answer

C) Oxaloacetate

Answer

D) Malate

Question 13

Which enzyme fixes carbon dioxide in mesophyll cells of $C_4$ plants and exhibits no affinity for oxygen?

Accepted Answer

D) PEP carboxylase

Answer

A) RuBisCO

Answer

B) Carbonic anhydrase

Answer

C) Pyruvate kinase

Question 14

What is the first 4-carbon acid produced during primary carbon fixation in $C_4$ plants?

Accepted Answer

A) Oxaloacetic acid (OAA)

Answer

B) Citric acid

Answer

C) Succinic acid

Answer

D) Fumaric acid

Question 15

A researcher observes pineapple plants opening their stomata exclusively during nighttime to prevent excessive transpiration loss.

Which photosynthetic adaptation is demonstrated by these desert/succulent plants?

Accepted Answer

C) CAM pathway (Crassulacean Acid Metabolism)

Answer

A) $C_3$ pathway

Answer

B) $C_2$ cycle

Answer

D) Hydroponic pathway

Question 16

What phenomenon occurs when RuBisCO binds oxygen ($O_2$) instead of carbon dioxide ($CO_2$), leading to a wasteful loss of fixed carbon?

Accepted Answer

B) Photorespiration ($C_2$ cycle)

Answer

A) Photophosphorylation

Answer

C) Glycolysis

Answer

D) Fermentation

Question 17

How many total turns of the Calvin cycle are required to produce one net molecule of hexose glucose ($C_6H_{12}O_6$)?

Accepted Answer

D) 6

Answer

A) 1

Answer

B) 2

Answer

C) 3

Question 18

During non-cyclic photophosphorylation, what is the ultimate electron acceptor in the thylakoid membrane pathway?

Accepted Answer

A) $NADP^+$

Answer

B) Water

Answer

C) Cytochrome b6f

Answer

D) Oxygen

Question 19

According to Peter Mitchell's Chemiosmotic Hypothesis, ATP synthesis during light reactions requires a proton gradient across which membrane?

Accepted Answer

C) Thylakoid membrane

Answer

A) Outer mitochondrial membrane

Answer

B) Plasma membrane

Answer

D) Nuclear envelope

Question 20

Which environmental factor acts as a major limiting factor for photosynthesis on land due to low atmospheric concentration (~0.03-0.04%)?

Accepted Answer

B) Carbon dioxide ($CO_2$) concentration

Answer

A) Nitrogen concentration

Answer

C) Oxygen concentration

Answer

D) Soil salinity

Grade 11 : Biology - Photosynthesis (Set 2)