Question 1

Which of the following best describes the overall chemical equation for photosynthesis?

Accepted Answer

$$6\ CO_2$ + 6\ H_2O \rightarrow C_6H_{12}O_6$ + 6\ O_2$

Question 2

In the process of photosynthesis, which molecule is oxidized and which is reduced?

Accepted Answer

Water is oxidized and carbon dioxide is reduced.

Question 3

Which organelle is responsible for photosynthesis in plant cells?

Accepted Answer

Chloroplast

Question 4

What is the primary pigment involved in the light reactions of photosynthesis?

Accepted Answer

Chlorophyll a

Question 5

Which wavelengths of visible light are most efficiently absorbed by chlorophyll a?

Accepted Answer

Violet-blue (around 450 nm) and red (around 670 nm)

Question 6

What is the main function of accessory pigments such as carotenoids in photosynthesis?

Accepted Answer

They broaden the spectrum of light that can be used for photosynthesis and provide photoprotection.

Question 7

During the light reactions, what is the immediate source of electrons for Photosystem II?

Accepted Answer

Water ($$H_2O)$$

Question 8

Which process in the chloroplast is responsible for generating ATP during photosynthesis?

Accepted Answer

Photophosphorylation

Question 9

What is the main product of the Calvin cycle that can be used to synthesize glucose and other carbohydrates?

Accepted Answer

Glyceraldehyde 3-phosphate (G3P)

Question 10

Which enzyme catalyzes the fixation of carbon dioxide in the Calvin cycle?

Accepted Answer

Rubisco (Ribulose bisphosphate carboxylase-oxygenase)

Question 11

How many molecules of ATP and NADPH are required for the net synthesis of one G3P molecule in the Calvin cycle?

Accepted Answer

9 ATP and 6 NADPH

Question 12

Which of the following statements about the spatial organization of chemiosmosis in chloroplasts and mitochondria is correct?

Accepted Answer

In chloroplasts, protons are pumped into the thylakoid space and drive ATP synthesis as they diffuse back into the stroma.

Question 13

Which of the following best explains why leaves appear green?

Accepted Answer

Chlorophyll absorbs violet-blue and red light, reflecting and transmitting green light.

Question 14

What is the role of NADP+ in the light reactions of photosynthesis?

Accepted Answer

It acts as an electron acceptor and is reduced to NADPH.

Question 15

Which of the following is NOT a product of the light reactions of photosynthesis?

Accepted Answer

Glucose

Question 16

Which of the following statements about cyclic electron flow in photosynthesis is correct?

Accepted Answer

It produces ATP but does not produce NADPH or oxygen.

Question 17

A plant is exposed to light with a wavelength of 700 nm. Which photosystem is most likely to absorb this light efficiently?

Accepted Answer

Photosystem I (P700)

Question 18

Which of the following best describes the relationship between photosynthesis and cellular respiration?

Accepted Answer

Photosynthesis stores energy in organic molecules, while cellular respiration releases energy from organic molecules.

Question 19

Which of the following organisms are capable of photosynthesis?

Accepted Answer

Plants, multicellular algae, unicellular protists, cyanobacteria, and purple sulfur bacteria

Question 20

If a plant's stomata are closed during the day, which of the following is most likely to occur?

Accepted Answer

Photosynthesis will decrease due to limited CO2 intake.

Photosynthesis: Mechanisms and Importance in the Biosphere

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