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

Question 1

Which of the following best represents the overall equation for photosynthesis?

Accepted Answer

$$6CO_2 + 6H_2O + 	ext{Energy} ightarrow C_6H_{12}O_6$ + 6O_2$$

Question 2

During photosynthesis, which molecule is reduced and which is oxidized?

Accepted Answer

$$CO_2 is $$reduced and $$H_2O is $$oxidized

Question 3

Which structure in the leaf is primarily responsible for gas exchange?

Accepted Answer

Stoma

Question 4

What is the main function of the waxy cuticle on a leaf?

Accepted Answer

To minimize water loss

Question 5

Which part of the chloroplast contains the thylakoid membranes where the light reactions occur?

Accepted Answer

Thylakoid

Question 6

Why do most plants appear green to our eyes?

Accepted Answer

They reflect and transmit green light

Question 7

Which pigment is directly involved in the light reactions of photosynthesis?

Accepted Answer

Chlorophyll a

Question 8

What is the primary role of carotenoids in photosynthesis?

Accepted Answer

Photoprotection by absorbing excess light

Question 9

What happens to an electron in a pigment molecule when it absorbs a photon of light?

Accepted Answer

It becomes excited and moves to a higher energy state

Question 10

Which of the following best describes the process of photolysis in the light reactions?

Accepted Answer

Splitting of water to provide electrons to photosystem II

Question 11

What is the final electron acceptor in the light reactions of photosynthesis?

Accepted Answer

NADP+

Question 12

How is ATP produced during the light reactions?

Accepted Answer

By chemiosmosis as protons diffuse through ATP synthase

Question 13

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

Accepted Answer

Glucose

Question 14

A plant is exposed only to green light. What is the most likely outcome for its rate of photosynthesis?

Accepted Answer

It will decrease because green light is mostly reflected or transmitted

Question 15

Which of the following best explains why the thylakoid space becomes acidic during the light reactions?

Accepted Answer

Protons are pumped into the thylakoid space by the electron transport chain

Question 16

If a mutation prevented the formation of ATP synthase in chloroplasts, which process would be directly affected?

Accepted Answer

Photophosphorylation

Question 17

Which of the following is a correct sequence of events in the light reactions?

Accepted Answer

Photon absorbed by photosystem II → Electron transport chain → Photosystem I → NADPH formation

Question 18

Which of the following best describes the role of guard cells in plant leaves?

Accepted Answer

They regulate the opening and closing of stomata to control gas exchange and water loss

Question 19

A scientist exposes a plant to only red and blue light. What is the expected effect on photosynthesis and why?

Accepted Answer

Photosynthesis will be efficient because chlorophyll a absorbs red and blue light best

Question 20

Which of the following statements about the electron transport chain in the light reactions is correct?

Accepted Answer

It uses the energy of electrons to pump protons into the thylakoid space, creating a gradient for ATP synthesis

Chapter 7: Photosynthesis – Structure, Function, and Light Reactions

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