Question 1

Which of the following best describes the role of autotrophs in an ecosystem?

Accepted Answer

They produce organic molecules using solar energy through photosynthesis.

Question 2

During photosynthesis, which molecule acts as the initial electron donor in the light reactions?

Accepted Answer

Water ($H_2O$)

Question 3

Which equation correctly represents the overall process of photosynthesis?

Accepted Answer

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

Question 4

In the light reactions of photosynthesis, what is the primary function of Photosystem II?

Accepted Answer

To split water molecules and energize electrons.

Question 5

Which of the following is a direct product of the Calvin Cycle?

Accepted Answer

G3P (glyceraldehyde-3-phosphate)

Question 6

A plant is exposed to light but deprived of $CO_2$. Which stage of photosynthesis will be directly affected?

Accepted Answer

Calvin Cycle

Question 7

Which statement best explains why carnivores depend on photosynthesis for survival?

Accepted Answer

Carnivores eat herbivores, which obtain energy from plants that perform photosynthesis.

Question 8

What is the main purpose of splitting water molecules during the light reactions?

Accepted Answer

To replace electrons lost by chlorophyll and release oxygen as a byproduct.

Question 9

Which molecule is regenerated at the end of the Calvin Cycle to allow the cycle to continue?

Accepted Answer

RuBP (ribulose bisphosphate)

Question 10

If a mutation prevents the formation of NADPH during photosynthesis, which process will be directly impaired?

Accepted Answer

Carbon fixation in the Calvin Cycle

Question 11

Which of the following best describes the flow of energy through an ecosystem?

Accepted Answer

Energy flows from the sun to producers, then to consumers, and is eventually lost as heat.

Question 12

A scientist measures the rate of oxygen production in a plant exposed to light. Which process is being monitored?

Accepted Answer

Photosynthesis (light reactions)

Question 13

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

Accepted Answer

Glucose ($C_6H_{12}O_6$)

Question 14

In a real-world scenario, why might a farmer be concerned about the rate of photosynthesis in crops?

Accepted Answer

It affects the growth and yield of crops by controlling the production of organic molecules.

Question 15

Which process in photosynthesis directly uses the energy of photons?

Accepted Answer

Light reactions

Question 16

If the thylakoid membrane is damaged, which process will be most affected?

Accepted Answer

Light reactions

Question 17

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

Accepted Answer

Absorption of light by Photosystem II, water splitting, electron transfer, ATP and NADPH formation

Question 18

Which molecule acts as the final electron acceptor in the light reactions of photosynthesis?

Accepted Answer

NADP^+$

Question 19

A leaf is placed in darkness for 24 hours. Which process will be most directly inhibited?

Accepted Answer

Light reactions

Question 20

Which of the following best explains the relationship between photosynthesis and cellular respiration in the environment?

Accepted Answer

Photosynthesis stores solar energy in organic molecules, which are then broken down by cellular respiration to release energy.

Energy Flow and Photosynthesis: Study Notes for General Biology

Study Guide - Practice Questions