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

$$6 \mathrm{CO}_2 + 6 \mathrm{H}_2\mathrm{O} \xrightarrow{\text{light}} \mathrm{C}_6\mathrm{H}_{12}\mathrm{O}_6 + 6 \mathrm{O}_2$$

Question 1

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

Accepted Answer

$$6 \mathrm{CO}_2 + 6 \mathrm{H}_2\mathrm{O} \xrightarrow{	ext{light}} \mathrm{C}_6\mathrm{H}_{12}\mathrm{O}_6 + 6 \mathrm{O}_2$$

Question 2

A scientist discovers a new bacterium in Lake Superior that produces oxygen gas. What is the most likely explanation for this observation?

Accepted Answer

The bacterium performs photosynthesis using water as an electron donor, releasing $$\mathrm{O}_2 as a $$byproduct.

Question 3

Which of the following substances provides the majority of the atoms that make up the sugar produced by photosynthesis?

Accepted Answer

Carbon dioxide

Question 4

During the light reactions of photosynthesis, what is the primary role of water?

Accepted Answer

To donate electrons to photosystem II, resulting in the release of $$\mathrm{O}_2$$

Question 5

Which of the following statements about the Calvin cycle is correct?

Accepted Answer

ATP and NADPH produced in the light reactions are used to fix carbon dioxide into organic molecules.

Question 6

A toxin is found to inhibit the uptake of $$\mathrm{CO}_2$$ into plant leaves. This toxin would most directly affect the:

Accepted Answer

Calvin cycle

Question 7

Which of the following best explains why the Calvin cycle is sometimes called the 'light-independent reactions'?

Accepted Answer

The Calvin cycle does not directly require light, but depends on ATP and NADPH produced by the light reactions.

Question 8

Which of the following is a major difference between C4 and CAM photosynthetic pathways?

Accepted Answer

C4 plants spatially separate carbon fixation and the Calvin cycle, while CAM plants temporally separate these processes.

Question 9

A botanist discovers a new plant species in the Amazon rainforest that has blue leaves. What can be inferred about the pigments in the leaves of this plant?

Accepted Answer

The pigments reflect blue wavelengths and absorb other wavelengths of visible light.

Question 10

Which of the following best describes the energy transformation that occurs during the light reactions of photosynthesis?

Accepted Answer

Light energy is converted to chemical energy in the form of ATP and NADPH.

Question 11

If a plant's leaves are the primary site of photosynthesis, what would you expect to find in large amounts in the leaf cells?

Accepted Answer

Chloroplasts

Question 12

Which of the following is a product of the light reactions of photosynthesis that is used in the Calvin cycle?

Accepted Answer

NADPH

Question 13

Which of the following is a correct comparison between photosynthesis and cellular respiration?

Accepted Answer

Photosynthesis is endergonic overall, while cellular respiration is exergonic overall.

Question 14

Which of the following best explains why red wavelengths of light have less energy than purple wavelengths?

Accepted Answer

Red light has a longer wavelength and lower frequency than purple light, resulting in lower photon energy ($$E = h 
u).$$

Question 15

If the primary electron acceptor of photosystem II is inhibited, what would happen to the levels of NADPH and ATP in the stroma?

Accepted Answer

Both NADPH and ATP production would decrease because electron flow through the electron transport chain would stop.

Question 16

Which of the following is a benefit of photosynthetic products to humans?

Accepted Answer

All of the above (to make starch, to make cellulose, to make molecules used in protein synthesis)

Question 17

Which of the following is a common misconception about the greenhouse effect?

Accepted Answer

The greenhouse effect is always bad, but in reality, it is necessary for maintaining Earth's temperature.

Question 18

Which of the following best describes the role of RuBP in the Calvin cycle?

Accepted Answer

RuBP is regenerated in the final chemical reaction, allowing the cycle to continue.

Question 19

Which of the following is a long-term change of the global climate for long periods of time?

Accepted Answer

Climate change

Question 20

Which of the following best explains why the splitting of water is essential for the light reactions of photosynthesis?

Accepted Answer

It provides electrons to replace those lost by chlorophyll in photosystem II.

Photosynthesis: Using Light to Make Food – Study Guide

Guida di studio - Domande di pratica

Study guide - Flashcard