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

Question 1

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

Accepted Answer

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

Question 2

Which structure within the chloroplast is primarily responsible for the light-capturing reactions of photosynthesis?

Accepted Answer

Thylakoid membrane

Question 3

Why do plants appear green to the human eye?

Accepted Answer

Chlorophyll reflects and transmits green wavelengths of light

Question 4

Which of the following statements about the energy of photons is correct?

Accepted Answer

The energy of a photon is inversely proportional to its wavelength

Question 5

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

Accepted Answer

The rate of photosynthesis will decrease because chlorophyll does not absorb green light efficiently

Question 6

What is the primary function of carotenoids in photosynthetic organisms?

Accepted Answer

They absorb wavelengths of light not absorbed by chlorophyll and protect chlorophyll from damage

Question 7

Which part of the chlorophyll molecule is directly involved in absorbing light energy?

Accepted Answer

The head, which contains a large ring structure with a magnesium atom

Question 8

What is the main ecological significance of the Calvin cycle?

Accepted Answer

It fixes inorganic carbon dioxide into organic molecules, supporting nearly all life on Earth

Question 9

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

Accepted Answer

Rubisco (Ribulose-1,5-bisphosphate carboxylase/oxygenase)

Question 10

Why is Rubisco considered an inefficient enzyme?

Accepted Answer

It can catalyze the addition of both CO$$_2$$ and O$$_2$$, leading to photorespiration

Question 11

Which of the following best describes the three phases of the Calvin cycle?

Accepted Answer

Fixation, reduction, regeneration

Question 12

What is the fate of glyceraldehyde-3-phosphate (G3P) produced in the Calvin cycle?

Accepted Answer

It is used to synthesize glucose, fructose, and other organic molecules

Question 13

How do plants minimize water loss while still allowing for gas exchange during photosynthesis?

Accepted Answer

By opening and closing stomata, which are surrounded by guard cells

Question 14

Which of the following is a direct product of the light-capturing reactions of photosynthesis?

Accepted Answer

ATP and NADPH

Question 15

A mutation causes a plant to lack carotenoids. Which of the following is a likely consequence?

Accepted Answer

The plant will be more susceptible to damage from free radicals

Question 16

Which of the following best explains why the Calvin cycle is dependent on the light-capturing reactions?

Accepted Answer

The Calvin cycle requires ATP and NADPH produced by the light-capturing reactions

Question 17

Which of the following is a real-world application of understanding photosynthesis in agriculture?

Accepted Answer

Optimizing light conditions in greenhouses to maximize crop yield

Question 18

If a plant's stomata remain closed for an extended period, what is the most likely effect on photosynthesis?

Accepted Answer

Photosynthesis will decrease due to limited CO$$_2$$ uptake

Question 19

Which of the following statements about the fate of sucrose and starch in plant cells is correct?

Accepted Answer

Sucrose is synthesized in the cytosol, while starch is produced inside the chloroplast

Photosynthesis: Mechanisms, Pigments, and Carbon Fixation

Study Guide - Practice Questions