Question 1

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

Accepted Answer

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

Question 2

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

Accepted Answer

Water is oxidized and carbon dioxide is reduced.

Question 3

Which pigment is primarily responsible for the absorption of light in the light reactions of photosynthesis?

Accepted Answer

Chlorophyll a

Question 4

What is the main function of the Calvin cycle in photosynthesis?

Accepted Answer

To fix carbon dioxide and produce sugar using ATP and NADPH

Question 5

Which structure within the chloroplast is the site of the light reactions?

Accepted Answer

Thylakoid membrane

Question 6

Why do leaves appear green to the human eye?

Accepted Answer

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

Question 7

Which of the following wavelengths of light is most effective for photosynthesis?

Accepted Answer

Around 450 nm (violet-blue) and 670 nm (red)

Question 8

What is the role of water in the light reactions of photosynthesis?

Accepted Answer

It is split to provide electrons and protons, and oxygen is released as a by-product.

Question 9

Which process in photosynthesis is responsible for generating ATP?

Accepted Answer

Photophosphorylation

Question 10

In the Calvin cycle, what enzyme catalyzes the fixation of carbon dioxide?

Accepted Answer

Rubisco (R u B P carboxylase-oxygenase)

Question 11

Which of the following statements about the relationship between photosynthesis and cellular respiration is correct?

Accepted Answer

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

Question 12

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 13

Which of the following best explains why accessory pigments such as carotenoids are important in photosynthesis?

Accepted Answer

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

Question 14

Which of the following is true about the energy of photons and their wavelength?

Accepted Answer

Shorter wavelengths have higher energy per photon.

Question 15

What is the primary electron acceptor in the reaction center of a photosystem?

Accepted Answer

It accepts excited electrons from chlorophyll a molecules.

Question 16

Which photosystem is best at absorbing light with a wavelength of 680 nm?

Accepted Answer

Photosystem II (P680)

Question 17

What is the main difference between cyclic and linear electron flow in the light reactions?

Accepted Answer

Cyclic electron flow produces ATP but not NADPH or O2.

Question 18

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

Accepted Answer

9 ATP and 6 NADPH

Question 19

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

Accepted Answer

Both use a proton gradient across a membrane to drive ATP synthesis.

Question 20

Which of the following is a real-world consequence of photosynthesis for life on Earth?

Accepted Answer

It provides the energy and organic molecules necessary for nearly all living organisms.

Photosynthesis: Mechanisms, Pigments, and Importance in the Biosphere

Guida di studio - Domande di pratica