Q: Which of the following correctly summarizes the overall equation for photosynthesis?

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

Question 1

Which of the following best describes the difference between autotrophs and heterotrophs?

Accepted Answer

Autotrophs produce organic molecules from inorganic sources, while heterotrophs must consume organic molecules produced by other organisms.

Question 2

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

Accepted Answer

Thylakoid membrane

Question 3

What is the three-carbon sugar molecule produced directly by the Calvin cycle that is used to synthesize glucose?

Accepted Answer

Glyceraldehyde 3-phosphate (G3P)

Question 4

Which experiment demonstrated that the oxygen produced during photosynthesis comes from water and not carbon dioxide?

Accepted Answer

Using heavy oxygen ($$^{18}\mathrm{O}) in $$water and detecting its presence in released O$$_2$$

Question 5

Which of the following correctly summarizes the overall 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 6

What is the main function of the stomata in plant leaves?

Accepted Answer

To facilitate gas exchange by allowing CO$$_2 in $$and O$$_2$$ out

Question 7

Which pigment is primarily responsible for absorbing light energy during photosynthesis, and what is the central ion in its porphyrin ring?

Accepted Answer

Chlorophyll a; magnesium ($$\mathrm{Mg}^{2+})$$

Question 8

What is the role of NADP$$^+ in $$the light reactions of photosynthesis?

Accepted Answer

It is the final electron acceptor, becoming reduced to NADPH.

Question 9

Which of the following best describes photophosphorylation?

Accepted Answer

The process of using light energy to add a phosphate group to ADP, forming ATP.

Question 10

Which photosystem is most efficient at absorbing light with a wavelength of 680 nm, and what is the special pair of chlorophyll a molecules called?

Accepted Answer

Photosystem II; P680

Question 11

During the linear electron flow in the light reactions, what is the correct sequence of electron movement?

Accepted Answer

Photosystem II → Electron Transport Chain → Photosystem I → NADP$$^+$$

Question 12

Which enzyme catalyzes the fixation of CO$$_2 to $$ribulose bisphosphate (RuBP) in the Calvin cycle?

Accepted Answer

Rubisco (RuBP carboxylase/oxygenase)

Question 13

How many turns of the Calvin cycle are required to produce one molecule of glucose ($$\mathrm{C}_6\mathrm{H}_{12}\mathrm{O}_6$$)?

Accepted Answer

Six

Question 14

Which of the following best explains why photorespiration is considered inefficient and energetically wasteful?

Accepted Answer

It consumes O$$_2$$ and organic fuel without producing ATP or sugar.

Question 15

C4 plants have evolved a mechanism to minimize photorespiration. Which two types of cells are involved in this process, and how does this adaptation help?

Accepted Answer

Mesophyll and bundle-sheath cells; CO$$_2 is $$concentrated in bundle-sheath cells, reducing oxygenase activity of rubisco.

Question 16

Which statement best describes the difference between chemiosmosis in mitochondria and chloroplasts?

Accepted Answer

Both generate ATP, but mitochondria pump protons into the intermembrane space, while chloroplasts pump protons into the thylakoid lumen.

Question 17

Which adaptation allows CAM plants to survive in arid environments?

Accepted Answer

They open their stomata at night to fix CO$$_2$$ and close them during the day to minimize water loss.

Question 18

What is the fate of most of the sugar produced by photosynthesis in plants?

Accepted Answer

Some is used for the plant's metabolism, while the rest supports other organisms in the ecosystem.

Question 19

Which device is used to measure the absorption spectrum of pigments such as chlorophyll?

Accepted Answer

Spectrophotometer

Chapter 8: Photosynthesis – Study Guide and Learning Objectives

Study Guide - Practice Questions

Study Guide - Flashcards