Chapter 8 BIOL 131

Question 1

What waste product do plants give off during photosynthesis?

Answer 1

Oxygen

This oxygen comes from photolysis.

Question 2

How many turns of the Calvin cycle are required to produce one molecule of glucose?

Answer 2

6

Question 3

Which process produces ATP by light energy?

Answer 3

Cyclin photophosphorylation

Question 4

Which component is not used by both plants and cyanobacteria for photosynthesis?

Answer 4

Chloroplasts

Question 5

What are the two main products of photosynthesis?

Answer 5

Sugars/carbohydrates and oxygen

Question 6

In which compartment of the plant cell do the light-independent reactions occur?

Answer 6

Stroma

Question 7

Which statement about thylakoids in eukaryotes is not correct?

Answer 7

Thylakoids exist as a maze of folded membranes

Question 8

What is the predicted end result if light-independent enzymes in a chloroplast cannot activate in response to light?

Answer 8

ATP and NADPH accumulation

Question 9

How are NADPH and G3P similar?

Answer 9

They both store energy in chemical bonds

Question 10

Which structure is not a component of a photosystem?

Answer 10

ATP synthase

Question 11

How many photons are needed to fully reduce one molecule of NADP+ to NADPH?

Answer 11

2

Question 12

Which complex is not involved in ATP synthesis?

Answer 12

Photosystem I

Question 13

From which component of light-dependent reactions does NADPH form most directly?

Answer 13

Photosystem I

Question 14

What is the predicted order of plant growth under different colored lights: blue, green, and orange?

Answer 14

A, C, B

Question 15

Which plants harness the most energy for photosynthesis when exposed to different wavelengths?

Answer 15

Blue light irradiated plants

Question 16

Which molecule must continually enter the Calvin cycle?

Answer 16

CO2

Question 17

What is the correct order of molecular conversions in the Calvin cycle?

Answer 17

RuBP + CO2 → [RuBisCO] 3-PGA → G3P

Question 18

Where does the Calvin cycle take place in eukaryotic cells?

Answer 18

Chloroplast stroma

Question 19

What correctly describes carbon fixation?

Answer 19

The conversion of CO2 into an organic compound

Question 20

If four molecules of carbon dioxide enter the Calvin cycle, how many G3P molecules are produced?

Answer 20

4 G3P made, 1 G3P exported

Question 21

Please describe the major differences of photosynthesis in C3, C4, and CAM plants.

Question 22

What is photosynthesis?

Answer 22

The process by which organisms use energy from sunlight and electrons from water to reduce CO2 to glucose

Photosynthesis evolved around 3.5 billion years ago.

Question 23

What are photoautotrophs?

Answer 23

Organisms that use sunlight to produce their own food through photosynthesis

Examples include plants, algae, and some bacteria.

Question 24

What is the redox reaction that changed life on Earth?

Answer 24

H2O is oxidized to O2 gas, and CO2 is reduced to glucose (C6H12O6)

This reaction facilitated the evolution of aerobic life.

Question 25

What role do stromatolites play in photosynthesis?

Answer 25

They primed the atmosphere for aerobic life by producing oxygen ## Footnote Stromatolites are layered structures formed by the activity of microorganisms.

Question 26

What are the two main pathways of photosynthesis?

Answer 26

The Light Reactions and the Calvin Cycle ## Footnote The Light Reactions convert light energy to chemical energy, while the Calvin Cycle synthesizes carbohydrates.

Question 27

What are photons?

Answer 27

Discrete packets of light energy ## Footnote Photons can be scattered, transmitted, or absorbed by molecules.

Question 28

Why are most plants green?

Answer 28

Because chloroplasts absorb all but green light ## Footnote Chlorophyll pigments primarily absorb blue and red light.

Question 29

What is the absorption spectrum?

Answer 29

The range of wavelengths absorbed by a pigment ## Footnote It indicates which light wavelengths are utilized in photosynthesis.

Question 30

What are accessory pigments?

Answer 30

Pigments that assist in capturing light energy, including carotenoids and phycobilins ## Footnote They help broaden the spectrum of light absorbed for photosynthesis.

Question 31

What is the role of Rubisco in the Calvin Cycle?

Answer 31

Rubisco fixes CO2 to 5-C RuBP during the first step of the Calvin Cycle ## Footnote It is a crucial enzyme for carbon fixation.

Question 32

What is photorespiration?

Answer 32

A process that consumes O2 and releases CO2, reducing plant growth ## Footnote It occurs when Rubisco acts as an oxygenase instead of a carboxylase.

Question 33

What are C3 plants?

Answer 33

Plants that fix CO2 to 3PG, abundant in Rubisco in mesophyll cells ## Footnote Photorespiration is common in C3 plants, especially on hot days.

Question 34

What are C4 plants?

Answer 34

Plants that utilize two separate enzymes for CO2 fixation, producing 4-C oxaloacetate ## Footnote They minimize photorespiration by moving Rubisco to bundle sheath cells.

Question 35

What is the CAM pathway?

Answer 35

Crassulacean Acid Metabolism, where CO2 is fixed at night and stored as malic acid ## Footnote During the day, malic acid is decarboxylated to supply CO2 for the Calvin Cycle.

Question 36

How do C4 and CAM plants differ from C3 plants?

Answer 36

C4 and CAM plants have adaptations to minimize photorespiration and water loss ## Footnote They use different mechanisms for CO2 fixation and timing of stomatal opening.

Question 37

What is the Calvin Cycle's main function?

Answer 37

To synthesize carbohydrates using chemical energy ## Footnote It occurs in the stroma of chloroplasts.

Question 38

Fill in the blank: The enzyme that catalyzes the first step of the Calvin Cycle is _______.

Answer 38

Rubisco

Question 39

True or False: The light-independent reactions of photosynthesis do not require light.

Answer 39

True ## Footnote However, they are stimulated by light through changes in pH and electron flow.

Question 40

What happens during chemiosmosis in photosynthesis?

Answer 40

Protons are pumped from stroma into thylakoids, creating a proton gradient ## Footnote This gradient is used to synthesize ATP.