Photosynthesis & Respiration

Question 1

What are the two stages of photosynthesis?

Answer 1

The light-dependent stage and the Calvin Cycle (light-independent stage).

Question 2

Where does the light-dependent reaction occur?

Answer 2

In the thylakoid membranes.

Question 3

What is the role of chlorophyll in photosynthesis?

Answer 3

Absorbs light energy to excite electrons.

Question 4

What process produces oxygen in photosynthesis?

Answer 4

Photolysis of water.

Question 5

What are the main products of the light-dependent reaction?

Answer 5

ATP, NADPH, and oxygen.

Question 6

What is chemiosmosis in photosynthesis?

Answer 6

The movement of H+ ions through ATP synthase to form ATP.

Question 7

How is NADP+ reduced during photosynthesis?

Answer 7

By electrons from the electron transport chain and hydrogen ions.

Question 8

What pigment is the primary photosystem I (PSI) component?

Answer 8

Chlorophyll a.

Question 9

What limits the Calvin Cycle when there is insufficient light?

Answer 9

Reduced levels of ATP and NADPH.

Question 10

What is the role of stroma in photosynthesis?

Answer 10

It houses enzymes for the Calvin Cycle.

Question 11

Where does the Calvin Cycle occur?

Answer 11

In the stroma of chloroplasts.

Question 12

What enzyme catalyzes the fixation of CO2 in the Calvin Cycle?

Answer 12

Rubisco.

Question 13

What molecule does CO2 combine with to form 3-phosphoglycerate (GP)?

Answer 13

Ribulose bisphosphate (RuBP).

Question 14

What is the primary sugar product of the Calvin Cycle?

Answer 14

Glyceraldehyde 3-phosphate (G3P).

Question 15

How many molecules of ATP are consumed per turn of the Calvin Cycle?

Answer 15

Three ATP molecules.

Question 16

How many molecules of NADPH are used per turn of the Calvin Cycle?

Answer 16

Two NADPH molecules.

Question 17

What percentage of triose phosphate molecules are used to regenerate RuBP?

Answer 17

Five-sixths.

Question 18

What is the significance of triose phosphate in plants?

Answer 18

It is a precursor for carbohydrates, lipids, and amino acids.

Question 19

How many cycles of the Calvin Cycle are required to produce one glucose molecule?

Answer 19

Six cycles.

Question 20

Why does the Calvin Cycle stop in the absence of light?

Answer 20

It depends on ATP and NADPH produced in the light-dependent reactions.

Question 21

What are the four stages of aerobic respiration?

Answer 21

Glycolysis, Link Reaction, Krebs Cycle, and Oxidative Phosphorylation.

Question 22

Where does glycolysis occur?

Answer 22

In the cytoplasm.

Question 23

What is the net gain of ATP from glycolysis?

Answer 23

Two ATP molecules.

Question 24

What molecule is formed in the link reaction?

Answer 24

Acetyl CoA.

Question 25

How many ATP molecules are produced per glucose molecule in oxidative phosphorylation?

Answer 25

Around 34 ATP.

Question 26

What is the final electron acceptor in the electron transport chain?

Answer 26

Oxygen.

Question 27

What happens to NADH and FADH2 in oxidative phosphorylation?

Answer 27

They are oxidized to release electrons.

Question 28

What is the purpose of anaerobic respiration?

Answer 28

To provide the individual with quick energy needed to sustain intense levels of activity.

Question 29

What is the byproduct of lactic acid fermentation in muscles?

Answer 29

Lactate.

Question 30

What is chemiosmosis in respiration?

Answer 30

The use of a proton gradient to drive ATP synthesis in mitochondria.

Question 31

What molecule enters the Krebs Cycle?

Answer 31

Acetyl CoA (2C).

Question 32

Where does the Krebs Cycle occur?

Answer 32

In the mitochondrial matrix.

Question 33

What compound does Acetyl CoA combine with to form citrate?

Answer 33

Oxaloacetate (4C).

Question 34

How many CO2 molecules are released per turn of the Krebs Cycle?

Answer 34

Two CO2 molecules.

Question 35

What is the main purpose of the Krebs Cycle?

Answer 35

To produce reduced NAD (NADH), reduced FAD (FADH2), and ATP.

Question 36

How many NADH molecules are generated per cycle?

Answer 36

Three NADH molecules.

Question 37

What enzyme facilitates the substrate-level phosphorylation in the Krebs Cycle?

Answer 37

Succinyl-CoA synthetase.

Question 38

How many ATP (or GTP) molecules are produced per turn of the Krebs Cycle?

Answer 38

One ATP (or GTP).

Question 39

What molecule is regenerated at the end of the Krebs Cycle?

Answer 39

Oxaloacetate.

Question 40

How is FADH2 formed in the Krebs Cycle?

Answer 40

By the oxidation of succinate to fumarate.