Photosynthesis

Question 1

Where do light-dependent reactions occur?

Answer 1

In the chloroplast, specifically in the thylakoid membrane.

Question 2

What are the inputs for light-dependent reactions?

Answer 2

Water (H₂O), light energy, ADP, and NADP⁺.

Question 3

What is produced during light-dependent reactions?

Answer 3

O₂, ATP, and NADPH.

Question 4

What is the role of Photosystem II (PSII) in light-dependent reactions?

Answer 4

Absorbs light energy and splits water to produce oxygen, protons, and electrons.

Question 5

Fill in the blank: The proton concentration gradient drives ATP synthesis via _______.

Answer 5

ATP synthase.

Question 6

What is the first step of the Calvin Cycle?

Answer 6

Carbon fixation of CO₂ onto RuBP.

Question 7

What enzyme catalyzes the reaction in carbon fixation?

Answer 7

Rubisco.

Question 8

What is produced during the reduction phase of the Calvin Cycle?

Answer 8

G3P (glyceraldehyde-3-phosphate).

Question 9

How many G3P molecules exit the Calvin Cycle to form sugars?

Answer 9

1 out of 6 G3P molecules.

Question 10

What happens to the remaining G3P molecules in the Calvin Cycle?

Answer 10

They regenerate RuBP using ATP.

Question 11

What is the output of the Calvin Cycle?

Answer 11

Sugars, RuBP, ADP, and NADP⁺.

Question 12

True or False: Photorespiration occurs when Rubisco fixes O₂ instead of CO₂.

Answer 12

True.

Question 13

What are the consequences of photorespiration?

Answer 13

Loss of fixed carbon and inefficient use of energy.

Question 14

What is C4 photosynthesis an adaptation for?

Answer 14

Hot climates with low CO₂ and high O₂ levels.

Question 15

What enzyme is involved in C4 photosynthesis to fix CO₂?

Answer 15

PEPcase.

Question 16

What is malic acid’s role in C4 photosynthesis?

Answer 16

It is formed from CO₂ and is transferred to bundle sheath cells.

Question 17

What advantage does C4 photosynthesis have over C3 photosynthesis?

Answer 17

More efficient in hot, dry climates.

Question 18

In CAM photosynthesis, when do stomata open?

Answer 18

At night.

Question 19

What is the main advantage of CAM photosynthesis?

Answer 19

Minimizes water loss in extreme environments.

Question 20

What is the equation for cellular respiration?

Answer 20

C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + ATP.

Question 21

Where does glycolysis occur?

Answer 21

In the cytoplasm.

Question 22

What are the outputs of cellular respiration?

Answer 22

ATP, CO₂, and H₂O.

Question 23

What is a waste product of photorespiration?

Answer 23

Phosphoglycolate.

Question 24

What is the primary function of photosynthesis?

Answer 24

To convert light energy into chemical energy in the form of glucose.

Question 25

What are the two main stages of photosynthesis?

Answer 25

Light-dependent reactions and the Calvin cycle.

Question 26

Where do light-dependent reactions occur?

Answer 26

In the thylakoid membranes of chloroplasts.

Question 27

What is produced during the light-dependent reactions?

Answer 27

ATP, NADPH, and oxygen.

Question 28

What absorbs light energy in plants?

Answer 28

Chlorophyll.

Question 29

True or False: The Calvin cycle requires light directly.

Answer 29

False.

Question 30

What is the main purpose of the Calvin cycle?

Answer 30

To synthesize glucose from carbon dioxide using ATP and NADPH.

Question 31

Fill in the blank: The Calvin cycle occurs in the _____ of the chloroplast.

Answer 31

stroma.

Question 32

What is the first stable product of the Calvin cycle?

Answer 32

3-phosphoglycerate (3-PGA).

Question 33

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

Answer 33

Ribulose bisphosphate carboxylase/oxygenase (RuBisCO).

Question 34

What is CAM photosynthesis?

Answer 34

A photosynthetic pathway that allows plants to fix CO2 at night to minimize water loss.

Question 35

Which types of plants typically use CAM photosynthesis?

Answer 35

Cacti and succulents.

Question 36

What is the main advantage of C4 photosynthesis?

Answer 36

It allows plants to efficiently capture CO2 even in low concentrations.

Question 37

Where does C4 photosynthesis occur in the plant?

Answer 37

In specialized bundle sheath cells.

Question 38

Fill in the blank: In C4 plants, CO2 is initially fixed into a four-carbon compound called _____.

Answer 38

oxaloacetate.

Question 39

True or False: Both CAM and C4 pathways are adaptations to hot and dry environments.

Answer 39

True.

Question 40

What are the two types of cells involved in C4 photosynthesis?

Answer 40

Mesophyll cells and bundle sheath cells.

Question 41

What is the role of NADPH in photosynthesis?

Answer 41

It provides reducing power for the synthesis of glucose in the Calvin cycle.

Question 42

What byproduct is released during the light-dependent reactions?

Answer 42

Oxygen.

Question 43

Which molecule acts as the energy currency in the cell during photosynthesis?

Answer 43

ATP.

Question 44

What is the significance of water in photosynthesis?

Answer 44

It is a source of electrons and protons and is split to release oxygen.

Question 45

Fill in the blank: The process of converting light energy into chemical energy occurs in the _____ reactions.

Answer 45

light-dependent.

Question 46

What is the role of RuBP in the Calvin cycle?

Answer 46

It is the five-carbon sugar that reacts with CO2 to initiate the cycle.

Question 47

What is the final product of the Calvin cycle that can be used to form glucose?

Answer 47

Glyceraldehyde-3-phosphate (G3P).

Question 48

True or False: C4 photosynthesis is more efficient than C3 photosynthesis in high light and temperature conditions.

Answer 48

True.

Question 49

What type of plants primarily utilize C3 photosynthesis?

Answer 49

Most temperate plants, including wheat and rice.