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

Question 1

Which of the following best describes the overall chemical reaction for photosynthesis in land plants?

Accepted Answer

$$6CO_2 + 12H_2O + 	ext{light energy} ightarrow C_6H_{12}O_6$ + 6H_2O + 6O_2$$

Question 2

In the process of photosynthesis, which molecule acts as the primary electron carrier during the light-dependent reactions?

Accepted Answer

NADPH

Question 3

Where in a eukaryotic cell do the light-dependent reactions of photosynthesis take place?

Accepted Answer

Thylakoid membranes of the chloroplast

Question 4

Which pigment is primarily responsible for absorbing red and blue light and transmitting green light in photosynthetic organisms?

Accepted Answer

Chlorophyll a and b

Question 5

What is the main function of carotenoids in photosynthetic cells?

Accepted Answer

Absorb wavelengths of light not absorbed by chlorophyll and protect against photooxidative damage

Question 6

Which structure within the chloroplast is the site of the Calvin cycle?

Accepted Answer

Stroma

Question 7

What is the role of RuBisCO in photosynthesis?

Accepted Answer

It catalyzes the fixation of CO$$_2 to an $$organic molecule in the Calvin cycle

Question 8

Why does photorespiration decrease the efficiency of photosynthesis?

Accepted Answer

It uses ATP and produces CO$$_2$$ without generating sugars

Question 9

Which of the following best explains why stomata are usually open during the day?

Accepted Answer

To allow CO$$_2 to $$diffuse into the leaf for photosynthesis

Question 10

During the Calvin cycle, what is the immediate product after the reduction phase?

Accepted Answer

Glyceraldehyde 3-phosphate (G3P)

Question 11

If a plant closes its stomata during hot, dry conditions, what is the most likely consequence for photosynthesis?

Accepted Answer

Reduced CO$$_2$$ uptake, leading to increased photorespiration and decreased sugar production

Question 12

Which of the following statements about the Z scheme in photosynthesis is correct?

Accepted Answer

It describes the interaction between photosystem I and photosystem II to produce ATP and NADPH

Question 13

What is the fate of the G3P molecules produced in the Calvin cycle?

Accepted Answer

They are used to synthesize glucose, fructose, sucrose, and starch

Question 14

Which of the following is a correct comparison between photosynthesis and cellular respiration?

Accepted Answer

Photosynthesis stores energy in glucose, while cellular respiration releases energy from glucose

Question 15

A mutation causes a plant to produce defective carotenoids. What is the most likely effect on the plant?

Accepted Answer

Reduced ability to absorb certain wavelengths and increased susceptibility to photooxidative damage

Question 16

Which of the following best explains why green light is not effective for driving photosynthesis?

Accepted Answer

Green light is transmitted rather than absorbed by chlorophyll, so it does not excite electrons to usable energy levels

Question 17

Which phase of the Calvin cycle involves the attachment of carbon atoms from CO$$_2 to $$organic compounds?

Accepted Answer

Fixation

Question 18

If a plant is exposed only to green light, what would you expect to happen to its rate of photosynthesis?

Accepted Answer

It would decrease significantly because chlorophyll does not absorb green light

Question 19

Which of the following is true about the ATP produced in the light-dependent reactions of photosynthesis?

Accepted Answer

It is used specifically for the Calvin cycle, not for general cellular functions

BIO181- 3.4: Photosynthesis (UNIT3-Energy & Metabolism)

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