Question

Trees are sometimes called the “lungs” of the planet. The oxygen they release comes from

Select one:

a. Photosystem 2

b. The Krebs cycle

c. The Calvin cycle

d. Photosystem 1

e. Pyruvate oxidation

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Which of the following best describes the process of fermentation?

Select one:

a. It allows the production of ATP in oxygen-rich environments

b. It oxidizes NADH to NAD+

c. It leads to the production of lactic acid in yeast cells

d. It allows glycolysis to proceed in oxygen-poor environment by oxidizing NADH into NAD+

e. It leads to the production of ethanol in muscle cells

f. It produces 2 Lactase molecules per glucose

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Which of the following is correct about the cyclic electron flow that takes place during photosynthesis

Select one:

a. It is required because the Calvin cycle uses more ATP than NADPH

b. It happens when C3 plants get too hot

c. It happens when C3 plants have too much oxygen trapped in their cells

d. It is the most prevalent type of electron flow observed in the thylakoid membrane

e. It may happen in C3, C4, and CAM plants

f. Both A and E are correct

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Answer 1

Answere :

Question 1 :  The correct option is Option a i.e. "Photosystem 2".

Photosystem 2 is oxygen-evolving complex and act as a site of water oxidation which produces dioxygen gas and protons. Photosystem 2 splits water to replace its lost electrons and produces oxygen.

Question 2 : The correct option is Option d i.e. "It allows glycolysis to proceed in oxygen-poor environment by oxidizing NADH into NAD".

Fermentation takes place in oxygen-poor condition muscle cells, some bacteria and yeast. It produce less amount of ATP.

Question 3 : The correct option is Option f i.e. "Both A and E are correct".

Cyclic electron flow only uses Photosystem 1, and produces only ATP. It takes place in C3, C4 and CAM plants. It exists because of the Calvin cycle. The Calvin cycle uses more ATP than NADPH. Since non-cyclic electron flow produce equal amounts of ATP and NADPH it uses the cyclic pathway to compensate for it.

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