Q: What is the overall balanced chemical equation for photosynthesis?

$$6 \ \mathrm{CO}_2 + 12 \ \mathrm{H}_2\mathrm{O} + \text{Light energy} \rightarrow \mathrm{C}_6\mathrm{H}_{12}\mathrm{O}_6 + 6 \ \mathrm{O}_2 + 6 \ \mathrm{H}_2\mathrm{O}$$

Question 1

Which of the following organisms are capable of photosynthesis, as shown in the provided images and study materials?

Accepted Answer

Plants, multicellular algae, unicellular eukaryotes, and some prokaryotes

Question 2

What is the overall balanced chemical equation for photosynthesis?

Accepted Answer

$$6 \ \mathrm{CO}_2 + 12 \ \mathrm{H}_2\mathrm{O} + 	ext{Light energy} ightarrow \mathrm{C}_6\mathrm{H}_{12}\mathrm{O}_6 + 6 \ \mathrm{O}_2 + 6 \ \mathrm{H}_2\mathrm{O}$$

Question 3

Which structure in the leaf is primarily responsible for gas exchange during photosynthesis?

Accepted Answer

Stomata

Question 4

Why is photosynthesis considered an endergonic process?

Accepted Answer

It requires an input of energy from sunlight to drive the reaction

Question 5

Which pigment is the main photosynthetic pigment in plants, and what is its primary function?

Accepted Answer

Chlorophyll a; it absorbs light energy to drive the light reactions

Question 6

What is the significance of the absorption spectrum of chlorophyll a in photosynthesis?

Accepted Answer

It shows that violet-blue and red light are most effective for photosynthesis

Question 7

During the light reactions of photosynthesis, what is the primary function of the electron transport chain between Photosystem II and Photosystem I?

Accepted Answer

To create a proton gradient that drives ATP synthesis

Question 8

Which of the following best describes the role of water in the light reactions of photosynthesis?

Accepted Answer

Water is split to provide electrons to Photosystem II and releases O$$_2 as a by-$$product

Question 9

What is the main product of the Calvin cycle that can be used to form glucose and other organic molecules?

Accepted Answer

Glyceraldehyde 3-phosphate (G3P)

Question 10

Which enzyme catalyzes the first step of carbon fixation in the Calvin cycle, and what is a major limitation of this enzyme?

Accepted Answer

Rubisco; it can also bind O$$_2$$, leading to photorespiration

Question 11

In C$$_4$$ plants, what is the advantage of using PEP carboxylase for the initial fixation of CO$$_2$$?

Accepted Answer

PEP carboxylase has a higher affinity for CO$$_2$$ and can fix CO$$_2$$ even when its concentration is low

Question 12

Which of the following statements best explains why CAM plants are well adapted to arid environments?

Accepted Answer

They open their stomata at night to minimize water loss while still allowing CO$$_2$$ uptake

Question 13

Which of the following best describes the relationship between wavelength and energy in the electromagnetic spectrum?

Accepted Answer

Shorter wavelengths have higher energy

Question 14

What is the main function of carotenoids in the photosynthetic apparatus?

Accepted Answer

They absorb excessive light energy and provide photoprotection

Question 15

During the light reactions, what is the final electron acceptor that is reduced to form NADPH?

Accepted Answer

NADP$$^+$$

Question 16

Which of the following best explains why photorespiration is considered a wasteful process in C$$_3$$ plants?

Accepted Answer

It consumes O$$_2$$ and organic fuel, releases CO$$_2$$, and does not produce ATP or sugar

Question 17

A plant is exposed to only green light. What would you expect to happen to its rate of photosynthesis, and why?

Accepted Answer

The rate would decrease because chlorophyll reflects green light rather than absorbing it

Question 18

Which of the following is a correct sequence of events in the linear electron flow of the light reactions?

Accepted Answer

Photon excites P680 → Electron transferred to primary acceptor → Water split to replace electron → Electron transport chain → ATP synthesis → Electron excites P700 → NADP$$^+$$ reduced to NADPH

Question 19

A researcher wants to increase the yield of sugar production in a greenhouse. Which of the following strategies would most likely be effective, based on your knowledge of photosynthesis?

Accepted Answer

Increase the intensity of red and blue light provided to the plants

Photosynthesis: Mechanisms, Adaptations, and Energy Conversion

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