[23] Photosynthesis

Question 1

What is photosynthesis?

Answer 1

It’s the process by which green plants and some other organisms use sunlight to synthesize foods with the help of chlorophyll pigments.

Question 2

Where does photosynthesis take place?

Answer 2

In the chloroplasts of plant cells.

Question 3

What are the main stages of photosynthesis?

Answer 3

1. Light-dependent reactions
2. Calvin cycle (light-independent reactions)

Question 4

What is the overall equation for photosynthesis?

Answer 4

6CO2 (carbon dioxide) + 6H2O (water) + light energy = C6H12O6 (glucose) + 6O2 (oxygen)

Question 5

What role does light energy play in photosynthesis?

Answer 5

Light energy is absorbed by chlorophyll and converted into chemical energy in the form of ATP and NADPH.

Question 6

What are the products of light-dependent reactions?

Answer 6

1. ATP
2. NADPH
3. Oxygen

Question 7

What is the Calvin cycle?

Answer 7

It’s the set of light-independent reactions in photosynthesis where atmospheric carbon dioxide is reduced to form glucose.

Question 8

What are the products of the Calvin cycle?

Answer 8

1. Glucose
2. ADP
3. NADP+

Question 9

How does photosynthesis impact the global carbon cycle?

Answer 9

Photosynthesis removes carbon dioxide from the atmosphere and converts it into organic compounds, primarily in the form of stored glucose.

Question 10

What is chlorophyll?

Answer 10

It’s a green pigment found in the chloroplasts of plants that absorbs light energy for photosynthesis.

Question 11

What are the two main types of chlorophyll?

Answer 11

1. Chlorophyll a
2. Chlorophyll b

Question 12

How does water contribute to photosynthesis?

Answer 12

Water molecules are split in the process, releasing oxygen and providing electrons to replenish those lost by chlorophyll a in light-dependent reactions.

Question 13

What role does carbon dioxide play in photosynthesis?

Answer 13

Carbon dioxide is used in the Calvin cycle to produce glucose.

Question 14

What is photorespiration?

Answer 14

It’s a process that competes with the Calvin cycle, occurring when oxygen levels are high and carbon dioxide levels are low, leading to a net loss of carbon and nitrogen.

Question 15

What is ATP?

Answer 15

ATP (adenosine triphosphate) is a high-energy molecule that stores and provides energy in living cells.

Question 16

Define NADPH.

Answer 16

NADPH (nicotinamide adenine dinucleotide phosphate) is a coenzyme used in anabolic reactions, such as lipid and nucleic acid synthesis, which require NADPH as a reducing agent.

Question 17

How do temperature and light intensity affect photosynthesis?

Answer 17

Both can increase the rate of photosynthesis up to a certain point. Too high temperature or light intensity, however, can decrease the rate due to damage to the photosynthetic machinery.

Question 18

What is C4 photosynthesis?

Answer 18

It’s a modification of the traditional photosynthetic process, designed to efficiently handle high light intensities and temperatures, and low CO2 concentrations. C4 plants include corn and sugarcane.

Question 19

What is CAM photosynthesis?

Answer 19

CAM (Crassulacean Acid Metabolism) is another photosynthetic adaptation in plants living in arid conditions, allowing them to conserve water. CAM plants include succulents and cacti.