Bioenergetics

Question 1

What is the word equation for photosynthesis?

Answer 1

carbon dioxide + water -> glucose + oxygen

Question 2

How do plants use glucose?

Answer 2

• For respiration to transfer energy
• Making cellulose (for plant cell walls)
• Making amino acids
• Stored as lipids (oils and fats) in seeds
• Stored as starch in roots, stems or leaves to be used for when photosynthesis can’t occur

Question 3

What are the limiting factors of photosynthesis?

Answer 3

• light intensity
• CO2 concentration
• temperature

Question 4

How does light affect the rate of photosynthesis?

Answer 4

Light provides the energy for photosynthesis so as it is increased the rate of photosynthesis increases however this is only up to a certain point.

Question 5

How does the concentration of carbon dioxide affect the rate of photosynthesis?

Answer 5

Carbon dioxide will increase the rate of photosynthesis but only up to a certain point.

Question 6

How does temperature affect the rate of photosynthesis?

Answer 6

Enzymes need to have the right conditions for photosynthesis. If too cold, they will work slowly but if above 45° the enzymes will be destroyed.

Question 7

What is the inverse square law (relating to light intensity)?

Answer 7

light intensity ∝ 1/distance²

Question 8

What is respiration?

Answer 8

The process of transferring energy from glucose. It takes place in every cell.

Question 9

What do organisms use the energy from respiration for?

Answer 9

• building larger molecules from smaller molecules
• for muscle contraction (in animals)
• body temperature

Question 10

What is aerobic respiration?

Answer 10

Respiration using oxygen that occurs all the time in animals and plants.

Question 11

What is anaerobic respiration?

Answer 11

Respiration without oxygen that occurs when not enough oxygen is being supplied to your cells

Question 12

What is the word equation for aerobic respiration?

Answer 12

glucose + oxygen -> carbon dioxide + water

Question 13

What is the word equation for anaerobic respiration in animals?

Answer 13

glucose -> lactic acid

Question 14

What is the word equation for anaerobic respiration in plants and yeast?

Answer 14

glucose -> ethanol + carbon dioxide

Question 15

What happens to a body when it exercises?

Answer 15

• increased respiration
• breathing rate increases
• breath volume increases
• heart rate increases

Question 16

What happens when you do vigorous exercise?

Answer 16

Your body can’t supply enough oxygen so starts to respire anaerobically. This could lead to lactic acid building up in the muscles, which can be painful. It could also lead to muscle fatigue.

Question 17

What is oxygen debt?

Answer 17

After exercising and respiring anaerobically, the body will need extra amounts of oxygen to react with the lactic acid in the cells to remove it. As the oxygen needs to be repaid, you will have to keep breathing hard after you’ve stopped exercising.

Question 18

What is an alternative way to repaying oxygen (which is in debt) to get rid of a build up of lactic acid?

Answer 18

The blood transports lactic acid to the liver so that the liver can transport it back to glucose.