Topic 4 - Bioenergetics

Question 1

What is the equation for photosynthesis ?

Answer 1

Carbon dioxide + water to glucose and oxygen

Question 2

What is the effect of temperature on the rate of photosynthesis ?

Answer 2

With an increase in temperature, the rate of photosynthesis increases. As the reaction is controlled by enzymes, this trend continues up to a certain temperature until the enzymes begin to denature and the rate of reaction decreases.

Question 3

What is the effect of light intensity on the reate of photosynthesis?

Answer 3

For most plants, the higher the light intensity, the faster the rate of the reaction.

Question 4

What is the effect of carbon dioxide concentration on the rate of photosynthesis?

Answer 4

Carbon dioxide is also needed to make glucose (see equation). As the concentration of carbon dioxide increases, the rate of reaction increases.

Question 5

What is the effect of the amount of chlorophyll on the rate of photosynthesis?

Answer 5

Chlorophyll is a pigment in the leaf that converts light energy to food for the plant, and is therefore essential. If, for example, chlorophyll levels are reduced through a magnesium deficiency, then the rate of photosynthesis would decrease.

Question 6

What is inverse square law ?

Answer 6

The light intensity is inversely proportional to the square of distance

Question 7

What are the uses of glucose ?

Answer 7

• for respiration
• converted into insoluble starch for storage
• to produce fat or oil for storage in seeds
• to produce cellulose to strengthen cell walls
• combined with nitrates from the soil to form amino acids which produce proteins

Question 8

What is the equation for aerobic respiration ?

Answer 8

Glucose and oxygen to carbon dioxide and water

Question 9

What is the equation for anaerobic respiration ?

Answer 9

Glucose to lactic acid

Question 10

What is the equation for fermentation?

Answer 10

Glucose to ethanol and carbon dioxide

Question 11

How is more oxygen supplied to cells during exercise ?

Answer 11

• heart rate increasing
• breathing rate increasing
• breath volume increasing

Question 12

What is oxygen debt ?

Answer 12

The amount of extra oxygen the body needs after exercise to react with the accumulated lactic acid and remove it from the cells

Question 13

What is metabolism ?

Answer 13

The sum of all the reactions in a cell or body

Question 14

Name some examples of metabolic reactions ?

Answer 14

1. Glucose molecules being converted to starch, glycogen and cellulose by being joined together
2. A glycerol molecule and three molecules of fatty acids forming a lipid molecule
3. Glucose and nitrate ions forming amino acids, which are used to form proteins
4. The reactions in respiration
5. Urea forming from the breakdown of proteins for excretion