GCSE Bioenergetics

Question 1

Why are greenhouses useful?

Answer 1

Ability to control CO2 levels, temperature, light intensity, water concentration and mineral ions

Question 2

Define respiration

Answer 2

An endothermic chemical reaction inside cells that releases energy from glucose

Question 3

Define metabolism

Answer 3

The sum of all chemical reactions happening inside a cell

Question 4

Give uses of glucose from respiration in animals

Answer 4

Muscle contraction, maintain steady body temp (mammals & birds), perform anabolic reactions (protein synthesis)

Question 5

Give uses of glucose from respiration in plants

Answer 5

Creation of cellulose for growth & repair, building amino acids

Question 6

Give the word equation for anaerobic respiration in animals

Answer 6

Glucose —> 5% ATP of aerobic + lactic acid

Question 7

Give the word equation for anaerobic respiration in plants + fungi

Answer 7

Glucose —> ATP + ethanol + CO2

Question 8

Why does temperature raise while exercising?

Answer 8

Excess heat is produced by higher rates of respiration, raising core body temp

Question 9

Why does heart rate increase when exercising?

Answer 9

To increase the flow of blood to the lungs for increased oxygen uptake. To increase the flow of blood to the muscles to deliver oxygen & glucose for contraction

Question 10

Why does breath rate increase when exercising?

Answer 10

To increase the amount of oxygen taken into the body and to remove increased amounts of excess CO2 from aerobic respiration

Question 11

What is oxygen debt?

Answer 11

The amount of oxygen needed to oxidise lactic acid from anaerobic respiration into CO2 and water

Question 12

When does anaerobic respiration occur in plants?

Answer 12

When the plant cannot access enough oxygen (e.g - waterlogged soil)

Question 13

What is anaerobic respiration called in yeast?

Answer 13

Fermentation

Question 14

Give examples of catabolic reactions

Answer 14

Protein + amino acid breakdown

Question 15

Give examples of anabolic reactions

Answer 15

Lipid + protein synthesis, glucose reactions

Question 16

Describe how excess protein is broken down

Answer 16

Excess protein is broke down into amino acids, which can diffuse from a high concentration in cells to a low concentration in the blood, to diffuse into the liver to be broken down.

Question 17

Describe how amino acids are broken down

Answer 17

Once in the liver, enzymes remove an amine group from the amino acids (deamination), forming urea to be excreted by the kidneys

Question 18

Describe reactions of glucose

Answer 18

Glucose produced during photosynthesis is stored as insoluble starch or made into cellulose for growth + repair. Animals store glucose and glycogen in the liver

Question 19

Describe the synthesis of lipids

Answer 19

1 glycerol + 3 fatty acids —> lipid

Question 20

Describe the synthesis of proteins

Answer 20

Glucose + nitrate ions make amino acids. A chain of amino acids folded in a certain was is a protein