Bioenergetics

Question 1

What is respiration?

Answer 1

the process of transferring energy from the breakdown of glucose

this continuously occurs in living cells

Question 2

what do organisms need energy for?

Answer 2

• chemical reactions to build larger molecules
• movement
• keeping warm

Question 3

is aerobic or anaerobic respiration more efficient and why?

Answer 3

Aerobic respiration

because glucose is completely broken down and fully oxidised therefore it produces more energy

Question 4

What is the word equation for aerobic respiration

Answer 4

`glucose + oxygen = carbon dioxide + water

Question 5

What is the word equation for anaerobic respiration in the muscles

Answer 5

glucose = latic acid

Question 6

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

Answer 6

glucose = ethanol + carbon dioxide

Question 7

Why does the rate of respiration need to be increased during exercise?

Answer 7

because the body demands more energy

Question 8

How is are the muscles supplied with more oxygenated blood and glucose for the increase in aerobic respiration?

Answer 8

The heart rate, breathing rate and breath volume are increased

Question 9

Why does anaerobic respiration sometimes happen in the muscle cells?

Answer 9

during vigorous activity, the muscles may not get supplied with enough oxygen

Question 10

Why does lactic acid build up in the muscles and what is the effect on the muscles?

Answer 10

due to the incomplete oxidation of glucose which causes the build-up of lactic acid and creates an oxygen debt

lactic acid causes muscles to hurt and stops them from contracting efficiently

Question 11

What happens to lactic acid after exercise?

Answer 11

blood flowing through the muscles transport the lactic acid to the liver where it is converted back into glucose

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 cells

Question 13

what is Metabolism?

Answer 13

the sum of all the reactions in a cell or body

these reactions are controlled by enzymes and may need a transfer of energy

Question 14

What is the energy transferred by respiration in cells used for?

Answer 14

the continual enzyme controlled processes of metabolism that synthesise new molecules

Question 15

What new molecules are made in metabolism?

Answer 15

• conservation of glucose to starch, glycogen and cellulose
• the formation of lipid molecules from a molecule of glycerol and 3 molecules of fatty acids
• the use of glucose and nitrate ions to form amino acids which in turn are used to synthesise proteins
• breakdown of excess proteins to form urea for excretion

Question 16

What products can glucose be changed to?

photosynthesis

Answer 16

• insoluble starch, which is stored in the stem, leaves or roots
• fat or oil, which is also stored (e.g seeds)
• cellulose, to strengthen cell walls
• proteins, which are used for growth and for enzymes