B9

Question 1

cellular respiration

Answer 1

an exothermic reaction that occurs continuously in living cells

Question 2

aerobic respiration

Answer 2

glucose + oxygen -> carbon dioxide + water (energy transferred to the environment)
the energy transferred supplies all the energy needed for living processes

Question 3

mitochondria

Answer 3

• lots of chemical reaction controlled by different enzymes taking place in the mitochondria
• have folded inner membrane that provides large surface area for the enzymes in aerobic respiration

Question 4

need for respiration

Answer 4

• energy breaks down large molecules to smaller ones in digestion and in cells
• energy makes muscles contract in animals
• energy maintains the right body temp.
• energy moves mineral ions from soil to root hair cells in plants

Question 5

exercise

Answer 5

during exercise the human body responds to the increased demand for energy

Question 6

body responses to exercise

Answer 6

• increase in heart rate in breathing rate and in breath volume
• glycogen stores in the muscles are converted to glucose for cellular respiration
• the flow of oxygenated blood to the muscles increases

Question 7

responses

Answer 7

act to increase the rate of supply of glucose and oxygen to the muscles and the rate of removal of carbon dioxide from the muscles

Question 8

anaerobic respiration

Answer 8

respiration without oxygen
takes place in animal cells, glucose is incompletely broken down to form lactic acid
transfers less energy than aerobic respiration

Question 9

oxygen debt

Answer 9

the amount of oxygen is needed to break down the lactic acid that has built up

Question 10

anaerobic respiration in plant cells

Answer 10

• such as yeast
• results in the production of ethanol and carbon dioxide

Question 11

metabolism

Answer 11

sum of all the reactions in the body

Question 12

energy transfer in cells

Answer 12

the energy transfer by respiration in cells is used by the organism for the continual enzyme controlled processes of metabolism that synthesise new molecules

Question 13

metabolic reactions

Answer 13

• conversion of glucose to starch, glycogen and cellulose
• formation of lipid molecules from a molecule of glycerol and three fatty acid molecules
• use of glucose and nitrate ions to form amino acids used to make proteins
• reactions of respiration
• reactions of photosynthesis
• breakdown of excess proteins in the liver to form urea for excretion in the urine by the kidneys

Question 14

role of the liver

Answer 14

• detoxifying poisonous substances like ethanol from alcohol
• passing breakdown of products into blood so it can be excreted in urine via kidneys
• break down old blood cells storing iron until it is needed to synthesis more blood cells

Question 15

removing lactic acid

Answer 15

blood flowing through the muscles transports lactic acid to the liver where its converted back to glucose