Chapter 7.1

Question 1

phosphofructokinase

Answer 1

enzyme!
catalyses one of the early “pump-priming” reactions, adding a phosphate group to the 6c sugar. Affected by the concentration of ATP and citrate
-high atp or/and citrate -> glycolysis slows down
-low atp or/and citrate -> glycolysis speeds up

Question 2

regulatory enzymes

Answer 2

enzymes that play an important role in controlling the rate of the entire pathway

Question 3

kreb’s cycle

Answer 3

it is a metabolic pathway. It is a sequence of chemical reactions where each step is controlled by an enzyme and the product is used in the next reaction

Question 4

cytochromes

Answer 4

protein pigments with an iron group (eg. haemoglobin) . They are reduced by electrons from FADH(reduced FAD) which is oxidised again

Question 5

cytochrome oxidase

Answer 5

enzyme that receives the e- from the cytochromes and is reduced as the cytochromes are oxidised

Question 6

chemiosmosis and ETC

Answer 6

• H+ ions pumped into intermembrane space
• build up of electrochemical and concentration gradient
• energy needed to pump the ions is obtained from the movement of electrons along the ETC
• H+ are released down their electrochemical and concentration gradient through ATPsynthase
• on the stalked particles
• and the energy released is used to phosphorylate ADP to ATP

Question 7

oxidative phosphorylation

Answer 7

• e- are passed along the electron transport chain ETC
• losing energy as they move along
• oxygen is the final electron acceptor
• the energy lost is used to add a phosphate to ADP in order to make ATP
• by ATPsynthase
• in chemiosmosis

Question 8

Describe how a sprinter is able to release sufficient energy in 100m sprint without having enough oxygen available in her muscles.

Answer 8

• energy for sprinting is obtained from ATP
• some ATP is already found stored in muscle cells
• and some can be obtained from creatine phosphate that exists in muscles
• ATP is produced from glycolysis
• glycolysis produces ATP rapidly (2 molecules of ATP per glucose molecule)
• in the cytoplasm.Pyruvate is produced
• there is oxygen shortage so anaerobic respiration takes place
• and so pyruvate is converted to lactate
• NAD is produced which is recycled and can be used in glycolysis again
• there is also some aerobic respiration due to some oxygen present

Question 9

effect of build up of lactate in the muscle of a sprinter

Answer 9

• lactate build up causes drop in ph
• this affects enzyme activity/
• this slows down glycolysis/atp production/ anaerobic respiration
• and also muscle contractions are affected

Question 10

what happens to lactic acid/lactate ?

Answer 10

• lactate can move to the blood
• and carried to the liver to be broken down/converted to glucose to be stored
• lactate is converted to pyruvate
• this involves oxidation and the production of reduced NAD
• so pyruvate is then oxidized
• it enters the Krebs cycle to be oxidized further and produce
• carbon dioxide and water
• this requires extra oxygen/the athlete is in oxygen debt

Question 11

autotrophic organism

Answer 11

make their own food (usually by photosynthesis)

Question 12

heterotrophic organism

Answer 12

eat and digest other organisms

Question 13

catabolic pathways

Answer 13

molecules release energy as they are degraded or oxidized

Question 14

anabolic pathways

Answer 14

store energy. Building up molecules

Question 15

decarboxylases

Answer 15

enzymes that remove CO2

Question 16

dehydrogenases

Answer 16

enzymes that remove hydrogen