CELLULAR RESPIRATION

Question 1

3 main pathways in cellular respiration

Answer 1

• Glycolysis
• Citric acid Cycle
• Electron transport chain

Question 2

glycolysis

Answer 2

the breakdown of glucose to pyruvate in the cytoplasm.

Question 3

glycolysis stage 1

Answer 3

• ATP is required for the phosphorylation of glucose and intermediates during the energy investment phase of glycolysis (2 ATP)
• this is the energy investment phase

Question 4

glycolysis stage 2

Answer 4

this leads to the generation of more ATP during the energy pay-off stage (4 ATP) and results in a net gain of ATP (“ net gain of ATP)

• this is the energy investment phase

Question 5

citric acid cycle

Answer 5

occurs in the matrix of the mitochondria

Question 6

citric acid cycle stage 1

Answer 6

• in aerobic conditions, pyruvate is converted into an acetyl group that combines with coenzyme A, forming acetyl coenzyme A.
• NADH and carbon dioxide are also formed during this process

Question 7

citric acid cycle stage 2

Answer 7

• in the CA cycle, the acetyl group from acetyl coenzyme A combines with oxaloacetate to form citrate during a series of enzyme-controlled steps
• citrate is gradually converted back into oxaloacetate which results in the generation of ATP and release of carbon dioxide.

Question 8

dehydrogenase enzymes

Answer 8

• DE remove hydrogen ions and electrons and pas them to the coenzyme NAD forming NADH
• occurs in glycolysis and citric acid cycle

Question 9

electron transport chain

Answer 9

a series of carrier proteins attached to the inner mitochondrial membrane , cristae

Question 10

stages of electron transport chain

Answer 10

• electrons passed along the electron transport chain, releasing energy
• this energy allows hydrogen ions to be pumped across inner mitochondrial membrane
• flow of these ions back through the membrane protein ATP result in production of ATP
• hydrogen ions and electrons combine with oxygen to form water

Question 11

fermentation

Answer 11

• in absence of oxygen fermentation takes place in the cytoplasm
• results in much less ATP produced than in aerobic respiration

Question 12

fermentation in animal cells

Answer 12

• pyruvate is converted to lactate in a reversible reaction
• lactate can be converted back into pyruvate when oxygen becomes available again

Question 13

fermentation in plant/yeast cells

Answer 13

ethanol and CO2 are produced in an irreversible reaction

Question 14

role of ATP in the transfer of energy.

Answer 14

ATP is used to transfer energy to cellular processes which require energy