Aerobic respiration

Question 1

What are the four stages in aerobic respiration

Answer 1

1) Glycolysis
2) link reaction
3) Krebs cycle
4) oxidative phosphorylation

Question 2

where does the 1st stage of aerobic respiration occur?

where do the other 3 staged of aerobic respiration occur?

Answer 2

• in the cytoplasm of cells

- in the mitochondria

Question 3

what else can be used instead of glucose to respire

Answer 3

• fatty acids and amino acids

Question 4

what is glycolysis

Answer 4

the splitting of a glucose molecule (6C)

into 2 molecules of pyruvate (3C)

Question 5

what are the two main steps on glycolysis?

Answer 5

1) Phosphorylation- adding phosphates

2) Oxidation- loss of hydrogen

Question 6

glycolysis ( PHOSPHORYLATION)

Answer 6

• Glucose is phosphorylated by adding 2 phosphates from 2 molecules of ATP
• which creates 1 molecule of hexose bisphosphate
• Then the hexose bisphosphate is split into 2 molecules of triose phosphate (3C)

Question 7

glycolysis ( OXIDATION)

Answer 7

• triose phosphate is oxidised (loses hydrogen), to form 2 molecules of pyruvate( 3C)
• NAD collects the 2 hydrogen ions forming 2NADH
• 4 ATP produced, BUT 2 ATP s used for phosphorylation part of glycolysis.

Question 8

what happens to the products of glycolysis ( 2NADH and pyruvate)?

Answer 8

• The 2NADH goes to the last stage, Oxidative phosphorylation.
• 2 molecules of pyruvate are actively transported into the matrix of the mitochondria for the Link reaction.

Question 9

what happens in the link reaction

Answer 9

Pyruvate is converted into acetyl coenzyme A

Question 10

link reaction

Answer 10

Pyruvate is DECARBOXYLATED ( loses carbon in the form of CO2)

• NAD is reduced to NADH, the hydrogen comes from the pyruvate, changing pyruvate into acetate.
• acetate combines with coenzyme A to form acetyl Co A

NO ATP PRODUCED IN THIS REACTION.

Question 11

what is the net gain of ATP in glycolysis

Answer 11

net gain of 2 ATP

Question 12

how many times does the link/krebs occur for every glucose molecule?

Answer 12

twice for every glucose molecule

Question 13

FOR EACH GLUCOSE MOLECULE:

Answer 13

1) 2 molecules of acetyl co A go into the krebs cycle
2) 2 molecules of CO2 are released as waste product of respiration
3) 2 molecules of NADH are formed which go to the last stage , oxidative phosphorylation stage