Respiration

Question 1

Can you outline where glycolysis fits into the overall process of respiration

Answer 1

Glycolysis is the first stage of anaerobic and aerobic respiration. It occurs in the cytoplasm and is an anaerobic process.

Question 2

Can you describe the main statges of glycolysis and its proucts

Answer 2

Glycolysis involves the following stages:

;phosphorylation of glucose to glucose phosphate, using ATP
;production of triose phosphate
;oxidation of triose phosphate to pyruvate with a net gain of ATP and reduced NAD.

Question 3

Can you outline the nature of the link reaction

Answer 3

The link reaction takes place in the matrix of the mitochondria

The steps are:

Pyruvate is oxidisedby enzymes to produceacetate, CH3CO(O)-andcarbon dioxide, requiring the reduction of NAD to NADH

Combination with coenzyme Ato formacetyl coenzyme A (acetyl CoA)

It produces:

Acetyl coA

Carbon dioxide (CO2)

Reduced NAD (NADH)

Question 4

Can you describe what happens during the krebs cycle

Answer 4

2 carbon (2C) Acetyl CoAenters the circular pathway from thelink reactionin glucose metabolism

4 carbon (4C)oxaloacetateaccepts the 2C acetyl fragment from acetyl CoA to form the 6 carbon (6C)citrate

Coenzyme A is released in this reaction

Citrate is then converted back to oxaloacetatethrough a series of oxidation-reduction (redox) reactions

Question 5

Can you explain the nature of the hydrogen carrier molecule and explain their role in the krebs cycle

Answer 5

They have potential to provide energy to produce ATP molecules by oxidative phosphorylation

Question 6

Can you describe where oxidative phosphorylation takes place?

Answer 6

This process occurs in the inner membrane of mitochonria

Question 7

Can you describe how ATP is synthesised during oxidative phosphorylation?

Answer 7

ATP synthase transports the protons. Protons are unable to diffuse through the phospholipid bilayer, so instead go through the enzymeATP synthase. Proton movement provides potential energy, which rotates a section of ATP synthase, and causesphosphorylation of ADP

Question 8

Can you explain the role of oxygen in aerobic respiration

Answer 8

oxygen combines with glucose to form carbon dioxide and water+ ATP

Question 9

Can you explain how energy is released by respiration in the absence of oxygen

Answer 9

Anaerobic respiration, produces energy in the form of ATP form the breakdown of glucose

Question 10

Can you explain how ethanol is produced by anaerobic respiration?

Answer 10

The process starts with the conversion of glucose into pyruvate, followed by the conversion of pyruvate into acetaldehyde and carbon dioxide. The acetaldehyde is then converted into ethanol.

Question 11

Can you explain how lactic acid is produced by anaerobic respiration