5. Respiration And Fermentation

Question 1

Gluconeogenesis

Answer 1

Almost the reverse of glycolysis.
Helps maintain body glucose levels during fasting or starvation state.
Carbohydrate biosynthesis.

Question 2

Three major components/steps of respiration.

Answer 2

• glycolysis
• krebs , the conversion of pyruvate (formed in the glycolysis pathway) to acetyl-coenzyme A. Krebs
• electron transport chain

Question 3

Glycolysis net gain and brief description.

Answer 3

It is the initial step in respiration. Anaerobic process.
It uses x2 ATP and d-glucose to create x2 3 carbon sugars, these x2, 3 carbon sugars are used to form: x4 ATP x2 NADH and x2 pyruvate molecules. Net gain of x2 ATP, x2 NDH, x2 pyruvate.

Question 4

Kerbs cycle net gain and description

Answer 4

It is the 2nd step in respiration and is an aerobic process. It requires the x2 molecules of pyruvate created in glycolysis to become oxidised and amongst other processes form a total net gain of x8 NADH, x2 FADH, x2 ATP and x4, CO2.

Question 5

Electron transport chain

Answer 5

3rd step in respiration. Chain of chemiosmotic potential gradient across the mitochondrial cell membrane to form ATP from x2 (glycolysis), x8 (krebs) NADH and x2 (krebs) FADH. Net gain of ATP from this process is 34 ATP.

Question 6

Respiration net gain

Answer 6

38 ATP

Question 7

Fermentation explained briefly

Answer 7

After glycolysis, the Krebs cycle cannot continue without oxygen. Therefore fermentation occurs. X2 NADH from glycolysis act as electron donors to the x2 pyruvate molecules created in glycolysis. These NADH are oxidised to form NAD+ allowing glycolysis to begin again and produce more ATP. The by product of oxidising the NADH from the pyruvate is alcohol or lactic acid depending the animal etc.