Cellular Respiration and Fermentation

Cellular Respiration and Fermentation

Facts to Remember

1. Cellular respiration is a catabolic series of reactions.

2. All living forms conduct some form of cellular respiration, either aerobic or anaerobic.

a. Aerobic is in the presence of oxygen

b. Anaerobic is in the absence of oxygen or none oxygen requiring.

3. The starting molecules consist of the biological molecules with carbohydrates (monosaccharides) as the first choice. The order of use is given below.

a. Carbohydrates

b. Lipids„Ñ-acetyl CoA (via beta oxidation)„Ñ- enters Krebs at the start site

c. Proteins„Ñ-amino acids-„Ñ- enters glycolysis, transitional step or Krebs (point of entry is determine the carbon chain)

d. Nucleotides„Ñ-five carbon sugars„Ñ- six carbon sugars

4. Cellular respiration and fermentation produce energy in the form of ATP and key intermediates needed for anabolic reactions.

5. Cellular respiration and fermentation are redox reactions.

Aerobic Respiration

Model: Eukaryote Cell

Locations: cytoplasm, matrix of mitochondrion, inner mitochondrial membrane

Starting Molecules: Glucose (monosaccharide), 2 ATP, oxygen, and 2 NAD+

End Products: 38-40 ATP, CO2, H20, FAD+ and NAD+ (from FADH2 and 2 NADH + H+ via electron transport)

Step I: Glycolysis (an anaerobic process)

Important steps are sited, please see textbook for full explanation.

1. Glucose to glucose-6-phosphate: 1 ATP energy input

2. Fructose-6-phosphate to fructose 1,6, bis-phosphofructose: Committal Step

a. Under allosteric regulation

b. Allosteric modulators: ATP and Citrate

c. Determines whether glycolysis will continue

d. 1 ATP energy input

3. Fructose 1,6 bisphosphate is cleaved to form dihydroxyacetone phosphate (DAP) and glyceraldehydes 3 phosphate (G3P).

a. Cell prefers G3P, thus will ultimately convert DAP to G3P. Thus all reactions series from this point must be counted twice, once for G3P and secondly for DAP, after conversion.

4. G3P to 1,3 bis-phosphoglycerate

a. An inorganic phosphate is used

b. NAD+ „Ñ- NADH + H+: a potential for ATP production in ETC

5. 1,3 bis- phosphoglycerate „Ñ-3 phosphoglycerate

a. ADP „Ñ-ATP: Method is substrate-level-phosphorylation (SLP)

6. 3-phosphoglycerate„Ñ-„Ñ-phosphoenol pyruvate

7. Phosphoenol pyruvate„Ñ-pyruvate + 1 ATP(via SLP)

8. Special Note: Pyruvate enters the matrix of mitochondrion

Glycolysis is over and has produced 4 ATP + 2 pyruvate + 2 NADH + H+

Step II: Transitional

Location: matrix of mitochondrion

Starting molecules: 2 pyruvate + 2 NAD+

End Products: 2 Acetyl CoA + 2 NADH+H+ + 2 CO2

Special Note: Acetyl CoA enters Krebs

Step III: Krebs Cycle

Location: Matrix of the Mitochondrion

Starting

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