Cellular Respiration

Types of Metabolism

• Catabolism– Degradation of fuel

molecules

• Anabolism– Biosynthesis of

molecules

Cellular Respiration- is to harvest electrons from carbon

compounds, such as glucose and use that energy to make ATP.

2 main parts:a. Glycolysis – anaerobic (do not require oxygen)

b. Aerobic Respiration

C6H12O6 + 6O2 6CO2 + 6H2O + energy

Glycolysis

Also known as Embden-

Meyerhof pathway

Glycolysis

Glucose – most common cell fuel- stores energy as a simple form of

food substance- easily penetrate a living cell- must be converted to pyruvic acid

Glycolysis- occurs in the cytoplasm of the cell – cytosol.

Stages of Glycolysis

1. Glucose is phosphorylated to glucose-6-phosphate. Initially, 2 ATP molecules are used in this degradation process.

2. Glucose-6-phosphate (6-C) into 3 carbon (3-C) molecules of PGAL = 2 PGAL

3. Phosphorylation transpires again. ATP provides a phosphate group to each PGAL & removes H. NAD picks up the H & reduced to NADH. 2 NADH are formed.

4. 2 ATP and an NADH are generated from every PGAL molecule as each is converted to pyruvic acid.

2 PGAL involved, 4 ATP and 2 NADH are produced.

Stages of Glycolysis

Fermentation

- A process that occurs when an intracellular molecule (pyruvic acid) w/c is generated by the breakdown of glucose to another nutrient molecule becomes the final acceptor of electrons.

Lactic Acid Fermentation

- Lactic acid forms glucose in the liver when pyruvic acid accepts hydrogen from NADH + +

O O

CH3 C C

Pyruvate O

NADH Lactate

NAD+ Dehydrogenase

OH O

CH3 C C

H O-

Alcohol Fermentation

- Pyruvic acid is converted to ethyl alcohol (CH3CH2OH), CO2 and NAD + +

O O

CH3 C C

Pyruvate O

Pyruvate decarboxylase

CH3CHO + CO2

acetaldehyde

NADH Alcohol

NAD+ Dehydrogenase

O

CH3 C OH

ethyl alcohol

Conversion of Pyruvic Acid to Acetyl CoA

- pyruvic acid from glycolysis is converted to acetyl-CoA (acetyl-coenzyme A.)

- 1 glucose = 2 pyruvic acid = Acetyl CoA

Krebs Cycle

- biochemical pathway of aerobic respiration- it forms citric acid- occurs in inner matrix of mitochondrion

• Dehydration (removal of water)• Hydration ( addition of water)

• Decarboxylation (removal of CO 2)

• Dehydrogenation (removal of H2)

Products of Krebs Cycle

Reduced H 2 3 molecules of NADH

Acceptors from 1 molecule of FADH 2

NAD & FAD 2 molecules of CO2

1 molecules of ATP8 H 2 atoms

Since 1 glucose = 2 P.A. = 2 Acetyl CoA (2 turns)

6 NADH + +, 2 FADH 2 , 4CO 2, 2 ATPs & 16 H 2

Electron Transport Chain

- also known as Oxidative Phosphorylation- at this point, the breakdown of glucose

is complete.4 ATP made12 carrier molecules produced (10 NADH + H + + & 2 FADH 2)

- metabolic pathway that uses energy to produce ATP.

- transpires in the cristae of the mitochondrion

- NADH & FADH 2 are oxidized to NAD + + & FAD

Products: 3 molecules of ATP from each NADH +H + +

2 molecules of ATP from each FADH 2

½ O 2 + 2H = H 2O

Electron Transport Chain