CELLULAR RESPIRATION-CHAPTER 7

CELLULAR RESPIRATION- CHAPTER 7 17 WORDS ALCOHOLIC FERMENTATION ACETYL COENZYME A ANAEROBIC PATHWAY AEROBIC RESPIRATION CELLULAR RESPIRATION CITRIC ACID FERMENTATION FAD ELECTRON TRANSPORT CHAIN GLYCOLYSIS KILOCALORIE KREBS CYCLE LACTIC ACID FERMENTATION MITOCHONDRIAL MATRIX NAD+ OXALOACETIC ACID PYRUVIC ACID

I. Glycolysis: An anaerobic reaction(no oxygen present) in which a 6 carbon molecule of glucose is broken down into two 3-carbon molecules of pyruvic acid

A. 2 ATP provides two phosphate which are attached to a glucose molecule to form a new 6-carbon compound.

B. The 6-carbon compound splits into two 3-carbon molecules of PGAL (G3P)

C. Each molecule of PGAL (G3P) receives a phosphate. This forms two new carbon compounds each with phosphates bonded to each end of their structures. NAD+, an electron acceptor, forms NADH

D. The two 3-carbon molecules have their phosphates removed. This forms 4 molecules of ATP and two molecules of pyruvic acid.

1. Since four ATP’s are formed and two ATP’s were used to start glycolysis there is a net gain of two molecules of ATP.

GLYCOLYSIS

II. Lactic Acid Fermentation: Pyruvic acid is converted into lactic acid and NAD+ is produced

A. NAD+ is used to keep glycolysis going.

B. Fermentation occurs in the absence of oxygen.

C. Yogurt and cheese are produced.

D. Muscle fatigue occurs.

III. Ethyl Alcohol fermentation: pyruvic acid is converted into ethyl alcohol and NAD+ is produced. CO2 is a byproduct.

A. NAD+ is used to keep glycolysis going.

B. Fermentation occurs in the absence of oxygen.

C. Wine and beer are produced.

D. Bread rises from the CO2 produced.

FERMENTATION

IV. Energy yield from glycolysis A. Efficiency of glycolysis = 3.5%

V. Aerobic respiration: an aerobic reaction (oxygen is present) in which the oxidation of glucose is completed. ATP is formed.

A. This reaction takes place in the mitochondria.

B. The Krebs cycle and the electron transport chain comprise this reaction.

Mitochondria

SUMMARY

VI. The Krebs cycle: a biochemical pathway that breaks down acetyl CoA producing ATP, CO2, and hydrogen atoms. This occurs in the mitochondria’s matrix.

A. Acetly CoA, a 2-carbon compound which

came from the breakdown of pyruvic acid, combines with a 4-carbon compound called oxaloacetic acid. This forms a 6-carbon compound called citric acid.

B. Citric Acid releases a CO2 to form a 5-carbon compound. NAD+ picks up a hydrogen and becomes NADH.

C. The 5-carbon compound releases a CO2 to become a 4-carbon compound. NAD+ NADH. ADP ATP.

D. The 4-carbon compound releases hydrogen which FAD bonds with to become FADH2.

E. The 4-carbon compound releases a hydrogen which turns it into oxaloacetic acid. NAD+ ->NADH.

KREB’S CYCLE

VII. The Electron Transport Chain A. This occurs on the inner membrane of the

mitochondria.

B. NADH and FADH2 provide the energized electrons to pump hydrogen atoms from the matrix to the other side of the inner mitochondrial membrane.

1. This builds up a higher concentration of hydrogen on the outside of the membrane compared with the inside of the membrane.

2. ATP synthase causes chemiosmosis to occur by allowing the higher concentration of hydrogen atoms to travel back to the area of lower concentration of hydrogen atoms in the matrix. The energy released forms ADP into ATP.

3. Oxygen atoms pick up the low energy electrons along with the hydrogens released by NADH and FADH2. This forms H2O.

ELECTRON TRANSPORT CHAIN

VIII. Energy Yield

A. Efficiency of aerobic respiration = 66%

B. C6H12O6 + 6O2 6CO2 + 6H2O + Energy (38 ATP)