When glucose enters a cell, a phosphate group (from ATP) gets attached to C #6. Phosphorylation C 6 H 12 O 6 + PO 4  glucose-6-phosphate

All glucose inside a cell must be in the form of gluc-6-phos in order to be used. Non-reversible process in all except LIVER CELLS.

Glycogenesis Glucose is stored as GLYCOGEN (long chains of gluc-6-phos molecules) “genesis” = formation

Glycolysis Gluc-6-phos + 2ATP  Pyruvate + 4ATP Anaerobic process “lysis” = breaking apart

Glucose H- C = O | H - C - OH | HO- C - H | H - C - OH | H - C - OH | H - C - OH H

Pyruvate (Pyruvic acid) CH 3 - C – COOH || O

Kreb’s Cycle Pyruvic acid (from glycolysis) goes into the mitochondria CO 2 + H + are split off and leaves a 2 carbon (acetyl) Group (step 1) Acetyl group combines w/ CoA  acetyl CoA

Coenzyme Organic compound made by cells that must combine with an enzyme in order to work. Coenzyme may be a hydrogen “carrier”

Hydrogen carriers NAD – nicotinamide adenine dinucleotide FAD – flavin adenine dinucleotide

NAD + H +  NADH + FAD + H +  FADH +

Coenzyme A Coenzyme that is NOT a hydrogen carrier. Coenzyme A carries a 2-carbon (acetyl) group

ADP Is also a coenzyme – carries phosphate groups

First part of Kreb’s cycle CoA carries acetyl groups into the Kreb’s cycle to transfer them to oxaloacetic acid to form CITRIC ACID (name of cycle) (step 2)

Kreb’s cycle is important in the metabolism of: Carbohydrates Proteins Lipids

In one “turn” of the Kreb’s cycle….. 2 molecules CO 2 4 molecules H 2 (3 NADH + 1FADH) 1 molecule acetyl CoA  1 molecule ATP

And, now for the Kreb’s Cycle itself………

From glycolysis CH 3 – C – COOH || O + CoA CH 3 – C – CoA || O Acetyl CoA Pyruvic acid

Step #1 CH 3 – C – CoA || O acetyl CoA COOH | C = O | CH 2 | COOH oxaloacetic acid COOH | CH 2 | HO – C – COOH | CH 2 | COOH citric acid NAD  NADH +

Animation s/Biology/Bio231/krebs.htmlhttp:// s/Biology/Bio231/krebs.html (step 2)

Step #2 COOH | CH 2 | HO – C – COOH | CH 2 | COOH citric acid COOH | CH 2 | C – COOH || CH | COOH cis-aconitic acid (unstable intermediate)

COOH | CH 2 | C – COOH || CH | COOH cis-aconitic acid (unstable intermediate) Step #3 COOH | CH 2 | H - C – COOH | HO - CH | COOH isocitric acid

Step #4 COOH | CH 2 | H - C – COOH | HO - CH | COOH isocitric acid COOH | CH 2 | H - C – COOH | C = O | COOH oxalosuccinic acid -2H

Step #5 COOH | CH 2 | H - C – COOH | C = O | COOH oxalosuccinic acid COOH | CH 2 | CH 2 | C = O | COOH  -ketoglutaric acid -CO 2

Step #6 COOH | CH 2 | CH 2 | C = O | COOH  -ketoglutaric acid COOH | CH 2 | CH 2 | C = O | CoA succinyl CoA -CO 2 -2H NADH +  NAD

Step #7 COOH | CH 2 | CH 2 | C = O | CoA succinyl CoA COOH | CH 2 | CH 2 | COOH succinic acid +H 2 O NAD  NADH +

Step #8 COOH | CH 2 | CH 2 | COOH succinic acid COOH | CH || CH | COOH fumaric acid -2H

Step #9 COOH | CH || CH | COOH fumaric acid COOH | HO - CH | CH 2 | COOH malic acid +H 2 O

Step #10 COOH | HO - CH | CH 2 | COOH malic acid COOH | C=O | CH 2 | COOH oxaloacetic acid (back to where we started!) -2H

Animation Summary s/Biology/Bio231/krebs.htmlhttp:// s/Biology/Bio231/krebs.html (step 3)

Summary to end of Kreb’s Cycle InOut 1 pyruvic acid1 CO 2 (as waste) 1 NAD1 NADH CoAAcetyl CoA 1 acetyl CoA2 CO 2 (as waste) 3 NAD3 NADH 1 FAD1 FADH 2 1 ADP1 ATP

What happens to the CO 2 produced in the Kreb’s Cycle? Diffuses from mitochondria  cytoplasm (cytosol)  bloodstream  exhaled (whew!)

Electron Transport Chain The pairs of hydrogen ions (-2H) from the Kreb’s Cycle enter the electron transport chain. There are a series of HYDROGEN ACCEPTORS (NAD, FAD & cytochromes) that, as they pass the hydrogen ions along, ATP is being produced.

What ultimately happens to pairs of H? Oxygen is final acceptor of H  produces H 2 O! From 4 pairs of H  ATPs produced in the electron transport chain!

Glucose ATP count? Phosphorylation & glycolysis: 8 ATP Kreb’s cycle & electron transport: 30 ATP Total = 38 ATPs

Electron Transport Chain (Animation)

Fat metabolism 1 unit of FAT 3 fatty acids 1 glycerol 18 C each chain glycolysis Kreb’s cycle & electron transport 38 ATP Each 18 C  6 pyruvic acid So total of 18 pyruvic acids 18 pyruvic acids  684 ATP So, = 722 ATPs!

What about protein? Single amino acids are used to build muscle, bones, connective tissue, and cytoplasm and cell membrane of cells. Not typically catabolized (broken down) for energy – only during starvation. 22 amino acids – 8 are “essential”

Chemistry of Digestion writing prompt: The carbohydrates, proteins and lipids have now been broken down into single sugars, amino acids or fatty acids and glycerol. They are now in the liver. Describe, in detail, the process by which glucose creates ATP and then how the other substances become ATP as well. Be sure to include structures to help your explanation.