Just some leftovers.


breaks down molecules and releases energy (exergonic)


builds up larger molecules and requires energy (endergonic)

Which steps of metabolism require oxygen?

Kreb's Cycle & ETC (Glycolysis does not)

Glycolysis by any other name...

Humans: lactic acid fermentation (pyruvate + H); Yeasts: alcohol fermentation

Overall equation of Glycolysis

glucose + 2NAD + 2ADP + 2P >2pyruvates + 2NADH + 2ATP

ATP production in Glycolysis

4, but 2 are used to phosphorylate glucose (to keep it inside the cell)

Lactic Acid Pathway

If anaerobic, extra Hs are given pyruvate to make lactic acid (only 2 ATPs per glucose; RBCs)


storing glucose as glycogen (for osmotic reasons; sk. muscles & liver)


removes glucose from glycogen as glucose 6-phosphate (sk. muscles use directly, liver injects into bloodstream by removing phosphate)

Cori cycle...

1. lactic acid from sk. muscle goes to liver; 2. becomes pyruvate again; 3. glucose is added to liver's glycogen (gluconeogenesis)


formation of glucose by non-carbohydrates (amino acids, glycerol, pyruvate); non-carb > ketones > pyruvates > glucose

Aerobic Respiration begins

when pyruvate enters mitochondria

Preparatory Step

CO2 is clipped off of pyruvate (becomes acetyl CoA which carries acetic acid; comes from vit B5); CO2 goes to lungs

Kreb's Cycle...

1. acetyl CoA combines w/ oxaloacetic acid (forms citric acid); 2. cycle occurs, citric becomes oxalo again; 3. Produces 1 GTP (guanasine triphosphate) which gives P to ADP; 4. 1ATP, 3NADH, 1FADH2

Electron Transport Chain

AKA Oxidative Phosphorylation 1. series of proteins in cristae of mitochondria (FMN, CoQ, Cytochromes); 2. energy used to phosphorylate ADP to ATP; 3. 26 ATPs formed

chemiosmotic theory

energy from ETC used to pump H's into outer mitochondrial chamber forming energy for forming ATP; H2O is formed at end with H's used

Net yield of glucose by aerobic respiration

30-32 ATPs/glucose

Net yield of glucose by anaerobic repiration

2 (only glycolysis & lactic acid fermentation)

Fat Metabolism

Triglycerides can be hydrolyzed to glycerol & fatty acids (can be run thru Kreb's)

Protein Metabolism

broken down into amino acids; deaminated (NH2 removed) & run thru Kreb's

When more energy is taken in than consumed, ATP synthesis is ______


Acetyl CoA

common substrate for energy and synthetic pathways


Acetyl CoAs can link to form fatty acids (occurs in adipose & liver); 9kcal/g

1. Lipolysis

fat (triglycerides) > fatty acids + glycerol (lipase hydrolyzes)

2. Acetyl CoA from Fat (Beta-oxidation)

clips acetyl CoA from fatty acid chains (10ATP/acetyl CoA, Beta-ox makes 4 itself)

Brown fat

found in children; used to produce lots of heat (instead of ATP; caused by uncoupling protein with H+ leakage by inner mito. membr.)

Ketone Bodies

Triglycerides > Ketones > Acetone > Pungent fruit breath of much nasty (fasting causes fat to break down forming ketone bodies)

Amino Acid Metabolism...

1. Nitrogen is ingested from proteins; 2. body uses amino acids; 3. excreted as urea (NH3); 4. excess amino acids can be made into carbs & fat

There are ___ essential amino acids



creation of new amino acids catalyzed by transaminase by adding NH2 to pyruvate or ketones of Kreb's

Oxidative Deamination

excess amino acids are eliminated; NH2 removed from glutamic acid forming ketones (to krebs, fat or glucose) and NH3 (to urea)

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