31 terms

Physiology-Chapter 5 (Metabolism)

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)