ucsd bild22 midterm2
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- Three stages of starvation
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1. glucose sparing: everything stops using glucose except NS. Use protein instead → lose muscle mass, organs, tissues
2. protein sparing: stop using protein for energy. Go back to using glucose/fat (higher % = fat → ketoacidosis)
3. glucose sparing: use whatever protein left → a.a. → pyruvate → glucose (conversion in liver)
Starvation takes 3-4 months assuming water. W/O water, much quicker. - Lipoprotein
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Means of fat transport in blood. Liver decides what to do based on lipid/protein ratio.
1. chylomicron: fewest in #, lowest density. Intestine → liver.
2. VLDL: changes form rapidly. Slightly higher conc. of chol. & TG. Liver → cells
3. LDL: “bad†high conc. of chol & TG. Liver → cells
4. HDL: “good†low conc. of chol. & TG. Cells → liver - Neg. & pos. aspect for including meat in diet.
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neg = ↑sat. Fat → ↑LDL “bad†cholesterol → heart disease
pos = protein is not the main source of energy but..
• Protein: building blocks for muscle, cartilage, bone, skin. Also, for enzyme, hormone, neurotransmitters
• has iron → ↑Hb. (also, protein increases iron uptake)
• Has B vitamins → RBC - Definition of vitamins
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⬢ Essential
⬢ No calories
⬢ Char. Deficiency/toxicity
⬢ Small, organic molecules
⬢ Acts as coenzymes - Which organisms cannot make vitamins
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⬢ Guinea pigs
⬢ Fruit bats
⬢ Monkeys
⬢ Humans - Toxicities of water soluble vitamins
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1. direct effect: ↑↑vit. C → ↑ kidney stone = false + for diabetes test
2. megadose: ↑↑vit. C → rebound scurvy (ie in pregnant women)
3. masks symptoms: folic acid supplements masks vit. B12 deficiency (pernicious anemia), but doesn’t correct the other side effects (ie. Neurological symptoms)
4. interactions: ↑↑ vit. C → ↑ vit E & Fe absorption
5. ↑ water soluble vitamins → ↑ fat soluble vitamins - what is Vit. A (description, deficiency, toxicity)
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Description = fat soluble vitamin. Retinal,retinol,retinoicacid. Derived from beta-carotene, changed into vit. A (stored in liver)
Deficiency = night blindness, abnormal epithelial cells, abnormal reproductive cycle, improper bone growth
Toxicity = - Vit. D (description, production pathway, function, toxicity, deficiency)
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Description = fat soluble protein
Production =
Skin: 7-dehydrocholesterol –uv→ vit. D (circulating in blood)
Liver: → 25-hydroxy D3
Kidney: 1,25-dihydroxy D3 (active)
Functions =
1. ↑ bone resorption
2. ↓ Ca++ excretion
3. ↑ Ca++ absorption in GI
Deficiency = osteoporosis
Toxicity = atherosclerosis & hypercalcemia → death - Vitamin C (aka-name, descript, function, deficiency, toxicity)
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“ascorbic acid†structurally similar to carb.
Function =
• anti-oxidant
• helps make collagen
• makes neurotransmitters and hormones (adrenaline)
• helps make carnitine for transport of FA into mitochondria
Deficiency = scurvy (cured w/ 10 mg/day)
Toxicity =
• megadose → rebound scurvy (esp pregnant women)
• vit.C enhances Fe absorption → hemachromatosis
• ↑vit.C → ↑vit. E and ↑↑vit. E → bleeding (b/c it’s an anti-coagulant) … but Vit.E is necessary as anti-oxidant
• kidney stones (false pos. for diabetes)
• thickening of arteries → high BP (collagen makes arteries harden) - What might cause Vit. C deficiency?
- Smoking. Nicotine ↓’s vit.C absorption
- vit. A & D deficiency might lead to:
- Rickets (bone disease, esp in children)
- Niacin (description, deficiency, toxicity)
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Deficiency → pellagra (dementia, diarrhea, dermatitis)
Trptophan → niacin → 200 mg/day
Niacin → ↓ BP via vasodilation - What are macrominerals
- minerals required in large amts: Ca++, Na+, Mg++, K+
- What are trace elements (microminerals)
- Fe, Cu, Fe, Zn, Se, Mn, F-
- fxn of minerals
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1. cofactor → ↑ rxn rate
2. oxygen → Fe makes Hb… as does Cu
3. redox → Cu required to make cytochrome oxidase in ETC to generate ATP