nutrition Flashcards
triglycerides
saturated (meat, dairy, trans fats)
unsaturated (seeds, nuts, olive and vegetable oils)
cholesterol
egg yolk
meats
organ meats
shellfish
milk
essential fatty acids
linoleic (omega 6) and linolenic (omega 3) acid->helps lower chances of heart disease
found in vegetable oil
functions of lipids
help absorb fat-soluble vitamins
major fuel of hepatocytes and skeletal muscle
cholesterol stabilizes membrane (precursor of bile salts and steroid hormones)
prostaglandins-> SM contraction, BP control, inflammation
phospholipids essential in myelin sheaths and all cell membranes
adipose tissue-> protection, insulation, fuel storage
complete proteins
contain all needed AA’s
eggs, milk, fish, most meats, soybeans
legumes+cereal grains= contain all essential AA’s
incomplete proteins
lack some essential AA’s
legumes, nuts, cereals
structural materials of proteins
keratin
collagen
elastin
actin
myosin
functions of proteins
enzymes
some hormones
nitrogen balance
rate of protein synthesis=rate of breakdown and loss
positive nitrogen balance
synthesis exceeds breakdown
in children, pregnancy, and tissue repair
negative nitrogen balance
breakdown exceeds synthesis
in stress, burns, infection, injury, starvation, poor dietary proteins
starch
complex carb
in grains and vegetables
sugars
fruits
sugarcane
sugar beets
honey
milk
insoluble fiber
cellulose
provides roughage
soluble fiber
pectin in apples and citrus fruits
lowers blood cholesterol
water-soluble vitamins
vitamins B and C
not stored in body->excreted if not used within 1 hr
vitamin C
aka ascorbic acid
promotes the laying down of collagen in CT
antioxidant->neutralizes free radicals
deficiency can result in scurvy (degeneration of skin, teeth, blood vessels)
overdose can result in GI upset
vitamin B6
aka pyridoxine
coenzyme used in AA metabolism
deficiency linked w/ neurological symp.
overdose can result in numbness of hands/feet and unstable gait
vitamin B3
aka niacin
deficiency can cause pellagra
overdose can result in liver damage and skin flush
vitamin B12
coenzyme in nucleic acid metabolism
deficiency can lead to pernicious anemia
fat-soluble vitamins
vitamins A, D, E, K
stores in body except for vit. K
vitamins A and E neutralize free radicals (antioxidants)
broccoli, cauliflower, brussel sprouts= good source of vit. A and C
vitamin A
provitamin A (B-carotene)
structural comp. of visual pigment retinol
antioxidant
deficiency can lead to night blindness
overdose can result in blurred vision, liver toxicity, alopecia
vitamin D
converted to calcitrol via PTH in kidneys
increases role of intestinal Ca2+ and phosphates absorption
deficiency can lead to osteomalacia in adults and rickets in children
overdose can result in brain, CV, and kidney damage
common cause of deficiency is steatorrhea (fat malabsoprtion syndrome)
vitamin E
stabilizes intracellular membranes
needed for hair/skin maintenance
helps prevent damage to cell membranes
antioxidant
vitamin K
aquamephyton, antihemorrhagic vitamin
synthesizes 3 clotting factors and prothrombin
produced by bacteria in LI
overdose can result in liver damage and anemia
coumatin (anticoagulant)= blocks vit. K uptake and utilization to decrease prothrombin formation by liver and prolong clotting times
minerals
inorganic ions released by dissociation of electrolytes
work w/ nutrients to ensure proper body functioning
Ca2+, phosphorous, K+, sulfur, Na+, Cl-, Mg2+, iron, iodine
vegetables, legumes, milk, some meats
carb metabolism
oxidation of glucose (C6H12O6+6O2->6H2O+6CO2+32 ATP + heat)
glucose enters cells via FD
phosphorylated to glucose-6-phosphate
most cells lack enzymes for reverse rxns-> traps glucose inside cell (intestines and kidneys)->liver can reverse rxn and release glucose
keeps intracellular glucose conc. low for continued glucose entry
glycolysis
10 steps
anaerobic
occurs in cytosol
glucose->2 pyruvic acid
final products are 2 pyruvic acid, 2 NADH+H+, 2 ATP, 2 H2O
if O2 present, moves onto krebs cycle in mitochondria
if no O2 present, pyruvic acid is reduced to lactic acid-> may be converted to glucose-6-phosphate for storage as glycogen in liver or de-phosphorylation
krebs cycle
aerobic, but does not directly use O2
NADH molecules must be oxidized to NAD+
pyruvic acid from glycolysis converted into acetyl coA (acetic acid+coenzyme A) and then enters krebs cycle
acetyl coA combines with oxaloacetate to form citrate
forms 4 CO2, 6 NADH, 2 FADH2, 2 ATP as products
chemiosmotic process
couples movement of substances across membrane to chemical rxns
energy used to pump H+ across mitochondrial membrane (flows through ATP synthase membrane channel->energy used to phosphorylate ADP)