CH 24- metabolism

nutrients

any substance the body uses for growth, repair and maintenance

macronutrients

carbs, lipids, proteins

micronutrients

vitamins and minerals

sources of carbs

mostly plants, dairy and meats(glycogen)

uses of carbs

ATP production, nucleic acid synthesis with pentose sugars, glycocalyx formation

type of carb used by ATP production

monosaccharides

recommended carb requirements

45-60%

complex carbs

grains and plants are unprocessed, nutrient-rich

empty carbs

processed sugars

sources of lipids

triglycerides and cholesterol

types of triglycerides

saturated and unsaturated

cholesterol

85% by liver, rest from meat, eggs and dairy

use of lipids

build adipose tissue, phospholipid cell membranes, bile salt, hormones, molecule construction, absorbing fat-soluble vitamins

lipid nutritional requirements

20-35%, limit saturated and cholesterol

sources of protein

complete and incomplete proteins

complete proteins

meet all body’s amino acid needs

incomplete proteins

short 1+ amino acid

sources of incomplete proteins

seeds, nuts and legumes

uses of protein

structural molecules, functional molecules

protein requirements

.8g per kg

nitrogen balance

when the rate of protein synthesis equals the rate of protein breakdown in the body

positive nitrogen balance

protein synthesis> protein breakdown

negative nitrogen balance

protein breakdown > protein synthesis

examples of negative nitrogen balance

stress, low protein, low quality diet, starvation

importance of vitamins

act as coenzymes

sources of vitamins

made by body and diet

vitamins by body

D,K,B

types of vitamins

water soluble and fat soluble

water soluble vitamins

b and c

fat soluble vitamins

A,D,E,K

sources of minerals

legumes, vegetables, dairy

mineral primary function

structural to make phospholipids, hormones and proteins

balance in uptake and excretion of minerals is needed

too much fat soluble vitamins causes toxic overload

example of toxic overload

iron overdose, low iodine, goiters, high Na and fluid retention

metabolism

the sum of the chemical reactions occurring in the cells of the body that is used to provide energy for vital processes and synthesizing new material

types of metabolic reactions

anabolic and catabolic

anabolic

building up

catabolic

breaks down like cellular respiration

oxidation

loss of electrons

reduction

gain of electrons

most coenzymes are derived from

derived from B complex vitamins

important coenzymes

nicotinamide adenine dinucleotide/NAD+, Flavin adenine dinucleotide/FAD

all carbs will be converted to glucose then

then to glucose-6-phosphate inside cell

breakdown of glucose pathways

glycolysis, krebs, electron transport chain and oxidative phosphorylation

glycolysis

anaerobic, glucose to 2 pyruvic acid, 2NADH H+, net gain 2 ATP

phase 1 of glycolysis

glycose is phosphorylated to fructose-1,6-bisphosphate using 2 ATP

phase 2 of glycolysis

fructose 1,6-biphosphate is split

phase 3 of glycolysis

4 ATP molecules made by oxidizing carbon fragments, 2NAD+ pick up H, 2 pyruvic acids produced

is oxygen is available in glycolysis

pyruvic acid into krebs

if oxygen is not available in glycolysis

pyruvic acid to lactic acid to be processed in liver

oxygen comes back in glycolysis

lactic acid oxidizes back to pyruvic acid to krebs

krebs cycle

aerobic, acetyl CoA to 3 co2, 4 NADH H+, FADH2, 1 ATP

pyruvic acid oxided to acetyl CoA and makes

1 CO2, NAD to NADH

acetyl CoA into cycle

2CO2, 3 NADH, 1 FADH2

ETC and oxidative phosphorylation

aerobic, NADH and FADH2 with oxygen to 28 ATP and 6 H2O

3 ways to store/access glucose

glycogenesis, glycogenolysis, gluconeogenesis

glycogenesis

glucose to glycogen in animal tissue

glycogen

polysaccharide in animal muscle tissue

tissue most active in glycogen production

skeletal muscle and liver

glycogenolysis

glycogen to glucose and glucose-6-phosphate for glycolysis

glucose-6-phosphate in skeletal muscle

cannot be released

glucose-6-phosphate in liver

hepatocytes convert it to free glucose for blood

gluconeogenesis

conversion of glycerol and amino acids to glucose

importance of gluconeogenesis

prevents important glucose-hogging organs from low blood sugar

lipid metabolism

for energy production, glycerol and fatty acids to be oxidized, glycerol to glyceraldehyde-3-phosphate

glyceraldehyde yields

15 ATP

fatty acids are converted

converted to acetyl CoA

ways to store/access lipids

lipogenesis and lipolysis

lipogenesis

synthesis of triglycerides, acetyl coa and glyceraldehyde-3-phosphate

begin triglyceride synthesis because

to prevent excessive buildup

acetyl coa forms

forms fatty acid chains

glyceraldehyde-3-phosphate form

form glycerol

glycerol + fatty acids=

= triglycerides

lipolysis

breakdown of triglycerides to glycerol and fatty acids into blood

protein metabolism

amino acids by degrading them into krebs cycle and converted to glucose

to use amino acids

needs amine/NH2 group removed

process of amino acid conversion

transamination, oxidative deamination, modification of keto acids

transamination

transfer of amine group from amino acid to keto acid

alpha-ketoglutaric acid accepts

accepts amine group into glutamic acid/glutamate

amino acid into

into keto acid

oxidative deamination

amine of glutamate to removed as ammonia to form urea with CO2

oxidative deamination is when

regeneration of alpha-ketoglutaric acid

modification of keto acids

keto acids formed in 1 are altered

absorptive state

nutrient uptake, lasts 4 hours after meal to enter bloodstream, lots of glucose needed

hormone in absorptive state

insulin

insulin

hypoglycemic hormone, absorptive hormone, from beta pancreatic cells to high glucose and AA levels

hypoglycemic hormone

absorptive state hormone to lower blood glucose levels

uptake of amino acids stimulates

stimulates protein synthesis

insulin prevents

prevents gluconeogenesis and glucose export by liver

postabsorptive state

nutrients used to make energy

when GI tract is completely empty

no absorption occurring

importance of postabsorptive state

maintains blood glucose level at 110g/dL

sources of glucose in postabsorptive state

skeletal muscle, adipose tissue/liver, cellular proteins

liver postabsorptive state

glycogenolysis

skeletal muscle in postabsorptive state

glylcogenolysis, glucose oxidized to pyruvic acid to liver to make ATP

adipose tissue and liver in postabsorptive state

lipolysis beings, glycerol created converted to glucose in liver

cellular proteins in postabsorptive state

last resort, AA deaminated and converted to glucose in liver, kidneys eventually begin gluconeogenesis

postabsorptive state hormones

glucagon and epinephrine

glucagon

from alpha pancreas, hyperglycemic hormone

epinephrine

SNS to adipose to promote glycogenolysis