Chapter 24: Nutrition, Metabolism, and Energy Balance Flashcards
Nutrients
food substances that the body uses to promote normal growth, maintenance, and repair
Essential Nutrients
must be consumed
Macronutrients
needed in large amts; can be hydrolyzed to make ATP; include carbs, lipids, proteins
Micronutrients
needed in minute amts; CANNOT be hydrolyzed to make ATP; include vitamins and minerals
Energy Content of FOod
measured in kilocalories (kcal) per 1 gram; 1 gram carbs and proteins = 4 kcal; 1 gram lipid = 9kcal
Carbohydrates
organic compounds containing C, H, and O; about same number as C as there is O
Dietary Sources of Carbs
primarily from plants; monosaccahrides and disaccharides; fruits, sugar cane, beets, honey, milk; polysaccharides (complex carbs) such as starch (grain and veggies), cellulose (insoluble fiber from plants), pectin (soluble fiber from fruits)
Uses of Carbs in the Body
glucose is main carb used by body cells to make ATP; excess glucose is stored as glycogen (polysaccharide) or fat
ADD CARB EXCESS AND DEFICIT
L
Lipids
organic compound containing C, H, and O; much more carbon than O
Dietary Sources of Lipids
dervied from plants and animals; triglycerides (neutral fats and #1 dietary lipid), satruated, transfat, and unsaturated, cholestorl
Saturated Fats
single bonds with H; found in coconut, animal products (meat, lard, butter, dairy) and hydrogenated oil
TransFats
take a unsaturated fat and make it saturated; such as margarine so it stays solid at room temp
Unsaturated Fats
carbon carbon double bond; more healthy; found in seeds, nuts, olive and vegetable oil
What two fatty acids are essential?
linoleic (omega 6 fatty acid) and linolenic (omega 3 fatty acid); cannot be synthesized by liver
Cholesterol
found in shell fish, egg yolk, meat (especially organ meat) and milk products; liver produces 85% of blood cholesterol regardless of intake
Uses of Lipids in the Body
adipose, phospholipids, cholesterol, triglercerids, prostaglandins and fats needed to absorb fat soluble vitamins
Adipose
cushions internal organs; forms insulating layer beneath skin; concentrated sourcce of energy
Phospholipids
components of cell membranes and myalin sheaths
Cholesterol
stabilizes cell membrane; precursor of bile salts and steroid hormones
Triglycerids
main energy source for skeletal uscles and hepatocytes
Prostagalndins
play a role in control of blood pressure
Dietary Source of Proteins
animal proteins (complete proteins); adults must consume 8 essential amino acids; infants must consume 10 essential amino acids;
Structural Material of Proteins
keratin, collagen, elastin, actin, and myosin
Functional Proteins
enzymes and some hormones
Protein oxidized for ATP when…
if aminoacid needed to make a specific protein are missing (all or nothing rule); insufficient dietary carbohydrate or fat is ingested
The body is in nitrogen balance when…
the amount of protein ingested = the amount of protein lost in urine and feces
Positive Nitrogen Balance
occurs when amount of protein incorporated into tissues is greater amoiunt of protein used for energy (children, pregnancy, and following injury/repair)
Negative Nitrogen Balance
occue when protein breakdown for production of ATP exceeds amount of protein incorporated into tissues ; physical/emotional stress, poor quality dietary protein or starvation
Vitamins
organic compounds needed in minute amounts; most function as coenzymes (helpers) ; ALL must be ingested except vit D (in skin) and some Vit b and K synthesized by intestinal bacteria
Water Soluble Vitamins
B and C; absorbed with water from GI tract (except b12); excess secreted in urine
Vit B1
deficiency causes beriberi (nerve disorder)
Vit B3
niacin; extreme excess can cause liver damage
Vit B9
folic acid; deficit = anemia and birth defects
Vit B12
maturation of RBC; deficit = anemia and NS disorder
Vit C
collagen synthesis, antioxidant; deficit = scurvy (degeneration of skin, teeth, blood vessels); excess - GI upset
Fat Soluble Vitamins
A, D, E, and K; absorbed with fat from GI tract; excess A, D and E sotred in body (may cause toxicity)
Vit A
visual pigments; deficit = blindness; extreme excess- headache, vomiting, hair loss, blurred vision
Vit D
absorption and use of calcium and phorphorus; deficit= rickets in kids; excess = brain, cardiovascular and kidney damage
Vit E
antioxidant
Vit K
blood clotting; deficit = defective blood clotting
Minerals
inorganic compounds; 7 needed in moderate amts; Ca, P, S, K, Cl, Na, Mg; greater than 200 mg per day
10 Trace Minerals
such as iron, flurine, zinc, iodine
Iron
component of hemoglobin
Fluorine
deficit = higher frequency of tooth decay
Zinc
deficit = impaired immunity
Iodine
thyroid hormones; deficity = goiter
Metabolism
all biochemical rxns within cells
Anabolism
use energy to build lg molecules from smaller ones
Catabolism
release energy when lg molecules broken down into smaller ones
What cells can get the full 32 ATP per glucose?
cardiac, liver, and kidney
Substrate Level Phosporylation
transferring phosphorus to ADP to make ATP
Oxidative Phosphrylation
proton gradient and ATP synthase which uses that gradient to go from ADP to ATP
Glycogenesis
occurs in response to high blood glucose levels; glucose is removed from blood and combined to form glycogen
Glycogenolysis
opposit of glycogeneiss; occurs in response to low blood glucose levels; glycogen is dydrolyzed to glucose monosaccharides and released to blood stream
Gluconeogenesis
forming glucose from lipids and proteins; occurs when glycogen stores are low an dblood glucose levels begin to drop; liver cells synthesize glucose from noncarbohydrate molecules; ensures neurons and RBC have sufficient glucose to make ATP bc they can only use glucose
Lipid Metabolism
triglycerides are only lipids that are routinely catabolized to yield energy; 3 processes- beta oxidation, lipolysy, and lipogenesis
Lipolysis
occurs when glycogen stores are low and blood glucose begins to drop; if carbohydrate too low intermediate citric acid cycle converted to glucose (for neurons and RBC) and acytl coa accumulates and the excess is converted to ketones via ketogenesis
Beta Oxidation
fatty acid chains broken apart and converted to acetyl coa; also leads to ketogenesis which leads to ketones
Lipogenesis
glycerol and fatty acids recombined to form triglycerides and stored; occurs when cellular ATP and glucose leels are high (glycerol and fatty acids not needed to make ATP)
Protein Metabolism
proteins can not be stored; excess amino acids are oxidized to generate ATP or stored as fats; 3 processes- transamination, oxidative deamination, and protein synthesis
Transamination
occurs in liver; amino group is switched from amino acid to keto acidO
Oxidative Deamination
amine group of glutamic acid is removed as ammonia and combined with co2 to form urea; occurs in liver
What are the two metabolic states?
absorptive and postabsorptive state
Absorptive State
when you are fed state; occurs are meal; anabolism exceeds catabolism; major energy fuel is dietary glucose; excess nutrients stored as glycogen and fat; events controlled primarily by insulin
Postabsorptive State
fasting state; occurs when GI tract is empty; catabolism exceeds anabolism; glucose made available to blood by glycogenolysis, lipolysis, and gluconeogenesis; during prolonged fasting, brain begins metabolizing ketone bodies; events controlled primarily by glucagon
