Nat Sci 179—Lecture Notes Ch. 26: Nutrition And Metabolism

Front 1

Calories

Back 1

-a measure of the amount of energy that can be obtained from food
-in the body, this energy is often stored as ATP

Front 2

-in chemistry one calorie =

Back 2

amt. of heat to raise 1g of water 1 degree C

Front 3

in nutrition, one “calorie” is actually

Back 3

1 kilocalorie, or 1000 calories

Front 4

Nutrients

Back 4

-ingested substances used for growth, maintenance or repair

Front 5

macronutrients

Back 5

water, CHOs, fats (lipids), proteins
-needed in relatively large amounts

Front 6

micronutrients

Back 6

vitamins and minerals
-needed in relatively small amounts

Front 7

-Recommended Daily Allowance (RDA)

Back 7

-has been determined for these nutrients
-often revised
-average need for a healthy person

Front 8

essential nutrients

Back 8

those the body cannot make, itself
-include some amino acids & fatty acids, most vitamins & minerals

Front 9

Carbohydrates (found)

Back 9

three places in the body:
-blood
-stored as glycogen in muscle and liver

Front 10

carbphydrates

uses in the body pt 1

Back 10

-most CHOs are burned for fuel
-easily oxidized (“burned”) for energy
-neurons use ONLY CHOs as their energy source
-hypoglycemia (low blood sugar) can cause dizziness, irritability,
weakness, trembling

Front 11

pt 2

Back 11

-form structural parts of other molecules
-glycoproteins, glycolipids, others
-can be converted to proteins and fats when needed

Front 12

-regulation of blood glucose is by hormones:

Back 12

-glucagon and insulin from pancreas
-glucagon increases blood sugar, insulin lowers
-they regulate balance btwn glycogen & blood glucose

Front 13

complete oxidation of fats requires CHOs

Back 13

-incompletely oxidized fats become ketone bodies
-ketones are acidic, can lead to metabolic acidosis

Front 14

monosaccharides:

Back 14

glucose, galactose, fructose (fruit sugar)

Front 15

-disaccharides:

Back 15

sucrose (table sugar), lactose, maltose

Front 16

-complex CHOs (polysaccharides)

Back 16

starch, cellulose (fiber)
-most dietary CHOs come from plants
-very little glycogen in meat (mostly protein)

Front 17

fiber needed for

Back 17

intestinal health
-not a nutrient
-stimulates peristalsis in intestine

Front 18

water-soluble fiber

Back 18

-lowers blood cholesterol & LDLs (“bad” cholesterol)
-found in oats, beans, fruit, others

Front 19

-water-insoluble fiber

Back 19

-no effect on blood cholesterol or LDLs
-mostly cellulose

Front 20

Lipids

Back 20

-makes up the largest part of the body’s stored energy
-average female body has a higher % of fat than male
-“reference” male is 15%, female 25%

Front 21

fat has glucose-sparing & protein-sparing effects

Back 21

-body will use fat before protein for energy
-body will reserve glucose for cells that require it (neurons)

Front 22

other uses of lipids in body

Back 22

-cholesterol used in making cell membranes, steroid hormones, clotting factors
-protective cushioning for organs
-conserve body heat

Front 23

dietary sources from both plant and animal sources (3 things)

Back 23

cholesterol, saturated fats (unsaturated & monosaturated fats)

Front 24

cholesterol

Back 24

only from animal (meat, eggs & dairy)
-too high blood cholesterol associated with heart disease

Front 25

saturated fats

Back 25

associated with heart disease (“clogged arteries”); can raise blood
cholesterol

Front 26

unsaturated & monounsaturated fats

Back 26

are healthful (nuts, seeds, fish, canola oil)

Front 27

-cholesterol & serum lipoproteins

Back 27

-lipids are not soluble in blood, so are transported as lipoproteins
-molecules made of protein, cholesterol, triglycerides

Front 28

4 types of lipoproteins:
-in order from greatest to smallest density (not size); density = mass/unit
volume, as in ug/ul:

Back 28

-chylomicron
-HDLs (high density lipoproteins)
-LDLs (low density lipoproteins)
-VLDLs (very low density lipoproteins)

Front 29

-HDLs are “good cholesterol”

Back 29

-help remove excess cholesterol from the blood
-cholesterol can be removed as a component of bile, made in liver
-total plasma cholesterol below 200 mg/dL is good

Front 30

-LDLs are “bad cholesterol”

Back 30

-can help form fatty deposits in arteries
-diet, exercise, drug intervention can improve blood cholesterol

Front 31

Proteins
-uses in body:

Back 31

-muscle - in cell membranes as cell-identity markers, ion channels, receptors - collagen, elastin, keratin in skin, hair, nails, tendons, ligaments - antibodies - hormones

-hemoglobin - catalysts of many metabolic reactions (enzymes) - one of the blood buffer systems - albumin in blood needed for water balance

Front 32

incomplete proteins

Back 32

in the diet, do not have all of the essential amino acids
-those the body cannot make, itself

Front 33

complete proteins

Back 33

do have all the essential amino acids

Front 34

food sources (Protein)

Back 34

-animal (meat, dairy, eggs) are mostly complete
-many plant sources incomplete, but combinations can be complete (beans &
grain)

Front 35

-if needed, muscle can be broken down for fuel

Back 35

-but CHO and fat will be used first (“protein-sparing”)
-usually occurs only if diet lacks CHOs and fat

Front 36

Minerals

Back 36

-micronutrients
-most readily obtained in diet
-calcium & iron are those most commonly lacking

Front 37

Vitamins

Back 37

-micronutrients
-most are easily obtained in a varied diet

Front 38

-fat-soluble

Back 38

ADEK

-can be stored in fat, so possible to overdose
-D produced in skin with exposure to UV light (sun)

Front 39

some abnormalities associated with lack

Back 39

-A: night blindness, other vision abnormalities
-D: rickets
-K: blood clotting

Front 40

water-soluble

Back 40

-Bs include folic acid; helps prevent neural tube defects
-lack of C causes scurvy
-lack of B1 causes beri-beri
-lack of B12 causes pernicious anemia

Front 41

-glycogenesis

Back 41

synthesis of glycogen
-stimulated by insulin (removes glucose from blood)

Front 42

gluconeogenesis

Back 42

synthesis of glucose from amino acids or fat
-occurs mostly in liver

Front 43

-glycolysis

Back 43

breakdown of glucose during aerobic respiration or fermentation
-energy (ATP) production in most cells

Front 44

glycogenolysis

Back 44

breakdown of glycogen
-releases glucose to blood btwn meals
-stimulated by glucagon (raises blood glucose)

Front 45

lipogenesis

Back 45

synthesis of lipids from amino acids or CHOs

Front 46

lipolysis

Back 46

breakdown of fat for fuel
-triglyceride  fatty acids + glycerol
-further processing produces ketone bodies; they are acidic
-when large amounts of fat are being broken down, excess ketone bodies
are produced  acidosi

Front 47

proteins can be converted to

Back 47

CHOs or fats

Front 48

breakdown of proteins produces N-containing compounds

Back 48

-esp. ammonia; this is converted to urea
-urea leaves body in urine
-products of breakdown are amino acids
-can be used to make new proteins
-body can also make some aa from other aa’s

Front 49

protein synthesis uses the scheme DNA  RNA  protein

Back 49

-transcription & translation
-occurs on free ribosomes & those associated with rough ER

Front 50

Basal Metabolic Rate (BMR)

Back 50

-rate at which the body burns calories in an awake resting state
-average is about 2000kcal/day, with individual variation
-usually decreases with age
-not in text: not to be confused with BMI (body mass index)
-a measure of body fat based on weight and height

Front 51

metabolic syndrome

Back 51

-a group of conditions perhaps related to heart disease, stroke, diabetes
-symptoms: obesity, high BP, high blood triglycerides, low HDLs (“good
cholesterol”), resistance to insulin (glucose may not leave blood as efficiently as it should)
-may have higher than normal blood insulin (body is trying to compensate)
-may be seen as elevated fasting blood sugar
-may be related to the “vicious cycle” of overeating, lack of exercise excessive hunger or cravings and fatigue  more overeating, even less activity, etc.