nutrition and metabolism lecture

chapter 24

nutrients

substances that promote growth, maintenance, and repair

macronutrients

carbs, lipids, proteins

micronutrients

vitamins and minerals

classes of carbohydrates

mono-,di-, and poly saccharides that derive mainly from plants

glucose

monosaccharide main molecule for cellular respiration (ATP/energy creation)

cellulose

dietary fiber (indigestible) helps move food

pectin

soluble fiber, lowers blood cholesterol and water soluble

carbs can be converted into ?

glycogen or lipids

classes of lipids

triglycerides, phospholipids, and steroids that derive from plants and animals

triglycerides

make up most of fatty foods (butter, oils, etc.)

phospholipids make up most of our ?

plasma membranes

steroids act as ?

hormones/ chemical msgers

lipids help with ?

vit. absorption, energy storage, insulation, cushioning, membrane, hormones

classes of proteins

complete or incomplete (depending on if they have all amino acids)

T or F: we can make essential amino acids (AAs)

false, we obtain them from food

essential AAs for infants vs adults

10 infants, 8 adults

what is needed for protein synthesis

necessary amino acids and sufficient calories

what encourages protein synth

anabolic hormones

vitamins

organic, larger molecules, monstly function as coenzymes

what role do enzymes play in reactions

they catalyze reactions (increase efficiency)

coenzyme function

enzyme helper (increase efficiency MOOORE!!!)

vitamins made by body

vit D (skin), vit B and K (gut)

fat-soluble vitamins

vit A, D, E, K (idek) easily stored

water-soluble vitamins

vit B complex (different versions of B vit) and C

vitamins and mineral that act as antioxidants

vit A, C, E (ace of antioxidants) and selenium

minerals

inorganic, smaller nutrients with many uses

uses of minerals

structural (building), influence membrane potentials, act as cofactors, parts of organic molecules

cofactor

mineral version of an enzyme helper (coenzyme)

how many major minerals, how much needed per day

7, need more than 200 mg/day

7 major minerals

calcium, chlorine, phosphorus, potassium, magnesium, sulfur, sodium (Ca, Cl, P, K, Mg, S, Na) trick: CCPPSSM

how many trace minerals

10

metabolism

all biochemical reactions in an organism

anabolism (anabolic reactions)

build larger molecules

catabolism (catabolic reactions)

break down large molecules

phosphorylation

donation of a phosphate group (covalent bond formation) to another molecule, thus giving energy

reduction-oxidation (redox)

chemical reaction where oxidation states of reactants change due to loss of electrons (LEO) and gain of electrons (GER)

LEO meaning

Loss of Electrons is Oxidation

GER meaning

Gain of Electrons is Reduction

in both phosphorylation and redox, the receiving molecule gains ?

energy (either a phosphate group is gained or an electron)

ATP

Adenosine Triphosphate (energy currency molecule for reactions)

substrate-level phosphorylation

adding phosphate group to an ADP to form ATP

oxidative phosphorylation

adding phosphate group to an ADP from a long series of redox reactions

aerobic cellular respiration

how cells convert glucose and oxygen into energy (ATP), CO2m and water

4 important reaction sets of aerobic cellular respiration

glycolysis, transition reaction, citric acid (Krebs) cycle, electron transport chain (ETC)

glycolysis (step 1)

breaks down glucose (which has 6 carbons) to form 2 pyruvate molecules (each with 3 carbons)

glycolysis byproducts

2 ATP (4 total created, but 2 are used up) and 2 NADH (responsible for transporting electrons during reactions)

how many reactions take place during glycolysis

10 reactions

where does glycolysis occur

in the cytoplasm (filling) of a cell

if oxygen is unavailable after glycolysis is complete, the aerobic cellular respiration process will cease and ? will happen instead

anaerobic respiration (pyruvates will convert into lactic acid)

transition reaction (step 2)

as the 2 pyruvates (3C) move into the mitochondria, they turn into 2 Acetyl CoA (2C)

transition reaction byproducts

2 CO2 (2 carbons are lost) and 2 NADH are produced

citric acid (Krebs) cycle (step 3)

2 Acetyl CoA (2C) from transition reaction (step 2) + 2 Oxaloacetate (4C) = 2 Citric Acid (6C)

where does citric acid cycle occur

mitochondrial matrix

citric acid cycle byproducts

2 ATP, 6 NADH, 2 FADH₂ (similar to NADH=carries electrons)

electron transport chain ETC (step 4)

electrons are dropped off by the 10 NADH and 2 FADH₂ from previous steps

where does ETC occur

mitochondrial inner membrane

what occurs each time electrons are passed along in the ETC

redox

what is energy generated from ETC used for?

pump H+ ions into intermembrane space of mitochondria and electrochemical gradient is formed

what happens after electrochemical gradient of H+ forms?

chemiosmosis occurs

chemiosmosis

H+ leaks back through membrane channel (ATP synthase) leading to ATP synthesis

what happens to leftover electrons at the end of ETC

oxygen and hydrogen join with electron to form water

results of ETC

each NADH yields 3 ATP (10 NADH x 3= 30 ATP), each FADH₂ yields 2 ATP (2 FADH₂ × 2= 4 ATP) —> total of 34 ATP produced

total ATP per glucose from aerobic cellular respiration

2 (glycolysis) + 2 (citric acid cycle) + 24 (ETC) = 38 ATP p. glucose max

which of the 4 aerobic cellular respiration steps is aerobic (requires oxygen to occur)

electron transport chain

other metabolic reactions that involve glucose

glycogenesis, glycogenolysis, gluconeogenesis

glycogenesis

making glycogen from glucose when ATP or sugar lvls are high

glycogenolysis

breaking down glycogen into glucose (opposite of glycogenesis)

gluconeogenesis

making glucose from non-carbs

2 types of lipid metabolism

lipogenesis (make lipids/triglycerides) and lipolysis (break lipids)

amino acids can be used for ?

protein synthesis or for energy

proteins are regularly ?

broken down and recycled (catabolic-anabolic equilibrium)

what happens to extra proteins

oxidized for energy or converted into fats

absorptive state

anabolic reactions dominate in cells and lasts about 4 hours after eating (glycogenesis, lipogenesis, protein synthesis)

postabsorptive state

catabolic reactions dominate when the gut is empty (glucagon stim. glycogenolysis, gluconeogenesis, lipolysis, protein breakdown)

what occurs if postabsorptive state goes on too long

glucose sparing (body uses fats and proteins for energy to conserve glucose for brain)

how many metabolic functions does the liver have?

over 500

metabolic roles of the liver

Synthesizes (85% of blood cholesterol), Forms (plasma proteins and urea), Stores (vitamins and minerals), Detoxifies (toxins, drugs, alcohol)

how much cholesterol comes from food

15%

good total cholesterol level

200 mg p. 100 ml of blood

high density lipoprotein (HDL)

good cholestrol, protects against heart disease (40-60mg p. 100 ml of blood) keep high high!

low density lipoprotein (LDL)

bad cholesterol (160mg p. 100 ml or less) keep low low!

energy balance

energy intake will eventually = output

energy intake comes from ?

oxidation of food molecules

how much energy output is lost as heat during reactions

60%

caloric intake > energy use —>

weight gain

body mass index formula

weight in lbs/ (height in inches)²

obesity body mass index (BMI) value

over 30

what is important when considering BMI

body fat %

what controls energy intake (hunger) in body

levels of glucose, AAs, fatty acids, insulin and body temp (high blood levels and high body temp decrease hunger)

what increases hunger

glucagon and epinephrine

what other factor can affect hunger

psychological/mental state

basal metabolic rate (BMR)

how many calories u spend in your body per hour (Kcal/m² of body surface area)/hour

what increases BMR

thinner, younger, male, stress, high temps, high thyroid hormone lvls

total metabolic rate (TMR)

calorie consumption while active and at rest

what increases TMR

exercise and being in absorptive state

what regulates body temp

hypothalamus

avg body temp

98.7 F or 37 C

when is body temp highest and lowest throughout the day

peak afternoon and low morning

what increases body heat

shivering, increased TMR, increased thyroxine, exercise

what decreases body heat

cutaneous vasodilation (dilation of skin’s vessels), sweating, relaxation