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199 Cards in this Set

  • Front
  • Back
nutrient
substance that promotes normal growth, maintenance, and repair
types of nutrients
major: carbs, lipids, and proteins

other: vitamins & minerals (aka water)
complex carbohydrates
starches

found in bread, cereal, flour, pasta, nuts, and potatoes

*most have vitamins and minerals
simple carbohydrates
sugars

soft drinks, candy, fruit, and ice cream
glucose
-molecule ultimately used by the body cells to make ATP

-neurons and RBC need this to supply energy
what happens to excess glucose?
It is converted into glycogen or fat and store
What is the minimum amount of carbs needed to maintain adequate blood glucose levels?
100 grams per day
refined carbohydrate foods
candy and soft drinks

-provide energy source
-"empty calories"
What essential fatty acids are found in vegetables?
linoleic and linolenic acid
what do dietary fats do?
-help body absorb vitamins
-major energy fuel for hapatocytes & skeletal muscle
-component of myelin sheath & cell membrane
What are the most abundance dietary lipid that is found in animal and plant food?
triglycerides
what do fatty deposits in adipose tissue provide?
-protective cushion around organs
-insulating layer beneath skin
-sotred concentrated source of energy
what is the function of prostaglandins?
-smooth muscle contraction
-control of blood pressure
-inflammation
what is cholesteral?
-stabalizes membranes
-precursor of bile salts and steroid hormones
what are the dietary requirements for lipids?
> for infants and children
American Heart Association suggests that..
-fats should be <30% of total calorie intake
-saturated fats should be <10% of ones total fat intake
-daily cholesterol should not exceed 200 mg
where are proteins that meet al the body's amino acid needs?
-eggs
-milk
-milk products
-meat
-fish
where are incomplete proteins found?
-legumes
-nuts
-seeds
-grains
-vegetables
what do proteins supply?
-essentential amino acids
-nitrogen for nonprotein nitrogen-containing substances
what is the daily intake of proteins>
.08 g/kg of body weight
amino acids
building blocks for nonessential amino acids
all-or-none rule

(synthesis)
all amino acids must be present at the same time for protein synthesis
adequacy of caloric inake
protein will be used as fuel if there is insuffiecient carbs or fat available
nitrogen balance
rate of protein synthesis equals the rate of breakdown and loss
positive synthesis
positive: synthesis exceeds breakdown
(normal in children & tissue repair)
negative synthesis
negative: breakdown exceeds synthesis
- stress, burns, infection, injury
hormonal control
anabolic hormones accelerate protein synthesis
vitamins
-organic compounds needed for growth and good health
-crucial in helping body use nutrients
-function as coenzymes
what vitamins are synthesizes?
vitamin B
vitamin D
vitamin K
Where are water-soluble vitamins (such as B-complex & C) absorbed?
Gastrointestinal tract

*B-12 needs gastric intrinsic factor to be absorbed
Where do fat-soluble vitamins bind and get absorbed?
-bind to ingested lipids
-absorbed with their digestion products
What vitamins act as an antioxidant cascade?
Vitamin A, C, & E
What 7 minerals are required?
-calcium
-phosphorus
-potassium
-sulfur
-sodium
-chloride
-magnesium
what minerals harden bones?
-calcium
-phosphorus
-magnesium
What do minerals and nutrients do together?
ensure proper body functioning
What do sodium and chloride help maintain and what are they essential for?
-maintain normal osmolarity, water balance

-essential for nerve and muscle functions
What prevents toxic overload?
uptake and excretion
metabolism
all chemical reactions necessary to maintain life
cellular respiration
food fuels are broken down within ceels and some energy is captured to produce ATP
anabolic reactions
synthesis of larger molecules from smaller ones
catabolic reactions
hydrolysis of complex structures into smaller ones
during metabolism what so eznymes do?
they shift the high-energy phosphate groups of ATP to other molecules
what do phosphorylated molecules activated to do?
perform cellular functions
three stages of metabolism (energy-containing nutrients)
-digestion (1)
-oxidative breakdown (3)
-anabolism & formation of catabolic intermediates (2)
digestion
breakdown of food, and nutrients are transported to tissues
oxidative breakdown
nutrients are catabolized to carbon dioxide, water, and ATP
anabolism and formation of catabolic intermediates where nutrients are built into and broken down by?
-built into lipids, proteins, and glycogen
-broken down by catabolic pathways to pyruvic acid and acetyl CoA
oxidation-reduction (REDOX) reactions
oxidation occurs via the gain of oxygen or the loss of hydrogen

when one substance is oxidized the other is reduced
oxidized substances _____ energy
lose
reduced substances ______ energy
gain
coenzymes act as what in redox reactions?

what two are important?
-act as hydrogen or electron acceptor

-NAD+ & FAD
Mechanisms of ATP Synthesis
in Substrate-Level Phosphorylation
high-energy phospate groups are transferred to ADP

ATP is synthesized via substrate level phosphorylation in glycosis and Krebs cycle
Mechanisms of ATP Synthesis
in Oxidative Phosphorylation
-uses chemiosmotic process whereby movement of substances across a membrane is coupled to chemical reactions
how is oxidative phosphorylation carried out?
-electron transport proteins in cristae of mitochondiria
-nutrient energy is used to pump hydrogen ions into intermembrane space (steep diffusion results
-when hydrogen ions flow back across (via ATP synthase) energy is capture and attached to ADP to make ATP
STEPS of Carbohydrate/glucose metabolism
3 ways:
-glycolysis
-kreb's cycle
electron transport chain & oxidative phosphorylation
example reaction of oxidation of glucose
C6H12O6 + 6O2 --> 6H2O + 6CO2 + 36 ATP + heat
what is glycolysis?
three-phase pathway
-glucose is oxidized into pyruvic acid
-NAD+ reduced to NADH + H+
-ATP is synthesized by substrade-level phosphorylation
what happens to pyruvic acid in an anaerobic environment?
reduced to lactic acid in anaerobic environment
Phase 1 of Glycolysis
sugar activation

-two ATP molecules activate glucose into fructose- 1,6 diphosphate
Phase 2 Glycolysis
Sugar cleavage

-fructose 1,6-biphosphade is cleaved into 3-carbon isomers
(bihydroxyacetone phosphate & glyceraldehyde 3-phosphate)
Phase 3 of glycolysis
oxidation & ATP formation
-3-carbon sugars are oxidized (reducing NAD)
-inorganic phosphate groups are attached to each oxidized fragment
-termal phosphates are captured by ADP to form 4 ATP molecules
Final product of glycolysis
-two pyruvic acid molecules
-two NADH + H+ molecules (reduced NAD+)
-net gain of two ATP molecules
Krebs Cycle
-Preparatory Step
-occurs in mitochondrial matrix & fueld by pyruvic & fatty acids

* pyruvic acid converted into acetyl CoA in the streps
-decarboxylation
-carbon removed from acid and CO2 released
Oxidation of Krebs cycle
hydrogen atoms are removed from pyruvic acid
NAD+ reduced to NADH + H+
formation of acetyl CoA
resulting acetic acid is combined with coenzyme A (sulfur constaining coenzyme) to form acetyl CoA
Eight step cycle of krebs cycle
acetic acid is decarboxylated & oxidized generating
-3 molecules of NADH + H+
-1 molecule of FADH2
-2 molecules of CO2
-1 molecule of ATP
for each molecule of glucose entering glycolysis, how many molecules of acetyl coA enter krebs cycle?
two
electron transport chain
food(glucose) is oxidized & released hydrogens
-transported by coenzymes (NADH & FADH2)
-cmbine with molecular oxygen to form water
-release energy
what happens to the energy released in the electron transport chain?
harnessed to attach inorganic phosphate groups to ADP, making ATP by oxidative phosphorylation
mechanism of oxidative phosphorylation
-hydrogens delivered to chain and split into protons and elections
what happens to the protons of oxidative phosphorylation
pumped across inner mitrocondrial membrane by NADH dehydrogenase, cytochrome, cytocrome oxidase
what happens to the electrons of oxidative phosphorylation
shuttled from one acceptor to the next
-delivered to oxygen to form oxygen ions
-oxygen ions attract to H+ to form water
-which diffused back to the matrix via ATP synthase
-releases energy to make ATP
electronic energy gradient
transfer of energy from NADH + H+ and FADH2 to oxygen releases large amount of energy
-this energy is released through electron transport chain
electrochemical proton gradient accross the inner membrane creates and generates?
-creates a pH gradient
-generates a voltage gradient

=cause H+ to flow back to matrix via ATP sythase
ATP synthase uses what 3 enzymes?
-enzyme: rotor, knob, & rod
-current created by H+ causes rotor and rod to rotate
what does the roation of rotor and rod do?
activates catalytic sites in the knob where ADP and P are combined to make ATP
glycogenesis
formation of glycogen when glucose supplies exceed cellular need to ATP synthesis
glycogenolysis
breakdown of glycogen in response to low blood glucose
gluconeogenesis
process of forming sugar from noncarbohydrate molecules
-takes place in liver
-protects body (esp brain) from damaging effects of hypoglycemia by ensuring ATP synthesis occurs
where are products of fat metabolism transported and as what?
-in lymph as chylomicrons
what fats are oxidized for energy?
neutral
catabolism of fats occur in what two pathways?
glycerol & fatty acid
how are lipids in chylomicros hydrolyzed?
plasma enzymes and absorbed by cells
what happens to glycerol in lipid metabolism?
-converted to glyceraldehyde phosphate
-glyceraldehyde is converted into acetyl CoA (CoA enters Krebs cycle)
What happens when fatty acids undergo beta oxidation, what do they produce?
produce:
-two-carbon acetic acid fragments (enter Krebs cycle)
-reduced coenzymes (enter electron transport chain)
what happens to dietary glycerol and fatty acids?
-undergo lipogenesis to form triglycerides
acetyl CoA is a ____ which makes glucose easily turned into fat
-intermediate in glucose catabolism
-starting molecule for synthesis of fatty acids
what is lipolysis?
breakdown of stored fat

*lipogenesis in reverse
what is oxaloacetic acid necessary for?
-complete oxidation of fat

-without it CoA is converted into ketones
what are phospholipids important components of?
-myelin
-cell membranes
what does the liver do in synthesis of structural materials?
-synthesizes lipoproteins for transport of cholesterol & fat
-makes tissue factor, a clotting factor
-synthesizes cholestoral for acetyl CoA
-uses cholesterol to form bile salts
What do certain endocrine organs use to sythesize steroid hormones?
cholesterol
Excess dietary protein results in amin acids being..
-oxidized for energy
-converted into fat for storage

*amino acids must be deaminated prior to oxidation for energy
What are deaminiated amino acids converted into?
-pyruvic acids
-one of the keto acid intermediates of Krebs cycle
transamination
switching of an amine group from an amino to keto acid

*glutamic acid is formed during this process
oxidative deamination
amine group of glutamic acid is
-release as AMMONIA
-combined with CO2 in liver
-excreted as UREA by kidneys
keto acid motification
keta acids form transamination are altered to produce metabolites that can enter Krebs cycle
What is the most important anabolic nutrient?
amino acids
what do amino acids form?
-protein structures
-bulk of body's functional molecules
what is necessary for protein synthesis?
a complete set of amino acids
what do the amount and types of proteins reflect?
-hormonally controlled
-reflect each life cycle stage
what is the body's state?
dynamic catabolic-anabolic state
What are continuously broken down and rebuilt and what isnt
is: ORGANIC MOLECULES
isn't: DNA
what does the body's total supply of nutrients constitute
nutrient pool
amino acid pool
body's total supply of free amino acids
what is the source of free amino acides
-resynthesize body proteins
-forming amino acid derivatives
-gluconeogenesis
pathways of nutrients
-linked by key intermediates

1. acetol
2. pyruvate
how does the pathway of nutrients different from amino acid pool?
-fats and carbs are oxidized directly to produce energy
-excess of carbs and fats can be stored
what do metablic controls equalize?
blood concentraions of nutrients between two states
absorbtive states
time during and shortly after nutrient intake
postabsorbtive state
-time when GI tract is empty
-energy sources are supplied by the breakdown of body reserves
absorptive state explain further
major metabolic thrust is anabolism and energy storage
-amino acids become proteins
-glucose is stored as glycogen
what are glycerol and fatty acids converted into
triglycerides
what is the major energy fuel of the absorbtive state
dietary glucose
what are excess amino acids deaminated and used for
-energy or stored as fat in the liver
muscle pathway of absorbtive state
-amino acids become protein
-glucose is converted to glycogen
liver pathway of absorbtive state
-amino acids become protein or keto acids
-glucose is stored as glycogen or coverted to fat
adipose tissue of absorbtive state
glucose and fats are converted and stored as fat

*all tissues use glucose to synthesize ATP
what does insulin enhance? 2 types of transport..
-active transport of amino acids to tissue cells
-facilitated diffusion of glucose into tissue
secretion of insulin is stimulated by?
-increased blood glucose
-elevated amino acid levels in blood
diabetes mellitus
conseqeunce of inadequate insulin production or receptors

glucose becomes unavailable to body cells

fats and tissue proteins are used for energy
replacement of fuels in blood of postabsorbtive state
-glucose is provided by glycogenolysis and gluconeogenesis
-fatty acids and ketones are major energy fuels
-amino acids are converted to glucose in the liver
muscle pathway of postabsorptive state
-protein is broken down to amino acids
-glycogen is converted to ATP and pyruvic acid
what does glucagon stimulate?
-glycogenolysis & gluconeogenesis
-fat breakdown in adipose tissue
-glucose sparing
hormal & neural controls of postabsorptive state
decreased plasma glucose concetration and rising amino acid levels stimulate alpha cells of pancreas to secrete glucagon
what is the response of low plasma glucose?
sympathetic nervous system releases epinephrine which acts on the liver, skeletal muscle, adipose tissue to mobilize fat and promote glycogenolysis
liver metabolism
hepatocytes carry out over 500 metabolic functions
liver function of metabolism
-packages fatty acids to be stored
-synthesize plasma proteins
-forms nonessential amino acids
-converts ammonia from deaminiation to urea
-stores glucose as glycogen and regulates blood glucos homeostatis
-stores vitamin, conserves iron, degrades hormones, and detoxifies substance
what is cholesteral
-structual basis of bile salts, steroid hormones, and vitamin D
-transported to and from tissue via lipoproteins
lipoproteins are classified as
HDLS- high-density lipoproteins have more protein content

LDLs- low-density lipoproteins have considerable cholesterol component

VLDL- very low density lipoproteins are mostly triglycerides
what is liver the main source of?
VLDLs

(which transport triglycerides to peripheral tissues) *esp adipose
LDLs
transport cholesterol to peripheral tissue and regulate cholesterol synthesis
HDLs
transport excess cholesterol from peripheral tissues to the liver
-serve as the need of steroid-producing organs (ovaries & adrenal glands)
high levels of HDL
protect against heart attack
high levels of LDL
especially lipoprotein, increase risk of heart attack
liver produces cholesterol at
-basal level of cholesterol regardless of diet
-via negative feedback loop involving serum cholesterol levels
-in response to saturated fatty acids
what do unsaturated fatty acids lower
proportions of saturated fats and cholesterol
fatty acids regulate..
excretion of cholesterol
unsaturated fatty acids
enhance excretion
saturated fatty acids
inhibit excretion
nondietary factors affecting cholesterol
-stress, smoking, and coffee drinking increase LDL levels
-aerobic excercise increase HDL levels
-body shape with cholesterol levels
-fat carried in upper body is correlated with high levels
-fat carried in hips & thighs is lower levels of cholesterol
bond energy balance
bond energy released from catabolized food must equal the total energy output
energy intake is equal to what?
equal to energy liberated during oxidation of food
energy output includes the energy that..
-immediately lost as heat (60%)
-used to do work (driven by ATP)
-stored in the form of fat and glycogen
what is all energy derived from food converted into
heat
heat of body
-warms tissues and blood
-helps maintain homeostatic body temperature
-allows metabolic reactions to occur
when is the body stable?
when energy intake and outflow are balanced
hypothalamus release peptides that influence feeding behavior..
-orexins = powerful appetite enhancers
-neuropeptide Y causes a craving for carbs
-galanin produces craving for fats
-GLP-1 and serotonin makes us feel full and satisfied
what give factors feed into behavior and hunger?
-neural signals from digestive tracts
-bloodborne signals related to body energy stores
-hormones
-body temperature
-psychological factors
high plasma levels of nutrients signal depressed eating
-plasma glucose levels
-amino acids in plasma
-fatty acids and leptin
what do glucagon and epinephrine do?
stimulate hunger
what do insulin and cholecystokinin do?
depress hunger
What does increased body temperature do?
inhibit eating behavior
leptin
secreted by fat tissue - satiety signal

-acts on ventromedial hypothalamus
-controls appetite and energy output
-suppressessecretion of neuropeptide Y
what regulates leptin release?
-blood levels of insulin
-glucocorticoids
metabolic rate
rate of energy (by hour) = total heat produced
what two things is the total heat produced by?
-chemical reactions in body
-mechanical work of body
how is metabolic weight measured?
-directly w/ calorimeter
-indirectly w/ respirometer
basal metabolic rate (BMR)
reflects the energy the body needs to perform its most essential activities
total metabolic rate (TMR)
total rate of kilocalorie consumption to fuel all ongoing activities
factors that influence BMR
-surface area
-age
-gender
-stress
-hormones
When does BMR increase?
-ration to surface area to volume increase
-stress increases
What does thyroxin increase?
-oxygen consumption
-cellular respiration
-BMR
who have a higher BMR males of females?
males
body temperature
balance between heat production and heat loss
what places is the most heat produced?
-rest
-the liver
-heart
-brain
-endocrine organs
how much does heat production go up during vigorous exercise?
-heat production from skeletal muscles can increase 30-40 times
normal body tempertature is
98.2 degrees F
36.2 degrees C

enzyme activity occurs at this temperature
what happens if body temperature is over normal?
-denature proteins
-depress neurons
what four terms cause heat loss?
-radiation
-conduction/convection
-evaporation
heat production is caused by
-basal metabolism
-muscular activity (shivering)
-thyroxine & epinephrine (effects on metabolic rate)
-temperature effect on cells
organs in the core have what and in what cavities?
highest temperature

(skull, thoracic, & abdominal cavities)
what has the lowest temperature?
the shell

essentially the SKIN
what serves as a major agent of heat transfer between the core and shell
blood
what temperature remains constant, and what fluctuates?
constant : core
fluctuates : shell
radiation
loss of heat in the form of infrared rays
conduction
transfer of heat by direct contact
convection
transfer of heat to the surrounding air
evaportion
heat loss due to evaporation of water from lungs, mouth mucose, and skin

*insensible heat loss*
when does evaporative heat loss become sensible?
-when body temperature rises & sweating produces increased water for vaporization
role of hypothalamus
-receives input from thermoreceptors in skin and core
-responds by initiating appropraite heat-loss and heat-promoting activities

*heat-loss & heat-promoting comprmise thermoregulatory centers
what is the main thermoregulation center?
preoptic region of hypothalamus
low external temperature/low tempertature of circulating blood activiates heat-promoting centers of hypothalumus to cause..
-vasoconstriction of cutaneous blood vessels
-increased metabolic rate
-shivering
-enhanced thryoxine release
when to core temperature rises, the heat-loss center is activated to case..
-vasodilation of cutaneous blood vessels
-enhanced sweating
voluntary measures common taken to reduce body heat include
-reducing activity and seeking a cooler environment
-wearing a light-colored & loose-fitting clothing
hyperthermia
normal heat loss processes become inneffective and elevated body temperatures depress hypothalamus

-sets up a + feedback mechanism, sharply increasing body temp and metabolic rate

HEAT STROKE- can be fatal if not corrected
heat exhaustion
heat-associated collapse after vigorous exercise, evidenced by elevated body temp, confusion, and fainting
-due to dehydration and low blood pressure
-heat-loss mechanisms are fully functional
-can progress to heat stroke if body isn't cool or rehydrated
fever
controlled hyerthermia, often a result of infection, cancer, allergic reactions, or central nervous system injuries

= white blood cells, injured tissue cells, and macrophages release pyrogens that act on hypothalamus causing release of prostaglandins
what resets the hypothalamic thermostat?
prostaglandins
when is the higher set point maintained until?
natural body defenses reverse disease process
developmental aspects
-good nutrition is essential in utero
-lack of proteins needed for fetal growth & 1st three years can lead to mental deficits and learning disorders
-with exception of insulin-dependent diabetes mellitus, children free of genertic disorders rarely exhibit metabolic problems
-non-insulin dependent diabetes mellitus - BECOMES MAJOR
developmental aspects further..
many agents prescribed for age-related medical problems influence nutrition
-diuretics can cause hypokalemia promoting potassium loss
-antibiotics can interfere with food absorption
-mineral oil interfere with absorption of fat-soluble vitamines
-excessive alcohol consumption leads to malabsorption problems, certain vitamin deficiencies, deranged metabolism, and damage to liver & pancreas
what does insulin do?
acts a hormone and decreases blood sugar
is cholesterol lipid soluble?
yes
what are examples of saturated fats
animal fat
what are examples of unsaturated fat
olive oil
vegetable oil
thermoneutro zone
range of temperatures where your metabolic rate is flat
metabolic rate is at what period?
resting
what does the heat of the body do?
-Warms the tissues and blood
-Helps maintain the homeostatic body temperature
-Allows metabolic reactions to occur efficiently