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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 |