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HNF 461: FINAL EXAM
Endothermic what is G? |
Positive
reaction requires energy
|
Exothermic, what is G? |
G is negative
Reaction releases energy
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Three ways that enzymes are regulated? |
Allosteric regulation
Phosphorylation and Dephosphorylation
Regulation through gene expression
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The three amino acids that can be phosphorylated? why? |
Tyrosine, Serine and Threonine
Because they have an OH group
|
What is AMPK? |
Activated Protein Kinase
AMPK triggers a cell response to produce more ATP hen the AMP/ATP ratio is higher. This means the cells is using more energy and needs to produce more. AMPK makes sure this happens.
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Processes that AMPK inhibits |
Anything energy consuming.
Synthesis productions such as
Protein synthesis
Gluconeogenesis
Glycogen synthesis
Fatty acid/Cholesterol synthesis
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Processes that AMPK stimulates |
Energy releasing productions such as:
mitochondrial biogenesis
glucose uptake
fatty acid oxidation
glycolysis
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Hypothalamic AMPK inhibits.... |
Food intake.
Leptin secreted from big fat cells stimulates hypothalamic AMPK which decreases food intake.
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Km of Glut 1 and 3 transporter |
VERY low
for basal uptake of many tissues
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Km of Glut 2 |
Very high Km
For liver and pancreatic beta cells
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Km of Glut 4 |
physiologically controlled by insulin
for muscle and adipose tissue
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Purpose of Glut 3 and Km |
for brain, very low Km
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What is glucose for in cells? |
Energy
Glycogenesis making glycogen (storage form of glucose)
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Main tissues that use Glucose for energy |
BRAIN
RBC
SKELETAL MUSCLE
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Glycogenesis = what --> what |
Converst GLUCOSE to GLYCOGEN
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Gluconeogenesis= what to what? |
PYRUVATE to GLUCOSE
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Glycogenolysis= what to what |
Glycogen glucose
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Glycolysis= what to what? |
glucose to pyruvate
reverse of gluconeogenesis
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Enzyme involved in Glucose phosphorylation? |
Hexokinase
|
Hexokinase |
phosphorylates Glucose-6-P
Tip for remembering: Hexo=6 Glucose 6 is phosphorylated
|
Glucokinase |
Hexokinase number 4 aka Glucokinase
enzyme that phosphorylates of glucose to glucose-6-phosphate.
Glucokinase occurs in cells in the liver, pancreas, gut, and brain of humans and most other vertebrates.
|
Phosphofructosekinase-1 activated by |
AMP
fructose 2,6 biphosphate
high insulin in blood
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What inhibits PFK? (phosphofructokinase) |
ATP citrate
Glucagon
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phosphofructokinase |
Phosphofructokinase is a kinase enzyme that phosphorylates fructose 6-phosphate in glycolysis.
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Pyruvate Kinase |
Pyruvate kinase is an enzyme involved in glycolysis (glucose to pyruvate). It catalyzes the transfer of a phosphate group from phosphoenolpyruvate (PEP) to ADP, yielding one molecule of pyruvate and one molecule of ATP.
basically releases energy
|
What inhibits Pyruvate Kinase |
Phosphorus |
Pyruvate Dehydrogenase |
Pyruvate dehydrogenase (E1) is the first component enzyme of pyruvate dehydrogenase complex (PDC). The pyruvate dehydrogenase complex contributes to transforming pyruvate into acetyl-CoA by a process called pyruvate decarboxylation.
Bridges the gap between glycolysis (glucose to pyruvate) and TCA cycle (pyruvate making ATP)
|
TCA cycle |
The citric acid cycle - also known as the tricarboxylic acid cycle, or the Krebs cycle, - is a series of chemical reactions used by all aerobic organisms to generate energy through the oxidation of acetate derived from carbohydrates, fats and proteins into carbon dioxide and chemical energy in the form of adenosine triphosphate (ATP).
|
PYruvate Dehydrogenase inhibited by... |
NADH and acetyl CoA
and controlled by phosphorylation and dephosphorylation
|
phosphorylation |
Phosphorylation is the addition of a phosphate (PO4-3) group to a protein or other organic molecule (see also: organophosphate).
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HOw many NADH are derived from aerobic glycolysis? |
2 |
How many NADH are derived from anaerobic glycolysis? |
0 |
A high ATP/ADP ratio will do what to ATP synthesis. (hint ATP not AMP...) |
A high ATP/ADP ratio will SLOW ATP synthesis.
A high AMP/ATP ratio with increase ATP synthesis with AMPK help.
|
Electron Transport Chain |
An electron transport chain couples electron transfer between an electron donor (such as NADH) and an electron acceptor (such as O2) with the transfer of H+ ions (protons) across a membrane.
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What is the gradient called in the ETC? |
CoQ
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What enzyme converts ADP to ATP? |
ATP synthase
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Uncoupling Proteins |
An uncoupling protein is a mitochondrial inner membrane protein that can dissipate the proton gradient before it can be used to provide the energy for oxidative phosphorylation.
Basically uses energy for heat not ATP
in Brown Adipose Tissue...Infants use
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Pentose phosphate Pathway |
The pentose phosphate pathway is a process that generates NADPH and pentoses (5-carbon sugars).
DOES NOT USE ATP
|
Oxidative stage of Pentose phosphate pathway |
non reversible
produces NADH
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Non Oxidative stage of Pentose phosphate pathway |
reversible
produces riboses
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Main site of Glycogenesis? And what other tissue is an important site? |
Liver
skeletal muscle
|
Purpose of Glycogen in liver? |
To help maintain stable glucose levels
|
Purpose of Glycogen in skeletal muscle? |
to provide fast acting energy for muscle cells
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Glycogen synthase |
Glycogen synthase is an enzyme involved in converting glucose to glycogen.
requires energy ATP and UTP
|
active form of glycogen synthase is phosphorylated or dephosphorylated? |
dephosphorylated
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what stimulates glycogen synthase? |
Insulin
when insulin levels are high, this stimulates the making of glycogen
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Triglyceride Synthesis |
aka TAG synthesis
When glucose is not needed for ATP, Phosphate shunt or glycogen it can be used to make fatty acids
|
What is a building block for fatty acids? |
acetyl CoA
|
Lipogenesis |
Lipogenesis is the process by which acetyl-CoA is converted to fatty acids.
requires alot of ATP and NADH
|
Palmitate |
C16:0
means there are no double bonds-0
Saturated
|
Oleic Acid |
C:18:1 Omega 9
Monounsaturated
one double bond
|
Linoleic |
Polyunsaturated
C:18:2 omega 6
two double bonds
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Stearic Acid |
Saturated fatty acid
C:18
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What B vitamins are needed in Lipogenesis? |
Biotin (formally B7) and Pantotheinic Acid (B5)
|
What determines food's Glycemic Index? |
the rate of glucose taken up
the rate of glucose transport to the tissues
|
Which organ secretes glucagon and insulin? |
pacrease |
Glucagon hormone stimulates production of what? |
cAMP |
Does Glucagon cause dephosphorylation or phosporylation of enzymes? |
phosphorylation of enzymes
making them inactive?
|
Insulin causes dephosphorylation or phosphorylation of enzyems? |
dephosphorylation of enzymes, turning them on
|
What cells secrete insulin? |
beta cells
|
what cells secrete glucagon? |
alpha cells
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Glycagon release activates protein kinases which active glycogenolysis (glucose breakdown) |
true |
glycogen phosphorylase |
cleaves glucose from glycogen one at a time
cAMP secondary messenger
|
Insulin/Glucagon response to : Glycogenolysis |
- insulin + glucagon
|
insulin/glucagon response to Glycolysis: |
breakdown of glucose to pyruvate
+ insulin - glucagon
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insulin/glucagon response to glycolysis |
glucagon breakdown
-insulin
+ glucagon
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GLuconeogenesis |
Gluconeogenesis is a metabolic pathway that results in the generation of glucose from non-carbohydrate carbon substrates such as pyruvate, lactate, glycerol, glucogenic amino acids, and odd-chain fatty acids.
|
Pyruvate kinase bypass |
Pyruvate makes oxaloacetate
oxaloacetate turns to malate
malate turns back into oxaloacetate in cytosol
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fatty acid oxidation yields.. |
acetyl CoA and NADH
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Acetyl CoA and NADH inhibit |
pyruvate dehydrogenase
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Cori Cycle |
lactate produced by anaerobic glycolysis in the muscles moves to the liver and is converted to glucose, which then returns to the muscles and is metabolized back to lactate.
production of lactate from glucose
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Alanine cycle |
The alanine cycle is quite similar to the Cori cycle. When muscles produce lactate during times of decreased oxygen, they also produce alanine.
pyruvate to alanine
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Glucocorticoids |
controlled by ACTH which responds to low blood sugar, injury/inflammation and stress
antagonize insulin production
|
ACTH |
Adrenocorticotropic hormone, also known as corticotropin, is a polypeptide tropic hormone produced and secreted by the anterior pituitary gland.
|
Pyruvate kinase is inhibited by |
glucagon
glucagon binds to the receptor on the cell which activates cAMP which activates PK which gets Phosphorylated and is inhibited.
Therefore glycolysis is inhibited.
|
PDHC |
Pyruvate dehydrogenase complex is a complex of three enzymes that transform pyruvate into acetyl-CoA by a process called pyruvate decarboxylation.
|
Acetyl CoA inhibits what complex? |
PDHC, pyruvate dehydrogenase complex
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major glucocorticoid in humans |
cortisol |
what gland releases ACTH |
pituitary |
what releases cortisol |
adrenal glands and kidney
|
hypothalamus releases... |
CRH coticotropin releaseing hormone
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direct calorimetry |
measures heat dissipation
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indirect calorimetry |
respiratory dissipation
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What cells releases intrinsic factor and HCL? |
Parietal cells
|
Chief cells |
secrete pepsinogen and lipase for protein digestion
|
segementation is by what kind of muscle? |
circular |
peristalsis is by what kind of muscle? |
longitudinal muscle
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Monosaccharide |
fructose, glucose and galactose
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Polysaccharides |
Sucrose-glucose and fructose
Lactose-glucose and galactose
Maltose-glucose and glcucose
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what bond does amylose have? |
alpha 1,4
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bond that amylopectin has |
alpha 1,6 and alpha 1,4
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Impaired fasting glucose measurement indicates Diabetes (give me numbers) |
IFG for positive diabetes result will be 126mg/dL or higher
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Impaired glucose tolerance of diabetes will read (give me #s) |
higher than 200 mg/dL
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Prediabetes diagnosis (fasting blood glucose, #s) |
between 100-125 mg/dL
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Plasma glucose for prediabetics |
between 140-199mg/dL
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Conversion of glucose from mM and mg/dL |
5mM: 90mg/dL
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how obesity can lead to type two diabetes |
insulin resistance
problems controlling gluconeogenesis which increases blood glucose, increases insulin but has no affect on cells and equals obesity and type two diabetes
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Insulin resistance in what tissue results in type two diabetes? |
liver tissue
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What are the two systems that metabolize alcohol in the body? |
alcohol dehydrogenase
acetyladehyde dehydrogenase
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what does alcohol do to the NAD/NADH ratio in the liver? |
it increases it
causes a fatty liver
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Where is hormone senstive lipase located? |
in the adipose tissue o'course!
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What does HSL do?! |
It hyrolizes TGs to NEFAs
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what activates HSL? |
glucagon and epinephrine
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what inhibits HSL? |
insulin!
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NEFAs bind to what to transport through the blood? |
albumin!
|
carnitine shuttle |
transports NEFAs to the mitochondria!
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what does Malonyl-CoA do? |
inhibits the carnitine shuttle
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What does beta oxidation of fatty acids produce? |
NADH and Acetyl CoA and FADH
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ketones are made in the... |
liver when fatty acids are broken down for energy
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Diabetic Ketoacidosis |
is caused by too much fatty acid breakdown and build up of ketones in the blood
lowers blood pH
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% of how much saturated fat we should eat |
<10%
<7% for people at risk for CVD
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Simple lipids |
TAGs, DAGs, MAGs
Cholesterol
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Compound lipids |
phospholipids
glycolipids
lipoproteins
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Difference between TAGs and phospholipids |
TAGs have 3 fatty acids(+ glycerol)
Phosphlipids have 2 fatty acids
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Omega system count from the |
methyl end (CH3)
|
Delta system couunt from the |
carboxyl end (C=O)
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Where is lingual lipase? |
mouth |
where is gastric lipase? |
stomach |
what produces bile? |
liver |
what stores bile? |
gall bladder
|
what secretes bile? |
pancreas |
Micelles |
spheres of fat that occur in water
|
what hormone signals the release of bile in the duodenum? |
CCK |
Components of bile |
bile acids, cholesterol, billirubin, water, electrolytes, phospholipids
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what role does bile play in fat digestion? |
it is an emulsifier
|
what percentage of bile gets reabsorbed? |
~90%
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Types of lipoproteins |
Chylomicrons, LDL, VLDL, HDL, IDL
|
What cells make chylomicrons |
enterocytes
|
chylomicrons |
Chylomicrons are lipoprotein particles that consist of triglycerides (85-92%), phospholipids (6-12%), cholesterol (1-3%), and proteins (1-2%).
|
what protein is associated with nascent chlymicrons? |
apo B48
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apolipoproteins what are they and give examples |
Apolipoproteins are proteins that bind lipids to form lipoproteins. They allow fat to travel through the blood.
V.I.D.L.-VLDL, IDL, LDL, HDL
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When chylomicrons get into the blood what additional lipoproteins do they require? |
Apo E and C
|
Apo C function |
activates lipoprotein lipase
aids in chylomicron metabolism
|
Function of Glutathione |
Antioxidant |
Function of Carnitine |
Transports fatty acids to mitochondria
|
Creatine |
provide energy to muscle by increasing formation of ATP
|
Carnosine |
Antioxidant |
Choline |
Precursor for acetylcholine
|
Name some Catecholines |
norepinephrine and epinephrine and dopamine
|
Seratonin is made from |
tryptophan |
Histamine is made from |
histadine |
Where is the free amino acid pool? (3 places) |
ISF-interstitial fluid
blood
cells
|
What makes up the amino acid pool? (2 things) |
turnover-breaking down of proteins
AAs from dietary proteins
|
Free amino acid pool size compared to total body AAs |
small roughly 100g
|
Why does amino acid deficiency result in a Negative Nitrogen balance? |
Because protein synthesis cannot skip a missing amino acid. The peptide product will be degraded and the free amino acids oxidized.
|
In what tissue are branched chain amino acids metabolized? |
skeletal |
Transamination |
When the NH2 group on an amino acid is changed to a Keto group C=O
produces alanine, aspartate and Glutamate
|
Two enzymes involved in transamination |
Asapartate amino transferase
Alanine amino transferase
|
Define Glucogenic |
AAs that can be converted into glucose
|
Define Ketogenic |
AAs cannot be converted into glucose, therefoore are converted to ketones
|
Oxaloactetate is a precursor for |
Glucose |
the breakdown of glutamate produces |
ammonia
we do not want build up of ammonia in blood
|
Does the urea cycle require energy? What does it produce? |
Urea and yes it requires energy
|
two amino acids that carry nitrogen from muscle to liver |
Glutamine
Alanine
|
Glutamine is required for what synthesis? |
DNA |
LIver uses glutamine for |
urea synthesis
|
When blood pH is low, what does the kidney do to correct it? |
Use more glutamine
this produces ammonia
ammonia reacts with H+ which produces ammonium
and is peed out
|
What hormones promote Nitrogen retention |
Growth hormone and insulin
|
What hormones promote protein catabolism |
epinephrine
glucocorticoids
glucagon
|
Protein turnover accounts for what % of the RMR? |
10-25%
|
AAS=Amino Acid Score define |
mg limiting amino acid in food / g protein / mg of aa / g reference protein
|
1 g N = ? g of protein |
6.25
|
protein intake very low, this means Nitrogen balance is.. |
negative
because dietary proteins are not able to compensate for protein turnover so balance is negative
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Fed state-protein metabolism |
+ insulin - catabolic hormones
+ protein synthesis - protein catabolism
|
Fasting-protein metabolism |
- insulin
**period of protein imbalance**
+ protein catabolism
|
Starvation |
+ AA's used in gluconeogenesis
+ ketogenesis
then later lower gluconeogenesis
|
RDA of protein based on.. |
nitrogen balance
|
DAAO procedure |
Direct Amino Acid Oxidation
eat adequate amino acid
when curve spikes, point of spiking is where requirement of protein is
graph curving up to the right
|
IAAO= |
Indirect Amino Acid oxidation
give excess phenylalanine
feed graded levels of amino acid
collect respired CO2
level off (graph going down to right, when levels off is where requirement is)
|
Kwashiorkor |
Kwashiorkor protein-energy malnutrition characterized by edema, irritability, anorexia, ulcerating dermatoses, and an enlarged liver with fatty infiltrates.
|
Marasmus |
Marasmus is a form of severe malnutrition characterized by energy deficiency. A child with marasmus looks emaciated.
|
Why edema and fatty liver in people with Kwarshiorkor? |
When defiecient in protein, liver stops making protein like albumin and apolipoproteins.
When albumin is low, the blood osmotic pressure decreases, fluid leaks out of ISF and causes edema.
Fat liver-When less apolipoproteins are made the liver can't transport the fat out of the liver and thus fatty liver.
|
Protein Energy malnutrition |
Protein-energy malnutrition refers to a form of malnutrition where there is inadequate protein intake.
|
Why reintroduce protein slowly to someone recovering from PEM? |
to allow the uptake of urea cycle
not enough enzymes to help urea cycle deaminate proteins, NH3 will build up
|
In injury and disease how do stress hormones change balance of protein metabolism? |
stress and cytokines- increase protein metabolism
insulin and growth hormone- resistance
hypermetabolic-net loss
negative nitrogen balance, protein catabolism increases
|
exercise favors protein synthesis in what two states? |
fed and fasting
|
What determines protein quailty? |
AA composition and protein digestibility
|
How to calculate BMI |
weight in kg over height in m^2
|
fat distribution waist circumference that is acceptable |
less than 35 for women (.8 w/h ratio)
less than 40 for men (.95 w/h ratio)
|
Densitonometry |
based on two compartments
fatt mass-essential and non essential fat
free fat mass-PFC and minerals
|