exam II Flashcards
[lipids, protein, metabolism + exercise, energy expenditure]
what elements are lipids composed of?
C, H, O
contain more carbon than carbs
how many carbons do most common fatty acids have?
18
medium chain fatty acids are how many carbons
6-12 carbons
where does the MCFAs go?
DIRECTLY into capillaries
how many carbons in LCFAs?
13 or more
how are LCFAs transported?
through chylomicrons
what make up the majority of fats in food?
triglycerides
the shorter the carbon chain…
the softer the oil at room temperature
which is more biologically preferential: cis or trans?
cis; bends, not as easily stackable
advantages to hydrogenation of fats
- prolongs shelf life
2. making liquid vegetable oils more solid like shortening
delta notation system
chain length & number, position of double bonds from CARBOXYL end
18:2[delta]^9, 12
omega notation system
locates position of double bonds counted from METHYL end
18:2[omega]-6
omega 3 & omega 6 structures
first points of unsaturation are at 3 and 6 carbons
which are the two essential fatty acids?
linolenic & alpha-linolic acid
how is 99% of body fat stored?
triglycerides
what are phospholipids?
phosphate containing lipids
biologically involved in the cell membrane formation
sphingolipids
build on amino acid sphingosine
insulators for nerve conduction, cellular recognition
sterols have a ___ structure
ring
cholesterol is a precursor for…
bile acids, sex hormones, adrenocortical hormones, vitamin D
how does the liver play a role in fat digestion?
creation of bile for EMULSIFICATION
how are fats absorbed?
intestinal lumen -> brush border membrane [enterocytes]
where does chylomicron formation occur?
in enterocytes
where are chylomicrons found?
within intestinal cells -> lymphatic system -> bloodstream
function of low-density lipoproteins?
liver regulation
function of high-density lipoproteins?
remove cholesterol from cell
anti-inflammatory properties
main function of lipoproteins?
transport lipids in the blood
trans-fatty acids and effect on cholesterol
raise LDL and lower HDL
how much does fat provide of the body’s ongoing energy needs at rest?
60%
does cholesterol contain energy?
no
features of brown adipose tissue
high vascularity, abundant mitochondria, H+ pores in inner membranes formed by UCPs
nutritional recommendations of fatty acids
AIs for essential FAs
minimize trans fatty acids
unsaturated FAs should be primary source of dietary fats
what percentage of energy should come from fat?
20-35%
how much fat should the diet be capped at regarding saturated fat?
< 20 g/ 10% of total cals
what is the max amount of dietary cholesterol should a person consume in a day?
< 300 mg
which amino acids contain sulfur?
cysteine + methionine
primary structure of amino acids
linear amino acid sequence
secondary structure of AAs
coiling, folding, bending [hydrogen bonds]
alpha-helices, beta-sheets
tertiary structure of AAs
overall total 3D confirmation of protein
quaternary structure of AAs
2+ polypeptide chains interacting
ESSENTIAL AMINO ACIDS
histidine isoleucine leucine lysine methionine phenylalanine therorinine tryptophan valine
conditionally essential amino acids
arginine cysteine glycine glutamate proline tyrosine
sources of exogenous [dietary] protein sources
meat, poultry, fish, eggs, dairy, grains, grain products, legumes, seeds, nuts, vegetables
endogenous protein sources [from the body]
desquamated mucosal cells
digestive enzymes + glycoproteins
end products of the digestion of proteins?
peptides + free AAs
pepsinogen
enzyme = HCl/pepsin
site of activity = stomach
end products = peptides
trypsinogen
enzyme = enteropeptidase/trypsin
site of activity = intestine
end products = smaller peptides, some free AAs
chymotrypsinogen
enzyme = trypsin
site of activity = intestine
end products = smaller peptides, some free AAs
how are the majority of AAs absorbed?
as peptides
how are amino acids catabolized?
removal of an amino group by transamination/deamination
what enzymes transfer amino groups?
aminotransferases
deamination is…
removal of an amino group
keto acid can serve as…
template if there is a nitrogen source available
which conenzyme is required for protein synthesis involving a keto acid?
vitamin B6
which two products are the products of deamination?
ammonia
C structure without its amino group [often keto acid]
3 enzymes involved for the disposal of ammonia
- glutamate dehydrogenase -> glutamate
- glutamine synthetase -> glutamine
- carbamoyl phosphate synthetase -> citrulline
if any of the enzymes involved in the production of ammonia are ineffective…
ammonia will NOT be produced
urea is made up of…
ammonia + CO2 + ammonia
water is removed
= urea
once amino group has been removed, the remaining molecule =
carbon skeleton/alpha-ketoacid
keto acids/carbon skeletons can be used to produce…
energy, glucose, ketone bodies, cholesterol, fatty acids
phenylalanine is converted to ___ by ___
tyrosine, phehydroxylase
PKU affects…
melanin + thyroid hormones
guthrie test…
detects increased phenylalanine
anabolism increases after…
ingestion of food
insulin is either anabolic or catabolic?
anabolic [promotes protein synthesis]
epi + cortisol effects on protein degradation?
release higher glucose-to-insulin ratio
enzymes involved in protein functions
dehydrogenases = remove/transfer H+ ions kinases = add phosphate group
cartinine
fatty acid transport… mitochondria
how is alanine formed?
in muscle cells from transamination w/ glutamate + pyruvate
range of amount of protein needed per day per kg BW
0.8-1.0
to keep urea in solution…
the body needs h2o
is there currently an UL for protein?
no
digestibility percentage of [most animal proteins]
90-99%
eggs are…
100% digestible
which plant proteins are MORE digestible?
soy + legumes
which proteins are fast absorbed?
whey, soy, AA mixtures, prohydrolases
which proteins are slow absorbed?
casein
slower and more prolonged
AA [conc] helps reduce protein breakdown
what happens to excessive protein without training?
converted to fat
muscle work builds muscle; protein does not
kwashiorkor
adequate energy intake w/o adequate protein intake
edema owing due to loss of blood proteins
marasumus
wasting, emaciation
chronic insufficiency of energy & protein
definition of metabolism
all chemical reactions and pathways that maintain life
which two compounds are present in every cell regardless of pathway?
pyruvate
acetyl CoA
anabolic reactions…
require energy
catabolic reactions…
release energy
catabolic reactions ___ macronutrients
BREAKDOWN
anabolic reactions ___ macronutrients
SYNTHESIZE
which organ does every product go through?
the liver
CO2 does what in TCA cycle?
initiate fatty acid synthesis, gluconeogenesis
how are most enzymes controlled?
allosterically
role of malonyl CoA
allosteric control of cartinine acyltransferase;
first step of FA synthesis
associated with limitation of food intake
role of AMP activated protein kinase
controls both catabolic + anabolic pathway involving all macronutrients
++ activated by low energy
the TCA cycle is an AMPHIBOLIC pathway. what does that mean?
both anabolic + catabolic
what are the major fuels of the muscle?
fatty acids and glucose [ketone bodies if necessary]
GLUT-4 transporter is used in…
the muscle!
exclusive source of fuel for RBCs
glucose
where does excessive glucose go when liver’s storage capacity is full?
FAs & triglycerols
fed state
lasts 3 hours after meal ingestion
post absorptive state
3-18 hours post meal
fasting state
18hours - 2 days without additional food intake
starvation state
> 2 days; full adaped state of deprivation
does the post-absorptive state contain ketone bodies?
no
when is a time period when the body is in the post absorptive state?
overnight fast; nearly all reserves of liver glycogen are depleated
what is the source of fuel for gluconeogenesis in the fasting state?
primarily AAs, glycerol, lactate
what physiological change occurs in the starvation state?
LIPOLYSIS, FAs used to a greater extent, increase in ketone body synthesis
which hormones promote anabolic reactions [energy storage]
insulin
which hormones promote catabolic reactions [energy utilization]
glucagon, epinephrine, cortisol
which hormones promote both anabolic AND catabolic reactions depending on the target tissue?
growth hormone
insulin role in metabolism
critical in fed state; removing glucose to prevent hyperglycemia
increases glycogen synthesis in liver + skeletal muscle; stimulates FA synthesis
glucagon role in metabolism
prominent in NONFED states
epinephrine role in metabolism
inhibits insulin secretion, stimulates glycogen breakdown, inhibits glycogen synthesis
cortisol role in metabolism
responds in decrease in BG levels
growth hormone role in metabolism
stimulates lipolysis + release of FAs from visceral adipose tissue
increase triglyceride uptake in liver
function of muscle in metabolism
release of more glucose, FAs, increase in gluconeogensis, glycogenolysis, lipolysis NO GLYCOLYSIS
pathway of the anaerobic [lactic acid system]
glucose -> pyruvate -> lactate
pathway of aerobic [oxidative system]
glucose -> pyruvate -> acetyl CoA
how much ATP produced in aerobic activity?
38 ATP + CO2 + h2o
how much ATP produced in anaerobic activity?
2 ATP + lactic acid
VO2 max
measurement of max amount of o2 that an individual can utilize during intense, maximum exercise
how to correct muscle fatigue?
reduce exercise + intensity OR consume glucose
what percentage of energy expenditure does the thermic effect of food account for?
5-30%
what does direct calorimetry measure?
energy expenditure:
highly expensive, conditions have to be “perfect”
indirect calorimetry
heat release calculated indirectly by measuring the consumption of OXYGEN
respiratory quotient
ratio of CO2 produced relative to O2 consumed
which macronutrient has the highest RQ?
carbohydrates
which macronutrient has the lowest RQ?
protein
range of RQ for “ordinary person’s” diet?
0.7-1.0
max HR is ___ of VO2 max
80%
how to calculate max HR?
220-age
basal metabolism:
energy needed to maintain life
when body is at complete digestive, physical, and emotional rest
basal metabolic rate
very complicated lab conditions; use resting metabolic rate > basal
how many hours does RMR require?
3 hours
which patients do Harris-Benedict equations support?
patients with liver disease
which sex has higher RMRs?
men > women
male formula for mifflin- st jeor equation
[10 x weight] + [6.25 x height] - [5 x age] + 5
female formula for mifflin-st jeor equation
[10 x weight] + [6.25 x height] - [5 x age] - 161
what influence energy expenditure?
duration, intensity, frequency of activity
PALs numbers
sedentary = 1.15
low active = 1.50
active = 1.75
very active = 2.20
which macronutrient has the greater thermic effect?
protein
what is the range of the body’s biological temperature to function optimally?
98.2-98.6
ideal body weight [hamwi method] for males
106 lbs for first 5f + 6 lbs for each additional inch
ideal BW [hamwi method] for females
100 lbs for first 5 ft + 5 lbs for each additional inch
BMI categories
underweight = < 18.5
normal/healthy weight = 18.5-24.9
overweight = 25.0-29.9
obese = > 30
what age range is pediatric BMI calculated?
2-20
what is “healthy” weight for pediatric BMI?
between 5th and 85th perecentile
