Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
180 Cards in this Set
- Front
- Back
- 3rd side (hint)
|
proteins make up how much of the content of cells?
|
half
|
|
|
|
categories of proteins?
|
enzymes
hormones structural protesin antibodies transport proteins others |
|
|
|
what type of glands release hormones?
|
endocrine
|
|
|
|
how do hormones act on things?
|
stimulus causes hormone to be released
hormone travels in blood to its target tissue hormone binds to a receptor often influences the synthesis or activity |
|
|
|
hormones v steroid hormones?
|
streoid hormones are dervived from cholesterol
|
|
|
|
hormones are typically made from
|
cholesterol or aa
|
|
|
|
polypeptide examples?
|
insulin, glucagon
|
|
|
|
structural proteins?
|
actin, myosin (contractile)
collagen, elastin, keratin (fibrous proteins) |
|
|
|
where are fibrous proteins found?
|
hair, teeth, nails, bone, blood vessels, cartilage, tendons
|
|
|
|
how many polypeptide chains make up a antibody?
|
4
|
|
|
|
what links the 4 polypeptide chains in antibodies?
|
disulfide bonds
|
|
|
|
example of transport proteins?
|
albumin, transthyretin and heme protein
|
|
|
|
what does transthyretin transport?
|
vit a
|
|
|
|
what does heme protein transport
|
iron and oxygen
|
|
|
|
conjugated protein is?
|
a protein joined with a non protein component (lipo protien)
|
|
|
|
what part of a polypeptide chain makes it unique?t
|
side chains. everything else is the same
|
|
|
|
what determines the organization structure of a polypeptide cahin?
|
side chains
|
|
|
|
secondary structures of aa are a result of
|
H bonding
|
|
|
|
rigid proteins are what structure?
|
2ndary
|
|
|
|
random coil?
|
another type of 2ndary structure that is unstable
|
|
|
|
proteins with a tertiary structure?
|
enzymes, transport proteins, antibodies
|
|
|
|
interactions in a tertiary structure?
|
hydrophobic, electrostatic and disulfide and other weaker bonds
|
|
|
|
how many polypeptides in a 4th degree structure?
|
2 or more
|
|
|
|
can quateranary structures undergo conformation changes?
|
yes
|
|
|
|
imino acid
|
proline
|
|
|
|
oligopeptides are:
|
4-10 aa linked together
|
|
|
|
what can be synthesize from Phe?
|
tyrosine
|
|
|
|
why can't PKU people synthesize tyrosin from phe?
|
b/c of phenylalanine hydroxylase inactivity
|
|
|
|
can sulfur aa form h bonds?
|
yes
|
|
|
|
protein digestion begins in the
|
stomach
|
|
|
|
what converts pepsinogen to pepsin?
|
HCl
|
|
|
|
pepsin is active at what pH
|
less than 3.5
|
|
|
|
pepsin is a
|
endopeptidase
|
|
|
|
endopeptidase is
|
enzyme that hydrolyzes peptide bonds in the interior of the polypeptide
|
|
|
|
how specific is pepsin in how it cleaves?
|
not specific
|
|
|
|
end products of HCl and pepsin?
|
aa and oligopeptides
|
|
|
|
trypsin activates
|
chymotrypsin
itself carboxypeptidases elastase |
|
|
|
endopeptidases
|
trypsin
chymotrypsin pepsin enteropeptidase elastase collagenase |
|
|
|
digestion of polypeptides in SI yields:
|
aa, di/tri/oligopeptides
|
|
|
|
where are aa absorbed?
|
all along SI
|
|
|
|
what percent of aa is absorbed?
|
99%
|
|
|
|
what kind of aa transporters are there to get them out of the SI and absorbed?
|
ones for basic, neutral and acidic aa
|
|
|
|
which aa are absorbed the fastest?
|
long chain neutral ones
|
|
|
|
types of aa and the speed at which they are absorbed?
|
neutral are fastest
then basic then acidic |
|
|
|
slowest aa absorbed?
|
acidic, nonessential aa: aspartate and glutamate
|
|
|
|
which aa compete for absorption?
|
those that share the same carrier
|
|
|
|
which is absorbed more quickly, peptides or free aa?
|
peptides
|
|
|
|
are aa absorbed mostly as di/tripeptides or as free aa?
|
peptides (67%)
|
|
|
|
what happens after peptides are absorbed?
|
they are hydrolyzed to free aa in the enterocyte
|
|
|
|
what happens to the aa that are absorbed into the enterocyte
|
some transported out into circulation
some usesd by the enterocyte to make: |
digestive enzymes
lipoproteins hormones other N containing compounds |
|
|
which aa is an important source of energy for the intestine and stimulates the proliferation of the enterocytes (mucosal cells)?
|
glutamine. this is also fed to burn pts
|
|
|
|
do aa enter the arteriole or venule when the leave the enterocyte?
|
arteriole. then what?
|
enter the portal vein and go to the liver
|
|
|
where do the majority of the aa in circulation go?
|
liver
|
|
|
|
3 fates of aa taken up by the liver
|
20% for the synthesis of protein (albumin, carnitine) and some is released into blood
23% released into the blood as free aa 57% catabolized by the liver |
|
|
|
what kind of aa are released from the liver into the blood?
|
branched
|
|
|
|
what stimulates HCl release
|
Ach
gastrin histidine |
|
|
|
exopeptidases
|
procarboxypeptidases
|
|
|
|
non protein N containing compounds synthesized in the liver:
|
glutathione, carnitine, creatine, carnosine, and choline.
|
|
|
|
proteins synthesized in the liver and released into the blood include:
|
albumin, transthyretin, retinol-binding protein, various globulins, and blood-clotting proteins
|
|
|
|
glutathione is:
|
a non protein N containing compound synthesized in the liver and released into the blood. It is synthesized from:
|
glycine, cysteine, and glutamate
|
|
|
glutathione functions:
|
vit c synthesis
free radical protection |
|
|
|
carnitine is synthesized from
|
lysine and methoionine
|
|
|
|
carnosine is synthesized from
|
histidine and beta alanine. function of carnosine?
|
nerve transmission
|
|
|
where is creatine synthesized
|
liver, kidney and pancreas
also comes from meat |
|
|
|
where is the majority of creatine (95%) located?
|
muscles
|
|
|
|
creatine phosphate is
|
high energy storage in the muscles
|
|
|
|
creatine phosphate is used to
|
regenerate ATP by transferring its phosphate group to ADP when muscle ATP is depleted (sprinting)
|
|
|
|
what is an alpha keto acid?
|
an aa with a ketone group instead of the amino group
|
|
|
|
transamination of Ala =
|
pyruvate
|
|
|
|
transamination of oaa =
|
aspartate
|
|
|
|
how are aa catabolized?
|
transamination and oxidative deamination
|
|
|
|
function of urea cycle?
|
metabolize the N from aa
|
|
|
|
can N provide energy?
|
nope
|
|
|
|
in transamination, the amino group of aa is transferred to:
|
alpha keto acid
|
|
|
|
what catalyzes transamination reactions?
|
transaminases aka aminotransferases. what coenzyme do they require?
|
b6
|
|
|
what is the relationship between aa conc. and aa transferases?
|
directly proportional
|
|
|
|
oxidative deamination of glutamate is catalyzed by
|
glutamate dehydrogenase
|
|
|
|
oxidative deamination starts with what reactants?
|
aa (glutamate) + water + NAD+
the products are: |
alpha keto gluterate
NADH NH4 (ammonium) |
|
|
what stimulates glutamate dehydrogenase?
|
ADP and GDP
(hence glutamate dehydrogenase activity is stimulated which initiates oxidative deamination which is necessary for aa catabolism and utilization of the C skeleton for energy/glc) |
|
|
|
where does the urea cycle occure
|
liver
|
|
|
|
urea cycle removes
|
N in the form of ammonia
|
|
|
|
How many ATP are necessary for the formation of carbamoyl phosphate
|
2
|
|
|
|
rate limitting step of the urea cycle
|
formation of carbamoyl phosphate from ammonia and CO2 by CPS1
|
|
|
|
citrulline is trasnported into the cytosol via
|
conc independent carrier
|
|
|
|
how many high energy bonds are required to make one urea?
|
4
|
|
|
|
in urea cycle, what is borrowed from the TCA cycle for transamination reactions?
|
alpha ketogluterate
|
|
|
|
complete oxidation of aa yields
|
co2 and ammonia
|
|
|
|
ketogenic aa can be degraded to form
|
acetoacetate (ketone) or AcCoA
|
|
|
|
are some aa both keto and glucogenic?
|
yes
|
|
|
|
all glucogenic aa are ketogenic as well, true or false?
|
ture
|
|
|
|
is the bbb permeable to ammonia?
|
yes
|
|
|
|
cirrhosis results in
|
urea cycle inhibited. Ammonia is not removed from the body. Goes to the brain and hurts it
|
|
|
|
healhty liver slows the release of ammonium into the blood by
|
increasing the synthesis of glutamate. how does it does this?
|
reductive amination (alphaketogluterate --> glutamate)
incorporates the ammonia into the glutamate instead of letting it into the blood |
|
|
reductive amination is:
|
alpha keto gluterate is reduced to form glutamate
|
|
|
|
effect of reductive amination of alphaketogluterate?
|
decreased ammonia
decreased alphaketogluterate TCA slows down AcCoA is increased in liver mitochondria increased ketone bodies ketoacidosis |
|
|
|
degradation of phe and Tyr yield:
|
acetoacetate and fumerate
|
|
|
|
Phe is converted to what other aa?
|
tyrosine. What enzyme does this and what cofactor is required?
|
phenyalanine hydroxylase and vit c
|
|
|
catecholamines are
|
epi and norepi
|
|
|
|
epi stimulates
|
lipolysis and glycogenolysis
|
|
|
|
When a diet is too high in Phe and a person has PKU
|
the alternative pathways to metabolize Phe can't handle all the Phe, and phe builds up and causes brain damage
|
|
|
|
degradation of tryptophad yields
|
pyruvate and AcCoA
|
|
|
|
trp can be used to produce
|
melatonin and seratonin
|
|
|
|
serotonin promotes
|
satiety and sleepiness
|
|
|
|
when does serotonin production peak?
|
after consumption of a carb rich meal
|
|
|
|
high carb or high protein meal will result in more production of serotonin
|
carb
|
|
|
|
amount of trp in meat compared to other aa?
|
low
|
|
|
|
most LCAA are uptaken after a meal by
|
the muscles. Only a small amount of trp is taken up though. trp is taken up by the
|
neurons mostly
|
|
|
dietary fat effect on trp in the blood?
|
increases the trp ratio (b/c albumin has a higher affinity for fat)
|
|
|
|
SAM is made from
|
methionine
|
|
|
|
methionine is used to create nonessential aa such as
|
taurine and cysteine
|
|
|
|
another function of methionine?
|
donates methyl group. but first it must be converted to
|
SAM
|
|
|
SAM is required for the syntheiss of
|
creatine, epi, carnitine, and the purines
|
|
|
|
high level of homocystein in the blood =
|
CAD
|
|
|
|
what is necessary for methionine to be generated from homocysteine?
|
folic acid and vit b12. this helps prevent CAD because homocystein is associated with CAD
|
|
|
|
homocystein can be metabolizied from a pathway involving serine. what cofactor is required?
|
b6. This is important to eat for cardiovascular heath
|
|
|
|
glutamin and alanine play important roles in
|
the transport of N among tissues
|
|
|
|
in extrahepatic tissues, ammonia/ammonium are used for synthesis of
|
glutamine
(b/c urea cycle only occurs in the liver!) |
|
|
|
catabolism of the BCAA in the muscles yields
|
ammonia and alpha keto acids.
The ammonia then does what? |
reacts with alpha ketogluterate to make glutamate
|
|
|
glutamate may aquire an amino group to become
|
glutamine
|
|
|
|
glutamine synthase catalyzes
|
glutamate to glutamine reaction
|
|
|
|
glutamate + ammonia =
|
glutamine. what cofactors are required?
|
Mg or maganese
ATP |
|
|
where does synthesis of glutamine from glutamate take place?
|
all tissues but esp.
muscle and lung |
|
|
|
glutamine released from the muscles/lungs goes to
|
transports its ammonia to other tissues (liver, kidney and intestines)
|
|
|
|
primary carrier of N among tissues is
|
glutamine
|
|
|
|
what tissues use glutamine for fuel?
|
intestines and immune system
|
|
|
|
glutaminase catalyzes what rxn
|
glutamine --> glutamate + NH4
|
|
|
|
eat a protein rich meal, and what happens to glutaminase?
|
increases in the liver. Therefore more glutamate and ammonia are produced
|
|
|
|
in starvation state, what happens to glutaminase?
|
decreases in liver. instead, glutamine is released into the blood to go to the liver
|
|
|
|
acidotic state
|
prolonged fasting or starvation
|
|
|
|
where is glutaminase located?
|
liver and kidney
|
|
|
|
where can BCAA be degradated?
|
muscles. where CANT they be degradated?
|
liver. Liver doesn't have BCAA transaminases
|
|
|
is the transamination of BCAA reversible?
|
yes
|
|
|
|
When does protein degradation occur in the muscles?
|
starvation
|
|
|
|
can ketone bodies be used as fuel?
|
yes
|
|
|
|
Why are the BCAA degraded simultaneously?
|
b/c the succinyl CoA produced by some is needed for full catabolism of the others
|
|
|
|
during starvation, the most abundant aa released from the muscles are:
|
ala and gln. Is this from actual ala and gln, or from transaminated ala and gln?
|
a lot transaminated.
|
|
|
another way to get rid of N from the muscles (besides ala and gln)
|
creatinine
|
|
|
|
____ is the primary site for synthesis of several aa
|
kidney.which aa?
|
Histamine
Arginine Glycine |
|
|
alpha keto acids are produced from:
|
transamination and
oxidative deamination |
|
|
|
only two organs that can do glucoenogenesis
|
kidney and liver
|
|
|
|
when does gluconeogenesis occur in the kidney?
|
prolonged starvation
(2+ days) |
|
|
|
what other organ besides the liver can remove N from the body?
|
kidney
|
|
|
|
what happens to the alpha KG generated during starvation state in the kidney from the transamination of glu
|
enters TCA cycle. (2 NADH are produced instead of 3 NADH)
|
|
|
|
3 places that can take up Gln in significant amounts during starvation?
|
kideny
liver Intestines |
|
|
|
which key Gln or Glu enzyme do the intestines have?
|
glutaminase which does:
|
Gln--> Glu + NH3
|
|
|
what stimulates glutaminase?
|
GCC
|
|
|
|
lysosomal proteases are:
|
proteases contained in lysosomes
|
|
|
|
what is a cathepsins?
|
lysosomal protease. What does it contian?
|
exo and endopeptidases
|
|
|
are cathepsins specific?
|
yes
|
|
|
|
when do cathepsins act? when insulin or glucagon is higher?
|
when glucagon is high
|
|
|
|
N balance of children?
|
positive
|
|
|
|
body builders N balance?
|
positive
|
|
|
|
burn pt N balance?
|
negative
|
|
|
|
metabolic stress N balance?
|
negative
|
|
|
|
inadequate protein consumption N balance?
|
negative
|
|
|
|
just one eAA is deficient? = __ N balance?
|
negative
|
|
|
|
does N balance depend on energy?
|
yes
|
|
|
|
burn pt N balance?
|
negative
|
|
|
|
metabolic stress N balance?
|
negative
|
|
|
|
inadequate protein consumption N balance?
|
negative
|
|
|
|
just one eAA is deficient? = __ N balance?
|
negative
|
|
|
|
does N balance depend on energy?
|
yes. adequate energy intake must be maintained or else the body will degrade muscles and be in neg N balance
|
|
|
|
glutaminase does what:
|
Gln --> Glu + NH3
|
|
|
|
glutamine synthase does waht:
|
Glu + NH3 --> Gln
|
|
|
|
Glutamate dehydrogenase does what:
|
Glu + H2O + NAD --> aKG + NH3 + NADH
|
|
|
|
nucleotides include:
|
all the compounds that are use for energy (ATP, FMN, FAD etc)
Also, IMP |
|
|
|
ribose-5-phosphate aka
|
(5-ribosyl-phosphate). This is a product of:
|
hexose monophosphate shunt
|
|
|
rate limiting step of nucleotide synthesis:
|
ribose 5 phosphate --> 5-phosphorylribosyl pyrophosphate. This rxn is catalyzed by:
|
5-phosphorylribosyl pyrophosphate synthetase
|
|
|
ribose 5 phosphate is a component of
|
nucleotides
|
|
|
|
the rate limiting step of nucleotide synthesis is inhibited by
|
AMP and GMP. It is stimulated by:
|
ATP and GDP
|
|
|
formyl groups are added in nucleotide synthesis by
|
n10 formyl THF
|
|
|
|
are purines and pyrimadines synthesized in the same pathways?
|
nope
|
|
|
|
nucleoSide is:
|
a nitrogenous base bounded to a pentose sugar.
Pentose sugar exs: |
deoxyribose
ribose |
|
|
nucleotide:
|
nucleoside covalently bounded to one or more phosphate groups
|
|
|
|
nucleic acids are:
|
polymers of A/G bases (DNA/RNA)
|
|
|
|
pyrimidines are hydrolyzed by
|
lysomal hydrolases
|
|
|
|
N released from pyrimidines is excreted in the form of
|
ammonia or urea
|
|
|
|
how are purines degraded?
|
oxidized in the liver.
This oxidation of purines yields: |
hypoxanthine and xanthine and uric acid
|
|
|
what can hypoxanthine and xanthine be converted to?
|
uric acid
|
|
|
|
AMP demaination yields
|
IMP and ammonia.
How are each of these then excreted? |
Ammonia: in the form of ammonia or urea
IMP: xanthine and hypoxanthine as well as uric acid are produced. the first two are also converted into uric acid. |
