CORSO Flashcards
What two functional groups form a peptide bond?
the amine (or ammonium) group of an amino acid
the carboxylic acid (or carboxylate) group of an amino acid
What conformation of hemoglobin binds oxygen?
R
What is cooperativity?
for proteins with multiple subunits, the subunits need to be in the same conformation as the ones next to them
BPG stabilizes which form of hemoglobin
the deoxygenated state
As the concentration of BPG increases what happens to hemoglobin?
hemoglobin releases oxygen
How many nitrogens on the heme coordinate with the central ion?
4
How many heme groups are in myoglobin?
one
Between the hemoglobin in the red blood cells, passing through the capillaries going through the tissue and the myoglobin in the cells of the tissue, which one has a higher oxygen affinity?
myoglobin
which has a higher oxygen affinity hemoglobin or myoglobin?
myoglobin
myoglobin has a
a. binds oxygen cooperatively
b. a linear hill plot
b. a linear hill plot
hemoglobin ______
a. binds oxygen cooperatively
b. has a linear hill plot
a. binds oxygen cooperatively
when oxygen binds to a heme-containing protein, the two open coordination bonds of Fe2+ are occupied by?
one O2 molecule and one amino acid nitrogen
in hemoglobin, the transition from T state to R state (low to high affinity) is triggered by:
oxygen binding
The interactions of ligands with proteins
are usually transient
what happens to oxygen binding to hemoglobin at low oxygen pressure?
it decreases
What is the charge on BPG?
-5
What happens to oxygen binding to hemoglobin if BPG is low?
it increases
what happens to oxygen binding to hemoglobin in lung capillaries?
it goes up
what happens to oxygen binding to hemoglobin in tissue capillaries
it goes down
what happens to oxygen binding if a patient is acidotic?
it goes down
what happens to oxygen binding if a patient is alkalotic?
it goes up
why does a fetus have hemoglobin F, rather than hemoglobin A?
F will pull oxygen out of the mother’s blood
What changes occur in the solubility of hemoglobin in sickle cell anemia?
the hemoglobin S precipitates inside the cell
Which hemoglobin elevates the most for a patient with homozygous sickle cell disease?
HbF
A patient is diagnosed with acute intermittent porphyria. This defect would cause _____
decreased production of hemoglobin
The amino acid substitution of Val for Glu in hemoglobin S results in aggregation of the protein because of ________ interactions between molecules?
hydrophobic
methemoglobin causes a decrease in oxygen binding due to:
the heme iron oxidizing from Fe2+ to Fe3+
Malaria resistance is associated with
a shorter half-life of RBC
carbon monoxide is toxic because it
binds to the Fe2+ more tightly than oxygen
which enzyme in the PPP is dependent on thiamine?
transketolase
what is glutathione needed for?
it is an antioxidant needed to neutralize peroxide
a defect of glucose-6-phosphate dehydrogenase causes?
hemolytic anemia
in G6PDD, which reducing equivalent is missing?
NADPH
which enzyme requires NADPH as a reducing agent
glutathione reductase
A patient who has G6PDD should take ________
antioxidant vitamins
A patient with G6PDD should not take ______ because it increases symptoms
aspirin
function of folate
one-carbon transfers
the biologically functional form of folate is _________
tetrahydrofolate
Action of methotrexate
dihydrofolate reductase inhibitor
action of 5-fluorouracil
thymidylate synthase inhibitor
action of caffeine
phosphodiesterase inhibitor
The conversion of homocysteine to methionine requires what 2 vitamins?
folate
B12
which has a phosphate?
a. nucleoside
b. nucleotide
b. nucleotide
What is the difference between DNA and RNA
DNA has a T with an extra methyl group
RNA has a U without the methyl group
DNA is missing an oxygen on carbon 2
RNA has an oxygen on carbon 2
A pairs with
T
C pairs with
G
what is the secondary structure of DNA?
double helix
What does BPG do?
stabilizes the T-state and causes Hb to let go of O2 (decreases Hbs affinity for O2)
What is hydroxyurea?
drug to treat sickle cell disease
increases the level of HbF
What structural feature of hemoglobin makes it cooperative?
it is a tetramere
What is the most common cause of hemolytic anemia?
G6PD deficiency
What is used to get rid of peroxide?
glutathione reductase
Primaquine (anti-malaria drug) should not be given to which patients?
patients with a G6PD deficiency
causes oxidative stress
Which amino acid is the source of the carbon when FH4 becomes N5,N10-methylene tetrahydrofolate
Serine (S)
What increases the rate of a deamination reaction
nitrosamine
what is depurination?
loss of a base
what causes thymine dimers?
UV-radiation
what causes an alkylation?
nitrogen mustards
what medical conditions are associated with a folate deficiency?
megaloblastic anemia
spina bifida
methotrexate blocks the recycling of ______
folate
5-FU blocks the methylation of ___ to ___
U to T
hyperhomocysteinemia can be caused by either ______ or ______ deficiency
folate or B12
what vitamin is used for methylation of homocysteine and eventual creation of SAM
B12
_____ is a methyl donor
SAM
a deficiency in which vitamin decreases the production of SAM
B12
