bich 2 exam final topics Flashcards
draw isopentyl pyrophosphate and what is the initial substrate?
one doc : initial substrate is Acetyl-CoA
Regulation of HMG-CoA reductase and why it is a drug target for cholesterol-lowering medications
Inactivated by cAMP-dependent phosphorylation (this is activated by glucagon (response to low blood glucose)
Protein degradation: high cholesterol increases the rate of degradation
Gene expression: mRNA levels depend on cholesterol: high cholesterol = low mRNA synthesis
Structure of the lipoprotein complex that transports fat and cholesterol (powerpoint)
on doc
LDL transports lipids
function of VLDL
(very low density lipoprotein) – carry lipids from liver to target sites (muscle and adipose)
function of LDL
(low density lipoprotein; highest in cholesterol) - major circulatory complex of cholesterol
and its esters
function of HDL
(high density lipoprotein; smallest and densest; highest in protein) - mainly formed in ER
of liver cells (and some in intestine)
good vs bad chloesterol
High [HDL]: very little cholesterol or fatty acids requires pickup and disposal: Good!
High [LDL]: too much cholesterol and fatty acids are left over: Bad!
recognize derivatives of cholestrol
look on doc
draw glutamate dehydrogenase
on doc
draw glutamine synthesis
on doc
what is the purpose of the urea cycle?
Uric cycle eliminates excess nitrogen from consumption and catabolism of amino acids
draw the structure of urea and carbamoyl phosphate
on doc
what is the regulation of carbamoyl-phosphate synthetase I?
Regulation: allosteric activation by N-acetylglutamate which is made through N-acetyl Glu synthesis caused by
Increased [glu] (by enzyme glutamate dehydrogenase and aminotransferases.
Purpose and reaction of aminotransferases in amino acid synthesis
converts an alpha-keto acid into an amino acid
shown on doc
draw methionine metabolisms
on doc
What does S-adenosylmethionine do?
universal methyl donor
Function of tetrahydrofolate in methionine and serine metabolism
5-methyl-THF adds the methyl group back to methionine to remake methionine and make it a cycle.
In serine metabolism : THF accepts CH2OH to make 10-CH2OH-THF which is used in the adenosine synthesis pathway.
name the three coenzymes that are used to transfer single carbons and state the type of reaction
they carry out
Tetrahydrofolate– carry different oxidation states: methyl, methylene, formyl
Biotin- carboxylation
S-adenosylmethionine- Methylation
draw guanine and write where each atom came from on it
on doc
Know the difference between de novo purine synthesis and purine salvage
De novo the purines are made as shown above (put together from parts of the reaction)
Salvage purines are free purinse recycled from diet and nucleic acid degradation
Draw the reaction of adenine phophoribosyltransferase
on doc
Draw the reactions (2) of hypoxanthine-guanine
on doc
Draw Ribose 5’-phosphate
on doc
Draw PRPP
on doc
what does PRPP stand for?
5-phosphoribosyl-a(alpha)-pyrophosphate
Draw the reaction of adenosine deaminase
on doc
draw uric acid
on doc
draw the reaction of ribonucleotide reductase
on slide
what is the regulation and activity and specificity of ribonucleotide reductase?
Allosteric site::
ATP bound: ON
dATP bould: OFF
Substrate specificity: achieving optimal ratio of four dNTPs
Memorize specificity on doc!!!!
Draw reaction of thymidylate synthase
on doc
Draw reaction of dihydrofolate reductase
on doc
Be able to explain why thymidylate synthase and dihydrofolate reductase are good drug targets for treating
cancer and microbial infections
Reduce dTTP availability → reduces DNA replication → stops rapidly dividing cells
Lesh-Nyhan syndrome
X-linked recessive
Involuntary self harm
HGPRT deficiency (less salvage of guanine)
**over production of uric acid and entrance through de novo synthesis
Allopurinol inhibits degradation
Severe combined immunodeficiency syndrome
Mutation in adenosine deaminase that prevents adenosine degradation
Converted into dAMP into DATP which inhibits ribonucleotide reductase which makes dNTPs so cells
Divides until DNA synthesis is complete, no proliferation in response to pathogens
Bone marrow infusions
Gout
Excess uric acid accumulation
Arthritis (3% of population)
Allopurinol (analog that inhibit xanthine oxidase (degradation)
