Exam 1 Random Flashcards
What nucleotide can be deaminated?
guanine -must be removed
RNA polymerase is a?
DNA directed RNA polymerase
RNA Guanine capping is in what direction?
5’-5’ linkage instead of 5’-3’
— stabilizes and protects from phosphates and nucleases
TF2H is a multiprotein that?
includes XPB (bubble) and XPD (encounters base)
unwinds DNA at transcription start site
unwinds DNA at the site of damage
contain two proteins that if one is mutated, causes xeroderma pigmentation (XPA)
etoposide
is a drug that targets the proteins (gyrase and topoisomerases) that detangle super-coils
sickle cell anemia arises due to?
insolubility of hemoglobin due to a point mutation in primary structure affecting beta subunit
chloramphenicol
inhibits protein synthesis by interfering with peptide bonds
human genome composed of how many nucleotides?
3.2x10^9 (3.2billion)
Shelterin complex
protect telomeres from DNA repair mechanisms, regulate telomerase activity. Consists of double- and single-stranded TTAGGG repeats and a single-stranded, G-rich overhang.
Cordycepin
RNA transciption inhibitor
looks like 3’deoxyadenosine
deoxyribose sugar plus a base is called?
nucleoside
Pentose + base + PO4-
nucleotide
template strand pairs with?
coding strand, mRNA strand, nascent DNA strand during DNA replication
What AA is achiral?
glycine
which AA are not used to assemble proteins in human cells?
D-amino
alpha helix is stabolized by?
H-bonds between every 4th AA
condition(s) resulting in reduced beta hemoglobin subunit
thalassemia major, beta-thallasemia, cooley anemia
binding of a substrate to an enzymatic active site is primarily dependent on?
multiple weak interactions (like H-bonds)
catalytic triad?
histidine, aspartate, serine
Name AA that can be phosphorylated?
Tyrosine, serine, threonine
difference between kinases and phosphatase?
- kinases= add phosphate to Tyrosine, serine, threonine
* phosphatases= remove phosphoryl group from Tyrosine, serine, threonine
is myoglobin allosterically regulated?
NO. But hemoglobin is, 23BPG is an allosteric regulator (more 23BPG to heme, lower O2 affinity)
when oxygen binds to hemoglobin, what happens?
O coordinates the iron atom in the heme prosthetic group, iron atom in heme moves into the plane of protoporphyin, histidine side chain is pulled closer to heme
hydrolytic deaminations cause cytosine to be converted into?
uracil
why does replication and transcription occur in 5’-3’ direction?
it would work 3’-5’ direction until proofreading removed a nucleotide… so it needs to be 5’-3’ so we have a mechanism of proofreading
reverse transcriptase is a?
RNA directed DNA polymerase
What gives DNA strand polarity?
the way base pairs are linked (pentose sugar linkages give a charge)
6 common steps in DNA processing?
site recognition, helicase, SSB, Nuclease, polymerase. ligase
proteins produced in human cells are comprised exclusively of?
L-amino acids
What AA is very like collagen?
glycine
What makes methionine and cysteine special?
They both have “S” in their side chains
AA zwitterion example?
alanine (increase pH= decrease H= deprotinates; lower pH=increase H= protinated)
What is a proenzyme?
an enzyme containing its reqired prothetic group or cofactor (Ex: holoenzyme)
What bonds contribute to 3rd structure?
H-bonds, ionic, disulfide, hydrophobic
What antibiotic acts by blocking the tRNA binding to the A-site in the ribosome?
tetracycline
What AA are in histones? Also in SSB?
Lysine and Arginine (bc they have a + charge)
Catalytic tetramer moves stuff into?
peroxisomes
TOM complex and transolcons?
Move stuff into the ER or the ER membrane
Zellweger Syndrome
mutation, “empty peroxisomes”
isozyme
similar enzymes/AA sequence that catalyze the same reaction (but typically under different conditions and different regulators)
o *point: catalyze same reactant and have similar AA
