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Biochem Week 2
UC MED 2015
39
Medical
Graduate
10/01/2011

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Cards

Term
Collection of urine can test for the following...
Definition
sugar, creatine, ketone bodies, and crystal or bacterial infiltration
Term
enzyme that separates the DNA and unwinds the parental duplex
Definition
helicase
Term
prevents the strands from reassociating and protects from enzymes that cleave single stranded DNA
Definition
single-strand binding proteins
Term
enzymes that break phosphodiester bonds and can rejoin them; relieve supercoiling DNA during unwinding
Definition
Topoisomerases
Term
DNA replication is...
Definition
semiconservative
Term
What enzymes catalyze the synthesis of DNA and what are 3 major ones for prokaryotic DNA synthesis
Definition
DNA polymerases

Pol I, Pol II, and Pol IIII and Pol III is the major one
Term
Why is quinolone used to treat UTIs?
Definition
It inhibits gyrase which is found only in prokaryotic cells or bacteria. so DNA cant replicate
Term
what does Pol III do to prevent errors in base pairs?
Definition
It rereads the chain and will remove and fix base pair mismatches
Term
What are the fragments of the DNA synthesis that occur on the lagging strand?
Definition
Okazaki fragments
Term
What two proteins are used for removal of RNA primes from the DNA?
Definition
DNA Polymerase I and RNase H
Term
enzyme joins two polynucleotide chains together
Definition
DNA ligase
Term
ZDV used to treat HIV has what that stops DNA replication
Definition
dideoxynucleoside
Term
Exposure to UV light causes cancer or melanomas by doing what to DNA
Definition
it cause pyrimidine dimers to be created
Term
what type of pigment causes people to have a broken DNA repair system and they are more likely to get melanoma
Definition
xeroderma pigmentosum
Term
Nucleotide Excision repair...tell me the steps
Definition
1) endonuclease cleave the abnormal DNA
2) gap is filled by DNA polymerase- its added from the 3' end
3) DNA ligase closes the segment
Term
Base excision repair...tell me the steps
Definition
1) DNA glycosylase recognizes small distortionsin DNA involving lesions caused by damage to a single base
2) Glycosylase cleaves the N-glycosidic bond that joins the damaged base to the deoxyribose
3) AP endonuclease cleaves the sugar phosphate strand at this site
4) normal DNA repair happens after this
Term
DNA sugar-phosphate backbone lacks a base at this site is known as
Definition
apurinic or apyrimididinic site or AP site
Term
genes that are actively transcribed to produce mRNA are repaired in this mechanism
Definition
transcription-coupled repair
Term
places where replication begins in e cells
Definition
point of origin for replication
Term
What is the repeating sequence of bases in humans?
Definition
TTAGGG
Term
what is the unusual base found in tRNA, that can form base pairs with U, C, A. Formed by the deamination of adenine
Definition
hypoxanthine (I) or inosine
Term
start codon-
stop codons-
Definition
start- AUG
stop- UGA, UAG, UUA
Term
a mutation from resulting from a single base change
Definition
point mutation
Term
a change that specifies the same amino acid
Definition
silent mutation
Term
a change that specifies a different amino acid
Definition
missense mutation
Term
a change that produces a stop codon
Definition
nonsense mutation
Term
an addition of one or more bases
Definition
insertion
Term
a loss of one or more bases
Definition
deletion
Term
Tell me about Group I chemicals?
Definition
They are initiators of cancer, they cause mutation in DNA
Term
Tell me about Group II chemicals?
Definition
these chemicals are promoters of cancers, they enhance the probability that cells previously initiated would develop a tumor...group II activate protein kinase C
Term
What tes can be used to see if a compound is an initiator of cancer?
Definition
Ames test
Term
What does cigarette smoke do?
Definition
It oxidizes benzo[alpha]pyrene, which will bind covalently to guanine residues in DNA, interrupting the G-C hydrogen bonds.
Term
What RNA polymerase is used to make rRNA?
Definition
RNA Polymerase I
Term
What RNA polymerase is used to make mRNA?
Definition
RNA Polymerase II
Term
What RNA polymerase is used to make tRNA and other small RNAs?
Definition
RNA Polymerase III
Term
mode of action of streptomycin
Definition
binds to 30S ribosomal subunit of prok., thereby preventing formation of the initiation complex...it also causes misreadings of the mRNA
Term
mode of action of tetracycline
Definition
binds to the 30S subunit ribosomal subunit and inhibits binding of aminoacyl-tRNA to the A site
Term
mode of action of chloramphenicol
Definition
binds to the 50S ribosomal subunit and inhibits peptidyltransferase
Term
mode of action of erythromycin
Definition
binds to 50S ribosomal subunit and prevents translocation
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