Molecular II

Question 1

nucleotide excision repair

Answer 1

endonuclease release damaged base

DNA polymerase and ligase fill and reseal

repair bulky lesions
occur in G1

Question 2

defective nucleotide excision repair

Answer 2

xeroderma pigmentosa

prevent repair of pyrimidine dimers (UVB damage)

Question 3

base excision repair

Answer 3

base specific glycosylase
-create site without pur or pyr

AP-endonuclease - remove one or more nucleotides - cleaves 5’ end

lyase cleaves 3’ end

DNA polymerase beta - fills gap and DIA ligase seals it

throughout cell cycle

Question 4

mismatch repair

Answer 4

newly synthesized strand recognized
-mismatched nucleotides removed - gap filled and sealed

G2 phase of cell cycle

Question 5

defective in hereditary nonpolyposis colorectal cancer

Answer 5

mismatch repair

Question 6

nonhomologous end joining

Answer 6

bring together 2 ends of DNA fragments repair ds breaks

Question 7

mRNA is read

Answer 7

5’ > 3’

Question 8

direction DNA and RNA synthesis

Answer 8

DNA and RNA - both synthesized 5 > 3

5’ end - high energy bond - tri-P

Question 9

protein synthesis direction

Answer 9

N-terminus to C-terminus

Question 10

start codon

Answer 10

AUG

Question 11

stop codon

Answer 11

UGA, UAA, UAG

Question 12

fMet

Answer 12

prokaryote start codon

stimulate neutrophil chemotaxis

Question 13

methionine

Answer 13

start codon - AUG - AA

Question 14

promoter

Answer 14

site where RNA polymerase II and other transcription factors bind DNA upstream gene locus

AT rich - TATA box

Question 15

enhancer

Answer 15

further upstream from promoter (TATA)

-alter gene expresion

Question 16

silencer

Answer 16

site where gene repressor binds

Question 17

RNA polymerse I

Answer 17

makes rRNA

Question 18

RNA polymerase II

Answer 18

makes mRNA - largest RNA

Question 19

RNA polymerase III

Answer 19

makes tRNA - smallest RNA

Question 20

a-amanitin

Answer 20

in amanita phalloides - death cap mushroom

inhibit RNA polymerase II - mRNA synthesis

severe hepatotoxicty

Question 21

rifampin MOA

Answer 21

inhibit RNA polymerase

Question 22

actinomycin D

Answer 22

inhibit RNA polymerase

Question 23

RNA processing - after transcription

Answer 23

occus in nucleus

1 - capping 5’ end - 7 methylguanosine cap
2 - polyadenylation 3’ end - 200 As
3 - splicing out introns

capped, tailed, spliced = mRNA

Question 24

cytoplasmic P-bodies

Answer 24

mRNA quality control

exonucleases, decapping enzymes, microRNAs

Question 25

snRNP

Answer 25

involved in splicing pre-mRNA lariat shaped loop generated -remove intron - join 2 exons

Question 26

anti-smith antibodies

Answer 26

Abs to spliceosomal snRNP specific for SLE

Question 27

anti-U1 RNP Ab

Answer 27

associated with mixed CT disease

Question 28

alternative splicing

Answer 28

different exon combination of single mRNA

Question 29

beta-thalassemia

Answer 29

abnormal splicing variant

Question 30

tRNA

Answer 30

CCA at 3' end opposite anticodon - binds the amino acid anticodon loop T-arm - contains thymine, pseudouracil, cytosine - for tRNA ribosome binding D-arm - dihydrouracil residues - for tRNA recognition by correct aminoacyl tRNA synthetase

Question 31

charging of tRNA

Answer 31

aminoacyl tRNA synthetase uses ATP to bind amino acid to CCA 3' end of tRNA

Question 32

wobble

Answer 32

accurate base pairing only required first 2 nucleotide positions of mRNA codon codon difference position 3 "wobble" may code for same AA - degeneracy of code

Question 33

steps protein synthesis

Answer 33

initiation elongation termination

Question 34

initiation

Answer 34

by GTP hydrolysis initiation factors assemble 40S ribosome subunit with initiator tRNA -released when mRNA and 60S subunit assemble with complex

Question 35

eukaryote ribosomes

Answer 35

40S and 60S

Question 36

prokaryote ribosomes

Answer 36

30S and 50S

Question 37

elongation

Answer 37

aminoacyl tRNA binds to A site rRNA catalyzes peptide bond formation - transfer growing polypeptide to AA in A site ribosome advances 3 nucleotides toward 3' end of mRNA - moving peptidyl tRNA to P site (translocation)

Question 38

A site

Answer 38

incoming aminoacyl-tRNA

Question 39

P site

Answer 39

accomodate growing peptide

Question 40

E site

Answer 40

holds empty tRNA as it exits

Question 41

termination

Answer 41

stop codon recognized by release factor polypeptide released from ribosome

Question 42

protein synthesis ATP and GTP

Answer 42

ATP - activation - charging | GTP - translocation

Question 43

trimming

Answer 43

remove N or C terminal propeptide from zymogen

Question 44

covalent alterations of peptide

Answer 44

``` phosphorylation glycosylation hydroxylation methylation acetylation ubiquitination ```

Question 45

chaperone proteins

Answer 45

intracellular proteins involved in facilitating protein folding yeast - Hsp60 - expressed at high temp - prevent protein denaturing/misfolding