GENE EXPRESSION I

Question 1

cell division occur
parent cell will divide into two daughter cells

Answer 1

mitotic phase

Question 2

responsible for variation in cell cycle in different organisms
cell’s irreversible decision to proliferate is made here
may enter a quiescent phase

Answer 2

G1 gap phase

Question 3

only period where DNA is synthesized
DNA replication precedes between actual cell division during mitosis

Answer 3

synthetic phase

Question 4

cells are prepared for mitosis
promoted by cyclin protein that triggers entry of cells into M phase

Answer 4

G2 phase

Question 5

STEPS IN DNA REPLICATION

involves association of sequence-specific double stranded (dsDNA) binding protein to DNA

dsDNA binding protein attaches to 150-250 base pair DNA sequences adjacent to a region rich in adenine and thymine

Answer 5

identification of ori site

Question 6

STEPS IN DNA REPLICATION

formation of protein to protein and protein to DNA interactions

Answer 6

unwinding DNA

Question 7

STEPS IN DNA REPLICATION
__________- unwinds short segments of DNA
hydrolyzes ATP- endergonic process

Answer 7

helicase

Question 8

STEPS IN DNA REPLICATION

helicase
protein to protein interaction

Answer 8

DNA B helicase

Question 9

STEPS IN DNA REPLICATION

helicase
protein-DNA interaction

Answer 9

DNA C protein

Question 10

undwinding of DNA

______________ cuts a single strand of the duplex

___________ nicks both strands

Answer 10

DNA topoisomerase I
DNA topoisomerase II

Question 11

DNA toposiomerase twists the duplex in the direction which favors __________

Answer 11

unwinding

Question 12

STEPS IN DNA REPLICATION

branch point in a replication eye at which DNA synthesis occur

Answer 12

formation of replication fork

Question 13

replication fork sequence of 4 events

________ unwinds parental DNA
________initiates the synthesis of RNA primer
________ initiates synthesis of daughter strand
_________ binds to single strand DNA

Answer 13

helicase
primase
DNA polymerase
SSB

Question 14

STEPS IN DNA REPLICATION

DNA polymerase is principal enzyme involved; elongates the daughter DNA from 5’ to 3’ direction

leading strand is replicated continuously

Answer 14

elongation step

Question 15

DNA polymerase I has 3 enzymatic activities

___________ - gap filling
___________ - allows Pol I to edit its mistakes
___________- removes the RNA primer

Answer 15

polymerase
3-5 exonuclease
5-3 exonuclease`

Question 16

participates in DNA repair
has 3’ exocnuclease activity only

Answer 16

DNA polymerase III

Question 17

major DNA replicase has 10 subunit complex
core subunits consists of alpha, epsilon, and beta subunit accounts for high stability of the complex

Answer 17

DNA Polymerase III

Question 18

EUKARYOTIC DNA POLYMERASES
replicates DNA by extending a primer in 5-3 direction
has a tightly associated primase activity
lacks exonuclease activity

Answer 18

DNA polymerase alpha

Question 19

EUKARYOTIC DNA POLYMERASES
lacks primase activity
exhibits a proofreading 3 prime exonuclease activity
eukaryotic lagging strand synthesis

Answer 19

DNA polymerase delta

Question 20

EUKARYOTIC DNA POLYMERASES
highly processive leading strand synthesis
function is facilitated by proliferating cell nuclear antigen

Answer 20

DNA polymerase epsilon

Question 21

EUKARYOTIC DNA POLYMERASES
participates in DNA repair

Answer 21

DNA polymerase beta

Question 22

STEPS IN REPLICATION

done by DNA polymerase I in prokaryotes and DNA polymerase delta in eukaryotes using their 5’ exonuclease acitivity

removes RNA primer nucleotide by nucleotide

Answer 22

removal of RNA primer

Question 23

STEPS IN REPLICATION
done by DNA ligase which connects the okasaki fragments to the lagging strand of the growing daughter DNA

Answer 23

splicing the okazaki fragments

Question 24

STEPS IN REPLICATION

done by the 3’ exonuclease activity of DNA polymerases in prokaryotes and eukaryotes reason for the high degree of fidelity of replication

Answer 24

proofreading and correction errors