8b Flashcards

1
Q

Define dna replication?

A

process by which DNA is duplicated, DNAβ€”>DNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Name the 3 possible mechanisms of dna replication

A

semiconstructive mechanism
conservative mechanism
dispersive mechanism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

define semiconstructive mechanism

A

dna replication produces 1 with parental strand and 1 newly made strand.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

define conservative mechanism

A

1 double helix with both parental strands and 1 with 2 new daughter strands

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

define dispersion mechanism

A

dna strands in which segments of new dna+parental dna are present 🧬

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

_______Showed that DNA Replication is semi-conservative.

A

Meselson and stahl experiment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what is the molecular process of semi conservative replication

A

1.untwisting of dna molecule-both the strands as templates
2.DNA polymerase help to link free nucleotides to form new strands.
3.new and old template antiparallel

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

untwisting of dna molecule?

A

Helicase, breaking the H bonds between nitrogenous bases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

after dna is divided into 2, each of the
2 strands are called_________

A

template

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what helps in the linking of nucleotide to form a new strand?

A

DNA polymerase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

the nucleotides are always added at what end?

A

3’- end, has a free OH group

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

the nucleotides are connected to form the _______ of the new strands.

A

sugar-phosphate back bone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

replication fork

A

very active area where dna replication takes place

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

topoisomerase?

A

avoid twisting of the DNA ahead of the replication fork by cutting the DNA, turning the DNA on side of the break in direction opposite to that of the twisting force and rejoining the twisting strand.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

____________ stabilizes single stranded DNA and prevent the 2 strands at __________ from reforming ______.

A

single-stranded binding proteins
replication fork
double stranded DNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

function of primase?

A

assembles RNA primers in the 5’ to 3’ direction to initiate a new DNA strand

17
Q

what is the function of sliding clamp?

A

attaches DNA polymerase III to the DNA template, making replication more efficient

18
Q

which is the main replication enzyme in E. coli?

A

DNA polymerase III

19
Q

function of DNA polymerase III

A

extends the RNA primer by adding DNA nucleotides to it, synthesize new DNA strands during replication

20
Q

function of DNA polymerase I

A

removing RNA primers and replacing them with DNA nucleotides

21
Q

what is responsible for synthesizing Okazaki fragments?

A

dna polymerase III

22
Q

tell 4 uses of dna polymerase 1?

A

1.primer removing and gap filling
2.exonuclease activity from 5’to3’ and 3’to5’.
3.nick sealing (dna ligation)

23
Q

define primer removing?

A

dna polymerase I removing the RNA primers and adding dna nucleotides, aka primer removal and gap filling

24
Q
A

DNA ligase functions to seal nicks and gaps in the adjacent bases by catalyzing the formation of phosphodiester bonds after RNA primers replaced with dna. Its main roles include joining Okazaki fragments during DNA replication, repairing DNA damage, and facilitating recombination events.

25
Q

what are Okazaki fragments

A

short, discontinuous DNA segments synthesized on the lagging strand , subsequently joined by DNA ligase to form a complete and continuous complementary strand.

26
Q

__________ joins short, discontinuous DNA segments to form a continous complementary strand?

A

DNA ligase

27
Q

________ have a single origin.

A

bacteria

28
Q

what is the rate of replication in bacteria as well as eukaryotes?

A

bacteria:500-1000 nucleotides per second
eukaryotes:50-100 per second