Chapter 5: Nucleic Acids (DNA Replication) Flashcards

1
Q

DNA replication: overview

A
  1. chromatin disassembly (eukaryotes)
  2. DNA double helix unwinding
  3. primer binding
  4. elongation
  5. termination
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

ATP-dependent chromatin remodeling complexes facilitate the sliding or removal of nucleosome from DNA ahead of the replication fork

A

chromatin disassembly (eukaryotes)

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

binds and breaks the hydrogen bonds between complementary bases

A

DNA helicase

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

breaks hydrogen bond between complementary bases

A

DNA helicase

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

point at which the DNA double helix is unwinding, which is constatnly changing (moving)

A

replication fork

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

the enzyme primase generates short strands of RNA hat bind to single-stranded DNA to initiate DNA synthesis

A

primer binding

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

generates short strands of RNA to prime strands for DNA synthesis

A

primase

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

no. of primer in leading strand

A

one

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

no. of primer in lagging strand

A

multiple

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

polymerase binds to strand at the site of the primer and begins adding new base pairs complementary to the strad by forming new phosphodiester linkages

A

elongation

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

binds to strand at site of primer and begin adding new base pairs

A

polymerase

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

continuous 5’ to 3’ direction (toward helicase)

A

leading strand

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

in short Okazaki fragments (elongation is away from helicase)

A

lagging strand

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

fragments in lagging strand

A

Okazaki fragments

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q
  • exonuclease removes all RNA primers
  • another exonuclease proofreads newly formed DNA
  • DNA ligase joins Okazaki fragments
  • telomerase catalyzes synthesis of telomere that act as protective cap
  • once completed, the parent strand and its complementary DNA strand coils into familiar double helix shape
A

termination

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q
  • removes all RNA primers from original strands
  • proofreads newly formed DNA and remove and replace any errors
A

exonuclease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

joins Okazaki fragments together forming a single unified strand

A

DNA ligase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

catalyzes the synthesis of telomere sequence at the ends of the DNA

A

telomerase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

alleviates positive supercoiling ahead of replication fork

A

topoisomerase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q
  • keep the parental strands apart
  • also protect strands from degradatioin and prevent secondary structure formation
A

single-strand binding proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q
  • nuclear SSB protein found in all eukaryotes
  • required for multiple processes in DNA metabolism such as DNA replication, DNA repair, DNA recombination, telomere maintenance and DNA damage signalling.
A

Replication protein A (RPA)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

“reads” each parental strand and catalyzes the polymerization of a complementary daughter strand

A

DNA polymerase III

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

precursors for DNA replication

A

deoxyribonucleotide triphosphate (dNTP)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

in 5’ to 3’ synthesis, a __ __ is released as a phosphoester bond is formed between 5’-phosphoryl group of the nucleotide being added to the chain and the 3’-OH of the nucleotide on the daughter strand

A

pyrophosphate group

25
Q

DNA pol III can only catalyze DNA chain in what direction

A

5’ to 3’

26
Q

serve as starting point for DNA replicatioin

A

RNA primer

27
Q

length of RNA primer

A

10 - 12 nucleotides

28
Q

where is the new primer synthesized in the lagging strand

A

at replication fork

29
Q

exist between Okazaki fragments and are easily recognizable by the DNA mismatch repair machinery prior to ligation

A

nicks

30
Q

Final steps of synthesis on lagging strand

A
  1. removal of primers
  2. repair of gaps
  3. sealing of fragments
31
Q

catalyzes the removal of RNA primer and its replacement with DNA nucleotides

A

DNA polymerase I

32
Q

covalently links the DNA fragments together

A

DNA ligase

33
Q

is also able to proofread the newly synthesized strand

A

DNA polymerase III

34
Q

dismantles after the convergence of the two replication forks

A

replisome complex

35
Q

in eukaryotes, it removes the RNA primer at the beginning of each Okazaki fragment

A

Ribonuclease H (RNAse H)

36
Q

after the first round, the new lagging strand is __ than its template

A

shorter

37
Q

after the second round, both the leading ang lagging strands have become __ than the original parental DNA

A

shorter

38
Q

repetitive sequences that code for no particular gene

A

telomeres

39
Q

in humans, a six base pair sequence, _____, is repeated __ to __ times

A
  • TTAGGG
  • 100 to 1000 times
40
Q

Telomeres shorten as a result of cellular replication, leading to a permanent cell cycle arrest, also known as __ __

A

replicative senescence

41
Q

are formed by telomere ends in order to be protected from cell’s DNA repair systems

A

protective loops

42
Q

protein complex known to protect telomeres in many eukaryotes from DNA repair mechanisms, as well as to regulate telomerase activity

A

Shelterin

43
Q

Shelterin is also called

A

telosome

44
Q

individual DNA molecule bound to a group of proteins

A

chromosome

45
Q

typically, a chromosome is __ by mass DNA, and __ by mass protein

A
  • 15% DNA
  • 85% protein
46
Q
  • have similar, but not identical, DNA base sequences
  • both code for the same traits but for different forms of trait
A

homologous chromosomes

47
Q

where does DNA replication begin

A

replication origin

48
Q

replication occurs __ at the rate of about __ new nucleotides every second

A
  • bidirectionally
  • 500
49
Q

the human genome consists of approx. how many nucleotide pairs

A

3 billion

50
Q

just one chromosome may nearly be __ times longer than bacterial chromosome

A

100

51
Q

two Y-shaped structures called replication forks are formed, together making up what’s called a __ __

A

replication bubble

52
Q

class of anticancer drug that interfere with DNA replication because their structures are similar to molecules required for normal DNA replication

A

antimetabolites

53
Q

an essential and necessary element for the synthesis of nucleotides and other biomolecules after reduction by dihydrofolate reductase

A

folic acid

54
Q

replication of DNA produces two daughter molecules in which each daughter molecule contains

A
  • one parent strand
  • one newly synthesized strand
55
Q

in DNA replication, the DNA double helix unwinds under the influence of

A

DNA helicase

56
Q

in DNA replication, the new strand that is synthesized in small segments is called

A

lagging strand
(murag Okazaki fragment man)

57
Q

in DNA replication, the unwinding of DNA double helix occurs at

A

many locations within double helix

58
Q

chromosme is a protein-DNA complex that contains

A

single DNA molecule