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Flashcards in DNA Replication Deck (41)
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1
Q

Watson and Crick’s model of DNA allowed for replication, and thus transfer of genetic information.

  1. Conservative
  2. Semiconservative
  3. Dispersive
A

Replication Models

2
Q

One parent double helix and one new double helix

A

Conservative Model

3
Q

One strand is from the parent and one is the novel strand from the new molecules, forming the double helix

A

Semiconservative Model

4
Q

Amounts of the parent strand are dispersed in the novel strand, forming a mixed double helix

A

Dispersive Model

5
Q
  • DNA polymerase
  • Helicase
  • Ligase
  • dNTP
  • Primers
  • Primase
  • Protein binding complex
  • Topoisomerase
  • Telomerase
  • SSb
  • Okazaki fragments
A

Molecules involved in replication

6
Q

Catalyzes phosphodiester bond formation

-polymerization of dNTPs,

A

DNA polymerase

7
Q

Breaks hydrogen bonds between the nitrogenous bases

“unzips genes”

A

Helicase

8
Q

Connects DNA strands

A

Ligase

9
Q

deoxynucleosidetriphosphate

-“nucleotide”

A

dNTP

10
Q

RNA fragments

A

Primer

11
Q

Synthesizes the RNA primer

-Can only add nucleotides to the existing strand of DNA.

A

Primase

12
Q

Untwist DNA to relieve pressure ahead of replication fork

A

Topoisomerase

13
Q

Synthesizes telomeres

A

Telomerase

14
Q

Single stranded binding protein

stabilize newly single stranded regions

A

SSb

15
Q

Discontinuous lagging strand

A

Okazaki Fragments

16
Q
  1. Replicator sequence is denatured by initiator proteins to form a replication bubble
    - new strand is made in accordance with complementary basepairing rules
  2. Helicase loaded onto the DNA
    - breaks H bonds, requires ATP
  3. Helicase recruits Primase
    - change in shape when helicase binds to DNA is recognized by Primase
  4. Primase synthesizes a short primer
    - RNA: 5-10 nucleotides long, annealed to template DNA strand according to complementary base pairing rules
A

Initiation of Replication Process

17
Q
  1. SSB proteins bind to the single stranded DNA
  2. Polymerase III adds nucleotides ONLY in the 5’ to 3’ direction
  3. DNA gyrase relaxes the tension ahead of the replication fork
  4. Polymerase I activity
  5. DNA ligase activity
A

Semidiscontinuous Replication

18
Q

Displaced by polymerase prevents reannealing

A

SSB proteins binding to the single stranded DNA in the fork

19
Q
  • synthesizes off of RNA primer for both leading & lagging strand
  • catalyzes 5’ to 3’ polymerization of dNTPs
  • reads template 3’ to 5’
A

DNA Polymerase III

20
Q

Synthesis from 5’ to 3’ direction

A

All polymerases synthesize this way

21
Q

-Introduces supercoiling in order to relieve stress

A

DNA Gyrase

22
Q
  • Joining of the Okazaki fragments
  • Digests RNA primer ahead of it using its 5’ to 3’ exonuclease activity.
  • Replaces RNA primer with dNTPs using its 5’ to 3’ polymerase activity
A

DNA Polymerase I

23
Q

Degrades sequence at the ends

A

Exonucleases

24
Q
  • Joining of Okazaki Fragments

- Seals the nick between adjacent fragments

A

DNA Ligase

25
Q

All known DNA polymerases:

a. can initiate DNA chain synthesis
b. have 5’ to 3’ polymerization activity
c. have 5’ to 3’ exonuclease activity
d. have 3’ to 5’ polymerization activity
e. all of the above

A

b. have 5’ to 3’ polymerization activity

26
Q

What is the primer for DNA pol. I?

a. RNA synthesized by primase
b. DNA synthesized by primase
c. Okazaki fragment
d. It doesn’t need a primer

A

c. Okazaki fragment

27
Q

Accuracy of polymerase

A

Fidelity

28
Q

How long DNA polymerase can stay on the strand

A

Procesicivity

29
Q
  • More mistakes to correct, less time to add nucleotides

- Almost always adds the correct complementary bp.

A

Polymerase’s proofreading activity

30
Q

Have 3’ to 5’ exonuclease activity

A

Both DNA Pol. I and DNA Pol. III

31
Q

Remove incorrect 3’ nucleotide, insert correct base, and keep synthesizing

A

DNA Polymerase

32
Q

DNA Polymerase ______ has 5’ to 3’ and 3’ to 5’ exonuclease activity.

a. I
b. III

A

a. I - only DNA Pol. I will chew up Okazaki primer.

33
Q
  • a complex molecular machine that carries out replication of DNA.
  • first unwinds double stranded DNA into two single strands.
  • For each of the resulting single strands, a new complementary sequence of DNA is synthesized.
A

The Replisome

34
Q

-Replication process similar to prokaryotes, but chromosomes are bigger and linear
-Contains multiple origins per chromosome
ex. autonomously replicating sequences in yeast.
-15 polymerases
not all participate in replication, many participate in DNA repair
-DNA is packed as it is synthesized

A

DNA Replication in Eukaryotes

35
Q

Area where one origin of replication to where 2 origins of replication fuse

A

Replicon

36
Q

Multiple Origins: Many start at the same time

A

Replication in Eukaryotes

37
Q
  • Tandemly repeated

- added by enzyme telomerase

A

Telomeres

38
Q

Is a reverse transcriptase

complex of protein (does the synthesizing) and RNA (template)

A

Telomerase

39
Q

Makes DNA from RNA template

A

Reverse transcriptase

40
Q

Telomerase_____

a. contains its own RNA template
b. is a reverse transcriptase
c. extends one strand of the telomere
d. is responsible for helping to maintain chromosome size
e. all of the above are true

A

e. all of the above are true

41
Q

Type of supercoiling that relieves stress

Think of DNA Gyrase and what it does

A

Positive supercoiling