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Flashcards in DNA Replication Deck (41):
1

Watson and Crick's model of DNA allowed for replication, and thus transfer of genetic information.
1. Conservative
2.Semiconservative
3. Dispersive

Replication Models

2

One parent double helix and one new double helix

Conservative Model

3

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

Semiconservative Model

4

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

Dispersive Model

5

-DNA polymerase
-Helicase
-Ligase
-dNTP
-Primers
-Primase
-Protein binding complex
-Topoisomerase
-Telomerase
-SSb
-Okazaki fragments

Molecules involved in replication

6

Catalyzes phosphodiester bond formation
-polymerization of dNTPs,

DNA polymerase

7

Breaks hydrogen bonds between the nitrogenous bases
"unzips genes"

Helicase

8

Connects DNA strands

Ligase

9

deoxynucleosidetriphosphate
-"nucleotide"

dNTP

10

RNA fragments

Primer

11

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

Primase

12

Untwist DNA to relieve pressure ahead of replication fork

Topoisomerase

13

Synthesizes telomeres

Telomerase

14

Single stranded binding protein
stabilize newly single stranded regions

SSb

15

Discontinuous lagging strand

Okazaki Fragments

16

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

Initiation of Replication Process

17

4. SSB proteins bind to the single stranded DNA

5. Polymerase III adds nucleotides ONLY in the 5' to 3' direction

6. DNA gyrase relaxes the tension ahead of the replication fork

7. Polymerase I activity

8. DNA ligase activity

Semidiscontinuous Replication

18

Displaced by polymerase prevents reannealing

SSB proteins binding to the single stranded DNA in the fork

19

-synthesizes off of RNA primer for both leading & lagging strand
-catalyzes 5' to 3' polymerization of dNTPs
-reads template 3' to 5'

DNA Polymerase III

20

Synthesis from 5' to 3' direction

All polymerases synthesize this way

21

-Introduces supercoiling in order to relieve stress

DNA Gyrase

22

-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

DNA Polymerase I

23

Degrades sequence at the ends

Exonucleases

24

-Joining of Okazaki Fragments
-Seals the nick between adjacent fragments

DNA Ligase

25

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

b. have 5' to 3' polymerization activity

26

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

c. Okazaki fragment

27

Accuracy of polymerase

Fidelity

28

How long DNA polymerase can stay on the strand

Procesicivity

29

-More mistakes to correct, less time to add nucleotides
-Almost always adds the correct complementary bp.

Polymerase's proofreading activity

30

Have 3' to 5' exonuclease activity

Both DNA Pol. I and DNA Pol. III

31

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

DNA Polymerase

32

DNA Polymerase ______ has 5' to 3' and 3' to 5' exonuclease activity.
a. I
b. III

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

33

- 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.

The Replisome

34

-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

DNA Replication in Eukaryotes

35

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

Replicon

36

Multiple Origins: Many start at the same time

Replication in Eukaryotes

37

-Tandemly repeated
-added by enzyme telomerase

Telomeres

38

Is a reverse transcriptase
complex of protein (does the synthesizing) and RNA (template)

Telomerase

39

Makes DNA from RNA template

Reverse transcriptase

40

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

e. all of the above are true

41

Type of supercoiling that relieves stress
(Think of DNA Gyrase and what it does)

Positive supercoiling