Chapter 4: 4.3 In vivo DNA Replication Flashcards

1
Q

True or False:

DNA within eukaryotic cells is very large

A

True

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2
Q

Are strands of DNA within eukaryotic cells separated?

A

They are not completely separate prior to replication

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3
Q

Where does DNA replication begin?

A

On specific locations designated as origins of replication

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4
Q

How do the multiple new strands of DNA meet one another and come together to form a brand new strand?

A

The replication bubbles extend out

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5
Q

How many origin of replications do prokaryotic chromosomes have?

A

One

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6
Q

How many origins of replication do eukaryotic chromosomes have?

A

Multiple

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7
Q

True or False:

DNA replication is conservative

A

False, it is semi-conservative

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8
Q

DNA replication is semi-conservative. What does this mean?

A

The newly double stranded DNA contains one strand from the original DNA and one newly synthesized strand

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9
Q

What is the origin of replication in prokaryotes known as?

A

Ori

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10
Q

Synthesis of New DNA (Prokaryotes):

At the origin of replication, what unwinds the DNA?

A

Helicase

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11
Q

Synthesis of New DNA (Prokaryotes):

Unwinding leaves two anti-parallel strands, creating a…

A

Replication fork

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12
Q

Synthesis of New DNA (Prokaryotes):

How do the two anti-parallel strands stay apart?

A

**Single stranded binding proteins (ssb) **keep the strands apart

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13
Q

Synthesis of New DNA (Prokaryotes):

What is the function of topoisomerase?

A

Responsible for “relaxing” the supercoiling of DNA

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14
Q

Synthesis of New DNA (Prokaryotes):

What is responsible for grabbing new nucleotides and mathcing them to the original DNA to create a new strand?

A

DNA polymerase III

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15
Q

Synthesis of New DNA (Prokaryotes):

What is required for DNA Polymerase III to bind to parental DNA?

A

RNA primer

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16
Q

Synthesis of New DNA (Prokaryotes):

What is an RNA primer? How is it created?

A

A short RNA sequence
* Created by an enzyme called primase

17
Q

Synthesis of New DNA (Prokaryotes):

What direction does DNA Polymerase III:
1. Read?
2. Create?

A
  1. Reads DNA in the 3’ to 5’ direction
  2. Creates a new strand in the 5’ to 3’ direction
18
Q

True or False:

DNA Polymerase III moves towards the replication fork

A

False, not necessarily true as leading and lagging strands move in different directions

19
Q

Synthesis of New DNA (Prokaryotes):

  1. The strand of polymerase that moves towards the replication fork is…
  2. The strand of polymerase that moves away from the replication fork is…
A
  1. Leading strand
  2. Lagging strand
20
Q

Synthesis of New DNA (Prokaryotes):

What is the purpose of the sliding clamp protein?

A

Tethers DNA polymerase to the strand and replication continues until the adjacent replication bubble is met

21
Q

True or False:

The leading strand has multiple primers and polymerases

A

False

22
Q

Synthesis of New DNA (Prokaryotes):

Which strand will have multiple primers and polymerases?

A

The Lagging Strand

23
Q

Synthesis of New DNA (Prokaryotes):

What does the multiple primases and polymerases of the lagging strand create?

A

Okazaki Fragments

24
Q

Synthesis of New DNA (Prokaryotes):

What is the purpose of DNA Polymerase I?

A

Removes the primer and replaces it with deoxyribonucleotides

25
Q

Synthesis of New DNA (Prokaryotes):

What is the purpose of DNA Ligase?

A

Moves along the lagging strand and ties the Okazaki fragments together

26
Q

What is the difference between DNA replication in prokaryotes and eukaryotes?

A

They are very similar
* Eukaryotes have different names

27
Q

Why is prokaryotic DNA replication often taught in detail?

A

It is well understood

28
Q

Compare in prokaryotes vs. eukaryotes:

Origins of replication

A
  • Prokaryotes: Only one
  • Eukaryotes: Multiple
29
Q

Compare in prokaryotes vs. eukaryotes:

Rate of Replication

A
  • Prokaryotes: Faster (~1000 nt/s)
  • Eukaryotes: Slower (50-100 nt/s)
30
Q

Compare in prokaryotes vs. eukaryotes:

Types of DNA Polymerase

A
  • Prokaryotes: 5
  • Eukaryotes: 14
31
Q

Compare in prokaryotes vs. eukaryotes:

Enzyme for RNA Primer Removal

A
  • Prokaryotes: DNA Polymerase I
  • Eukaryotes: RNase H
32
Q

Compare in prokaryotes vs. eukaryotes:

Enzyme for Strand Elongation

A
  • Prokaryotes: DNA Polymerase III
  • Eukaryotes: Polymerase a, Polymerase δ, Polymerase ε