DNA Replication

Question 1

DNA Polymerase

Answer 1

Adds new nucleotides to 3’OH of daughter strand

Question 2

Nucleoside Triphosphate

Answer 2

Three phosphate groups attached to a nucleotide

Question 3

Phosphodiester Bond

Done by what enzyme?

Answer 3

3’ OH connects with 5’ monophosphate

Done by DNA ligase

Question 4

Initiation

Answer 4

• Proteins bind to DNA and separate it into single strands
• Will serve as templates
• Then an enzyme synthesizes short RNA primer

Question 5

Elongation

Answer 5

DNA polymerase uses template and 3’OH to add new nucleotides

Question 6

DNA Polymerase III

DNA pol III

Answer 6

Primary enzyme for DNA synthesis

Question 7

DNA Polymerase I

DNA pol I

Answer 7

Enzyme that removes RNA primers

Question 8

DNA Helicase

Answer 8

Unwinds the double helix during replication

Question 9

Single-stranded proteins

Answer 9

Keeps helix open

After helicase unwinds the double helix, the single strands are unstable

Question 10

Primase

Answer 10

• Creates RNA primer
• Provides 3’OH groups for DNA pol III

Question 11

Origin of Replication

Answer 11

Where a replication bubble will form

Question 12

Dna A

Answer 12

Responsible for recognizing origin of replication and unwinding helix there

Question 13

Bidirectional Replication

Answer 13

Replication goes in two opposite directions after replication bubble is formed

Question 14

Leading Strand

Answer 14

• Only 1 primer needed for synthesis
• Synthesized by adding to 3’ end
• Synthesized in the same direction as the growing replication fork

Question 15

Lagging Strand

Answer 15

• Multiple primers needed for synthesis
• Synthesized by adding to 5’ end
• Synthesized in short segments called Okazaki fragments

Question 16

Proofreading

What has proofreading activity?

Answer 16

When a wrong nucleotide is added, DNApol can go back and fix it

Exonuclease (3’ to 5’ activity)

Question 17

Nuclease

Answer 17

Enzymes that break a phosphodiester bond

Question 18

Endonuclease

Answer 18

Breaks chain (phosphodiester bond) at or near the middle

Question 19

Exonuclease

Answer 19

Breaks chain (phosphodiester bond) near the end

Question 20

DNA Gyrase

What is it?

Answer 20

Cuts and rejoins DNA to eliminate supercoiling

A type of topoisomerase

Question 21

Topoisomerase

Answer 21

Relaxes supercoiling of DNA

Question 22

Origin Recognition Complex

Answer 22

Proteins that open DNA at AT-rich areas

Question 23

Telomere

Answer 23

• The end of a chromosome
• Consists of repeated segquences

Question 24

Telomerase

Answer 24

• Responsible for replicating telomeres
• But there’s no template strand, so telomerase brings its own template