DNA Replication

Question 1

Telomeres

Answer 1

Long regions of DNA repeats and proteins that don’t translate to DNA.

Protect DNA from being degraded. Produced in a reverse transcriptase fashion

Question 2

Single copy genes

Answer 2

Protein coding DNA

• can be tissue specific or house keeping genes

Question 3

Tissue specific genes

Answer 3

Code specific proteins for specific tissues

Ex: cardiac proteins specific for heart

Question 4

House keeping genes

Answer 4

Code for proteins that are common in all cells.

Ex: cytoskeletal proteins

Question 5

Satellite DNA

Answer 5

Non-transcribed DNA

• highly repetitive, cluster together
• micro DNA clustering causes diseases

Question 6

Dispersed repetitive DNA

Answer 6

LINES & SINES & Transposenes

Question 7

Direction of DNA polymerase reading

Answer 7

3’ - 5’

Question 8

Direction of exonuclease activity of DNA polymerase

Answer 8

3’ - 5’

Question 9

Direction of new synthesized strand of DNA

Answer 9

5’ - 3’

Question 10

DNA polymerase 3

Answer 10

Functional DNA polymerase in prokaryotic DNA replication

Question 11

RNA primase

Answer 11

Builds a short strand of RNA at the beginning of replication for DNA polymerase to bind to and begin its activity.

Found in both eukaryotic and prokaryotic replication.

Question 12

DNA ligase

Answer 12

Seals Okazaki fragments together

Question 13

Topoisomerase (gyrase)

Answer 13

Unweaves long DNA helix segments and prevents supercoiling

• gyrase is prokaryotic version
• topoisomerase is eukaryotic form

Question 14

DNA helicase

Answer 14

Unwinds short segments of DNA

Question 15

How are nucleotides added to new strand?

Answer 15

Phosphate bond between nucleotide and 3’ OH

Question 16

Polymerase (a & d)

Answer 16

Eukaroytic polymerases that Replicates and Exonuclease activity of lagging strand

Question 17

Polymerase (e)

Answer 17

eukaryotic polymerase that synthesizes and exonuclease activity on the leading strand

Question 18

Telomerase (TERT)

Answer 18

Lagging strand causes 3’ overhang on both sides.

uses reverse transcriptase activity by having own RNA template to synthesis DNA to extend this 3’ end. Creates telomerase

• active in germline/stem cells relatively inactive in somatic cells

Question 19

Inhibitors of DNA polymerases

Answer 19

Do not possess a 3’ OH group. Stop replication once integrated into DNA.

Question 20

Examples of inhibitors

Answer 20

Azidothymidine

Didanosine

Cylarabin

Vidarabin

Question 21

How is DNA achieved with high fidelity (low error rate)?

Answer 21

Exonuclease activity of DNA polymerases