DNA Replication

Question 1

What is the reverse transcriptase enzyme?

Answer 1

• RNA -> DNA
• used for HIV
• exception to central dogma

Question 2

What is DNA replication?

Answer 2

same genome split into 2 to make daughter cells

Question 3

What is translation?

Answer 3

turning RNA script into protein

Question 4

What are the condensed chromosomes

Answer 4

metaphase

Question 5

What occurs in each G phase of DNA replication?

Answer 5

1. G1: prepare for DNA replication; histone proteins are made
2. S: synthesis; DNA replication
3. G2: DNA done replicating, prepare for mitosis
4. G0: cell arrest; when cell is damaged it can get repaired or undergo apoptosis

Question 6

All nucleic acids grow in what direction?

Answer 6

5’ -> 3’

Question 7

What causes DNA to be polar?

Answer 7

asymmetry of phosphodiester bonds

Question 8

Bases are only added to what end of DNA?

Answer 8

3’

Question 9

What is the substrate for DNA replication?

Answer 9

triphosphate nucleotide (ATP, GTP, etc.)

Question 10

What is the role of DNA polymerase?

Answer 10

• phosphodiester bond formation
• fromation of H bonds b/w bases

Question 11

How many H bonds are in between A-T and G-C pairing?

Answer 11

• A-T: 2
• G-C: 3

Question 12

How many origins of replication do we have?

Answer 12

multiple

Question 13

The leading and lagging strand both grow in what direction?

Answer 13

5’ -> 3’

Question 14

Okazaki fragments are a part of which strand?

Answer 14

lagging

Question 15

What is the function of helicase?

Answer 15

uses ATP to unwind DNA to cause supercoiling

Question 16

What is the function of topoisomerase?

Answer 16

releases torisonal stress caused by helicase coiling

Question 17

What enzyme is able to break phosphodiester bonds?

Answer 17

topoisomerase

Question 18

Without topoisomerase, what can happen within DNA?

Answer 18

there can be breaks

Question 19

Which polymerase self-initiate?

Answer 19

RNA

Question 20

How does DNA polymerase get started with replication?

Answer 20

needs an RNA primer

Question 21

What does a primase add for replication?

Answer 21

20 bp

Question 22

What is the function of DNA ligase?

Answer 22

• links okazaki fragments together
• adds phosphodiester bonds

Question 23

What enzymes use ATP?

Answer 23

• helicase
• topoisomerase
• DNA ligase

Question 24

What is DNA polymerase alpha?

Answer 24

does 200 nucleotides after primase

Question 25

What is DNA polymerase delta?

Answer 25

* high processtivity * needs PCNA (clamp) * needs RFC (clamp loader)

Question 26

What enzyme destroys RNA nucleotides?

Answer 26

rnase

Question 27

What enzyme destroys RNA primers?

Answer 27

rnase H

Question 28

What is the decoy in replication?

Answer 28

* single-stranded binding protein * DNA polymerase E

Question 29

Mutations in helicase can cause what disease?

Answer 29

Bloom syndrome

Question 30

What is ambrucin?

Answer 30

potent topoisomerase inhibitor used in non-small cell lung cancer treatment

Question 31

What direction does exonucleolytic correction go in?

Answer 31

3' -> 5'

Question 32

What is the process of exonucleolytic correction?

Answer 32

removal of incorrect base and DNA polymerase adds correct base in 5' -> 3' direction

Question 33

How many base pairs do we ahve in our genome?

Answer 33

3 x 10 ^9

Question 34

What is NAP1?

Answer 34

a chaperone protein that facilitates the reassembly of nucleosomes

Question 35

What is the function of telomerase?

Answer 35

* protects ends of chromosomes from exonuclease activity * uses RNA template but is a DNA polymerase

Question 36

What phase of chromosomes are used in karyotyping?

Answer 36

metaphase

Question 37

What is FISH?

Answer 37

technique used to detect short segments of DNAusing fluorescent DNA probes

Question 38

What are the characteristics of active retinoblastoma (Rb)?

Answer 38

* P16 interacts with cyclin D/CDK4 * Rb not/lightly phosphorylated so it interacts with E2F that recruits HDAC * NO TRANSCRIPTION

Question 39

What are the characteristics of inactive retinoblastoma (Rb)?

Answer 39

* P16 does not interact with cyclin D/CDK4 * Rb is highly phosphorylated so it does not interact with E2F that will not recruit HDAC * TRANSCRIPTION OCCURS

Question 40

What is the purpose of PCR?

Answer 40

to amplify DNA sequence

Question 41

What polyermase does PCR use?

Answer 41

DNA

Question 42

What are the steps in PCR?

Answer 42

1. Separate double stranded (DS) DNA with Heat or Helicase (DS -> SS) aka doublestranded to single stranded 2. Cool and Mix known primers (20-30 NT) because DNA polyermase requires a primer 3. DNA Polymerase will extend the primers and W/C bp at needed area (DNA Synthesis) 4. Denature/Separate Strands and Repeat

Question 43

From the article "DNA Replication", what would be the effect of drug resistant topoisomerases for cancer prognosis?

Answer 43

1. cancer: if drugs target topoisomerase, it will stop replication -> decreasing cancer 2. cytotoxic effects: chemo has harsh side effects such as GI issues & hair loss 3. drug resistance: harder to treat, different forms of topoisomerase

Question 44

From the article "DNA Replication", according to Table 1, which cancer would be a best candidate for further tests?

Answer 44

ovarian because it has the lowest EC50

Question 45

From the "Telomeres Syndrome" article, what is dyskerin?

Answer 45

essential component of telomerase enzyme making telomeres

Question 46

From the "Telomeres Syndrome" article, what are the degenerative disorders linked to a shortened telomerase?

Answer 46

* idiopathic pulmonary fibrosis * bone marrow failure

Question 47

From the "Telomeres Syndrome" article, what is dyskeratosis congenita?

Answer 47

* linked to mutant short telomere defect * symptoms: skin hyperpig., luekopenia, nail dystrophy * mortality: bone marrow failure, cancer, pulmonary fibrosis

Question 48

From the "Telomeres Syndrome" article, what is TERT?

Answer 48

* gene providing instructions for making the telomerase gene * highest freq. in people with progressive idiopathic pulmonary fibrosis

Question 49

From the "Telomeres Syndrome" article, what does each length of a telomerase mean?

Answer 49

* short or too long: not healthy; can lead to disease * long: good, healthy