M1-C1-L18B --> Dna Replication (Eukaryote) Lecture Ii

Front 1

What are the three basic rules of DNA replication?

Back 1

1. DNA replication is semiconservative
2. Replication begins at defined origin and proceeds bidirectionally
3. DNA synthesis is in 5’ to 3’ direction and is semi-discontinuous

Front 2

All nucleic acid synthesis proceeds by linking a new nucleotides to _____ of a terminal _________.

Back 2

Free 3’OH group of a terminal PENTOSE SUGAR

Front 3

All DNA synthesis requires a short ______ to begin.

Back 3

PRIMER

Front 4

What is the name of the proteins that compacted DNA is bound to?

Back 4

HISTONES

Front 5

List 4 major differences between Eukaryote and Prokaryote DNA.

Back 5

1. Eukaryotes MUCH bigger
2. Replication occurs during small portion of cell cycle
3. DNA is bound by histones
4. Chromosomes are linear.

Front 6

Name the five polymerases in Eukaryotes, listing the location and major role.

Back 6

1. Beta – Nucleus – DNA Repair
2. Epsilon – Nucleus – DNA Repair.
3. Alpha – Nucleus – DNA Replication
4. Delta – Nucleus – DNA Replication
5. Gamma – Mitochondria – DNA Repl.

Front 7

How many origins of replication does Eukaryote chromosomes have?

Back 7

LOTS and LOTS

Front 8

What are the phases of DNA synthesis and in which phase does DNA replication occur?

Back 8

- G1 phase
- S phase (DNA replication)
- G2 phase
- M phase

Front 9

Discuss the ARS in yeast.

Back 9

Autonomous Replication Sequences.
A segment of DNA sequences necessary for initiation of replication. Generally a site recognized and bond by proteins of the replication mechanism.

Front 10

DNA binding proteins associated with initiation of replication are usually bound to what?

Back 10

ARS

Front 11

What is ORC?

Back 11

Origin recognition complex – binds to ARS

Front 12

What is ABF?

Back 12

ARS binding factor – binds to ARS

Front 13

What is ARS?

Back 13

Recruits other proteins to bind to the ARS, making it into a large complex

Front 14

In G1, what initiating enzyme is required to initiate DNA replication?

Back 14

Kinases required to initiate DNA replication in G1, just before G1-S transition.

Front 15

In S phase, what happens to the ARS’s phosphorylated proteins? What is this function?

Back 15

The phosphorylated proteins will leave, making the strands separate and replication begin.

Front 16

When the replication proteins leave the nucleus, why?

When do they move back into the nucleus and why?

Back 16

Once phosphorylated, these replication proteins of the ARS leave to prevent RE-replication.

They come back during telophase to reform the pre-replicative state.

Front 17

What is the function of RNAse H in eukaryotes and prokaryotes?

Back 17

Digest RNA in DNA-RNA hybrids

Front 18

In eukaryotes, how are the gaps in the lagging strand filled? What about the nicks?

Back 18

Gaps in lagging strand filled by Polymerase DELTA. Nicks taken care of by Ligase.

Front 19

In the Eukaryotic DNA replication, what is the clamp? What is the clamp loader?

Back 19

Clamp is PCNA Loader is RFC

Front 20

T/F: Primase and DNA Pol ALPHA are the same enzyme.

Back 20

TRUE

Front 21

What is the role of RPA?

Back 21

Helix stabilizing protein

Front 22

Discuss the priming of lagging strand DNA in eukaryotes.

Back 22

DNA Pol Alpha / Primase will lay down primer, which will be elongated by DNA Pol Delta.

Front 23

Discuss the synthesis of the lagging strand DNA in eukaryotes.

Back 23

With primer down, DNA Pol Delta will clamp on via PCNA. Then elongate. At same time RNase removes primer.

Front 24

What does RNase H do in eukaryotes?

Back 24

Removes primer in lagging strand.

Front 25

In eukaryotes, what is the end problem and how do telomeres get around it? Discuss the whole mechanism.

Back 25

The daughter strand of leading strand is complete, but the lagging strand is incomplete. Telomerase is RNA directed Polymerase. Will put down RNA template to template strand and extend complementary sequence (telomeres). Once long enough, primase puts down primer and strand synthesis starts. Ligase seals nick. And RNA primer removed.

Front 26

Telomerase is not active in most ____ cells.

Back 26

Somatic.

Front 27

In eukaryotes, inactivity of telomerase would lead to telomeres to do what? Why is this good?

Back 27

Inactive telomerase means short telomeres. This is good protection from cancer because cell division becomes difficult.

Front 28

Where are telomerase most active?

Back 28

In the germ-line cells

Front 29

T/F: CA cells express telomerase.

Back 29

True

Front 30

What is the biochemical mechanism of action of quinolone antibiotics?

Back 30

Inhibits topoisomerase II (Gyrase)

Front 31

List some examples (x4) of quinolone antibiotics.

Back 31

1. Ciprofloxacin
2. Levofloxacin
3. Nalidixic acid
4. Trovafloxacin

Front 32

What is the role of DNA topoisomerases in Pelvic Inflammatory Disease?

Back 32

Necessary to relieve POS supercoils generated by DNA replication and transcription.

Front 33

What is the genetic make up of the influenza virus? How does it replicate?

Back 33

Neg-stranded RNA virus. Replicates via RNA dependent RNA polymerase.

Front 34

What is the biochemical action of ribavirin? What types of viruses does it work against?

Back 34

Nucleoside analog that pair well with Cytosine and Uridine. Works against DNA & RNA viruses

Front 35

Ribavirin pairs equally well with what nucleotide bases?

Back 35

Uridine and Cytosine

Front 36

Topotecan has what type of drug function?

Back 36

Inhibits type I topoisomerase

Front 37

Teniposide has what type of drug function?

Back 37

Inhibits Gyrase (Type II topoisomerase)

Front 38

How does topotecan and teniposide become effective against CA?

Back 38

Inhibit topoisomerase which is essential in relieving supercoils generated by massive DNA replication and transcription.