Molecular Genetics - DNA Synthesis

Question 1

DNA replication happens in this fashion.

Answer 1

Semi-Conservative

• Each strand is a template
• Remains unaltered

Question 2

The steps in the semi-conservative fashion?

Answer 2

Unwind
Seperate
Each strand is a ‘template’

Question 3

IN DNA replication we start with one ___ to these____ to these.

Answer 3

Mother strand -> 2 strands (One strand from mother, one identical)
2->4 Strands (Maternal/new strand, daughter/new strand)

Question 4

T/F Without mutations there would be no evolution.

Answer 4

TRUE

Question 5

The initiation of DNA replication starts at…

Answer 5

Specific points of origin, sequences recognized by enzymes.

Question 6

In Bacteria there is ____ origin of replication.

Answer 6

One

Question 7

Enzymes in the Initiation Phase?

HTSPD

Answer 7

Helicase
Topoisomerase
(Single-strand DNA binding proteins)
Primase
DNA Polymerase III

Question 8

This enzyme unwinds & seperates the double helix. How?

Answer 8

Helicase - breaks hydrogen bonds

Question 9

Which enzyme forms the replication fork?

Answer 9

Helicase!

Question 10

The leading strand opens in the __-__ direction and is ________.

Answer 10

3-5, continuous

Question 11

Lagging stand opens in the __-__ direction and is ____________.

Answer 11

5-3, discontinuous

Question 12

This enzyme alleviates strain and periodically repairs cuts in strand (relieving pressure & tension)

Answer 12

Topoisomerase

Question 13

This guy prevents re-annealing, but isn’t an ______.

Answer 13

Single-Strand DNA Binding Proteins

Isn’t an enzyme

Question 14

This binds single stranded DNA & acts as the RNA primer.

Answer 14

Primase

Question 15

Primase is responsible for making a ______ ________ _______ as ____-___.

Answer 15

Hybrid Double Helix as dsDNA-RNA

Question 16

After primase works, the ds-NA is ready to be bound by

Answer 16

Polymerase

Question 17

This enzyme begins the synthesis of new DNA.

Answer 17

Polymerase

Question 18

The new DNA strand is synthesized in the __-__ direction.

Answer 18

5-3

Question 19

This is called the leading strand because…

Answer 19

It can continuously synthesize

Question 20

DNA Polymerase III kicks off the __ _____ _______ and only adds to the __’ end.

Answer 20

2 extra phosphates, and adds to the 3’ end.

Question 21

Nucloside triphoshphates, are added to the

Answer 21

3 Prime end only (ATP, GTP, CTP, TTP)

Question 22

The energy for the reaction to occur comes from:

Answer 22

Nucleotides

Question 23

Once DNAP3 is involved, DNA _______ and is ______.

Answer 23

Elongates, Read

Question 24

The lagging strand, on the other side, opens in the __-__ direction

Answer 24

3-5

Question 25

These are short newly synthesized DNA fragments on the lagging strand.

Answer 25

Okazaki Fragments

Question 26

On the lagging strand this makes RNA primer.

Answer 26

Primase

Question 27

When primer is completed, _____ synthesizes addding a NTP to the __’ end.

Answer 27

DNAP3

3’

Question 28

As it moves towards the right it will…

Answer 28

Hit another RNA primer & stop

Question 29

When it hits another RNA primer, the DNAP3

Answer 29

Bumps Off

Question 30

DNA->______->______->_____->

Answer 30

RNA PRIMER->DNA->RNA PRIMER

Question 31

The next enzyme that comes along is ______ and it moves from __-__’

Answer 31

DNAP1

moves 5-3

Question 32

What does DNAP1 do?

Answer 32

Removes ribonclueotide from RNA primer & replaces with deoxynucleotide.

Question 33

Can DNAP1 join the final nucleotide?

Answer 33

No

Question 34

So who comes in to seal the deal?

Answer 34

DNA Ligase

Question 35

T/F There are terminal RNA primers @ very ends of DNA molecules.

Answer 35

TRUE

Question 36

How do we get rid of the RNA primers?

Answer 36

Removal & replacement where a 3’ end available or No replacement and lagging strand is shorter.

Question 37

After 2 generations of replication?

Answer 37

Leading strand replicates shorter

Lagging strand now longer

Question 38

At the end of each DNA sequence is ‘junk DNA’ containing 100’s to 1000’s of repeats called:

Answer 38

Telomeres

Question 39

Telomeres act as a _________ doing this to the organisms genes.

Answer 39

Buffer - Protecting

Question 40

An enzyme called __________ catalyzes the lengthening of telomeres.

Answer 40

Telomerase - active in gametes & stem cells, turns off when mature.