DNA

Question 1

Nucleotides are _____ with 1 to 3 ________ ______ added

Answer 1

phosphate groups

Question 2

Nucleosides contain a ___ _____ _____ bonded to a _______ _____.

Answer 2

5 carbon sugar (ribose) bonded to a nitrogenous base

Question 3

What are the 5 nucleotides?

Answer 3

Adenine
Cytosine
Guanine
Thymine
Uracil

Question 4

DNA backbone is composed of alternating _______ and ______ groups

Answer 4

sugar & phosphate groups

Question 5

DNA backbone is always read __ to __

Answer 5

5’ to 3’

Question 6

Two DNA strands are ___________

Answer 6

antiparallel

Question 7

What are the 2 purines?

Answer 7

A & G

Question 8

What are the 3 pyramidines?

Answer 8

C, T, U

Question 9

How many bonds between A & T/U?

Answer 9

2 H bonds

Question 10

How many bonds between C & G?

Answer 10

3 H bonds

Question 11

When DNA strand is pulled apart

Answer 11

denatured

Question 12

When DNA strand is brought back together

Answer 12

reannealed

Question 13

in eukaryotes, DNA is wound around ______ ______

Answer 13

histone proteins

Question 14

DNA wound around histone proteins form _______ which may be stabilized by _______

Answer 14

nucleosomes

stabilized by H1

Question 15

DNA and its associated histones make up ______ in the nucleus

Answer 15

chromatin

Question 16

Heterochromatin is ____ transcriptionally ____ DNA

Answer 16

dense

transcriptionally silent

Question 17

Euchromatin is ____ transcriptionally ____ DNA

Answer 17

less dense

transcriptionally active

Question 18

Telomeres contain high ____ content to prevent _____ ___________

Answer 18

GC

DNA unraveling

Question 19

Centromeres contain high ____ content

Answer 19

GC

hold sister chromatids together

Question 20

DNA replication is __________

Answer 20

semiconservative

1 old parents strand + 1 new daughter strand incorporated into each of the 2 new DNA molecules

Question 21

DNA polymerase does what function? What direction does it work?

Answer 21

synthesizes new DNA

reads template 3’ to 5’
synthesizes new strand 5’ to 3’

Question 22

How is the lagging strand synthesized?

Answer 22

requires many primers, synthesized in discrete sections called Okazaki fragments

Question 23

How many origins of replication are there in prokaryotes? eukaryotes?

Answer 23

Prokaryotes - one per chromosome

Eukaryotes - multiple per chromosome

Question 24

How is DNA double helix unwound?

Answer 24

Helicase

Question 25

How are unwound template strands stabilized?

Answer 25

ss DNA binding protein

Question 26

How are RNA primers synthesized?

Answer 26

primase

Question 27

How is DNA synthesized in prokaryotes? eukaryotes?

Answer 27

Prokaryotes - DNA polymerase III

Eukaryotes - DNA polymerases alpha, delta, epsilon

Question 28

How are RNA primers removed in prokaryotes? eukaryotes?

Answer 28

Prokaryotes - DNA polymerase I

Eukaryotes - RNase H

both 5’ to 3’ exonucleases

Question 29

How is RNA replaced with DNA in prokaryotes? eukaryotes?

Answer 29

Prokaryotes - DNA polymerase I

Eukaryotes - DNA polymerase delta

Question 30

How are Okazaki fragments joined?

Answer 30

DNA ligase

Question 31

What do DNA topoisomerases do? (and DNA gyrase in prokaryotes)

Answer 31

removes positive supercoils ahead of advancing replication forks

Question 32

What synthesizes telomeres?

Answer 32

Telomerase

Question 33

Do prokaryotes have telomeres?

Answer 33

No - circular DNA

Question 34

Recombinant DNA is ….

Answer 34

DNA composed of nucleotides from 2 different sources

Question 35

DNA cloning introduces a fragment of DNA into a ____ _____.

Answer 35

vector plasmid

A restriction endonuclease cuts the plasmid & fragment, leaving them with sticky ends that can bind