FINAL - CH3

Question 1

purines

Answer 1

Adenine Gaunine

Question 2

pyrimidines

Answer 2

Cytosine Thymine Uracil

Question 3

Nomenclature for nucleosides and nucleotides

Answer 3

Question 4

2 different structures if DNA

Answer 4

Primary: SIngle strand of DNA

Secondary: 2 strands pair in an antiparallel fashion

Question 5

1 turn in B DNA =

Answer 5

10.5 bp

36 Å

Question 6

1 bp =

Answer 6

3.4 Å

Question 7

Chargaffs rule

Answer 7

A-T

C-G

Question 8

Base stacking

Answer 8

base pairs are stacked upon each other within van der Waals distance

Question 9

DNA stability:

Answer 9

Base stacking: hydrophobic effect and van der Waals interactions

Question 10

Different Helix forms

Answer 10

A-DNA- Short and wide, right handed

B-DNA- most stable DNA

Z-DNA- Long and narrow, Left handed

Question 11

Hyperchromic shift

Answer 11

Occurs when DNA is denatured (2 strands to 1 strand), It allows the aromatic rings of the base pairs to interact with light increasing absorbance

Question 12

Renature

Answer 12

“Annealing”

two DNA strands reform a helix.

Question 13

C-G binds with _____ H bonds

A-T binds with _____ H bonds

Answer 13

3

2

Question 14

T_m

Answer 14

Melting temperature

Affected by: GC content

DNA length

Ionic strength

Question 15

How does ionic strength afftect T_m

Answer 15

If you add NaCl to DNA the Na+ ions will interact with the negatively charged DNA backbone, therefore stabilizing the sturcture. This stabillity will require more heat to cause denaturing, so Tm goes up

Question 16

Supercoiling is found in _______and________

Answer 16

prokaryotes

eukaryotes

Question 17

Nucleosome

Answer 17

Circular DNA wrapped around histone proteins

(not sequence specific)

Question 18

Right handed supercoils

Answer 18

Negative

Question 19

Left handed supercoils

Answer 19

Positive

Question 20

DNA has _____ supercoils

Answer 20

Negative

Question 21

Topoisomerase

Answer 21

Breaks and removes positive supercoil, assists in DNA wrapping around histone

Question 22

Histone protein

Answer 22

Made up of 2 each:H2A, H2B, H3 and H4

and 1 H1

Question 23

Histone binding with DNA:

Answer 23

Positively charged surface of the protein binds to the negatively charged backbone of the DNA

Question 24

Autocleavage

Answer 24

Can occur in RNA which is more reactive because of extra O

Does NOT occur in DNA

Question 25

Spontaneous deamination

Answer 25

Cytosine --\> Uracil

Question 26

Ribozymes

Answer 26

RNA molecules with catalytic activity

Question 27

Heterochromatin vs Euchromatin

Answer 27

Euchromatin - coding DNA Heterochromatim - Non-coding DNA

Question 28

How chromosomes condense:

Answer 28

DNA, Nucleosomes, Chromatin, looped chromatin, Coiled chromatin, chromosome

Question 29

Telomere

Answer 29

G rich DNA forms loop structures that protect ends

Question 30

\_\_\_\_\_\_\_\_and ________ promote genetic diversity

Answer 30

Exon shuffling alternative splicing

Question 31

The field used in biochemistry to discover the function of an unknown gene, such as a human disease gene, that can be targeted with pharmaceutical drugs

Answer 31

Bioinformatics

Question 32

Hutchinson-Gilford progeria

Answer 32

LMNA mutation C --\> T substitution

Question 33

STR

Answer 33

Short tandem repeats Deletions and insertions in the genome

Question 34

VNTR

Answer 34

Variable number tandem repeats Repeats of a core sequence Can be used in forensic applications

Question 35

Plasmids are found in _________ organisms

Answer 35

both prokaryotic and eukaryotic

Question 36

3 modes of transfering genentic information in plasmids

Answer 36

Conjugation Transformation: when a cell dies it realeases its contents to be taken up by other cells Transduction: Visures infect bacteria through this process

Question 37

Enzymes that protect bacteria

Answer 37

DNA methylases: methylates DNA in bacteria Restriction nuclease: Cleaves non-mehtylated DNA, so attakcs viral DNA

Question 38

Restriction endonucleases

Answer 38

Type I and III: Require ATP Type II: Cleave DNA at specific recognition sequences Useful in gene cloning

Question 39

Lac Z gene

Answer 39

Codes for ß-galactosidase Helps break down lactose X-gal is a substrate for ß-galactosidase (blue color) Blue colonies will have functional enzyme White colonies will not (mutants)

Question 40

Type II REs:

Answer 40

Blunt end 5' over hang 3' over hang

Question 41

PCR three temperature phases:

Answer 41

Phase I – DNA denaturation Phase II – Annealing Phase III – Primer extension and DNA synthesis

Question 42

DNA polymerase

Answer 42

DNA replication

Question 43

DNA plyerization ocurs in a _______ direction

Answer 43

5' --\> 3'

Question 44

ATP bonds

Answer 44

Phosphoanhydride

Question 45

How does ATP transfer energy

Answer 45

It is an energy carrier that has high energy phosphoanhydride bonds