chapter 2

Question 1

Tautomer

Answer 1

a molecule which a proton migrated to a new place

humans- 100,000 BP are
source of genetic variation

Question 2

DNA

Answer 2

polymer of nucleotides
antiparallel
5’ P and 3’ OH

Question 3

Pyrimidine and Purine

Answer 3

A and G are purines

C, T, U are pyridines

Question 4

Double stranded

Answer 4

more stable by van Der wals attraction

Question 5

A strand

Answer 5

right handed

11 BP, and tilted base pairs

Question 6

B strand

Answer 6

right handed

10.5 BP

Question 7

Z strand

Answer 7

left handed

comes from methylation, high stressor salt

Question 8

supercoil

Answer 8

right=postive= overwinding

left= negative = underwinding

molecule is cut and the other twists= changes in BP

Question 9

Topoisomerase

Answer 9

add or remove super coils

needs energy

Question 10

Twist

Answer 10

of turns in a DNA fragment (+1 per 360 twist)

Tw +1 for each repeat of the double helix in B-DNA
Tw > 0 for right-handed
Tw < 0 for left-handed helix

Question 11

writhe

Answer 11

Supercoiling of closed circular or constrained linear DNA

Relaxed plasmid Wr = 0
Positive coil Wr > 0
Negative coil Wr < 0

Question 12

Linkage number

Answer 12

of times one strand wraps around the other

as Tw increases then Wr decreases

Question 13

Purifying cells

Answer 13

1. get DNA out
2. lyse and solubilize (physical/detergents..)
3. remove contaminants (water and ethanol)

Question 14

RNA

Answer 14

U with A
C2’ OH
good for short term study

Question 15

-2OH sugar

Answer 15

sugar pucker
- favours A- RNA and less stable

Ribose = C3ʹ endo- A type helix

Deoxyribose = C2ʹ endo- B type helix

Question 16

Folding- non coding

Answer 16

Primary structure: 5-3

Secondary structure: short II helical

Tertiary: II and I in final arrangement = BP stacking= tRNA

Double II- stem
Unpaired- loop

Question 17

Electrophoreses

Answer 17

DNA is (-)
moves away from (-) to (+)
agarose gell helps so DNA can pass more gel smaller fragments

Question 18

Plasmids

Answer 18

Nicked- 1 close/1 open
Linear- no shape
supercoiled- Tw and Wr
circular- rather BP

Question 19

Monogenic mutation

Answer 19

PKU only one gene

Question 20

Polygenic

Answer 20

alzihmers and many genes

Question 21

Missence

Answer 21

changes AA but not the sequence

Question 22

Silent

Answer 22

AA stays the same

Question 23

frameshift

Answer 23

deleting 1 or more= loss of function

Question 24

pET-28a

Answer 24

a mutation at T7 region it can’t make insulin

Question 25

How to fix pET-28a problem

Answer 25

1. take off promotor and BS
2. encode it for the plasmid (using both ^)
3. once mRNA reaches then it finds the BP and AUG
4. ribosome will stick, finds triplets and folds

Question 26

Regulation

Answer 26

@ transcription (closer= more)
@Processing
@translation= (splicing amounts)

Question 27

Hy5 protein

Answer 27

in arabdopsis
controls seed height
more light= stable/short
less light= tall

Question 28

even-skipped gene

Answer 28

control proper segmentation of the embryo (fruit flies)

Question 29

forward genetics

Answer 29

mutant pheno seen and then discovered

Question 30

reverse genetics

Answer 30

gene mutated on purpose then pheno is seen

Question 31

Polyploidy

Answer 31

strawberries

Extra copies of the genome can provide a back-up if one copy of a gene is defective