Unit 2 - Names And Main Processes

Question 1

Miescher

Answer 1

Studied nuclei of white blood cells

Named “nuclein”

Found material was rich in nitrogen and phosphorus atoms

Question 2

Levene

Answer 2

DNA is made up of nucleotides

Question 3

Griffith

Answer 3

Two strains of Pneumococcus bacteria

Rough R-strain = non-virulent

Smooth S-strain = virulent

Dead virulent strain “transformed” the living non-virulent strain
(Non-virulent rough strain picked up DNA to become virulent)

Question 4

Hammerling

Answer 4

Algae

Experiment #1 - nucleus at bottom of stalk, plant only grew back from stalk

Experiment #2 - attached middle stalk and bottom stalk of different algae to see what characteristics the “head” would have

Hereditary info is stored in nucleus

Question 5

Avery, McCarty, Macleod

Answer 5

Continued Griffith’s work

s strain + protease
s strain + RNase
s strain + DNase

Sample with DNase did not grow (transformation)

Question 6

Chargaff

Answer 6

Concentration:
A=T
G=C
(Chargaff’s Rule)

Noticed that organisms w more Gs and Cs tended to be more complex

Question 7

Hershey & Chase

Answer 7

Definitively determine that DNA is the hereditary material

Studied bacteriophage (DNA inside, protein outside)

Radiation on phosphorus(DNA) and sulphur(protein), figured out DNA was needed

Question 8

Wilkins & Franklin

Answer 8

X-ray Crystallography

Photo indicated:

1. Backbone of alternating phosphate and sugars
2. Backbone has a helical structure
3. Double helix structure (molecule is a uniform helix)
4. Nitrogenous bases are in the middle of the molecule
5. Bases are at right angles to the backbone

Question 9

Watson & Crick

Answer 9

Purine-pyrimidine pairs (fit in double helix): A+T G+C

Double helix model offered an easy method for replication

Question 10

Alternating sugar-phosphate backbone attached by ___ bonds

Answer 10

Phosphodiester

Question 11

DNA is read from ___ to ___

Answer 11

5’ to 3’

Question 12

Opposing backbones are ___

Answer 12

Antiparallel

Question 13

____ bonds between G&C

____ bonds between A&T

Answer 13

3 H-bonds (G&C)

2 H-bonds (A&T)

Question 14

What are the genetic mechanisms?

Answer 14

Replication
Transcription
Translation

Question 15

Replication theories

Answer 15

Conservative
Semiconservative
Dispersive

Question 16

Meselson & Stahl

Answer 16

Grew E. coil in 15N media (heavy N isotope)

Density centrifugation

> semi-conservative, each parent strand serves as a template for the new

Question 17

Three main steps to replication:

Answer 17

1. Initiation
2. Elongation
3. Termination

Question 18

Replication overview:

Answer 18

Helicase, SSBPs, Gyrase (initiation)

Templates, leading&lagging strands, primase, DNA polymerase III, DNA polymerase I, DNA ligase (elongation)

Telomerase (termination)

Mistakes: exonuclease

Question 19

Steps to termination:

Answer 19

Internal RNA template

DNA synthesis

Telomerase translocation

DNA synthesis