Unit 3 - History of Molecular genetics

Question 1

Mid 1800

Answer 1

Gregor Mendel
-studying pea plants determined = characteristics inherited in discrete units (genes)

segragated and assorted

dominant or recessive

Question 2

Late 1800’s

Answer 2

Fredrich Miescher
- In 1869 discovered a white substance from nucleus of a cell and figured it was slightly acidic
- named nuclein bc found in the nucleus

Question 3

Early 1900’s

Answer 3

Thomas Hunt Morgan
- worked at Columbia Uni
- studied fruit fly eye colour determining that trait was sex linked
- wom Nobel prize in 1933 on chromes and genetics

Question 4

Late 1920’s

Answer 4

Federick Griffth
- worked w bacteria (harmless live bacteria mixed w heat killed infections causing disease in mice)
= substance transfer from dead bacteria to live
= tranformation

Question 5

experiment on mice

Answer 5

R and S bacteria

R strain lacked smooth capsule resulted in rough and irregular colones when cultured

s strain colones look smooth and glossy when grown on agar

Question 6

what mouse lives

Answer 6

r strain mice lives
s strain mice die

Question 7

Transformation

Answer 7

change in a genotype and phenotype due to the incorporation of external DNA by a cell

Question 8

Oswald Avery

Answer 8

American biologist and physician born in Canada lived in NYC
colleagues = McCarty and MacLeod

Question 9

Averys work

Answer 9

involved seperating DNA and proteins and then attempting to see which substance could transform live , nonpathogenic bacteria into pathogenic bacteria

Question 10

averys conclusion…

Answer 10

DNA is the transforming substance but most scientists believed it was a protein

Question 11

Hershey and Chase

Answer 11

early 1950’s
-used bacteriophage
-called T2 bacteria

Question 12

H and C question

Answer 12

which part of virus protein coat or DNA in resposible for tranforming E. coil

Question 13

H and C conclusion

Answer 13

DNA is responsible for transformation of bacteria not proteins. so DNA is the hereditary material

Question 14

Phoebus Levene

Answer 14

1920 found DNA had 3 major components
1) deoxyribose sugar
2) phosphate groups
3) nitrogenous bases

Question 15

Erwin Chargaff

Answer 15

• columbia uni
• studied purines and pyrimidines in DNA

Question 16

chargaff rule

Answer 16

a= 30.9%
t= 29.4%
g= 19.9%
c= 19.8%

a=t g=c

Question 17

Linus Pauling

Answer 17

• Caltech
• won NPP in chemistry in 1954 for chemical bonding and in 1964 for a campaign against above-ground nuclear testing
• came up with triple helix (though DNA was 3 strands) but he did discover a-helix and beta-pleated protein shapes

Question 18

Franklin and Wilkins

Answer 18

Rosaline Franklin: Maurice Wilkins
- used x-ray to look at shape of DNA
their info gave watson and crick info needed to come up with double helixstructure
- spacing of nitrogenous bases
- width of helix

Question 19

Frankline

Answer 19

• bases on inside while sugar backbone on the outside
• DNA was a double helix which rotates in a clockwise direction
• DNA mols diameter of 2nm and that one turns of the helix was 3,4 nm long.

Question 20

James Watson and Franci Crick

Answer 20

• used wire model to confirm measurements of F and W x-ray
• won NPP in medicine in 1962
• maurice wilkins also included in NPP

Franklin was not bc she had dies in 1958 from cancer

Question 21

Matthew Meselson and Franklin Stahl

Answer 21

in 1958 discovered DNA replication is semi- conservative
ie. 1/2 of double helix is old 1/2 is new