Bi 140 Patterns Of Inheritance 28

Front 1

James Watson and Francis Crick

Back 1

Informally learned about Franklin's result before they were published in 1953, quickly worked out a likely structure of DNA molecule. Never actually performed their own experiments for DNA but used available info to produce models

Front 2

Rosalind Franklin

Back 2

British chemist who used X-ray diffraction technique to analyze DNA

Front 3

Maurice Wilkins

Back 3

Another researcher working in same lab as Franklin, was able to prepare more uniformly oriented DNA fibers than anyone else at the time. Franklin used these to obtain crude diffraction info on natural DNA. Suggested that DNA is in the shape of a helix

Front 4

Linus Pauling

Back 4

-American chemist
-Double nobel prize winner
-Looked for structures of many molecules using ball and stick models
-Worked too quickly and created the wrong model, giving W/C another chance

Front 5

x-ray crystallography

Back 5

-Crystal form of DNA
-Light hits crystals to form regular pattern
-First clue to structure

Front 6

Erwin Chargaff

Back 6

-Expert in chemistry of NA
-Explained to W/C the rules of chemistry of DNA
-Pairs AT, GC
-First clue to structure

Front 7

Ball and stick models

Back 7

-Used by Watson and Crick and Linus Pauling
-W/C chose to build models (minimum data) instead of crystallography
-Linus Pauling used the models to look for the structures of many molecules

Front 8

X pattern

Back 8

The X pattern on the x-ray diffraction photograph of DNA fibers made in 1953 by Rosalind Franklin was interpreted to show the double helical structure of DNA.

Front 9

Nucleotide

Back 9

Compound consisting of a nucleotide linked to a phosphate group. They form the basic structural unit of DNA and RNA.

Front 10

Deoxyribonucleic acid

Back 10

-3 main components
1) 5 carbon sugar with OH group attached to 3' sugar
2) Phosphate group (PO4) attached to (C5) 5'
3)Nitrogenous base group
-Made up of nucleotides attached to form chain (strand) and connected by hydrogen bonding between the nitrogenous bases

Front 11

Ribonucleic acid

Back 11

-3 main components
1) 5 carbon sugar with OH group attached to 3' sugar
2) Phosphate group (PO4) attached to (C5) 5'
3)Nitrogenous base group

Front 12

Five carbon sugar

Back 12

The nucleotide subunits of DNA and RNA are composed of this

Front 13

Phosphate group

Back 13

Attached to a five carbon sugar in a nucleotide subunit on 5' or the fifth carbon. Connects with OH group of another nucleotide subunit

Front 14

Nitrogenous base

Back 14

Purine or pyrimidine
ACTG

Front 15

5', 3', 1'

Back 15

5' end connects with Phosphate group
3' end connects with OH group
1' connects with complementary nitrogenous base

Front 16

Phosphodiester bond

Back 16

linkage of 5' phosphate and 3' hydroxyl group which are linked to the two sugars by ester bonds. Many thousands of nucleotides can join together via these linkages to form long nucleic acid polymers

Front 17

Adenine

Back 17

Nitrogenous base that pairs with Thymine to form the DNA structure.

Front 18

Guanine

Back 18

Nitrogenous base that pairs with Cytosine to form the DNA structure.

Front 19

Cytosine

Back 19

Nitrogenous base that pairs with Guanine to form the DNA structure.

Front 20

Thymine

Back 20

Nitrogenous base that pairs with Adenine to form the DNA structure.

Front 21

Uracil

Back 21

Nitrogenous base that forms complementary bond with Adenine in the mRNA strand. Replaces T

Front 22

Double helix

Back 22

Key to the model was figured out by W/C that each strand is made up of two chains of nucleotides that are intertwined

Front 23

Phosphodiester backbone

Back 23

Strand of nucleotides, sequence varies

Front 24

Antiparallel

Back 24

The two strands of DNA connect to each other one running 5' to 3', the other 3' to 5'

Front 25

Complementary

Back 25

Complementary base pairing occurs by double bonding between A and T and triple bonding between C and T

Front 26

Who were the groups of scientists involved in the race to discover the structure of DNA?

Back 26

Watson and Crick (Cambridge)
Rosalind Franklin and Maurice Wilkins (King's College)
Linus Pauling
Erwin Chargaff helped W/C

Front 27

How did the scientific approaches of these groups differ?

Back 27

Watson and Crick used a carefree approach and the ball and stick models that Linus Pauling also used.
Rosalind Franklin and Maurice Wilkins used X-ray crystallography.
Erwin Chargaff used his expert knowledge of chemistry to predict the DNA structure

Front 28

Purines

Back 28

Bigger than Pyrimidines
Adenine
Thymine

Front 29

Pyrimidines

Back 29

Smaller than purines
Cytosine
Guanine

Front 30

How did personality and competition get in the way of discovery?

Back 30

Most personality issues occurred between Franklin and Wilkins who worked in the same lab but didn't collaborate. Watson and Crick used questionable methods to obtain the info that led them to their discoveries and Linus Pauling used his fast and arguably overconfident technique hoping to be the first to discover the structure.

Front 31

How did Wilkin's "let the cat out of the bag?"

Back 31

Wilkins showed Watson the photograph that Franklin had obtained through X-ray crystallography which led W/C to use their other info to determine the DNA structure.

Front 32

Describe how Watson used Chargaff's and Franklin's data to develop a DNA model on February 28, 1953.

Back 32

-Knowing that 4 chemicals join in pairs
-The shape would lead to the function of the molecule
-Used Cardboard models to show that
-2 base pairs were identical in shape
-Stacked on top of each other and twisted around

Front 33

How does complementarity hold the backbones of the double helix together?

Back 33

The hydrogen bonding holds the double stranded DNA together by hydrogen bonds in which A forms 2 bonds with T and C forms 3 bonds with G.