1. Chapter 10 sections 1, 2,3
Student 2015

2. 10.1 SCIENTIFIC DISCOVERY: Experiments showed that DNA is the genetic material
Until the 1940s, the case for proteins serving as the genetic material was stronger than the case for DNA.
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3. DNA is the Genetic Material Fredrick Griffith Experiment 1928:The Transforming Factor

4. Figure 10.1A
Head
DNA
Tail
Tail fiber
Figure 10.1A Phage T2 4

5. DNA is the Genetic Material Hershey and Chase Experiment 1952

6. DNA is the Genetic Material Hershey and Chase Experiment 1952
What convinced Hershey and Chase that DNA was the genetic material?
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7. 10.2 DNA and RNA are polymers of nucleotides
At the time of Hershey and Chase much was known about the chemical make up of DNA however much was not understood.
Specific arrangement of atoms
How it stored genetic information
copied it
Passed genetic information from generation to generation

8. 10.2 DNA and RNA are polymers of nucleotides
DNA and RNA are nucleic acids.
Polymers
A nucleotide (monomer)is composed of a
nitrogenous base,
five-carbon sugar, and
phosphate group.
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9. Thymine (T) Phosphate group
Figure 10.2A_3
Nitrogenous base (can be A, G, C, or T)
Thymine (T)
Phosphate group
Figure 10.2A_3 The structure of a DNA polynucleotide (part 3)
Sugar (deoxyribose)
DNA nucleotide 9

10. DNA nitrogenous bases have a double or single ring
Thymine (T)
Cytosine (C)
Adenine (A)
Guanine (G)
Pyrimidines
Purines
Figure 10.2B The nitrogenous bases of DNA 10

11. The nucleotides are joined to one another by a sugar-phosphate backbone.

12. Sugar-phosphate backbone
Figure 10.2A A T C G T A
Sugar-phosphate backbone C G
Phosphate group A T G C A G A
Nitrogenous base
Nitrogenous base (can be A, G, C, or T)
Covalent bond joining nucleotides A T G C
Sugar T A T A C C C C C G T A
DNA nucleotide
Thymine (T)
A DNA double helix T T T
Phosphate group
Figure 10.2A The structure of a DNA polynucleotide G G
Sugar (deoxyribose)
DNA nucleotide G G
Two representations of a DNA polynucleotide 12

13. 10.2 DNA and RNA are Polymers of Nucleotides
RNA (ribonucleic acid) is unlike DNA in that it
uses the sugar ribose (instead of deoxyribose in DNA) and
RNA has the nitrogenous base uracil (U) instead of thymine.
Single strand
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14. 10.3 SCIENTIFIC DISCOVERY: DNA is a double-stranded helix
In 1952, the race was on to
describe the structure of DNA and
explain how the structure and properties of DNA can account for its role in heredity.
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15. 10.3 SCIENTIFIC DISCOVERY: DNA is a double-stranded helix
In 1953, James D. Watson and Francis Crick deduced the structure of DNA, using
Chargaff’s observation that in DNA,
the amount of adenine was equal to the amount of thymine and
the amount of guanine was equal to that of cytosine.
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16. 10.3 SCIENTIFIC DISCOVERY: DNA is a double-stranded helix
X-ray crystallography data of DNA from the work of Rosalind Franklin and Maurice Wilkins

17. 10.3 SCIENTIFIC DISCOVERY: DNA is a double-stranded helix
Watson and Crick reported that DNA consisted of two polynucleotide strands wrapped into a double helix.
The sugar-phosphate backbone is on the outside.
The nitrogenous bases are perpendicular to the backbone in the interior.
Specific pairs of bases give the helix a uniform shape.
A pairs with T, (complementary) 2 hydrogen bonds
G pairs with C, (complementary) 3 hydrogen bonds
Strands run antiparallel
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18. Partial chemical structure
Figure 10.3D
Hydrogen bond
Base pair
Figure 10.3D Three representations of DNA
Ribbon model
Partial chemical structure
Computer model 18

19. Animation: DNA Double Helix
Animation: DNA Double Helix
Right click on animation / Click play
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