1. The Molecular Basis of Inheritance13
The Molecular Basis of Inheritance

2. Experiment Mixture of heat-killed S cells and living R cells Living
Figure 13.2
Experiment
Mixture of
heat-killed
S cells and
living R cells
Living
S cells
(control)
Living
R cells
(control)
Heat-killed
S cells
(control)
Figure 13.2 Inquiry: Can a genetic trait be transferred between different bacterial strains?
Results
Mouse dies
Mouse healthy
Mouse healthy
Mouse dies
Living S cells 2

3. Avery-MacLeod-McCarty

4. Phage head Tail sheath Tail fiber DNA 100 nm Bacterial cell
Figure 13.3
Phage
head
Tail
sheath
Tail fiber
DNA
Figure 13.3 Viruses infecting a bacterial cell
100 nm
Bacterial
cell 4

5. Evidence That Viral DNA Can Program Cells
Animation: Phage T2 Reproduction 5

6. Batch 1: Radioactive sulfur (35S) in phage protein
Figure 13.4
Experiment
Batch 1: Radioactive sulfur (35S) in phage protein 1
Labeled phages
infect cells. 2
Agitation frees outside
phage parts from cells. 3
Centrifuged cells
form a pellet.
Radioactive
protein 4
Radioactivity
(phage protein)
found in liquid
Centrifuge
Pellet
Batch 2: Radioactive phosphorus (32P) in phage DNA
Radioactive
DNA
Figure 13.4 Inquiry: Is protein or DNA the genetic material of phage T2?
Centrifuge 4
Radioactivity (phage
DNA) found in pellet
Pellet 6

7. Figure 13.1
Figure 13.1 How was the structure of DNA determined? 7

8. Figure 13.UN01
Figure 13.UN01 Skills exercise: working with data in a table 8

9. (b) Franklin’s X-ray diffraction photograph of DNA
Figure 13.6
Figure 13.6 Rosalind Franklin and her X-ray diffraction photo of DNA
(a) Rosalind Franklin
(b) Franklin’s X-ray diffraction
photograph of DNA 9

10. Sugar Sugar Adenine (A) Thymine (T) Sugar Sugar Guanine (G)
Figure 13.8
Sugar
Sugar
Adenine (A)
Thymine (T)
Figure 13.8 Base pairing in DNA
Sugar
Sugar
Guanine (G)
Cytosine (C) 10

11. Purine  purine: too wide
Figure 13.UN02
Purine  purine: too wide
Pyrimidine  pyrimidine: too narrow
Purine  pyrimidine: width
consistent with X-ray data
Figure 13.UN02 In-text figure, purines and pyrimidines, p. 250 11

12. Sugar– Nitrogenous bases phosphate backbone 5 end Thymine (T)
Figure 13.5
Sugar–
phosphate
backbone
Nitrogenous bases
5 end
Thymine (T)
Adenine (A)
Cytosine (C)
Figure 13.5 The structure of a DNA strand
Guanine (G)
3 end
DNA
nucleotide 12

13. (b) Partial chemical structure (c) Space-filling model
Figure 13.7
5 end C G C G
Hydrogen bond
3 end G C G C T A
3.4 nm T A G C G C C G A T
1 nm C G T A C G G C C G A T
Figure 13.7 The double helix A T
3 end A T
0.34 nm T A
5 end
(a) Key features of
DNA structure
(b) Partial chemical structure
(c) Space-filling
model 13

14. (b) Separation of parental strands into templates (c) Formation of new
Figure A T A T A T A T C G C G C G C G T A T A T A T A A T A T A T A T G C G C G C G C
(a) Parental
molecule
(b) Separation of parental
strands into templates
(c) Formation of new
strands complementary
to template strands
Figure A model for DNA replication: the basic concept (step 3) 14

15. Additional Evidence That DNA Is the Genetic Material
Animation: DNA and RNA Structure 15

16. Getting Started
Animation: DNA Replication Overview 16

17. (a) Origin of replication in an E. coli cell
Figure 13.13a
(a) Origin of replication in an E. coli cell
Parental
(template) strand
Origin of
replication
Daughter
(new) strand
Replication
fork
Double-
stranded
DNA
molecule
Replication
bubble
Two
daughter DNA
molecules
Figure 13.13a Origins of replication in E. coli and eukaryotes (part 1: E. coli)
0.5 m 17

18. Origin of replication Replication fork
Figure 13.13b
(b) Origins of replication in a eukaryotic cell
Origin of
replication
Double-stranded
DNA molecule
Daughter (new)
strand
Parental (template)
strand
Replication fork
Bubble
Figure 13.13b Origins of replication in E. coli and eukaryotes (part 2: eukaryotes)
0.25 m
Two daughter DNA molecules 18

19. Single-strand binding proteins
Figure 13.12
Primase
Topoisomerase 3
RNA
primer 5 3 5
Replication
fork 3
Helicase
Figure Some of the proteins involved in the initiation of DNA replication 5
Single-strand binding
proteins 19

20. Overall directions of replication
Figure 13.15a
Overview
Leading
strand
Origin of replication
Lagging
strand
Primer
Leading
strand
Lagging strand
Overall
directions
of replication
Figure 13.15a Synthesis of the leading strand during DNA replication (part 1) 20

21. Figure 13.15 Synthesis of the leading strand during DNA replication21

22. Figure 13.17
Figure A summary of bacterial DNA replication 22

23. The DNA Replication Complex
Animation: DNA Replication Overview 23

24. Replicating the Ends of DNA Molecules
Animation: DNA Packing 24

25. Replicated chromosome (1,400 nm)
Figure 13.21
Chromatid
(700 nm)
Nucleosome
(10 nm in diameter)
DNA
double helix
(2 nm in diameter)
30-nm
fiber
Loops
Scaffold H1
300-nm
fiber
Histone tail
Histones
Figure Exploring chromatin packing in a eukaryotic chromosome
Replicated chromosome
(1,400 nm) 25

26. Cell containing Bacterium gene of interest Gene inserted into plasmid
Figure 13.22a
Cell containing
gene of interest
Bacterium 1
Gene inserted
into plasmid
Bacterial
chromosome
Plasmid
DNA of
chromosome
(“foreign” DNA)
Recombinant
DNA (plasmid)
Gene of interest 2
Plasmid put into
bacterial cell
Recombinant
bacterium
Figure 13.22a An overview of gene cloning and some uses of cloned genes (part 1: steps) 3
Host cell grown in culture to
form a clone of cells containing
the “cloned” gene of interest
Gene of
interest
Protein expressed
from gene of interest 26

27. Gene for pest resistance inserted into plants Human growth hormone
Figure 13.22b
Gene of
interest
Protein expressed
from gene of interest
Copies of gene
Protein harvested 4
Basic
research
and various
applications
Gene for pest resistance
inserted into plants
Human growth hormone
treats stunted growth
Figure 13.22b An overview of gene cloning and some uses of cloned genes (part 2: applications)
Gene used to alter bacteria
for cleaning up toxic waste
Protein dissolves blood clots
in heart attack therapy 27

28. Animation: Restriction Enzymes28

29. Restriction enzyme cuts the sugar-phosphate backbones.
Figure
Restriction site 5 3
DNA G A A T T C C T T A A G 3 5 1
Restriction enzyme cuts
the sugar-phosphate
backbones. 3 5 5 3 G A A T T C C T T A A G 5 3 3 5
Sticky end 5 2
DNA fragment added
from another molecule
cut by same enzyme.
Base pairing occurs. A A T 3 T C G 3 5
Figure Using a restriction enzyme and DNA ligase to make recombinant DNA (step 3) 5 3 5 3 5 3 G A A T T C G A A T T C C T T A A G C T T A A G 3 5 3 5 3 5 3
DNA ligase
seals the strands.
One possible combination 5 3 3
Recombinant DNA molecule 5 29

30. (a) Negatively charged DNA molecules will move
Figure 13.24
Mixture of
DNA mol-
ecules of
different
sizes
Power
source
Cathode
Anode
Wells
Gel
(a) Negatively charged DNA molecules will move
toward the positive electrode.
Figure Gel electrophoresis
Restriction fragments
(b) Shorter molecules are impeded less than
longer ones, so they move faster through the gel. 30

31. Sugar– Nitrogenous bases phosphate backbone 5 end Thymine (T)
Figure 13.5
Sugar–
phosphate
backbone
Nitrogenous bases
5 end
Thymine (T)
Adenine (A)
Cytosine (C)
Figure 13.5 The structure of a DNA strand
Guanine (G)
3 end
DNA
nucleotide 31