1. Mixture of heat-killed S cells and living R cells
Figure 16.2
EXPERIMENT
Mixture of heat-killed S cells and living R cells
Heat-killed S cells (control)
Living S cells (control)
Living R cells (control)
RESULTS
Figure 16.2 INQUIRY: Can a genetic trait be transferred between different bacterial strains?
Griffith (1928)
Mouse dies
Mouse healthy
Mouse healthy
Mouse dies
Living S cells

2. Phage head Tail sheath Tail fiber DNA 100 nm Bacterial cell
Figure 16.3
Phage head
Tail sheath
Tail fiber
Figure 16.3 Viruses infecting a bacterial cell.
Hershey and Chase (1952)
DNA
100 nm
Bacterial cell

3. Radioactivity (phage protein) in liquid Phage
Figure
EXPERIMENT
Empty protein shell
Radioactive protein
Radioactivity (phage protein) in liquid
Phage
Bacterial cell
Batch 1: Radioactive sulfur (35S)
DNA
Phage DNA
Centrifuge
Radioactive DNA
Pellet (bacterial cells and contents)
Figure 16.4 INQUIRY: Is protein or DNA the genetic material of phage T2?
Batch 2: Radioactive phosphorus (32P)
Centrifuge
Radioactivity (phage DNA) in pellet
Pellet

4. Sugar–phosphate backbone
Figure 16.5
Sugar–phosphate backbone
Nitrogenous bases
5 end
Thymine (T)
Adenine (A)
Cytosine (C)
Figure 16.5 The structure of a DNA strand.
Phosphate
Guanine (G)
Sugar (deoxyribose)
DNA nucleotide
Nitrogenous base
3 end

5. Franklin’s X-ray diffraction photograph of DNA
Figure 16.6
Figure 16.6 Rosalind Franklin and her X-ray diffraction photo of DNA.
(a) Rosalind Franklin
(b)
Franklin’s X-ray diffraction photograph of DNA

6. Figure 16.1
Figure 16.1 How was the structure of DNA determined?
Watson and Crick (Wilkins and Franklin) (1953)

7. 5 end 3 end 3 end 5 end Hydrogen bond 3.4 nm 1 nm 0.34 nm (a)
Figure 16.7
5 end C G
Hydrogen bond C G
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 16.7 The double helix. A T
3 end A T
0.34 nm
5 end T A
(a)
Key features of DNA structure
(b) Partial chemical structure
Space-filling model
(c)

8. Purine  purine: too wide
Figure 16.UN01
Purine  purine: too wide
Pyrimidine  pyrimidine: too narrow
Figure 16.UN01 In-text figure, p. 310
Purine  pyrimidine: width consistent with X-ray data

9. Sugar Sugar Adenine (A) Thymine (T) Sugar Sugar Guanine (G)
Figure 16.8
Sugar
Sugar
Adenine (A)
Thymine (T)
Figure 16.8 Base pairing in DNA.
Sugar
Sugar
Guanine (G)
Cytosine (C)

10. (a) Parent molecule A T C G T A A T G C Figure 16.9-1
Figure 16.9 A model for DNA replication: the basic concept.

11. (a) Parent molecule (b) Separation of strands A T A T C G C G T A T A
Figure A T A T C G C G T A T A A T A T G C G C
(a) Parent molecule
(b)
Separation of strands
Figure 16.9 A model for DNA replication: the basic concept.

12. (a) Parent molecule (b) Separation of strands (c)
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) Parent molecule
(b)
Separation of strands
(c)
“Daughter” DNA molecules, each consisting of one parental strand and one new strand
Figure 16.9 A model for DNA replication: the basic concept.

13. Parent cell First replication Second replication
Figure 16.10
Parent cell
First replication
Second replication
(a)
Conservative model
(b)
Semiconservative model
Figure Three alternative models of DNA replication.
(c) Dispersive model

14. Bacteria cultured in medium with 15N (heavy isotope)
Figure 16.11a
EXPERIMENT 1 2
Bacteria cultured in medium with 15N (heavy isotope)
Bacteria transferred to medium with 14N (lighter isotope)
RESULTS 3
Less dense
DNA sample centrifuged after first replication 4
DNA sample centrifuged after second replication
Figure INQUIRY: Does DNA replication follow the conservative, semiconservative, or dispersive model?
More dense

15. Semiconservative model
Figure 16.11b
CONCLUSION
Predictions:
First replication
Second replication
Conservative model
Semiconservative model
Figure INQUIRY: Does DNA replication follow the conservative, semiconservative, or dispersive model?
Dispersive model

16. (a) Origin of replication in an E. coli cell
Figure 16.12a
(a) Origin of replication in an E. coli cell
Origin of replication
Parental (template) strand
Daughter (new) strand
Double- stranded DNA molecule
Replication fork
Replication bubble
Two daughter DNA molecules
Figure Origins of replication in E. coli and eukaryotes.
0.5 m

17. (b) Origins of replication in a eukaryotic cell
Figure 16.12b
(b) Origins of replication in a eukaryotic cell
Double-stranded DNA molecule
Origin of replication
Parental (template) strand
Daughter (new) strand
Bubble
Replication fork
Figure Origins of replication in E. coli and eukaryotes.
Two daughter DNA molecules
0.25 m

18. Single-strand binding proteins
Figure 16.13
Primase 3
Topoisomerase
RNA primer 5 3 5 3
Helicase
Figure Some of the proteins involved in the initiation of DNA replication. 5
Single-strand binding proteins

19. Nucleoside triphosphate
Figure 16.14
New strand
Template strand 5 3 5 3
Sugar A T A T
Base
Phosphate C G C G G C G C
DNA polymerase OH 3 A T A
Figure Incorporation of a nucleotide into a DNA strand. T P OH P
P i P P C 3
Pyrophosphate C OH
Nucleoside triphosphate
2 P i 5 5

20. Overall directions of replication
Figure 16.15
Overview
Leading strand
Lagging strand
Origin of replication
Primer
Leading strand
Lagging strand
Origin of replication
Overall directions of replication 3 5 5
RNA primer 3 3
Sliding clamp
DNA pol III
Parental DNA 5
Figure Synthesis of the leading strand during DNA replication. 3 5 5 3 3 5

21. Overall directions of replication
Figure 16.16 3
Overview 5
Template strand 3
Leading strand
Origin of replication
Lagging strand
RNA primer for fragment 1 5 3
Lagging strand 2 1 5
Leading strand 1 3
Overall directions of replication 5 3
Okazaki fragment 1 5 1
RNA primer for fragment 2 3 5 5
Okazaki fragment 2 3 2 1 3 5 5
Figure Synthesis of the lagging strand. 3 2 1 3 5 5 3 2 1 3 5
Overall direction of replication

22. Overall directions of replication
Figure 16.16a
Overview
Leading strand
Origin of replication
Lagging strand
Lagging strand 2 1
Leading strand
Figure Synthesis of the lagging strand.
Overall directions of replication

23. 3 5 3 Template strand 5 Figure 16.16b-1
Figure Synthesis of the lagging strand.

24. RNA primer for fragment 1
Figure 16.16b-2 3 5
Template strand 3 5 3
RNA primer for fragment 1 5 1 3 5
Figure Synthesis of the lagging strand.

25. RNA primer for fragment 1
Figure 16.16b-3 3 5
Template strand 3 5 3
RNA primer for fragment 1 5 1 3 5 3
Okazaki fragment 1 5 1 3 5
Figure Synthesis of the lagging strand.

26. RNA primer for fragment 1
Figure 16.16b-4 3 5
Template strand 3 5 3
RNA primer for fragment 1 5 1 3 5 3
Okazaki fragment 1 5 1
RNA primer for fragment 2 3 5 5 3 2
Okazaki fragment 2 1 3 5
Figure Synthesis of the lagging strand.

27. RNA primer for fragment 1
Figure 16.16b-5 3 5
Template strand 3 5 3
RNA primer for fragment 1 5 1 3 5 3
Okazaki fragment 1 5 1
RNA primer for fragment 2 3 5 5 3 2
Okazaki fragment 2 1 3 5
Figure Synthesis of the lagging strand. 5 3 2 1 3 5 5 3

28. RNA primer for fragment 1
Figure 16.16b-6 3 5
Template strand 3 5 3
RNA primer for fragment 1 5 1 3 5 3
Okazaki fragment 1 5 1
RNA primer for fragment 2 3 5 5 3 2
Okazaki fragment 2 1 3 5
Figure Synthesis of the lagging strand. 5 3 2 1 3 5 5 3 2 1 3 5
Overall direction of replication

29. Overall directions of replication
Figure 16.17
Overview
Leading strand
Origin of replication
Lagging strand
Leading strand
Lagging strand
Overall directions of replication
Leading strand 5
DNA pol III 3
Primer
Primase 3 5 3
Parental DNA
Figure A summary of bacterial DNA replication.
DNA pol III
Lagging strand 5
DNA pol I
DNA ligase 4 3 5 3 2 1 3 5

30. Lagging strand template 3 5 DNA pol III Lagging strand 3 5
Figure 16.18
DNA pol III
Parental DNA
Leading strand 5 5 3 3 3 5 3 5
Connecting protein
Helicase
Lagging strand template 3 5
Figure A current model of the DNA replication complex.
DNA pol III
Lagging strand 3 5

31. 5 3 3 5 Nuclease 5 3 3 5 DNA polymerase 5 3 3 5 DNA ligase
Figure 16.19 5 3 3 5
Nuclease 5 3 3 5
DNA polymerase 5 3
Figure Nucleotide excision repair of DNA damage. 3 5
DNA ligase 5 3 3 5

32. Ends of parental DNA strands Lagging strand 3
Figure 16.20a 5
Leading strand
Ends of parental DNA strands
Lagging strand 3
Last fragment
Next-to-last fragment
RNA primer
Lagging strand 5 3
Parental strand
Figure Shortening of the ends of linear DNA molecules.
Removal of primers and replacement with DNA where a 3 end is available 5 3

33. Second round of replication
Figure 16.20b 5 3
Second round of replication 5
New leading strand 3
New lagging strand 5 3
Figure Shortening of the ends of linear DNA molecules.
TTAGGG repeats = telomeres (100 to 1000 tandem repeats)
Further rounds of replication
Shorter and shorter daughter molecules

34. Figure 16.21
Figure Telomeres.
1 m

35. Nucleosome (10 nm in diameter)
Figure 16.22a
Nucleosome (10 nm in diameter)
DNA double helix (2 nm in diameter) H1
Histone tail
Figure Exploring: Chromatin Packing in a Eukaryotic Chromosome
Histones
Nucleosomes, or “beads on a string” (10-nm fiber)
DNA, the double helix
Histones

36. Replicated chromosome (1,400 nm)
Figure 16.22b
Chromatid (700 nm)
30-nm fiber
Loops
Scaffold
300-nm fiber
30-nm fiber
Figure Exploring: Chromatin Packing in a Eukaryotic Chromosome
Replicated chromosome (1,400 nm)
Looped domains (300-nm fiber)
Metaphase chromosome

37. Figure 16.UN04
Figure 16.UN04 Test Your Understanding, question 10