1. DNA Replication
When a cell or organism reproduces, a complete set of genetic instructions must pass from one generation to the next

2. Watson and Crick’s model for DNA suggested that DNA replicated by a template mechanism
Parental (old)
DNA molecule
Daughter
(new) strand
Daughter
DNA molecule
(double helices)
Figure 10.6

3. THE FLOW OF GENETIC INFORMATION FROM DNA TO RNA TO PROTEIN
DNA functions as the inherited directions for a cell or organism
How are these directions carried out?

4. How an Organism’s DNA Genotype Produces Its Phenotype
An organism’s genotype, its genetic makeup is the sequence of nucleotide bases in DNA
The phenotype is the organism’s specific traits

5. What is the language of nucleic acids?
DNA molecule
Gene 1
Gene 2
In DNA, it is the linear sequence of nucleotide bases
Gene 3
DNA strand
Transcription
RNA
Translation
Codon
Polypeptide
Amino acid
Figure 10.10

6. DNA specifies the synthesis of proteins in two stages
Nucleus
DNA
Transcription
RNA
Transcription
Translation
Translation
Protein
Cytoplasm
Figure 10.9

7. When DNA is transcribed, the result is an RNA molecule
RNA is then translated into a sequence of amino acids in a polypeptide

8. Transcription: From DNA to RNA
In transcription
Genetic information is transferred from DNA to RNA
An RNA molecule is transcribed from a DNA template

9. (a) A close-up view of transcription
RNA nucleotides
RNA
polymerase
Newly made
RNA
Direction of
transcription
Template
strand of DNA
(a) A close-up view of transcription
Figure 10.13a

10. Transcription of an entire gene
RNA polymerase
DNA of gene
Promoter
DNA
Terminator
DNA
Initiation
RNA
Area shown
in part (a)
Elongation
Termination
Growing
RNA
Completed RNA
RNA
polymerase
(b) Transcription of a gene
Figure 10.13b

11. RNA processing includes
Intron
Exon
Exon
Intron
Exon
DNA
Transcription
Addition of cap and tail
Cap
Adding a cap and tail
Removing introns
Splicing exons together
RNA
transcript
with cap
and tail
Introns removed
Tail
Exons spliced together
mRNA
Coding sequence
Nucleus
Cytoplasm
Figure 10.14

12. Transcription and translation
Are the processes whereby genes control the structures and activities of cells

13. Triplets of bases
Specify all the amino acids
Are called codons

14. The Genetic Code
The genetic code is the set of rules relating nucleotide sequence to amino acid sequence
Figure 10.11

15. The genetic code is shared by all organisms
Figure 10.12

16. Translation: The Players
Is the conversion from the nucleic acid language to the protein language

17. Messenger RNA (mRNA)
mRNA
Is the first ingredient for translation

18. An mRNA molecule has a cap and tail that help it bind to the ribosome
Start of genetic message
End
Cap
Tail
Figure 10.17

19. Transfer RNA (tRNA) tRNA Acts as a molecular interpreter
Carries amino acids
Matches amino acids with codons in mRNA using anticodons
Amino acid attachment site
Hydrogen bond
RNA polynucleotide chain
Anticodon
Anticodon
Figure 10.15

20. A fully assembled ribosome holds tRNA and mRNA for use in translation
Next amino acid
to be added to
polypeptide
Growing
polypeptide
tRNA
mRNA
(b)
Figure 10.16b

21. The process of elongation
Amino acid
Polypeptide
P site
Anticodon
mRNA
A site
Codons 1
Codon recognition
Elongation 2
Peptide bond formation
New peptide
bond
mRNA
movement 3
Translocation
Figure 10.19

22. Sickle-cell hemoglobin
Mutations
A mutation
Is any change in the nucleotide sequence of DNA
Normal hemoglobin DNA
Mutant hemoglobin DNA
mRNA
mRNA
Normal hemoglobin
Sickle-cell hemoglobin
Glu
Val
Figure 10.21

23. Mutations may result from
Mutagens
Mutations may result from
Errors in DNA replication
Physical or chemical agents called mutagens

24. DNA can be damaged by ultraviolet light
The enzymes and proteins involved in replication can repair the damage
Figure 10.7

25. Although mutations are often harmful
They are the source of the rich diversity of genes in the living world
They contribute to the process of evolution by natural selection
Figure 10.23

26. VIRUSES: GENES IN PACKAGES
Viruses sit on the fence between life and nonlife
They exhibit some but not all characteristics of living organisms
Figure 10.24

27. Bacteriophages, or phages
Attack bacteria
Head
Tail
Tail fiber
DNA of virus
Bacterial
cell
Figure 10.25

28. Viruses that infect plants
Plant Viruses
Viruses that infect plants
Can stunt growth and diminish plant yields
Can spread throughout the entire plant
Protein
RNA
Figure 10.27

29. VIRUS
Protein spike
Viral RNA (genome)
Protein coat
Envelope 1
Plasma membrane of host cell
Entry 2
Uncoating
RNA synthesis
by viral enzyme 3 4
Protein
synthesis 5
RNA synthesis
(other strand)
mRNA
Template
New viral genome 6
Assembly
New viral proteins
Exit 7
Figure 10.29

38. Signaling between biomolecules

39. Gene therapy