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General Biology 1004 Chapter 10 Lecture Handout, Summer 2005Dr. Frisby
Slide 1
Copyright ©2004 Pearson Education , Inc. publishing as Benjamin Cummings
PowerPoint® Lecture Slides forEssential Biology, Second Edition & Essential Biology with Physiology
Neil Campbell, Jane Reece, and Eric Simon
Presentation prepared by Chris C. Romero
CHAPTER 10CHAPTER 10Molecular Biology of the Gene
Slide 2
Copyright ©2004 Pearson Education , Inc. publishing as Benjamin Cummings
• AIDS is one of the most challenging health problems facing the world today
BIOLOGY AND SOCIETY:SABOTAGING HIV
– Infection by HIV can cause AIDS
Slide 3
Copyright ©2004 Pearson Education , Inc. publishing as Benjamin Cummings
• The drug AZT is effective at preventing the spread of HIV
Figure 10.1
Thymine(T)
AZT Part of a T nucleotide
General Biology 1004 Chapter 10 Lecture Handout, Summer 2005Dr. Frisby
Slide 4
Copyright ©2004 Pearson Education , Inc. publishing as Benjamin Cummings
• DNA
THE STRUCTURE AND REPLICATION OF DNA
Slide 5
Copyright ©2004 Pearson Education , Inc. publishing as Benjamin Cummings
• DNA and RNA are nucleic acids
DNA and RNA: Polymers of Nucleotides
Slide 6
Copyright ©2004 Pearson Education , Inc. publishing as Benjamin Cummings
Figure 10.2
Phosphate group Nitrogenous base
Sugar
Nucleotide
Polynucleotide Sugar-phosphate backbone
Nitrogenous base(A,G,C, or T)
Thymine (T)
Phosphategroup
Sugar(deoxyribose)
DNA nucleotide
General Biology 1004 Chapter 10 Lecture Handout, Summer 2005Dr. Frisby
Slide 7
Copyright ©2004 Pearson Education , Inc. publishing as Benjamin Cummings
• The four nucleotides found in DNA
• RNA has uracil (U) in place of thymine
Slide 8
Copyright ©2004 Pearson Education , Inc. publishing as Benjamin Cummings
• James Watson and Francis Crick determined that DNA is a double helix
Watson and Crick’s Discovery of the Double Helix
Figure 10.3a(a) James Watson and Francis Crick
Slide 9
Copyright ©2004 Pearson Education , Inc. publishing as Benjamin Cummings
• Watson and Crick used X-ray crystallography data to reveal the basic shape of DNA
Figure 10.3b
(b) Rosalind Franklin
General Biology 1004 Chapter 10 Lecture Handout, Summer 2005Dr. Frisby
Slide 10
Copyright ©2004 Pearson Education , Inc. publishing as Benjamin Cummings
• The model of DNA is like a rope ladder twisted into a spiral
Figure 10.4Twist
Slide 11
Copyright ©2004 Pearson Education , Inc. publishing as Benjamin Cummings
• Detailed representations of DNA
– Notice that the bases pair in a complementary fashion
Figure 10.5
Hydrogen bond
(a) (b) (c)
Slide 12
Copyright ©2004 Pearson Education , Inc. publishing as Benjamin Cummings
• When a cell or organism reproduces, a complete set of genetic instructions must pass from one generation to the next
DNA Replication
General Biology 1004 Chapter 10 Lecture Handout, Summer 2005Dr. Frisby
Slide 13
Copyright ©2004 Pearson Education , Inc. publishing as Benjamin Cummings
• Watson and Crick’s model for DNA suggested that DNA replicated by a template mechanism
Figure 10.6
Parental (old)DNA molecule
Daughter(new) strand
DaughterDNA molecule(double helices)
Slide 14
Copyright ©2004 Pearson Education , Inc. publishing as Benjamin Cummings
• DNA can be damaged by ultraviolet light
Figure 10.7
Slide 15
Copyright ©2004 Pearson Education , Inc. publishing as Benjamin Cummings
• DNA replication
Figure 10.8
Origin ofreplication
Origin ofreplication
Origin ofreplication Parental strand
Daughter strand
Bubble
Two daughter DNA molecules
General Biology 1004 Chapter 10 Lecture Handout, Summer 2005Dr. Frisby
Slide 16
Copyright ©2004 Pearson Education , Inc. publishing as Benjamin Cummings
• DNA functions as the inherited directions for a cell or organism
THE FLOW OF GENETIC INFORMATION FROM DNA TO RNA TO PROTEIN
Slide 17
Copyright ©2004 Pearson Education , Inc. publishing as Benjamin Cummings
• An organism’s genotype, its genetic makeup is the sequence of nucleotide bases in DNA
How an Organism’s DNA Genotype Produces Its Phenotype
Slide 18
Copyright ©2004 Pearson Education , Inc. publishing as Benjamin Cummings
• DNA specifies the synthesis of proteins in two stages
– Transcription
– Translation
Figure 10.9
DNANucleus
Transcription
RNA
Translation
ProteinCytoplasm
General Biology 1004 Chapter 10 Lecture Handout, Summer 2005Dr. Frisby
Slide 19
Copyright ©2004 Pearson Education , Inc. publishing as Benjamin Cummings
• The one gene–one protein hypothesis states that the function of an individual gene is to dictate the production of a specific protein
• Archibald Garrod 1909
• Beadle and Tatum 1940s
Slide 20
Copyright ©2004 Pearson Education , Inc. publishing as Benjamin Cummings
• The information, or “language,” in DNA is ultimately translated into the language of polypeptides
From Nucleotide Sequence to Amino Acid Sequence: An Overview
Slide 21
Copyright ©2004 Pearson Education , Inc. publishing as Benjamin Cummings
• What is the language of nucleic acids?
Figure 10.10
DNA molecule
Translation
Polypeptide
Gene 1
Gene 2
Gene 3
DNA strand
Transcription
RNA
Codon
Amino acid
General Biology 1004 Chapter 10 Lecture Handout, Summer 2005Dr. Frisby
Slide 22
Copyright ©2004 Pearson Education , Inc. publishing as Benjamin Cummings
• When DNA is transcribed, the result is an RNA molecule
• RNA is then translated into a sequence of amino acids in a polypeptide
Slide 23
Copyright ©2004 Pearson Education , Inc. publishing as Benjamin Cummings
• What is the correspondence between the nucleotides of an RNA molecule and the amino acids of a polypeptide?
Slide 24
Copyright ©2004 Pearson Education , Inc. publishing as Benjamin Cummings
• Triplets of bases
General Biology 1004 Chapter 10 Lecture Handout, Summer 2005Dr. Frisby
Slide 25
Copyright ©2004 Pearson Education , Inc. publishing as Benjamin Cummings
• The genetic code is the set of rules relating nucleotide sequence to amino acid sequence
The Genetic Code
Figure 10.11
Slide 26
Copyright ©2004 Pearson Education , Inc. publishing as Benjamin Cummings
• The genetic code is shared by all organisms
Figure 10.12
Slide 27
Copyright ©2004 Pearson Education , Inc. publishing as Benjamin Cummings
Transcription: From DNA to RNA
• In transcription
General Biology 1004 Chapter 10 Lecture Handout, Summer 2005Dr. Frisby
Slide 28
Copyright ©2004 Pearson Education , Inc. publishing as Benjamin Cummings
Figure 10.13a
RNApolymerase
RNA nucleotides
Newly madeRNA Direction of
transcription Templatestrand of DNA
(a) A close-up view of transcription
Slide 29
Copyright ©2004 Pearson Education , Inc. publishing as Benjamin Cummings
• Transcription of an entire gene
Figure 10.13b
RNA polymerase
DNA of gene
PromoterDNA Initiation Terminator
DNA
RNAElongation
Area shownin part (a)
TerminationGrowingRNA
Completed RNA
RNApolymerase(b) Transcription of a gene
Slide 30
Copyright ©2004 Pearson Education , Inc. publishing as Benjamin Cummings
• The “start transcribing” signal is a nucleotide sequence called a promoter
Initiation of Transcription
• The first phase of transcription is initiation
General Biology 1004 Chapter 10 Lecture Handout, Summer 2005Dr. Frisby
Slide 31
Copyright ©2004 Pearson Education , Inc. publishing as Benjamin Cummings
• The second phase of transcription is elongation
RNA Elongation
Slide 32
Copyright ©2004 Pearson Education , Inc. publishing as Benjamin Cummings
• The third phase of transcription is termination
Termination of Transcription
Slide 33
Copyright ©2004 Pearson Education , Inc. publishing as Benjamin Cummings
• The eukaryotic cell processes the RNA after transcription
The Processing of Eukaryotic RNA
General Biology 1004 Chapter 10 Lecture Handout, Summer 2005Dr. Frisby
Slide 34
Copyright ©2004 Pearson Education , Inc. publishing as Benjamin Cummings
• RNA processing includes
Figure 10.14
DNA
RNAtranscriptwith capand tail
mRNA
Exon Intron ExonIntron Exon
Cap
Intronsremoved Tail
Exons spliced together
Coding sequence
Nucleus
Cytoplasm
TranscriptionAddition of cap and tail
Slide 35
Copyright ©2004 Pearson Education , Inc. publishing as Benjamin Cummings
• Translation
Translation: The Players
Slide 36
Copyright ©2004 Pearson Education , Inc. publishing as Benjamin Cummings
• mRNA
Messenger RNA (mRNA)
General Biology 1004 Chapter 10 Lecture Handout, Summer 2005Dr. Frisby
Slide 37
Copyright ©2004 Pearson Education , Inc. publishing as Benjamin Cummings
• tRNA
Transfer RNA (tRNA)
Figure 10.15
Amino acid attachment site
Hydrogen bond
RNA polynucleotide chain
AnticodonAnticodon
Slide 38
Copyright ©2004 Pearson Education , Inc. publishing as Benjamin Cummings
• Ribosomes
Ribosomes
Figure 10.16a
tRNAbinding sites
P site A site
P A
Largesubunit
mRNAbindingsite
Smallsubunit
(a)
Slide 39
Copyright ©2004 Pearson Education , Inc. publishing as Benjamin Cummings
• A fully assembled ribosome holds tRNA and mRNA for use in translation
Figure 10.16b
Next amino acidto be added topolypeptide
Growingpolypeptide
mRNA
tRNA
(b)
General Biology 1004 Chapter 10 Lecture Handout, Summer 2005Dr. Frisby
Slide 40
Copyright ©2004 Pearson Education , Inc. publishing as Benjamin Cummings
• Translation is divided into three phases
Translation: The Process
Slide 41
Copyright ©2004 Pearson Education , Inc. publishing as Benjamin Cummings
• The first phase brings together
Initiation
Slide 42
Copyright ©2004 Pearson Education , Inc. publishing as Benjamin Cummings
• An mRNA molecule has a cap and tail that help it bind to the ribosome
Figure 10.17
Start of genetic message
Cap End
Tail
General Biology 1004 Chapter 10 Lecture Handout, Summer 2005Dr. Frisby
Slide 43
Copyright ©2004 Pearson Education , Inc. publishing as Benjamin Cummings
• The process of initiation
Figure 10.18.1
MetInitiator tRNA
mRNA
Large ribosomalsubunit
Start codon
Small ribosomalsubunit
Initiation P siteA site
1
2
Slide 44
Copyright ©2004 Pearson Education , Inc. publishing as Benjamin Cummings
• Step 1, codon recognition
Elongation
Slide 45
Copyright ©2004 Pearson Education , Inc. publishing as Benjamin Cummings
• Step 2, peptide bond formation
General Biology 1004 Chapter 10 Lecture Handout, Summer 2005Dr. Frisby
Slide 46
Copyright ©2004 Pearson Education , Inc. publishing as Benjamin Cummings
• Step 3, translocation
Slide 47
Copyright ©2004 Pearson Education , Inc. publishing as Benjamin Cummings
Polypeptide
Amino acid
P site
AnticodonmRNA A site
Codons
Elongation
2
3 Translocation
Codonrecognition
Peptide bond formation
• The process of elongation
Figure 10.19
mRNAmovement
New peptidebond
1
Slide 48
Copyright ©2004 Pearson Education , Inc. publishing as Benjamin Cummings
• Elongation continues until the ribosome reaches a stop codon
Termination
General Biology 1004 Chapter 10 Lecture Handout, Summer 2005Dr. Frisby
Slide 49
Copyright ©2004 Pearson Education , Inc. publishing as Benjamin Cummings
• The flow of genetic information in a cell
Review: DNA RNA Protein
Slide 50
Copyright ©2004 Pearson Education , Inc. publishing as Benjamin Cummings
Figure 10.20
1
2
3
4
Am ino acid attachment
5 Elongation
Init iation of translation
6 Termination
Transcription
RNA processing
RNA Polymerase
Nucleus
DNA
RNAtranscript
Intron
Tail
Intron
mRNA
CAP
tRNA
Enzyme
Amino acid
Ribosomal subunits
AnticodonCodon
Stop codon
Slide 51
Copyright ©2004 Pearson Education , Inc. publishing as Benjamin Cummings
• In eukaryotic cells
General Biology 1004 Chapter 10 Lecture Handout, Summer 2005Dr. Frisby
Slide 52
Copyright ©2004 Pearson Education , Inc. publishing as Benjamin Cummings
• Transcription and translation
Slide 53
Copyright ©2004 Pearson Education , Inc. publishing as Benjamin Cummings
• A mutation
Mutations
Figure 10.21
Normal hemoglobin Sickle-cell hemoglobinGlu Val
Normal hemoglobin DNA Mutant hemoglobin DNA
mRNA mRNA
Slide 54
Copyright ©2004 Pearson Education , Inc. publishing as Benjamin Cummings
• Mutations within a gene
Types of Mutations
Figure 10.22a
mRNA
Protein Met Lys Phe Gly Ala
(a) Base substitution
Met Lys Phe Ser Ala
General Biology 1004 Chapter 10 Lecture Handout, Summer 2005Dr. Frisby
Slide 55
Copyright ©2004 Pearson Education , Inc. publishing as Benjamin Cummings
• Insertions and deletions
Figure 10.22b
Met Lys Leu Ala His
(b) Nucleotide deletion
mRNA
Protein Met Lys Phe Gly Ala
Slide 56
Copyright ©2004 Pearson Education , Inc. publishing as Benjamin Cummings
• Mutations may result from
Mutagens
Slide 57
Copyright ©2004 Pearson Education , Inc. publishing as Benjamin Cummings
• Although mutations are often harmful
Figure 10.23
General Biology 1004 Chapter 10 Lecture Handout, Summer 2005Dr. Frisby
Slide 58
Copyright ©2004 Pearson Education , Inc. publishing as Benjamin Cummings
• Viruses sit on the fence between life and nonlife
VIRUSES: GENES IN PACKAGES
Figure 10.24
Slide 59
Copyright ©2004 Pearson Education , Inc. publishing as Benjamin Cummings
• Bacteriophages, or phages
Bacteriophages
Figure 10.25
Head
Tail
Tail fiber
DNA of virus
Bacterialcell
Slide 60
Copyright ©2004 Pearson Education , Inc. publishing as Benjamin Cummings
• Phages may have two reproductive cycles
Figure 10.26
Phage DNA
1
2
3
4
Phage DNA circularizes
New phage DNA andproteins are sythesized
5 Phage DNA inserts into the bacterialchromosome by recombination
Cell lyses,releasing phages
6 Lysogenic bacteriumreproduces normally,replicating the prophageat each cell division
7 Occasionally a prophagemay leave the bacterialchromosome
Bacterial chromosome (DNA)
Lytic cycle Lysogenic cycle
Prophage
Many cell divisions
General Biology 1004 Chapter 10 Lecture Handout, Summer 2005Dr. Frisby
Slide 61
Copyright ©2004 Pearson Education , Inc. publishing as Benjamin Cummings
• Viruses that infect plants
Plant Viruses
Figure 10.27
Protein RNA
Slide 62
Copyright ©2004 Pearson Education , Inc. publishing as Benjamin Cummings
• Genetic engineering methods
Slide 63
Copyright ©2004 Pearson Education , Inc. publishing as Benjamin Cummings
• Virus studies help establish molecular genetics
Animal Viruses
• Molecular genetics helps us understand viruses
Figure 10.28
Membranousenvelope
RNA
Proteincoat
Proteinspike
General Biology 1004 Chapter 10 Lecture Handout, Summer 2005Dr. Frisby
Slide 64
Copyright ©2004 Pearson Education , Inc. publishing as Benjamin Cummings
• The reproductive cycle of an enveloped virus
Slide 65
Copyright ©2004 Pearson Education , Inc. publishing as Benjamin Cummings
Figure 10.29
VIRUS
Entry1
2
3
4
Uncoating
RNA synthesisby viral enzyme
5 RNA synthesis(other strand)
Proteinsynthesis
6 Assembly
7
Exit
Viral RNA (genome)
Protein spike
Protein coatEnvelope
Plasma membrane of host cell
mRNA
New viral proteins
Template
New viral genome
Slide 66
Copyright ©2004 Pearson Education , Inc. publishing as Benjamin Cummings
• HIV is a retrovirus
HIV, the AIDS Virus
Figure 10.30a
EnvelopeProtein
Protein coat
RNA(two identical
strands)
Reversetranscriptase
(a) HIV
General Biology 1004 Chapter 10 Lecture Handout, Summer 2005Dr. Frisby
Slide 67
Copyright ©2004 Pearson Education , Inc. publishing as Benjamin Cummings
1
23
4
5
6
DNA strand
Viral RNA Reverse transcriptase
Cytoplasm
Double-stranded DNA
Chromosomal DNA
Provirus DNA
Viral RNA and proteins
Nucleus
(b) The behavior of HIV nucleic acid in an infected cell
• How HIV reproduces inside a cell
Figure 10.30b
Slide 68
Copyright ©2004 Pearson Education , Inc. publishing as Benjamin Cummings
• AIDS is
Figure 10.30c
(c) HIV infecting a white blood cell
Slide 69
Copyright ©2004 Pearson Education , Inc. publishing as Benjamin Cummings
• Many new viruses have emerged in recent years
EVOLUTION CONNECTION:EMERGING VIRUSES
Figure 10.31
(a) Ebola virus
(b) Hantavirus
General Biology 1004 Chapter 10 Lecture Handout, Summer 2005Dr. Frisby
Slide 70
Copyright ©2004 Pearson Education , Inc. publishing as Benjamin Cummings
• How do new viruses arise?
Figure 10.32
Chapter 10 Study Objectives
1. Describe the cause of AIDS. Explain how AZT prevents the spread of the disease.2. Explain what was and was not known about DNA by the early 1950s.3. Describe and compare the chemical compositions of DNA and RNA.4. Describe the key features of the overall shape of a DNA molecule. Explain how Watson
and Crick determined these features of DNA structure.5. Describe the process of DNA replication.6. Define transcription and translation. Explain why the hypothesis “one gene-one enzyme”
is not completely correct.7. Explain how the language of DNA directs the production of polypeptides.8. Explain how codons are used to construct polypeptides.9. Describe the steps transcription and the processing of RNA before it leaves the nucleus.10. Compare the structures and functions of mRNA, tRNA, and rRNA.11. Describe in detail the step-by-step process of translation.12. Distinguish between insertion, deletion, and substitution mutations. Explain how
mutations can be harmful or beneficial to organisms.13. Compare the lytic an lysogenic cycles of bacteriophages.14. Compare the life cycles of RNA and DNA viruses. Describe the spread, symptoms, and
treatment of viral diseases in plants and animals.15. Describe the reproductive cycle of retroviruses such as HIV.16. Explain how viruses might have first evolved and how new viral diseases evolve.