1. Growing RNA 3 Termination Completed RNA RNA polymerase Figure 10.9B_3
Figure 10.9B_3 The transcription of a gene (part 3)
Completed RNA
RNA polymerase 1

2. 10.10 Eukaryotic RNA is processed before leaving the nucleus as mRNA
Messenger RNA (mRNA)
encodes amino acid sequences and
conveys genetic messages from DNA to the translation machinery of the cell, which in
prokaryotes, occurs in the same place that mRNA is made, but in
eukaryotes, mRNA must exit the nucleus via nuclear pores to enter the cytoplasm.
Eukaryotic mRNA has
introns, interrupting sequences that separate
exons, the coding regions.
Student Misconceptions and Concerns
Beginning college students are often intensely focused on writing detailed notes. The risk is that they will miss the overall patterns and the broader significance of the topics discussed. Consider a gradual approach to the subjects of transcription and translation, beginning quite generally and testing comprehension, before venturing into the finer mechanics of each process.
Teaching Tips
Many analogies can be developed to represent the selective expression of a gene requiring the deletion of introns. Instructors that only assign some modules of a chapter are treating the chapters like sections of exons and introns, portions to be read and portions to be skipped. Alternately, students who highlight a chapter might be thought of as editing the book into exons, portions to be reviewed, and introns, nonhighlighted sections that will not be studied. Both analogies are imperfect, but may still convey the concept of selective reading.
© 2012 Pearson Education, Inc. 2

3. 10.10 Eukaryotic RNA is processed before leaving the nucleus as mRNA
Eukaryotic mRNA undergoes processing before leaving the nucleus.
RNA splicing removes introns and joins exons to produce a continuous coding sequence.
A cap and tail of extra nucleotides are added to the ends of the mRNA to
facilitate the export of the mRNA from the nucleus,
protect the mRNA from attack by cellular enzymes, and
help ribosomes bind to the mRNA.
Student Misconceptions and Concerns
Beginning college students are often intensely focused on writing detailed notes. The risk is that they will miss the overall patterns and the broader significance of the topics discussed. Consider a gradual approach to the subjects of transcription and translation, beginning quite generally and testing comprehension, before venturing into the finer mechanics of each process.
Teaching Tips
Many analogies can be developed to represent the selective expression of a gene requiring the deletion of introns. Instructors that only assign some modules of a chapter are treating the chapters like sections of exons and introns, portions to be read and portions to be skipped. Alternately, students who highlight a chapter might be thought of as editing the book into exons, portions to be reviewed, and introns, nonhighlighted sections that will not be studied. Both analogies are imperfect, but may still convey the concept of selective reading.
© 2012 Pearson Education, Inc. 3

4. Transcription Addition of cap and tail Cap
Figure 10.10
Exon
Intron
Exon
Intron
Exon
DNA
Transcription Addition of cap and tail
Cap
RNA transcript with cap and tail
Introns removed
Tail
Exons spliced together
mRNA
Coding sequence
Figure The production of eukaryotic mRNA
NUCLEUS
CYTOPLASM 4

5. 10.11 Transfer RNA molecules serve as interpreters during translation
Transfer RNA (tRNA) molecules function as a language interpreter,
converting the genetic message of mRNA
into the language of proteins.
Transfer RNA molecules perform this interpreter task by
picking up the appropriate amino acid and
using a special triplet of bases, called an anticodon, to recognize the appropriate codons in the mRNA.
Student Misconceptions and Concerns
Beginning college students are often intensely focused on writing detailed notes. The risk is that they will miss the overall patterns and the broader significance of the topics discussed. Consider a gradual approach to the subjects of transcription and translation, beginning quite generally and testing comprehension, before venturing into the finer mechanics of each process.
Teaching Tips
The unique structure of tRNA, with binding sites for an amino acid and its codon, permits the translation of the genetic code. Like an interpreter who speaks two languages, the tRNA molecules match codons to the specified amino acid.
© 2012 Pearson Education, Inc. 5

6. Amino acid attachment site A simplified schematic of a tRNA
Figure 10.11A
Amino acid attachment site
Hydrogen bond
RNA polynucleotide chain
Figure 10.11A The structure of tRNA
Anticodon
A tRNA molecule, showing its polynucleotide strand and hydrogen bonding
A simplified schematic of a tRNA 6

7. Enzyme tRNA ATP Figure 10.11B
Figure 10.11B A molecule of tRNA binding to an enzyme molecule (blue) 7

8. 10.12 Ribosomes build polypeptides
Translation occurs on the surface of the ribosome.
Ribosomes coordinate the functioning of mRNA and tRNA and, ultimately, the synthesis of polypeptides.
Ribosomes have two subunits: small and large.
Each subunit is composed of ribosomal RNAs and proteins.
Ribosomal subunits come together during translation.
Ribosomes have binding sites for mRNA and tRNAs.
Student Misconceptions and Concerns
Beginning college students are often intensely focused on writing detailed notes. The risk is that they will miss the overall patterns and the broader significance of the topics discussed. Consider a gradual approach to the subjects of transcription and translation, beginning quite generally and testing comprehension, before venturing into the finer mechanics of each process.
Teaching Tips
1. Students might wonder why the details of transcription and translation are important. As the text notes, differences in the composition of prokaryotic and eukaryotic ribosomes form the basis of action for antibiotics. By identifying differences, we can develop drugs that target crucial features of prokaryotic pathogens without harming their eukaryotic hosts.
2. Ribosomal RNA is transcribed in the nucleolus of eukaryotic cells. The ribosomal subunits are assembled in the nucleus using proteins imported from the cytosol. These subunits are then exported to the cytosol, where they are only assembled into a functional ribosome when they attach to an mRNA molecule. Some of these details are not specifically noted in the text, but may be required to fill out your explanations.
3. If you use a train analogy for the assembly of monomers into polymers, the DNA and RNA trains are traded in on a three-for-one basis for the polypeptide train during translation. In general, this produces polypeptides that have about one-third as many monomers as the mRNA that coded for them.
© 2012 Pearson Education, Inc. 8

9. Growing polypeptide tRNA molecules Large subunit Small subunit mRNA
Figure 10.12A
Growing polypeptide
tRNA molecules
Large subunit
Small subunit
Figure 10.12A The true shape of a functioning ribosome
mRNA 9

10. tRNA binding sites Large subunit P site A site Small subunit
Figure 10.12B
tRNA binding sites
Large subunit
P site
A site
Small subunit
Figure 10.12B A ribosome with empty binding sites
mRNA binding site 10

11. The next amino acid to be added to the polypeptide Growing polypeptide
Figure 10.12C
The next amino acid to be added to the polypeptide
Growing polypeptide
mRNA
tRNA
Codons
Figure 10.12C A ribosome with occupied binding sites 11

12. 10.13 An initiation codon marks the start of an mRNA message
Translation can be divided into the same three phases as transcription:
initiation,
elongation, and
termination.
Initiation brings together
mRNA,
a tRNA bearing the first amino acid, and
the two subunits of a ribosome.
Student Misconceptions and Concerns
Beginning college students are often intensely focused on writing detailed notes. The risk is that they will miss the overall patterns and the broader significance of the topics discussed. Consider a gradual approach to the subjects of transcription and translation, beginning quite generally and testing comprehension, before venturing into the finer mechanics of each process.
Teaching Tips
1. Ribosomal RNA is transcribed in the nucleolus of eukaryotic cells. The ribosomal subunits are assembled in the nucleus using proteins imported from the cytosol. These subunits are then exported to the cytosol, where they are only assembled into a functional ribosome when they attach to an mRNA molecule. Some of these details are not specifically noted in the text, but may be required to fill out your explanations.
2. If you use a train analogy for the assembly of monomers into polymers, the DNA and RNA trains are traded in on a three-for-one basis for the polypeptide train during translation. In general, this produces polypeptides that have about one-third as many monomers as the mRNA that coded for them.
© 2012 Pearson Education, Inc. 12

13. 10.13 An initiation codon marks the start of an mRNA message
Initiation establishes where translation will begin.
Initiation occurs in two steps.
An mRNA molecule binds to a small ribosomal subunit and the first tRNA binds to mRNA at the start codon.
The start codon reads AUG and codes for methionine.
The first tRNA has the anticodon UAC.
A large ribosomal subunit joins the small subunit, allowing the ribosome to function.
The first tRNA occupies the P site, which will hold the growing peptide chain.
The A site is available to receive the next tRNA.
Student Misconceptions and Concerns
Beginning college students are often intensely focused on writing detailed notes. The risk is that they will miss the overall patterns and the broader significance of the topics discussed. Consider a gradual approach to the subjects of transcription and translation, beginning quite generally and testing comprehension, before venturing into the finer mechanics of each process.
Teaching Tips
1. Ribosomal RNA is transcribed in the nucleolus of eukaryotic cells. The ribosomal subunits are assembled in the nucleus using proteins imported from the cytosol. These subunits are then exported to the cytosol, where they are only assembled into a functional ribosome when they attach to an mRNA molecule. Some of these details are not specifically noted in the text, but may be required to fill out your explanations.
2. If you use a train analogy for the assembly of monomers into polymers, the DNA and RNA trains are traded in on a three-for-one basis for the polypeptide train during translation. In general, this produces polypeptides that have about one-third as many monomers as the mRNA that coded for them.
© 2012 Pearson Education, Inc. 13

14. Start of genetic message
Figure 10.13A
Start of genetic message
Cap
Figure 10.13A A molecule of eukaryotic mRNA
End
Tail 14

15. Large ribosomal subunit
Figure 10.13B
Met
Met
Initiator tRNA
Large ribosomal subunit
P site
A site
mRNA U A C U A C A U G A U G
Start codon
Figure 10.13B The initiation of translation
Small ribosomal subunit 1 2 15

16. 10.14 Elongation adds amino acids to the polypeptide chain until a stop codon terminates translation
Once initiation is complete, amino acids are added one by one to the first amino acid.
Elongation is the addition of amino acids to the polypeptide chain.
Student Misconceptions and Concerns
Beginning college students are often intensely focused on writing detailed notes. The risk is that they will miss the overall patterns and the broader significance of the topics discussed. Consider a gradual approach to the subjects of transcription and translation, beginning quite generally and testing comprehension, before venturing into the finer mechanics of each process.
Teaching Tips
1. Students might want to think of the A and P sites as stages in an assembly line. The A site is where a new amino acid is brought in, according to the blueprint of the codon on the mRNA. The P site is where the growing product/polypeptide is anchored as it is being built. To help students better remember details of translation, they might think of the letters for the two sites as meaning A for addition, where an amino acid is added, and P for polypeptide, where the growing polypeptide is located.
2. If you use a train analogy for the assembly of monomers into polymers, the DNA and RNA trains are traded in on a three-for-one basis for the polypeptide train during translation. In general, this produces polypeptides that have about one-third as many monomers as the mRNA that coded for them.
© 2012 Pearson Education, Inc. 16

17. 10.14 Elongation adds amino acids to the polypeptide chain until a stop codon terminates translation
Each cycle of elongation has three steps.
Codon recognition: The anticodon of an incoming tRNA molecule, carrying its amino acid, pairs with the mRNA codon in the A site of the ribosome.
Peptide bond formation: The new amino acid is joined to the chain.
Translocation: tRNA is released from the P site and the ribosome moves tRNA from the A site into the P site.
Student Misconceptions and Concerns
Beginning college students are often intensely focused on writing detailed notes. The risk is that they will miss the overall patterns and the broader significance of the topics discussed. Consider a gradual approach to the subjects of transcription and translation, beginning quite generally and testing comprehension, before venturing into the finer mechanics of each process.
Teaching Tips
1. Students might want to think of the A and P sites as stages in an assembly line. The A site is where a new amino acid is brought in, according to the blueprint of the codon on the mRNA. The P site is where the growing product/polypeptide is anchored as it is being built. To help students better remember details of translation, they might think of the letters for the two sites as meaning A for addition, where an amino acid is added, and P for polypeptide, where the growing polypeptide is located.
2. If you use a train analogy for the assembly of monomers into polymers, the DNA and RNA trains are traded in on a three-for-one basis for the polypeptide train during translation. In general, this produces polypeptides that have about one-third as many monomers as the mRNA that coded for them.
© 2012 Pearson Education, Inc. 17

18. Animation: Translation
10.14 Elongation adds amino acids to the polypeptide chain until a stop codon terminates translation
Elongation continues until the termination stage of translation, when
the ribosome reaches a stop codon,
the completed polypeptide is freed from the last tRNA, and
the ribosome splits back into its separate subunits.
Student Misconceptions and Concerns
Beginning college students are often intensely focused on writing detailed notes. The risk is that they will miss the overall patterns and the broader significance of the topics discussed. Consider a gradual approach to the subjects of transcription and translation, beginning quite generally and testing comprehension, before venturing into the finer mechanics of each process.
Teaching Tips
1. Students might want to think of the A and P sites as stages in an assembly line. The A site is where a new amino acid is brought in, according to the blueprint of the codon on the mRNA. The P site is where the growing product/polypeptide is anchored as it is being built. To help students better remember details of translation, they might think of the letters for the two sites as meaning A for addition, where an amino acid is added, and P for polypeptide, where the growing polypeptide is located.
2. If you use a train analogy for the assembly of monomers into polymers, the DNA and RNA trains are traded in on a three-for-one basis for the polypeptide train during translation. In general, this produces polypeptides that have about one-third as many monomers as the mRNA that coded for them.
Animation: Translation
© 2012 Pearson Education, Inc. 18

19. Polypeptide Amino acid Anticodon mRNA Codons Codon recognition P site
Figure 10.14_s1
Polypeptide
Amino acid
P site
A site
Anticodon
mRNA
Codons 1
Codon recognition
Figure 10.14_s1 Polypeptide elongation (step 1) 19

20. Polypeptide Amino acid Anticodon mRNA Codons Codon recognition
Figure 10.14_s2
Polypeptide
Amino acid
P site
A site
Anticodon
mRNA
Codons 1
Codon recognition
Figure 10.14_s2 Polypeptide elongation (step 2) 2
Peptide bond
formation 20

21. Polypeptide Amino acid Anticodon mRNA Codons Codon recognition
Figure 10.14_s3
Polypeptide
Amino acid
P site
A site
Anticodon
mRNA
Codons 1
Codon recognition
Figure 10.14_s3 Polypeptide elongation (step 3) 2
Peptide bond
formation
New peptide bond 3
Translocation 21

22. Polypeptide Amino acid Anticodon mRNA Codons Codon recognition
Figure 10.14_s4
Polypeptide
Amino acid
P site
A site
Anticodon
mRNA
Codons 1
Codon recognition
mRNA movement
Stop codon
Figure 10.14_s4 Polypeptide elongation (step 4) 2
Peptide bond
formation
New peptide bond 3
Translocation 22

23. 10.15 Review: The flow of genetic information in the cell is DNA  RNA  protein
Transcription is the synthesis of RNA from a DNA template. In eukaryotic cells,
transcription occurs in the nucleus and
the mRNA must travel from the nucleus to the cytoplasm.
Student Misconceptions and Concerns
Beginning college students are often intensely focused on writing detailed notes. The risk is that they will miss the overall patterns and the broader significance of the topics discussed. Consider a gradual approach to the subjects of transcription and translation, beginning quite generally and testing comprehension, before venturing into the finer mechanics of each process.
Teaching Tips
1. If you use a train analogy for the assembly of monomers into polymers, the DNA and RNA trains are traded in on a three-for-one basis for the polypeptide train during translation. In general, this produces polypeptides that have about one-third as many monomers as the mRNA that coded for them.
2. After translation is addressed, consider asking your students (working singly or in small groups) to list all of the places where base pairing is used (in the construction of a DNA molecule during DNA replication, in transcription, and during translation when the tRNA attaches).
© 2012 Pearson Education, Inc. 23

24. 10.15 Review: The flow of genetic information in the cell is DNA  RNA  protein
Translation can be divided into four steps, all of which occur in the cytoplasm:
amino acid attachment,
initiation of polypeptide synthesis,
elongation, and
termination.
Student Misconceptions and Concerns
Beginning college students are often intensely focused on writing detailed notes. The risk is that they will miss the overall patterns and the broader significance of the topics discussed. Consider a gradual approach to the subjects of transcription and translation, beginning quite generally and testing comprehension, before venturing into the finer mechanics of each process.
Teaching Tips
1. If you use a train analogy for the assembly of monomers into polymers, the DNA and RNA trains are traded in on a three-for-one basis for the polypeptide train during translation. In general, this produces polypeptides that have about one-third as many monomers as the mRNA that coded for them.
2. After translation is addressed, consider asking your students (working singly or in small groups) to list all of the places where base pairing is used (in the construction of a DNA molecule during DNA replication, in transcription, and during translation when the tRNA attaches).
© 2012 Pearson Education, Inc. 24

25. Figure 10.15 A summary of transcription and translation
DNA
mRNA 1
Transcription
RNA polymerase
Translation
CYTOPLASM
Amino acid
Amino acid 2
attachment
Enzyme
tRNA
ATP
Anticodon
Initiator tRNA
Large ribosomal subunit 3
Initiation of
polypeptide synthesis
Start Codon
Small ribosomal subunit
mRNA
New peptide bond forming
Growing polypeptide
Figure A summary of transcription and translation 4
Elongation
Codons
mRNA
Polypeptide 5
Termination
Stop codon 25

26. Transcription DNA Transcription mRNA RNA polymerase 1 Figure 10.15_1
Figure 10.15_1 A summary of transcription and translation (part 1) 26

27. Large ribosomal subunit Initiation of polypeptide synthesis
Figure 10.15_2
CYTOPLASM
Translation
Amino acid 2
Amino acid
attachment
Enzyme
tRNA
ATP
Anticodon
Initiator tRNA
Large ribosomal subunit 2 3
Initiation of
Figure 10.15_2 A summary of transcription and translation (part 2)
polypeptide synthesis
Start Codon
Small ribosomal subunit
mRNA 27

28. New peptide bond forming Growing polypeptide
Figure 10.15_3
New peptide bond forming
Growing polypeptide 4
Elongation
Codons
mRNA
Polypeptide
Figure 10.15_3 A summary of transcription and translation (part 3) 5
Termination
Stop codon 28

29. 10.16 Mutations can change the meaning of genes
A mutation is any change in the nucleotide sequence of DNA.
Mutations can involve
large chromosomal regions or
just a single nucleotide pair.
Student Misconceptions and Concerns
1. Beginning college students are often intensely focused on writing detailed notes. The risk is that they will miss the overall patterns and the broader significance of the topics discussed. Consider a gradual approach to the subjects of transcription and translation, beginning quite generally and testing comprehension, before venturing into the finer mechanics of each process.
2. Mutations are often discussed as part of evolutionary mechanisms. In this sense, mutations may be considered a part of a creative process. The dual nature of mutations, potentially deadly yet potentially innovative, should be clarified.
Teaching Tips
1. A simple way to demonstrate the effect of a reading frame shift is to have students compare the following three sentences. The first is a simple sentence. However, look what happens when a letter is added (2) or deleted (3). The reading frame, or words, are re-formed into nonsense.
(1) The big red pig ate the red rag.
(2) The big res dpi gat eth ere dra g.
(3) The big rep iga tet her edr ag.
2. The authors have noted elsewhere that “A random mutation is like a random shot in the dark. It is not likely to improve a genome any more than shooting a bullet through the hood of a car is likely to improve engine performance!”
© 2012 Pearson Education, Inc. 29

30. 10.16 Mutations can change the meaning of genes
Mutations within a gene can be divided into two general categories.
Base substitutions involve the replacement of one nucleotide with another. Base substitutions may
have no effect at all, producing a silent mutation,
change the amino acid coding, producing a missense mutation, which produces a different amino acid,
lead to a base substitution that produces an improved protein that enhances the success of the mutant organism and its descendant, or
change an amino acid into a stop codon, producing a nonsense mutation.
Student Misconceptions and Concerns
1. Beginning college students are often intensely focused on writing detailed notes. The risk is that they will miss the overall patterns and the broader significance of the topics discussed. Consider a gradual approach to the subjects of transcription and translation, beginning quite generally and testing comprehension, before venturing into the finer mechanics of each process.
2. Mutations are often discussed as part of evolutionary mechanisms. In this sense, mutations may be considered a part of a creative process. The dual nature of mutations, potentially deadly yet potentially innovative, should be clarified.
Teaching Tips
1. A simple way to demonstrate the effect of a reading frame shift is to have students compare the following three sentences. The first is a simple sentence. However, look what happens when a letter is added (2) or deleted (3). The reading frame, or words, are re-formed into nonsense.
(1) The big red pig ate the red rag.
(2) The big res dpi gat eth ere dra g.
(3) The big rep iga tet her edr ag.
2. The authors have noted elsewhere that “A random mutation is like a random shot in the dark. It is not likely to improve a genome any more than shooting a bullet through the hood of a car is likely to improve engine performance!”
© 2012 Pearson Education, Inc. 30

31. 10.16 Mutations can change the meaning of genes
Mutations can result in deletions or insertions that may
alter the reading frame (triplet grouping) of the mRNA, so that nucleotides are grouped into different codons,
lead to significant changes in amino acid sequence downstream of the mutation, and
produce a nonfunctional polypeptide.
Student Misconceptions and Concerns
1. Beginning college students are often intensely focused on writing detailed notes. The risk is that they will miss the overall patterns and the broader significance of the topics discussed. Consider a gradual approach to the subjects of transcription and translation, beginning quite generally and testing comprehension, before venturing into the finer mechanics of each process.
2. Mutations are often discussed as part of evolutionary mechanisms. In this sense, mutations may be considered a part of a creative process. The dual nature of mutations, potentially deadly yet potentially innovative, should be clarified.
Teaching Tips
1. A simple way to demonstrate the effect of a reading frame shift is to have students compare the following three sentences. The first is a simple sentence. However, look what happens when a letter is added (2) or deleted (3). The reading frame, or words, are re-formed into nonsense.
(1) The big red pig ate the red rag.
(2) The big res dpi gat eth ere dra g.
(3) The big rep iga tet her edr ag.
2. The authors have noted elsewhere that “A random mutation is like a random shot in the dark. It is not likely to improve a genome any more than shooting a bullet through the hood of a car is likely to improve engine performance!”
© 2012 Pearson Education, Inc. 31

32. 10.16 Mutations can change the meaning of genes
Mutagenesis is the production of mutations.
Mutations can be caused by
spontaneous errors that occur during DNA replication or recombination or
mutagens, which include
high-energy radiation such as X-rays and ultraviolet light and
chemicals.
Student Misconceptions and Concerns
1. Beginning college students are often intensely focused on writing detailed notes. The risk is that they will miss the overall patterns and the broader significance of the topics discussed. Consider a gradual approach to the subjects of transcription and translation, beginning quite generally and testing comprehension, before venturing into the finer mechanics of each process.
2. Mutations are often discussed as part of evolutionary mechanisms. In this sense, mutations may be considered a part of a creative process. The dual nature of mutations, potentially deadly yet potentially innovative, should be clarified.
Teaching Tips
1. A simple way to demonstrate the effect of a reading frame shift is to have students compare the following three sentences. The first is a simple sentence. However, look what happens when a letter is added (2) or deleted (3). The reading frame, or words, are re-formed into nonsense.
(1) The big red pig ate the red rag.
(2) The big res dpi gat eth ere dra g.
(3) The big rep iga tet her edr ag.
2. The authors have noted elsewhere that “A random mutation is like a random shot in the dark. It is not likely to improve a genome any more than shooting a bullet through the hood of a car is likely to improve engine performance!”
© 2012 Pearson Education, Inc. 32

33. Sickle-cell hemoglobin
Figure 10.16A
Normal hemoglobin DNA
Mutant hemoglobin DNA C T T C A T
mRNA
mRNA G A A G U A
Normal hemoglobin
Figure 10.16A The molecular basis of sickle-cell disease
Sickle-cell hemoglobin
Glu
Val 33

34. Nucleotide substitution
Figure 10.16B
Normal gene A U G A A G U U U G G C G C A
mRNA Protein
Met
Lys
Phe
Gly
Ala
Nucleotide substitution A U G A A G U U U A G C G C A
Met
Lys
Phe
Ser
Ala U
Deleted
Nucleotide deletion A U G A A G U U G G C G C A U
Figure 10.16B Types of mutations and their effects
Met
Lys
Leu
Ala
His
Inserted
Nucleotide insertion A U G A A G U U G U G G C G C
Met
Lys
Leu
Ala
His 34

35. THE GENETICS OF VIRUSES AND BACTERIA
© 2012 Pearson Education, Inc. 35

36. 10.17 Viral DNA may become part of the host chromosome
A virus is essentially “genes in a box,” an infectious particle consisting of
a bit of nucleic acid,
wrapped in a protein coat called a capsid, and
in some cases, a membrane envelope.
Viruses have two types of reproductive cycles.
In the lytic cycle,
viral particles are produced using host cell components,
the host cell lyses, and
viruses are released.
Student Misconceptions and Concerns
1. Students and many parents with young children expect antibiotics to be used to treat many respiratory infections, even though such infections may result from a virus. Students will benefit from a thorough explanation of why antibiotics are inappropriate for viral infections as well as the rising numbers of antibiotic-resistant bacteria that have evolved as a result of the overuse of antibiotics.
2. The success of modern medicine has perhaps led to overconfidence in our ability to treat disease. Students often do not understand that there are few successful treatments for viral infections. Instead, the best defense against viruses is prevention, by reducing the chances of contacting the virus and through the use of vaccines.
Teaching Tips
Students (and instructors) might enjoy thinking of a prophage as a smudge mark on the master copy of a class handout. The smudge is replicated every time the original is copied!
© 2012 Pearson Education, Inc. 36

37. 10.17 Viral DNA may become part of the host chromosome
2. In the Lysogenic cycle
Viral DNA is inserted into the host chromosome by recombination.
Viral DNA is duplicated along with the host chromosome during each cell division.
The inserted phage DNA is called a prophage.
Most prophage genes are inactive.
Environmental signals can cause a switch to the lytic cycle, causing the viral DNA to be excised from the bacterial chromosome and leading to the death of the host cell.
Student Misconceptions and Concerns
1. Students and many parents with young children expect antibiotics to be used to treat many respiratory infections, even though such infections may result from a virus. Students will benefit from a thorough explanation of why antibiotics are inappropriate for viral infections as well as the rising numbers of antibiotic-resistant bacteria that have evolved as a result of the overuse of antibiotics.
2. The success of modern medicine has perhaps led to overconfidence in our ability to treat disease. Students often do not understand that there are few successful treatments for viral infections. Instead, the best defense against viruses is prevention, by reducing the chances of contacting the virus and through the use of vaccines.
Teaching Tips
Students (and instructors) might enjoy thinking of a prophage as a smudge mark on the master copy of a class handout. The smudge is replicated every time the original is copied!
Animation: Phage Lambda Lysogenic and Lytic Cycles
Animation: Phage T4 Lytic Cycle
© 2012 Pearson Education, Inc. 37

38. The phage DNA circularizes
Figure 10.17_s1
Phage
Attaches to cell
Phage DNA
Bacterial chromosome 4
The cell lyses, releasing phages 1
The phage injects its DNA
Lytic cycle
Phages assemble 2
The phage DNA circularizes
Figure 10.17_s1 Two types of phage replication cycles (step 1) 3
New phage DNA and proteins are synthesized 38

39. The phage DNA circularizes
Figure 10.17_s2
Phage
Attaches to cell
Phage DNA
Bacterial chromosome 4
The cell lyses, releasing phages 1
The phage injects its DNA 7
Environmental stress
Many cell divisions
Lytic cycle
Lysogenic cycle
Phages assemble 2
The phage DNA circularizes 6
The lysogenic bacterium replicates normally
Prophage
Figure 10.17_s2 Two types of phage replication cycles (step 2) OR 3
New phage DNA and proteins are synthesized 5
Phage DNA inserts into the bacterial chromosome by recombination 39

40. The phage DNA circularizes
Figure 10.17_1
Phage
Attaches to cell
Bacterial chromosome
Phage DNA 4
The cell lyses, releasing phages 1
The phage injects its DNA
Lytic cycle
Figure 10.17_1 Two types of phage replication cycles (part 1)
Phages assemble 2
The phage DNA circularizes 3
New phage DNA and proteins are synthesized 40

41. The phage DNA circularizes
Figure 10.17_2
Phage
Attaches to cell
Phage DNA
Bacterial chromosome
The phage injects its DNA 1 7
Environmental stress
Many cell divisions
Lysogenic cycle
Figure 10.17_2 Two types of phage replication cycles (part 2) 2
The phage DNA circularizes 6
The lysogenic bacterium replicates normally, copying the prophage at each cell division
Prophage 5
Phage DNA inserts into the bacterial chromosome by recombination 41

42. 10.18 CONNECTION: Many viruses cause disease in animals and plants
Viruses can cause disease in animals and plants.
DNA viruses and RNA viruses cause disease in animals.
A typical animal virus has a membranous outer envelope and projecting spikes of glycoprotein.
The envelope helps the virus enter and leave the host cell.
Many animal viruses have RNA rather than DNA as their genetic material. These include viruses that cause the common cold, measles, mumps, polio, and AIDS.
Student Misconceptions and Concerns
1. Students and many parents with young children expect antibiotics to be used to treat many respiratory infections, even though such infections may result from a virus. Students will benefit from a thorough explanation of why antibiotics are inappropriate for viral infections as well as the rising numbers of antibiotic-resistant bacteria that have evolved as a result of the overuse of antibiotics.
2. The success of modern medicine has perhaps led to overconfidence in our ability to treat disease. Students often do not understand that there are few successful treatments for viral infections. Instead, the best defense against viruses is prevention, by reducing the chances of contacting the virus and through the use of vaccines.
Teaching Tips
As noted in Module 10.18, viruses can spread throughout a plant by moving through plasmodesmata. This is like smoke spreading throughout a building by moving through air ducts.
© 2012 Pearson Education, Inc. 42

43. 10.18 CONNECTION: Many viruses cause disease in animals and plants
The reproductive cycle of the mumps virus, a typical enveloped RNA virus, has seven major steps:
entry of the protein-coated RNA into the cell,
uncoating—the removal of the protein coat,
RNA synthesis—mRNA synthesis using a viral enzyme,
protein synthesis—mRNA is used to make viral proteins,
new viral genome production—mRNA is used as a template to synthesize new viral genomes,
assembly—the new coat proteins assemble around the new viral RNA, and
exit—the viruses leave the cell by cloaking themselves in the host cell’s plasma membrane.
Student Misconceptions and Concerns
1. Students and many parents with young children expect antibiotics to be used to treat many respiratory infections, even though such infections may result from a virus. Students will benefit from a thorough explanation of why antibiotics are inappropriate for viral infections as well as the rising numbers of antibiotic-resistant bacteria that have evolved as a result of the overuse of antibiotics.
2. The success of modern medicine has perhaps led to overconfidence in our ability to treat disease. Students often do not understand that there are few successful treatments for viral infections. Instead, the best defense against viruses is prevention, by reducing the chances of contacting the virus and through the use of vaccines.
Teaching Tips
As noted in Module 10.18, viruses can spread throughout a plant by moving through plasmodesmata. This is like smoke spreading throughout a building by moving through air ducts.
© 2012 Pearson Education, Inc. 43

44. 10.18 CONNECTION: Many viruses cause disease in animals and plants
Some animal viruses, such as herpesviruses, reproduce in the cell nucleus.
Most plant viruses are RNA viruses.
To infect a plant, they must get past the outer protective layer of the plant.
Viruses spread from cell to cell through plasmodesmata.
Infection can spread to other plants by insects, herbivores, humans, or farming tools.
There are no cures for most viral diseases of plants or animals.
Student Misconceptions and Concerns
1. Students and many parents with young children expect antibiotics to be used to treat many respiratory infections, even though such infections may result from a virus. Students will benefit from a thorough explanation of why antibiotics are inappropriate for viral infections as well as the rising numbers of antibiotic-resistant bacteria that have evolved as a result of the overuse of antibiotics.
2. The success of modern medicine has perhaps led to overconfidence in our ability to treat disease. Students often do not understand that there are few successful treatments for viral infections. Instead, the best defense against viruses is prevention, by reducing the chances of contacting the virus and through the use of vaccines.
Teaching Tips
As noted in Module 10.18, viruses can spread throughout a plant by moving through plasmodesmata. This is like smoke spreading throughout a building by moving through air ducts.
Animation: Simplified Viral Reproductive Cycle
© 2012 Pearson Education, Inc. 44

45. Plasma membrane of host cell
Figure 10.18
Glycoprotein spike
Protein coat
Membranous envelope
Viral RNA (genome)
Plasma membrane of host cell 1
Entry
CYTOPLASM 2
Uncoating
Viral RNA (genome) 3
RNA synthesis by viral enzyme
Protein synthesis 4 5
RNA synthesis (other strand)
Template
mRNA
New viral genome
Figure The replication cycle of an enveloped RNA virus
New viral proteins 6 6
Assembly
Exit 7 45

46. Plasma membrane of host cell
Figure 10.18_1
Glycoprotein spike
Protein coat
Membranous envelope
Viral RNA (genome)
Entry
CYTOPLASM
Plasma membrane of host cell 1 2
Uncoating
Figure 10.18_1 The replication cycle of an enveloped RNA virus (part 1)
Viral RNA (genome)
RNA synthesis by viral enzyme 3 46

47. RNA synthesis (other strand)
Figure 10.18_2
Protein synthesis
RNA synthesis (other strand) 4 5
Template
mRNA
New viral genome
New viral proteins 6
Assembly
Figure 10.18_2 The replication cycle of an enveloped RNA virus (part 2)
Exit 7 47

48. 10.19 EVOLUTION CONNECTION: Emerging viruses threaten human health
Viruses that appear suddenly or are new to medical scientists are called emerging viruses. These include the
AIDS virus,
Ebola virus,
West Nile virus, and
SARS virus.
Student Misconceptions and Concerns
1. Students and many parents with young children expect antibiotics to be used to treat many respiratory infections, even though such infections may result from a virus. Students will benefit from a thorough explanation of why antibiotics are inappropriate for viral infections as well as the rising numbers of antibiotic-resistant bacteria that have evolved as a result of the overuse of antibiotics.
2. The success of modern medicine has perhaps led to overconfidence in our ability to treat disease. Students often do not understand that there are few successful treatments for viral infections. Instead, the best defense against viruses is prevention, by reducing the chances of contacting the virus and through the use of vaccines.
Teaching Tips
1. There is an interesting relationship between the speed at which a virus kills or debilitates a host and the extent to which it spreads from one organism to another. This is something to consider for a class discussion. Compare two viral infections. Infection A multiplies within the host, is spread by the host to other people through casual contact, but does not cause its lethal symptoms until 5–10 years after infection. Virus B kills the host within 1–2 days of infection, is easily transmitted, and causes severe symptoms within hours of contact. Which virus is likely to spread the fastest through the human population on Earth? Which might be considered the most dangerous to humans?
2. Students might wonder why a person needs to get a new seasonal flu vaccination every year. The annual mutations and variations in flu viruses require the production of a new flu vaccine annually. The Centers for Disease Control and Prevention monitors patterns of flu outbreaks, especially in Asia (where many variations of flu viruses originate). They must predict which strains are most likely to be dangerous in the coming year and then synthesize an appropriate vaccine.
© 2012 Pearson Education, Inc. 48

49. 10.19 EVOLUTION CONNECTION: Emerging viruses threaten human health
Three processes contribute to the emergence of viral diseases:
mutation—RNA viruses mutate rapidly.
contact between species—viruses from other animals spread to humans.
spread from isolated human populations to larger human populations, often over great distances.
Student Misconceptions and Concerns
1. Students and many parents with young children expect antibiotics to be used to treat many respiratory infections, even though such infections may result from a virus. Students will benefit from a thorough explanation of why antibiotics are inappropriate for viral infections as well as the rising numbers of antibiotic-resistant bacteria that have evolved as a result of the overuse of antibiotics.
2. The success of modern medicine has perhaps led to overconfidence in our ability to treat disease. Students often do not understand that there are few successful treatments for viral infections. Instead, the best defense against viruses is prevention, by reducing the chances of contacting the virus and through the use of vaccines.
Teaching Tips
1. There is an interesting relationship between the speed at which a virus kills or debilitates a host and the extent to which it spreads from one organism to another. This is something to consider for a class discussion. Compare two viral infections. Infection A multiplies within the host, is spread by the host to other people through casual contact, but does not cause its lethal symptoms until 5–10 years after infection. Virus B kills the host within 1–2 days of infection, is easily transmitted, and causes severe symptoms within hours of contact. Which virus is likely to spread the fastest through the human population on Earth? Which might be considered the most dangerous to humans?
2. Students might wonder why a person needs to get a new seasonal flu vaccination every year. The annual mutations and variations in flu viruses require the production of a new flu vaccine annually. The Centers for Disease Control and Prevention monitors patterns of flu outbreaks, especially in Asia (where many variations of flu viruses originate). They must predict which strains are most likely to be dangerous in the coming year and then synthesize an appropriate vaccine.
© 2012 Pearson Education, Inc. 49

50. Figure 10.19
Figure People in Mexico City wearing masks in an attempt to prevent spread of the 2009 H1N1 virus 50

51. Figure 10.19_1
Figure 10.19_1 People in Mexico City wearing masks in an attempt to prevent spread of the 2009 H1N1 virus (part 1) 51

52. Figure 10.19_2
Figure 10.19_2 People in Mexico City wearing masks in an attempt to prevent spread of the 2009 H1N1 virus (part 2) 52

53. 10.20 The AIDS virus makes DNA on an RNA template
AIDS (acquired immunodeficiency syndrome) is caused by HIV (human immunodeficiency virus).
HIV
is an RNA virus,
has two copies of its RNA genome,
carries molecules of reverse transcriptase, which causes reverse transcription, producing DNA from an RNA template.
Student Misconceptions and Concerns
1. Students and many parents with young children expect antibiotics to be used to treat many respiratory infections, even though such infections may result from a virus. Students will benefit from a thorough explanation of why antibiotics are inappropriate for viral infections as well as the rising numbers of antibiotic-resistant bacteria that have evolved as a result of the overuse of antibiotics.
2. The success of modern medicine has perhaps led to overconfidence in our ability to treat disease. Students often do not understand that there are few successful treatments for viral infections. Instead, the best defense against viruses is prevention, by reducing the chances of contacting the virus and through the use of vaccines.
3. Many misconceptions about AIDS exist. A list of 18 common misconceptions is located at
Teaching Tips
1. The Centers for Disease Control and Prevention has extensive information about AIDS at
2. Students often do not understand the disproportionate distribution of HIV infections and AIDS in our world. Consider an Internet assignment, asking students to identify the regions of the world most affected by HIV/AIDS and then discuss why this uneven distribution of disease exists.
© 2012 Pearson Education, Inc. 53

54. RNA (two identical strands)
Figure 10.20A
Envelope
Glycoprotein
Protein coat
RNA (two identical strands)
Reverse transcriptase (two copies)
Figure 10.20A A model of HIV structure 54

55. 10.20 The AIDS virus makes DNA on an RNA template
After HIV RNA is uncoated in the cytoplasm of the host cell,
reverse transcriptase makes one DNA strand from RNA,
reverse transcriptase adds a complementary DNA strand,
double-stranded viral DNA enters the nucleus and integrates into the chromosome, becoming a provirus,
the provirus DNA is used to produce mRNA,
the viral mRNA is translated to produce viral proteins, and
new viral particles are assembled, leave the host cell, and can then infect other cells.
Student Misconceptions and Concerns
1. Students and many parents with young children expect antibiotics to be used to treat many respiratory infections, even though such infections may result from a virus. Students will benefit from a thorough explanation of why antibiotics are inappropriate for viral infections as well as the rising numbers of antibiotic-resistant bacteria that have evolved as a result of the overuse of antibiotics.
2. The success of modern medicine has perhaps led to overconfidence in our ability to treat disease. Students often do not understand that there are few successful treatments for viral infections. Instead, the best defense against viruses is prevention, by reducing the chances of contacting the virus and through the use of vaccines.
3. Many misconceptions about AIDS exist. A list of 18 common misconceptions is located at
Teaching Tips
1. The Centers for Disease Control and Prevention has extensive information about AIDS at
2. Students often do not understand the disproportionate distribution of HIV infections and AIDS in our world. Consider an Internet assignment, asking students to identify the regions of the world most affected by HIV/AIDS and then discuss why this uneven distribution of disease exists.
Animation: HIV Reproductive Cycle
© 2012 Pearson Education, Inc. 55

56. Reverse transcriptase
Figure 10.20B
CYTOPLASM
Viral RNA
Reverse transcriptase 1
NUCLEUS
DNA strand
Chromosomal DNA 2
Double- stranded DNA 3
Provirus DNA 4
Viral RNA and proteins 5
RNA
Figure 10.20B The behavior of HIV nucleic acid in a host cell 6 56

57. 10.21 Viroids and prions are formidable pathogens in plants and animals
Some infectious agents are made only of RNA or protein.
Viroids are small, circular RNA molecules that infect plants. Viroids
replicate within host cells without producing proteins and
interfere with plant growth.
Prions are infectious proteins that cause degenerative brain diseases in animals. Prions
appear to be misfolded forms of normal brain proteins,
which convert normal protein to misfolded form.
Student Misconceptions and Concerns
1. Students and many parents with young children expect antibiotics to be used to treat many respiratory infections, even though such infections may result from a virus. Students will benefit from a thorough explanation of why antibiotics are inappropriate for viral infections as well as the rising numbers of antibiotic-resistant bacteria that have evolved as a result of the overuse of antibiotics.
2. The success of modern medicine has perhaps led to overconfidence in our ability to treat disease. Students often do not understand that there are few successful treatments for viral infections. Instead, the best defense against viruses is prevention, by reducing the chances of contacting the virus and through the use of vaccines.
Teaching Tips
Viroids can cause significant damage to plants. More than 30 million coconut palms in the Philippines have been killed by viroids.
© 2012 Pearson Education, Inc. 57

58. 10.22 Bacteria can transfer DNA in three ways
Viral reproduction allows researchers to learn more about the mechanisms that regulate DNA replication and gene expression in living cells.
Bacteria are also valuable but for different reasons.
Bacterial DNA is found in a single, closed loop, chromosome.
Bacterial cells divide by replication of the bacterial chromosome and then by binary fission.
Because binary fission is an asexual process, bacteria in a colony are genetically identical to the parent cell.
Student Misconceptions and Concerns
1. Students and many parents with young children expect antibiotics to be used to treat many respiratory infections, even though such infections may result from a virus. Students will benefit from a thorough explanation of why antibiotics are inappropriate for viral infections as well as the rising numbers of antibiotic-resistant bacteria that have evolved as a result of the overuse of antibiotics.
2. The success of modern medicine has perhaps led to overconfidence in our ability to treat disease. Students often do not understand that there are few successful treatments for viral infections. Instead, the best defense against viruses is prevention, by reducing the chances of contacting the virus and through the use of vaccines.
Teaching Tips
1. The authors note that the figures in Module represent the size of the bacterial chromosome as much smaller than they actually are. They note that a bacterial chromosome is hundreds of times longer than the cell. These chromosomes use extensive folding to fit inside the cell.
2. You might challenge students to explain why conjugation is sometimes called bacterial sex. Students might note that two organisms cooperate to produce a new, genetically unique bacterium.
© 2012 Pearson Education, Inc. 58

59. 10.22 Bacteria can transfer DNA in three ways
Bacteria use three mechanisms to move genes from cell to cell.
Transformation is the uptake of DNA from the surrounding environment.
Transduction is gene transfer by phages.
Conjugation is the transfer of DNA from a donor to a recipient bacterial cell through a cytoplasmic (mating) bridge.
Once new DNA gets into a bacterial cell, part of it may then integrate into the recipient’s chromosome.
Student Misconceptions and Concerns
1. Students and many parents with young children expect antibiotics to be used to treat many respiratory infections, even though such infections may result from a virus. Students will benefit from a thorough explanation of why antibiotics are inappropriate for viral infections as well as the rising numbers of antibiotic-resistant bacteria that have evolved as a result of the overuse of antibiotics.
2. The success of modern medicine has perhaps led to overconfidence in our ability to treat disease. Students often do not understand that there are few successful treatments for viral infections. Instead, the best defense against viruses is prevention, by reducing the chances of contacting the virus and through the use of vaccines.
Teaching Tips
1. The authors note that the figures in Module represent the size of the bacterial chromosome as much smaller than they actually are. They note that a bacterial chromosome is hundreds of times longer than the cell. These chromosomes use extensive folding to fit inside the cell.
2. You might challenge students to explain why conjugation is sometimes called bacterial sex. Students might note that two organisms cooperate to produce a new, genetically unique bacterium.
© 2012 Pearson Education, Inc. 59

60. A fragment of DNA from another bacterial cell
Figure 10.22A
DNA enters cell
A fragment of DNA from another bacterial cell
Figure 10.22A Transformation
Bacterial chromosome (DNA) 60

61. A fragment of DNA from another bacterial cell (former phage host)
Figure 10.22B
Phage
A fragment of DNA from another bacterial cell (former phage host)
Figure 10.22B Transduction 61

62. Mating bridge Sex pili Donor cell Recipient cell Figure 10.22C
Figure 10.22C Conjugation
Donor cell
Recipient cell 62

63. Recipient cell’s chromosome Recombinant chromosome
Figure 10.22D
Donated DNA
Crossovers
Degraded DNA
Figure 10.22D The integration of donated DNA into the recipient cell’s chromosome
Recipient cell’s chromosome
Recombinant chromosome 63

64. 10.23 Bacterial plasmids can serve as carriers for gene transfer
The ability of a donor E. coli cell to carry out conjugation is usually due to a specific piece of DNA called the F factor.
During conjugation, the F factor is integrated into the bacterium’s chromosome.
The donor chromosome starts replicating at the F factor’s origin of replication.
The growing copy of the DNA peels off and heads into the recipient cell.
The F factor serves as the leading end of the transferred DNA.
Student Misconceptions and Concerns
1. Students and many parents with young children expect antibiotics to be used to treat many respiratory infections, even though such infections may result from a virus. Students will benefit from a thorough explanation of why antibiotics are inappropriate for viral infections as well as the rising numbers of antibiotic-resistant bacteria that have evolved as a result of the overuse of antibiotics.
2. The success of modern medicine has perhaps led to overconfidence in our ability to treat disease. Students often do not understand that there are few successful treatments for viral infections. Instead, the best defense against viruses is prevention, by reducing the chances of contacting the virus and through the use of vaccines.
Teaching Tips
1. The figures in Module provide essential imagery for a detailed discussion of bacterial conjugation. The abstract details presented in Module are likely new to most of your students.
2. Module notes the possible consequences of widespread use of antibiotics. Consider asking your students to consider the value of widespread use of antibacterial soaps throughout their homes.
© 2012 Pearson Education, Inc. 64

65. F factor starts replication and transfer of chromosome
Figure 10.23A-B
F factor (integrated)
F factor (plasmid)
Donor
Donor
Origin of F
replication
Bacterial chromosome
Bacterial chromosome
F factor starts replication and transfer of chromosome
F factor starts replication and transfer
Recipient cell
Figure 10.23A-B Transfer of chromosomal DNA by an integrated F factor (left) and transfer of an F factor plasmid (right)
The plasmid completes its transfer and circularizes
Only part of the chromosome transfers
Recombination can occur
The cell is now a donor 65

66. F factor starts replication and transfer of chromosome
Figure 10.23A
F factor (integrated)
Donor
Origin of F
replication
Bacterial chromosome
F factor starts replication and transfer of chromosome
Recipient cell
Figure 10.23A Transfer of chromosomal DNA by an integrated F factor
Only part of the chromosome transfers
Recombination can occur 66

67. 10.23 Bacterial plasmids can serve as carriers for gene transfer
An F factor can also exist as a plasmid, a small circular DNA molecule separate from the bacterial chromosome.
Some plasmids, including the F factor, can bring about conjugation and move to another cell in linear form.
The transferred plasmid re-forms a circle in the recipient cell.
R plasmids
pose serious problems for human medicine by
carrying genes for enzymes that destroy antibiotics.
Student Misconceptions and Concerns
1. Students and many parents with young children expect antibiotics to be used to treat many respiratory infections, even though such infections may result from a virus. Students will benefit from a thorough explanation of why antibiotics are inappropriate for viral infections as well as the rising numbers of antibiotic-resistant bacteria that have evolved as a result of the overuse of antibiotics.
2. The success of modern medicine has perhaps led to overconfidence in our ability to treat disease. Students often do not understand that there are few successful treatments for viral infections. Instead, the best defense against viruses is prevention, by reducing the chances of contacting the virus and through the use of vaccines.
Teaching Tips
1. The figures in Module provide essential imagery for a detailed discussion of bacterial conjugation. The abstract details presented in Module are likely new to most of your students.
2. Module notes the possible consequences of widespread use of antibiotics. Consider asking your students to consider the value of widespread use of antibacterial soaps throughout their homes.
© 2012 Pearson Education, Inc. 67

68. F factor starts replication and transfer
Figure 10.23B
F factor (plasmid)
Donor
Bacterial chromosome
F factor starts replication and transfer
Figure 10.23B Transfer of an F factor plasmid
The plasmid completes its transfer and circularizes
The cell is now a donor 68

69. Figure 10.23C
Plasmids
Figure 10.23C Plasmids and part of a bacterial chromosome released from a ruptured E. coli cell 69

70. You should now be able to
Describe the experiments of Griffith, Hershey, and Chase, which supported the idea that DNA was life’s genetic material.
Compare the structures of DNA and RNA.
Explain how the structure of DNA facilitates its replication.
Describe the process of DNA replication.
Describe the locations, reactants, and products of transcription and translation.
© 2012 Pearson Education, Inc. 70

71. You should now be able to
Explain how the “languages” of DNA and RNA are used to produce polypeptides.
Explain how mRNA is produced using DNA.
Explain how eukaryotic RNA is processed before leaving the nucleus.
Relate the structure of tRNA to its functions in the process of translation.
Describe the structure and function of ribosomes.
© 2012 Pearson Education, Inc. 71

72. You should now be able to
Describe the step-by-step process by which amino acids are added to a growing polypeptide chain.
Diagram the overall process of transcription and translation.
Describe the major types of mutations, causes of mutations, and potential consequences.
Compare the lytic and lysogenic reproductive cycles of a phage.
Compare the structures and reproductive cycles of the mumps virus and a herpesvirus.
© 2012 Pearson Education, Inc. 72

73. You should now be able to
Describe three processes that contribute to the emergence of viral disease.
Explain how the AIDS virus enters a host cell and reproduces.
Describe the structure of viroids and prions and explain how they cause disease.
Define and compare the processes of transformation, transduction, and conjugation.
Define a plasmid and explain why R plasmids pose serious human health problems.
© 2012 Pearson Education, Inc. 73

74. Sugar- phosphate backbone
Figure 10.UN01
Sugar- phosphate backbone
Nitrogenous base G
Phosphate group A
Sugar
Nucleotide C
DNA
RNA C C T
Nitrogenous bases G G
Figure 10.UN01 Reviewing the Concepts, 10.2 A A T U G
Deoxy- ribose
Sugar
Ribose
DNA
Polynucleotide 74

75. Large ribosomal subunit Amino acid
Figure 10.UN02
Growing polypeptide
Large ribosomal subunit
Amino acid
tRNA
Anticodon
mRNA
Figure 10.UN02 Reviewing the Concepts, 10.14
Small ribosomal subunit
Codons 75

76. is a polymer made from monomers called DNA (a)
Figure 10.UN03
is a polymer made from monomers called
DNA
(a)
is performed by an enzyme called
(b)
(c)
(d)
comes in three kinds called
RNA
(e)
(f)
molecules are components of
Figure 10.UN03 Connecting the Concepts, question 1
use amino-acid-bearing molecules called
(g)
is performed by structures called
(h)
one or more polymers made from monomers called
Protein
(i) 76

77. Figure 10.1_UN
Figure 10.1_UN Phage T2 model resembles a lunar landing craft 77

78. Figure 10.17_UN
Figure 10.17_UN Bacterial cell lysis due to phage 78

79. Figure 10.18_UN
Figure 10.18_UN Herpesvirus 79