2. Molecular Genetics Section 1: DNA: The Genetic Material
Section 2: Replication of DNA
Section 3: DNA, RNA, and Protein
Section 4: Gene Regulation and Mutation

3. I. DNA discoveries A. Griffith
Section 1
Molecular Genetics
DNA: The Genetic Material
I. DNA discoveries
A. Griffith
Performed the first major experiment that led to the discovery of DNA as the genetic material

4. Concluded that when the S cells were killed, DNA was released
Section 1
Molecular Genetics
DNA: The Genetic Material
B. Avery
Identified the molecule that transformed the R strain of bacteria into the S strain
Concluded that when the S cells were killed, DNA was released
R bacteria incorporated this DNA into their cells and changed into S cells.

5. Used radioactive labeling to trace the DNA and protein
Section 1
Molecular Genetics
DNA: The Genetic Material
C. Hershey and Chase
Used radioactive labeling to trace the DNA and protein
Concluded that the viral DNA was injected into the cell and provided the genetic information needed to produce new viruses

6. DNA: The Genetic Material
Section 1
Molecular Genetics
DNA: The Genetic Material
II. DNA Structure
A. Nucleotides
Consist of a five-carbon sugar, a phosphate group, and a nitrogenous base (Know shapes of the rings!)

7. Bases will “base pair” with their appropriate match to form double strands. Purines will pair with pyridimines.
*A pairs with T G pairs with C

8. Chargaff’s rule: C = G and T = A
Section 1
Molecular Genetics
DNA: The Genetic Material
B. Chargaff
Chargaff’s rule: C = G and T = A
Each base combination codes for amino acids.

9. *The “code” is universal because all living organisms share the same code.
*it is degenerative because more than one set of 3 codes for the same amino acid

10. X-ray diffraction data helped solve the structure of DNA
Section 1
Molecular Genetics
DNA: The Genetic Material
C. X-ray Diffraction
X-ray diffraction data helped solve the structure of DNA
Watson and Crick used Rosalind Franklins data along with chargaff’s rules to determine the shape
Indicated that DNA was a double helix

11. two outside strands consist of alternating deoxyribose and phosphate
Section 1
Molecular Genetics
DNA: The Genetic Material
Watson and Crick
Built a model of the double helix that conformed to the others’ research
two outside strands consist of alternating
deoxyribose and phosphate
cytosine and guanine bases pair to each
other by three hydrogen bonds
thymine and adenine bases pair to each
other by two hydrogen bonds

12. DNA often is compared to a twisted ladder.
Section 1
Molecular Genetics
DNA: The Genetic Material
D. DNA Structure
DNA often is compared to a twisted ladder.
Rails of the ladder are represented by the alternating deoxyribose and phosphate.
The pairs of bases (cytosine–guanine or thymine–adenine) form the steps.

13. DNA: The Genetic Material
Section 1
Molecular Genetics
DNA: The Genetic Material
Orientation
On the top rail, the strand is said to be oriented 5′ to 3′.
The strand on the bottom runs in the opposite direction and is oriented 3′ to 5′.

14. DNA: The Genetic Material III. Chromosome Structure
Section 1
Molecular Genetics
DNA: The Genetic Material
III. Chromosome Structure
In prokaryotes, DNA in cytoplasm. In eukaryotes:
DNA coils around histones to form nucleosomes, which coil to form chromatin fibers.
The chromatin fibers supercoil to form chromosomes that are visible in the metaphase stage of mitosis.

15. Come up with a 15 base single strand of DNA for your partner to complete for tomorrows prework.
Complete p

16. The experiments of Avery, Hershey and
Chapter
Molecular Genetics
Section 1 Formative Questions
The experiments of Avery, Hershey and
Chase provided evidence that the carrier
of genetic information is _______.
carbohydrate
DNA
lipid
protein A B C D
FQ 1

17. What is the base-pairing rule for purines
Chapter
Molecular Genetics
Section 1 Formative Questions
What is the base-pairing rule for purines
and pyrimidines in the DNA molecule?
A—G and C—T
A—T and C—G
C—A and G—T
C—U and A—G A B C D
FQ 2

18. What are chromosomes composed of?
Chapter
Molecular Genetics
Section 1 Formative Questions
What are chromosomes composed of?
chromatin and histones
DNA and protein
DNA and lipids
protein and centromeres A B C D
FQ 3

19. I. Semiconservative Replication
Section 2
Molecular Genetics
Replication of DNA
I. Semiconservative Replication
Parental strands of DNA separate, serve as templates, and produce DNA molecules that have one strand of parental DNA and
one strand of new DNA.

20. II. Unwinding (Process and the enzymes)
Section 2
Molecular Genetics
Replication of DNA
II. Unwinding (Process and the enzymes)
1. DNA helicase, an enzyme, is responsible for unwinding and unzipping the double helix.
2. RNA primase adds a short segment of RNA, called an RNA primer, on each DNA strand.

21. Section 2
Molecular Genetics
3. DNA polymerase continues adding appropriate nucleotides (in base pairs)to the chain by adding to the 3′ end of the new DNA strand.

22. Section 2
Molecular Genetics
Replication of DNA
One strand is called the leading strand and is elongated as the DNA unwinds.
The other strand of DNA, called the lagging strand, elongates away from the replication fork.
The lagging strand is synthesized discontinuously into small segments, called Okazaki fragments.

23. 4. DNA ligase links the two sections.
Molecular Genetics
Replication of DNA
Joining
DNA polymerase removes the RNA primer and fills in the place with DNA nucleotides.
4. DNA ligase links the two sections.

24. III. Comparing DNA Replication in Eukaryotes and Prokaryotes
Section 2
Molecular Genetics
Replication of DNA
III. Comparing DNA Replication in Eukaryotes and Prokaryotes
Eukaryotic DNA unwinds in multiple areas as DNA is replicated.
In prokaryotes, the circular DNA strand is opened at one origin of replication.

25. The work of Watson and Crick solved the mystery of how DNA works as a
Chapter
Molecular Genetics
Section 2 Formative Questions
The work of Watson and Crick solved the mystery of how DNA works as a
genetic code.
True
False A B
FQ 4

26. Which is not an enzyme involved in DNA replication?
Chapter
Molecular Genetics
Section 2 Formative Questions
Which is not an enzyme involved in DNA
replication?
DNA ligase
DNA polymerase
helicase
RNA primer A B C D
FQ 5

27. I. Central Dogma (DNA->RNA->protein)
Section 3
Molecular Genetics
DNA, RNA, and Protein
I. Central Dogma (DNA->RNA->protein)
A. RNA
Contains the sugar ribose and the base uracil instead of thymine
Usually is single stranded
Sugar=ribose

28. Associates with proteins to form ribosomes in the cytoplasm
Section 3
Molecular Genetics
II. Types of RNA
A. Messenger RNA (mRNA)
Long strands of RNA nucleotides that are formed complementary to one strand of DNA
B. Ribosomal RNA (rRNA)
Associates with proteins to form ribosomes in the cytoplasm
C. Transfer RNA (tRNA)
Smaller segments of RNA nucleotides that transport amino acids to the ribosome

29. III. Transcription (A. The process)
Section 3
Molecular Genetics
DNA, RNA, and Protein
III. Transcription (A. The process)
Through transcription, the DNA code is transferred to mRNA in the nucleus.
DNA is unzipped in the nucleus and RNA
polymerase binds to a specific section where an
mRNA will be synthesized.

30. B. RNA Processing (components)
Section 3
Molecular Genetics
DNA, RNA, and Protein
B. RNA Processing (components)
The code on the DNA is interrupted periodically by sequences that are not in the final mRNA.
Intervening sequences are called introns.
Remaining pieces of DNA that serve as the coding sequences are called exons.
DNA and Genes

31. 2. unambiguous (no repeats of codons)
Section 3
Molecular Genetics
DNA, RNA, and Protein
IV. The Code
A. Characteristics
1. universal
2. unambiguous (no repeats of codons)
3. degenerate-repeats of amino acids

32. C. AUG=start codon B. Codons 3 stop codons
Groups of 3 bases on the mRNA strand that “code” for amino acids. These are used in translation (next step)
C. AUG=start codon
3 stop codons

33. V. Translation (mRNA->protein)
Section 3
Molecular Genetics
DNA, RNA, and Protein
V. Translation (mRNA->protein)
In translation, tRNA molecules act as the interpreters of the mRNA codon sequence.
At the middle of the folded strand, there is a three-base coding sequence called the anticodon.
Each anticodon is complementary to a codon on the mRNA.

34. Section 3
Molecular Genetics
DNA, RNA, and Protein

35. Location: ribosome (out in the cytoplasm)
A. 5’ end of mRNA connects to ribosome
B. tRNA brings the aa’s where the anticodon scans the mRNA (anticodon 3’->5’)

36. C. Ribosome attach sites
EPA
Exit site-used tRNA’s leave
P (park) site-place of attachment
A site-waiting site

37. D. Bonds attach each neighboring aa
This creates a polypeptide chain (protein)
E. This continues until a stop codon is reached and then the ribosome subunits disassemble

38. Section 3
Molecular Genetics
DNA, RNA, and Protein

39. Section 3
Molecular Genetics
DNA, RNA, and Protein
VI. One Gene—One Enzyme
The Beadle and Tatum experiment showed that one gene codes for one enzyme. We now know that one gene codes for one polypeptide.

40. Which shows the basic chain of events
Chapter
Molecular Genetics
Section 3 Formative Questions
Which shows the basic chain of events
in all organisms for reading and expressing
genes?
DNA  RNA  protein
RNA  DNA  protein
mRNA  rRNA  tRNA
RNA processing  transcription  translation A B C D
FQ 6

41. In the RNA molecule, uracil replaces _______.
Chapter
Molecular Genetics
Section 3 Formative Questions
In the RNA molecule, uracil replaces
_______.
adenine
cytosine
purine
thymine A B C D
FQ 7

42. Which diagram shows messenger RNA (mRNA)?
Chapter
Molecular Genetics
Section 3 Formative Questions
Which diagram shows messenger
RNA (mRNA)? A. C. B. D. A B C D
FQ 8

43. Chapter
Molecular Genetics
Section 3 Formative Questions
What characteristic of the mRNA molecule do scientists not yet understand?
intervening sequences in the mRNA molecule called introns
the original mRNA made in the nucleus called the pre-mRNA
how the sequence of bases in the mRNA molecule codes for amino acids
the function of many adenine nucleotides at the 5′ end called the poly-A tail A B C D
FQ 9

44. I. Prokaryote Gene Regulation
Section 4
Molecular Genetics
Gene Regulation and Mutation
I. Prokaryote Gene Regulation
Ability of an organism to control which genes are transcribed in response to the environment
An operon is a section of DNA that contains the genes for the proteins needed for a specific metabolic pathway.
Operator
Promoter
Regulatory gene
Genes coding for proteins

45. The Trp Operon Gene Regulation and Mutation Section 4
Molecular Genetics
Gene Regulation and Mutation
The Trp Operon

46. The Lac Operon Gene Regulation and Mutation Section 4
Molecular Genetics
Gene Regulation and Mutation
The Lac Operon
Lac-Trp Operon

47. II. Eukaryote Gene Regulation
Section 4
Molecular Genetics
Gene Regulation and Mutation
II. Eukaryote Gene Regulation
Controlling transcription
Transcription factors ensure that a gene is used at the right time and that proteins are made in the right amounts
The complex structure of eukaryotic DNA also regulates transcription.

48. Section 4
Molecular Genetics
Gene Regulation and Mutation
A. Hox Genes
Hox genes are responsible for the general body pattern of most animals.

49. RNA interference can stop the mRNA from translating its message.
Section 4
Molecular Genetics
Gene Regulation and Mutation
B. RNA Interference
RNA interference can stop the mRNA from translating its message.

50. A permanent change that occurs in a cell’s DNA is called a mutation.
Section 4
Molecular Genetics
Gene Regulation and Mutation
III. Mutations
A permanent change that occurs in a cell’s DNA is called a mutation.
Types of mutations
Point mutations- 1 base pair change
Substitutions-1 base exchanged for another
1. missense: type of substitution; codes for a different amino acid!
2. nonsense: changes aa codon to stop! Terminates translation early; protein functions abnormally!

51. Mutations continued..
Frameshift mutations: gain or loss of nucleotides (changes the multiples of 3)!! *most disastrous! Changes reading frame!
Types:
1. insertion-addition
2. deletion-loss
*everything will shift at the spot of the mutation because codons are groups of 3!

52. Mutations cont C. Chromosome pieces Type:
Tandem repeats: increases the sequences on chromosomes

53. Gene Regulation and Mutation
Section 4
Molecular Genetics
Gene Regulation and Mutation

54. Protein Folding and Stability-can change by mutations
Section 4
Molecular Genetics
Gene Regulation and Mutation
Protein Folding and Stability-can change by mutations
Substitutions also can lead to genetic disorders.
Can change both the folding and stability of the protein

55. Can occur spontaneously DNA polymerase can add wrong
Section 4
Molecular Genetics
Gene Regulation and Mutation
Causes of Mutation
Can occur spontaneously
DNA polymerase can add wrong
Chemicals and radiation also can damage DNA.
High-energy forms of radiation, such as X rays and gamma rays, are highly mutagenic.

56. Body-cell v. Sex-cell Mutation
Section 4
Molecular Genetics
Gene Regulation and Mutation
Body-cell v. Sex-cell Mutation
Somatic cell (body cells) mutations are not passed on to the next generation.
Mutations that occur in sex cells are passed on to the organism’s offspring and will be present in every cell of the offspring.

57. Chapter
Molecular Genetics
Section 4 Formative Questions
Why do eukaryotic cells need a complex control system to regulate the expression of genes?
All of an organism’s cells transcribe the same genes.
Expression of incorrect genes can lead to mutations.
Certain genes are expressed more frequently than others are.
Different genes are expressed at different times in an organism’s lifetime. A B C D
FQ 10

58. Which type of gene causes cells to become specialized in structure in
Chapter
Molecular Genetics
Section 4 Formative Questions
Which type of gene causes cells to
become specialized in structure in
function?
exon
Hox gene
intron
operon A B C D
FQ 11

59. What is an immediate result of a mutation in a gene?
Chapter
Molecular Genetics
Section 4 Formative Questions
What is an immediate result of a mutation
in a gene?
cancer
genetic disorder
nonfunctional enzyme
amino acid deficiency A B C D
FQ 12

60. Which is the most highly mutagenic?
Chapter
Molecular Genetics
Section 4 Formative Questions
Which is the most highly mutagenic?
chemicals in food
cigarette smoke
ultraviolet radiation
X rays A B C D
FQ 13

61. Chapter Resource Menu Chapter Diagnostic Questions
Molecular Genetics
Chapter Resource Menu
Chapter Diagnostic Questions
Formative Test Questions
Chapter Assessment Questions
Standardized Test Practice
connected.mcgraw-hill.com
Glencoe Biology Transparencies
Image Bank
Vocabulary
Animation
Click on a hyperlink to view the corresponding feature.

62. Which scientist(s) definitively proved
Chapter
Molecular Genetics
Chapter Diagnostic Questions
Which scientist(s) definitively proved
that DNA transfers genetic material?
Watson and Crick
Mendel
Hershey and Chase
Avery A B C D
CDQ 1

63. Name the small segments of the lagging DNA strand.
Chapter
Molecular Genetics
Chapter Diagnostic Questions
Name the small segments of the lagging
DNA strand.
ligase
Okazaki fragments
micro RNA
helicase A B C D
CDQ 2

64. Which is not true of RNA? It contains the sugar ribose.
Chapter
Molecular Genetics
Chapter Diagnostic Questions
Which is not true of RNA?
It contains the sugar ribose.
It contains the base uracil.
It is single-stranded.
It contains a phosphate. A B C D
CDQ 3

65. chromatin fibers chromosomes histones nucleosome
Chapter
Molecular Genetics
Chapter Assessment Questions
Look at the following figure. Identify the proteins that DNA first coils around.
chromatin fibers
chromosomes
histones
nucleosome A B C D
CAQ 1

66. Explain how Hox genes affect an organism.
Chapter
Molecular Genetics
Chapter Assessment Questions
Explain how Hox genes affect an organism.
They determine size.
They determine body plan.
They determine sex.
They determine number of body segments. A B C D
CAQ 2

67. Standardized Test Practice
Chapter
Molecular Genetics
Standardized Test Practice
What does this diagram show about the replication of DNA in eukaryotic cells?
DNA is replicated only at certain places along the chromosome.
DNA replication is both semicontinuous and conservative.
Multiple areas of replication occur along the chromosome at the same time.
The leading DNA strand is synthesized discontinuously. A B C D
STP 1

68. What is this process called?
Chapter
Molecular Genetics
Standardized Test Practice
What is this process called?
mRNA processing
protein synthesis
transcription
translation A B C D
STP 2

69. TTCAGG TTCTGG What type of mutation results in this change
Chapter
Molecular Genetics
Standardized Test Practice
What type of mutation results in this change
in the DNA sequence?
TTCAGG TTCTGG
deletion
frameshift
insertion
substitution A B C D
STP 3

70. Standardized Test Practice
Chapter
Molecular Genetics
Standardized Test Practice
How could RNA interference be used to treat diseases such as cancer and diabetes?
by activating genes to produce proteins that can overcome the disease
by interfering with DNA replication in cells affected by the disease
by preventing the translation of mRNA into the genes associated with the disease
by shutting down protein synthesis in the cells of diseased tissues A B C D
STP 4

71. Chapter
Molecular Genetics
Standardized Test Practice
The structure of a protein can be altered dramatically by the exchange of a single
amino acid for another.
True
False A B
STP 5

72. Glencoe Biology Transparencies
Chapter
Molecular Genetics
Glencoe Biology Transparencies

73. Chapter
Molecular Genetics
Image Bank

74. Chapter
Molecular Genetics
Image Bank

75. Section 1 Vocabulary double helix nucleosome Section 1
Molecular Genetics
Vocabulary
Section 1
double helix
nucleosome

76. Section 2 Vocabulary semiconservative replication DNA polymerase
Molecular Genetics
Vocabulary
Section 2
semiconservative replication
DNA polymerase
Okazaki fragment

77. Section 3 Vocabulary RNA messenger RNA ribosomal RNA transfer RNA
Molecular Genetics
Vocabulary
Section 3
RNA
messenger RNA
ribosomal RNA
transfer RNA
transcription
RNA polymerase
codon
intron
exon
translation

78. Section 4 Vocabulary gene regulation operon mutation mutagen Section 4
Molecular Genetics
Vocabulary
Section 4
gene regulation
operon
mutation
mutagen

79. Visualizing Transcription and Translation Lac-Trp Operon
Chapter
Molecular Genetics
Animation
Structure of DNA
DNA Polymerase
Transcription
Visualizing Transcription and Translation
Lac-Trp Operon

80. Chapter
Molecular Genetics

81. Chapter
Molecular Genetics

82. Chapter
Molecular Genetics

83. Chapter
Molecular Genetics

84. Chapter
Molecular Genetics