2. Chapter 12 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. What is DNA? link
Where is it found?
Why study it?
Where do you see or hear it mentioned?

4. 12-1 DNA
Griffith’s experiment

5. Avery discovered DNA caused transformation.
Chapter 12
Molecular Genetics
12.1 DNA: The Genetic Material
Avery discovered DNA caused transformation.
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.

6. Used radioactive labeling to trace the DNA and protein
Chapter 12
Molecular Genetics
Hershey and Chase link
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

7. Chapter 12
Molecular Genetics

8. DNA Structure Nucleotides
Chapter 12
Molecular Genetics
DNA Structure
Nucleotides
Consist of a five-carbon sugar, a phosphate group, and a nitrogenous base

9. Chargaff’s rule: C = G and T = A
Chapter 12
Molecular Genetics
12.1 DNA: The Genetic Material
Chargaff
Chargaff’s rule: C = G and T = A

10. X-ray diffraction data helped solve the structure of DNA- Franklin
Chapter 12
Molecular Genetics
12.1 DNA: The Genetic Material
X-ray Diffraction
X-ray diffraction data helped solve the structure of DNA- Franklin
Indicated that DNA was a double helix

11. two outside strands consist of alternating deoxyribose and phosphate
Chapter 12
Molecular Genetics
12.1 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 (double helix).
Chapter 12
Molecular Genetics
12.1 DNA: The Genetic Material
DNA Structure
DNA often is compared to a twisted ladder (double helix).
Rails of the ladder are represented by the alternating deoxyribose (sugar) and phosphate.
The pairs of bases (cytosine–guanine or thymine–adenine) form the steps.

13. 12.1 DNA: The Genetic Material
Chapter 12
Molecular Genetics
12.1 DNA: The Genetic Material

14. 12.1 DNA: The Genetic Material
Chapter 12
Molecular Genetics
12.1 DNA: The Genetic Material
Chromosome Structure
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. Chapter 12
Molecular Genetics
12.2 Replication of DNA
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.

16. Chapter 12
Molecular Genetics
12.2 Replication of DNA link
Base pairing
DNA polymerase continues adding appropriate nucleotides to the chain by adding to the new DNA strand.

17. Chapter 12
Molecular Genetics

18. Comparing DNA Replication in Eukaryotes and Prokaryotes
Chapter 12
Molecular Genetics
12.2 Replication of DNA
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.

19. Central Dogma DNA  RNA Protein
Chapter 12
Molecular Genetics
12.3 DNA, RNA, and Protein
Central Dogma DNA  RNA Protein
RNA – different from DNA
1. Contains the sugar ribose
2. Contains base uracil not thymine
3. single stranded

20. Associates with proteins to form ribosomes in the cytoplasm
Chapter 12
Molecular Genetics
Messenger RNA (mRNA)
Long strands of RNA nucleotides that are formed complementary to one strand of DNA
Ribosomal RNA (rRNA)
Associates with proteins to form ribosomes in the cytoplasm
Transfer RNA (tRNA)
Smaller segments of RNA nucleotides that transport amino acids to the ribosome

21. Chapter 12
Molecular Genetics

22. Chapter 12
Molecular Genetics

23. RNA will move to the cytoplasm.
Chapter 12
Molecular Genetics
Transcription link
RNA is made from the
DNA code (in nucleus).
RNA will move to the cytoplasm.
DNA is unzipped in the nucleus and RNA
polymerase binds to a specific section where an
mRNA will be synthesized.

24. Chapter 12
Molecular Genetics

25. The three-base code in DNA or mRNA is called a codon. Ex. AGC CCU AAC
Chapter 12
Molecular Genetics
The Code
Experiments during the 1960s demonstrated that the DNA code was a three-base code.
The three-base code in DNA or mRNA is called a codon.
Ex. AGC CCU AAC

26. Translation- the mRNA code is read.
Chapter 12
Molecular Genetics
Translation- the mRNA code is
read.
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.

27. Chapter 12 Molecular Genetics Visualizing Transcription
and Translation

28. Ex: Do babies go through puberty? Explain.
Chapter 12
Molecular Genetics
12.4 Gene Regulation and Mutation
Gene Regulation
Ability of an organism to control which genes are transcribed in response to the environment (turned on and off).
Ex: Do babies go through puberty? Explain.
Do birds nest in the fall? Explain.
Do you make proteins if you don’t need them?
An operon is a section of DNA that contains the genes for the proteins needed for a specific function.

29. Chapter 12
Molecular Genetics
Hox Genes
Hox genes are responsible for the general body pattern of most animals.

30. A permanent change that occurs in a cell’s DNA is called a mutation.
Chapter 12
Molecular Genetics
Mutations
A permanent change that occurs in a cell’s DNA is called a mutation.
Types of mutations
Point mutation –only one base is wrong
Insertion- extra base
Deletion – missing a base
Substitution –different base
Duplication – repeated bases

31. Can occur spontaneously (accidental)
Chapter 12
Molecular Genetics
12.4 Gene Regulation and Mutation
Causes of Mutation
Can occur spontaneously (accidental)
Chemicals and radiation also can damage DNA.
High-energy forms of radiation, such as X rays and gamma rays, are highly mutagenic.

32. Body-cell v. Sex-cell Mutation
Chapter 12
Molecular Genetics
Can mutations be passed on? Are all mutations bad?
Body-cell v. Sex-cell Mutation
Somatic (body cell) 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.
Different DNADifferent RNADifferent AADifferent protein

33. 12.4 Gene Regulation and Mutation
Chapter 12
Molecular Genetics
12.4 Gene Regulation and Mutation

34. Chapter Resource Menu Chapter Diagnostic Questions
Molecular Genetics
Chapter Resource Menu
Chapter Diagnostic Questions
Formative Test Questions
Chapter Assessment Questions
Standardized Test Practice
biologygmh.com
Glencoe Biology Transparencies
Image Bank
Vocabulary
Animation
Click on a hyperlink to view the corresponding lesson.

35. Which scientist(s) definitively proved
Chapter 12
Molecular Genetics
Chapter Diagnostic Questions
Which scientist(s) definitively proved
that DNA transfers genetic material?
Watson and Crick
Mendel
Hershey and Chase
Avery

36. Name the small segments of the lagging DNA strand.
Chapter 12
Molecular Genetics
Chapter Diagnostic Questions
Name the small segments of the lagging
DNA strand.
ligase
Okazaki fragments
polymerase
helicase

37. It contains the sugar ribose. It contains the base uracil.
Chapter 12
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.

38. The experiments of Avery, Hershey and
Chapter 12
Molecular Genetics
12.1 Formative Questions
The experiments of Avery, Hershey and
Chase provided evidence that the carrier
of genetic information is _______.
carbohydrate
DNA
lipid
protein

39. What is the base-pairing rule for purines
Chapter 12
Molecular Genetics
12.1 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

40. What are chromosomes composed of?
Chapter 12
Molecular Genetics
12.1 Formative Questions
What are chromosomes composed of?
chromatin and histones
DNA and protein
DNA and lipids
protein and centromeres

41. The work of Watson and Crick solved the mystery of how DNA works as a
Chapter 12
Molecular Genetics
12.2 Formative Questions
True or False
The work of Watson and Crick solved
the mystery of how DNA works as a
genetic code.

42. Which is not an enzyme involved in DNA replication?
Chapter 12
Molecular Genetics
12.2 Formative Questions
Which is not an enzyme involved in DNA
replication?
DNA ligase
DNA polymerase
hilicase
RNA primer

43. During DNA replication, what nucleotide
Chapter 12
Molecular Genetics
12.2 Formative Questions
During DNA replication, what nucleotide
base sequence is synthesized along an
original strand that has the sequence
TCAAGC?
AGTTCG
ATGGCG
CTGGAT
GACCTA

44. Which shows the basic chain of events
Chapter 12
Molecular Genetics
12.3 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

45. In the RNA molecule, uracil replaces _______.
Chapter 12
Molecular Genetics
12.3 Formative Questions
In the RNA molecule, uracil replaces
_______.
adenine
cytosine
purine
thymine

46. Which diagram shows messenger RNA (mRNA)?
Chapter 12
Molecular Genetics
12.3 Formative Questions
Which diagram shows messenger
RNA (mRNA)? A. C. B. D.

47. What characteristic of the mRNA molecule
Chapter 12
Molecular Genetics
12.3 Formative Questions
What characteristic of the mRNA molecule
do scientists not yet understand?

48. intervening sequences in the mRNA molecule
Chapter 12
Molecular Genetics
12.3 Formative Questions
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

49. Why do eukaryotic cells need a complex
Chapter 12
Molecular Genetics
12.4 Formative Questions
Why do eukaryotic cells need a complex
control system to regulate the expression
of genes?

50. All of an organism’s cells transcribe the same
Chapter 12
Molecular Genetics
12.4 Formative Questions
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.

51. Which type of gene causes cells to become specialized in structure in
Chapter 12
Molecular Genetics
12.4 Formative Questions
Which type of gene causes cells to
become specialized in structure in
function?
exon
Hox gene
intron
operon

52. What is an immediate result of a mutation in a gene?
Chapter 12
Molecular Genetics
12.4 Formative Questions
What is an immediate result of a mutation
in a gene?
cancer
genetic disorder
nonfunctional enzyme
amino acid deficiency

53. Which is the most highly mutagenic?
Chapter 12
Molecular Genetics
12.4 Formative Questions
Which is the most highly mutagenic?
chemicals in food
cigarette smoke
ultraviolet radiation
X rays

54. Look at the following figure. Identify the
Chapter 12
Molecular Genetics
Chapter Assessment Questions
Look at the following figure. Identify the
proteins that DNA first coils around.

55. chromatin fibers chromosomes histones nucleosome
Chapter 12
Molecular Genetics
Chapter Assessment Questions
chromatin fibers
chromosomes
histones
nucleosome

56. Explain how Hox genes affect an organism.
Chapter 12
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.

57. Explain the difference between body-cell and sex-cell mutation.
Chapter 12
Molecular Genetics
Chapter Assessment Questions
Explain the difference between body-cell
and sex-cell mutation.

58. Answer: A mutagen in a body cell becomes
Chapter 12
Molecular Genetics
Chapter Assessment Questions
Answer: A mutagen in a body cell becomes
part of the of the genetic sequence
in that cell and in future daughter
cells. The cell may die or simply not
perform its normal function. These
mutations are not passed on to the
next generation. When mutations
occur in sex cells, they will be
present in every cell of the offspring.

59. What does this diagram show about the replication of DNA
Chapter 12
Molecular Genetics
Standardized Test Practice
What does this
diagram show about
the replication of DNA
in eukaryotic cells?

60. DNA is replicated only at certain places along
Chapter 12
Molecular Genetics
Standardized Test Practice
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.

61. What is this process called?
Chapter 12
Molecular Genetics
Standardized Test Practice
What is this process called?

62. mRNA processing protein synthesis transcription translation
Chapter 12
Molecular Genetics
Standardized Test Practice
mRNA processing
protein synthesis
transcription
translation

63. TTCAGG TTCTGG What type of mutation results in this change
Chapter 12
Molecular Genetics
Standardized Test Practice
What type of mutation results in this change
in the DNA sequence?
TTCAGG TTCTGG
deletion
frameshift
insertion
substitution

64. How could RNA interference be used
Chapter 12
Molecular Genetics
Standardized Test Practice
How could RNA interference be used
to treat diseases such as cancer and
diabetes?

65. by activating genes to produce proteins that
Chapter 12
Molecular Genetics
Standardized Test Practice
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

66. The structure of a protein can be altered
Chapter 12
Molecular Genetics
Standardized Test Practice
True or False
The structure of a protein can be altered
dramatically by the exchange of a single
amino acid for another.

67. Glencoe Biology Transparencies
Chapter 12
Molecular Genetics
Glencoe Biology Transparencies

68. Chapter 12
Molecular Genetics
Image Bank

69. Chapter 12
Molecular Genetics
Image Bank

70. Section 1 Vocabulary double helix nucleosome Chapter 12
Molecular Genetics
Vocabulary
Section 1
double helix
nucleosome

71. Section 2 Vocabulary semiconservative replication DNA polymerase
Chapter 12
Molecular Genetics
Vocabulary
Section 2
semiconservative replication
DNA polymerase
Okazaki fragment

72. Section 3 Vocabulary RNA messenger RNA ribosomal RNA transfer RNA
Chapter 12
Molecular Genetics
Vocabulary
Section 3
RNA
messenger RNA
ribosomal RNA
transfer RNA
transcription
RNA polymerase
codon
intron
exon
translation

73. Section 4 Vocabulary gene regulation operon mutation mutagen
Chapter 12
Molecular Genetics
Vocabulary
Section 4
gene regulation
operon
mutation
mutagen

74. Visualizing Transcription and Translation
Chapter 12
Molecular Genetics
Animation
DNA Polymerase
Transcription
Visualizing Transcription and Translation
Lac-Trp Operon