1. 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

2. Section 1
Molecular Genetics
DNA: The Genetic Material
Griffith
Performed the first major experiment that led to the discovery of DNA as the genetic material in 1928.
Griffith's experiment, reported in 1928 by Frederick Griffith, was the first experiment suggesting that bacteria are capable of transferring genetic information through a process known as transformation.
He showed that bacteria can get DNA through a process called transformation. 

3. Concluded that when the S cells were killed, DNA was released
Section 1
Molecular Genetics
DNA: The Genetic Material
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
Avery was one of the first molecular biologists and a pioneer in immunochemistry, but he is best known for the experiment (published in 1944 with his co-workers Colin MacLeod and Maclyn McCarty) that isolated DNA as the material of which genes and chromosomes are made.
R bacteria incorporated this DNA into their cells and changed into S cells.
Identified DNA as the transforming factor in 1944

4. Used radioactive labeling to trace the DNA and protein
Section 1
Molecular Genetics
DNA: The Genetic Material
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
Proved that DNA was the genetic material in a virus in 1952

5. DNA: The Genetic Material
Section 1
Molecular Genetics
DNA: The Genetic Material
DNA Structure
Nucleotides
Consist of a five-carbon sugar, a phosphate group, and a nitrogenous base

7. Chargaff’s rule: C = G and T = A
Section 1
Molecular Genetics
DNA: The Genetic Material
Chargaff
Chargaff’s rule: C = G and T = A

8. X-ray diffraction data helped solve the structure of DNA
Section 1
Molecular Genetics
DNA: The Genetic Material
X-ray Diffraction
X-ray diffraction data helped solve the structure of DNA
Indicated that DNA was a double helix

9. 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

10. DNA often is compared to a twisted ladder.
Section 1
Molecular Genetics
DNA: The Genetic Material
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.

11. 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′.

12. The DNA strands are antiparallel
Structure of DNA
The DNA strands are antiparallel
They run in opposite directions.
One strand is arranged 5’ to 3’ while the other strand is 3’ to 5’
5’ and 3’ refer to the carbon atoms in the deoxyribose sugar.

13. DNA: The Genetic Material
Section 1
Molecular Genetics
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.

14. Semiconservative Replication
Section 2
Molecular Genetics
Replication of DNA
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.
Pg 122

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

16. Section 2
Molecular Genetics
Replication of DNA
Base pairing
DNA polymerase continues adding appropriate nucleotides to the chain by adding to the 3′ end of the new DNA strand.

17. 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.

18. Figure 12.8 DNA synthesis takes place in opposite directions on the two DNA template strands. DNA replication at a single replication fork begins when a double-stranded DNA molecule unwinds to provide two single-strand templates.

19. Figure 12.9 DNA synthesis is continuous on one template strand of DNA and discontinuous on the other.

20. 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.
DNA ligase links the two sections.

21. Comparing DNA Replication in Eukaryotes and Prokaryotes
Section 2
Molecular Genetics
Replication of DNA
Comparing DNA Replication in Eukaryotes and Prokaryotes
Eukaryotic DNA unwinds in multiple (many) areas as DNA is replicated (replication takes place in nucleus)
In prokaryotes, the circular DNA strand is opened at one origin of replication (replication takes place in cytoplasm)

23. Contains the sugar ribose and the base uracil instead of thymine
Section 3
Molecular Genetics
DNA, RNA, and Protein
Central Dogma
RNA
Contains the sugar ribose and the base uracil instead of thymine
Usually is single stranded

24. Form part of the ribosome
Section 3
Molecular Genetics
DNA, RNA, and Protein
Messenger RNA (mRNA)
Carry genetic information from the nucleus to the cytoplasm to direct protein synthesis
Ribosomal RNA (rRNA)
Form part of the ribosome
Transfer RNA (tRNA)
Carry amino acids to the ribosome

25. DNA is unzipped in the nucleus and RNA
Section 3
Molecular Genetics
DNA, RNA, and Protein
Transcription
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.

26. RNA Processing (RNA splicing/RNA Editing)
Section 3
Molecular Genetics
DNA, RNA, and Protein
RNA Processing (RNA splicing/RNA Editing)
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.
RNA splicing removes the introns from pre mRNA to produce the final set of instructions for the protein.

27. The three-base code in DNA or mRNA is called a codon.
Section 3
Molecular Genetics
DNA, RNA, and Protein
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.

28. Each anticodon is complementary to a codon on the mRNA.
Section 3
Molecular Genetics
DNA, RNA, and Protein
Translation
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.

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

30. Intervening sequences are called introns.
Section 3
Molecular Genetics
DNA, RNA, and Protein
RNA Processing
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. The three-base code in DNA or mRNA is called a codon.
Section 3
Molecular Genetics
DNA, RNA, and Protein
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.

32. Each anticodon is complementary to a codon on the mRNA.
Section 3
Molecular Genetics
DNA, RNA, and Protein
Translation
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.

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

34. Prokaryote Gene Regulation
Section 4
Molecular Genetics
Gene Regulation and Mutation
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

35. Types of Cells Affected
Germ Mutation - affects a reproductive cell (gamete or sperm/egg)
Does not affect the organism
Passed to offspring
Example: downs syndrome
Somatic Mutation – affects body cells
(all cells except gametes)
Not passed to offspring
Germ: An example of a chromosome mutation in a sex cell would be trisomy 21 (aka downs syndrome), where a sex cell has an extra chromosome due to a homologous pair of chromosomes failing to separate during meiosis.
The most common disease caused by these mutations is cancer.

36. A permanent change that occurs in a cell’s DNA is called a mutation.
Section 4
Molecular Genetics
Gene Regulation and Mutation
Mutations
A permanent change that occurs in a cell’s DNA is called a mutation.
Types of mutations
Point mutation: happens when there is a change in a single base pair in the DNA

37. Animated Intro to Cancer (12:07)
Mutagens
Mutations can be caused by chemical or physical agents mutagens
Chemical
pesticides, tobacco smoke, environmental pollutants
Physical
X-rays and ultraviolet light
Animated Intro to Cancer (12:07)

38. Point mutations include:
Insertions
Deletions
Substitutions

39. Frameshift mutation: happens when a single nitrogenous base is added or deleted from the whole DNA sequence.
Example: Deletion and insertion
Frameshift mutations can change every amino acid that follows the point of the mutation and can alter a protein so much that it is unable to perform its normal functions.

40. Frameshift Mutation
Insertions and deletions are also called frameshift mutations because they shift the “reading frame” of the genetic message.

41. Frameshift Mutation: Example: Deletion: THE FAT CAT ATE THE RAT
THE FAT ATA TET HER AT
Insertion:
THE FAT CAR TAT ETH ERA T

42. Section 4
Molecular Genetics
Substitution
A substitution mutation occurs when one base pair is substituted for another.
Substitutions also can lead to genetic disorders.

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

44. Body-cell v. Sex-cell Mutation
Section 4
Molecular Genetics
Gene Regulation and Mutation
Body-cell v. Sex-cell Mutation
Somatic 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.

45. 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

46. 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 Deoxyribose. A B C D
CDQ 3

47. 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

48. 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

49. 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

50. 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

51. 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

52. 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

53. 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

54. 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

55. 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

56. 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

57. 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

58. Explain the difference between body-cell and sex-cell mutation.
Chapter
Molecular Genetics
Chapter Assessment Questions
Explain the difference between body-cell and sex-cell mutation.
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.
CAQ 3

59. 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

60. 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

61. 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

62. 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