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. DNA stands deoxyribonucleic acid
Section 1
Molecular Genetics
DNA: The Genetic Material
What is DNA?
DNA stands deoxyribonucleic acid
DNA is a molecule that encodes the genetic instructions used in the development and functioning of all known living organisms and many viruses
What would the DNA of a building be?
Blueprints

4. Genetic info. stored in DNA codes for proteins
Section 1
Molecular Genetics
DNA: The Genetic Material
What is DNA?
Genetic info. stored in DNA codes for proteins
Genes are segments of DNA
DNA is a nucleic acid
Proteins, carbohydrates and nucleic acids compose the three major macromolecules essential for all known forms of life

5. The pairs of nitrogen bases form the steps.
Section 1
Molecular Genetics
DNA: The Genetic Material
DNA Structure
DNA is called a double helix and often is compared to a twisted ladder.
Rails of the ladder are represented by the alternating: deoxyribose sugar and phosphate.
The pairs of nitrogen bases form the steps.

6. Section 1
Molecular Genetics
DNA: The Genetic Material
DNA Structure

7. There are 4 nitrogen bases: cytosine (C) guanine (G) thymine(T)
Section 1
Molecular Genetics
DNA: The Genetic Material
Nitrogen bases
There are 4 nitrogen bases:
cytosine (C)
guanine (G)
thymine(T)
adenine(A)
The four bases pair up to make the “steps” on the “ladder”
C-G, A-T

8. 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′.

9. 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.

10. 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

11. 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
R bacteria incorporated this DNA into their cells and changed into S cells.

12. 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

13. 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

14. 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

15. 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

16. 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

17. 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.

18. 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.

19. 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.

20. 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.

21. 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.

22. 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 areas as DNA is replicated.
In prokaryotes, the circular DNA strand is opened at one origin of replication.

23. Section 3
Molecular Genetics
DNA, RNA, and Protein
Central Dogma: an explanation of the flow of genetic information within a biological system

24. Contains the sugar ribose and the base uracil instead of thymine
Section 3
Molecular Genetics
DNA, RNA, and Protein
RNA- Ribonucleic acid
Perform multiple important roles in the coding, decoding, regulation, and expression of genes.
Contains the sugar ribose and the base uracil instead of thymine
Usually is single stranded

25. Associates with proteins to form ribosomes in the cytoplasm
Section 3
Molecular Genetics
DNA, RNA, and Protein
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

26. 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.

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. DNA, RNA, and Protein Translation
Section 3
Molecular Genetics
DNA, RNA, and Protein
Translation
Based off of the codon RNA is converted to amino acids that are strung together to make proteins.
RNAProtiens

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

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

31. 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
Frame shift
Duplication

32. Involves a chemical change in one base pair
Section 4
Molecular Genetics
Gene Regulation and Mutation
Point mutations
Involves a chemical change in one base pair
Substitutions
Missense – codes for the wrong amino acid
Nonsense - change the code for an amino acid to a stop codon. Leads to improper function of proteins

33. Insertion – inserts the wrong base into the three base sequence
Section 4
Molecular Genetics
Gene Regulation and Mutation
Frameshift
Changes the multiples of three and cause the “frame” (codon) to shift right or left.
Insertion – inserts the wrong base into the three base sequence
Deletion - Removes a base from the three base sequence

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

35. 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.

36. Body-cell v. Sex-cell Mutation
Section 4
Molecular Genetics
Gene Regulation and Mutation
Body-cell v. Sex-cell Mutation
Somatic cell (normal 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.

37. Section 2
Genetics and Biotechnology
DNA Technology
Genetic Engineering
Technology that involves manipulating the DNA of one organism in order to insert the DNA of another organism

38. Genetically engineered organisms are used
Section 2
Genetics and Biotechnology
DNA Technology
Genetically engineered organisms are used
to study the expression of a particular gene.
to investigate cellular processes.
to study the development of a certain disease.
Genetically engineered bollworm
to select traits that might be beneficial to humans.

39. Mice, fruit flies, and the roundworm
Section 2
Genetics and Biotechnology
DNA Technology
Transgenic Animals
Scientists produce most transgenic animals in laboratories for biological research.
Mice, fruit flies, and the roundworm

40. Genetically engineered cotton resists insect infestation of the bolls.
Section 2
Genetics and Biotechnology
DNA Technology
Transgenic Plants
Genetically engineered cotton resists insect infestation of the bolls.
Sweet-potato plants are resistant to a virus that could kill most of the African harvest.
Rice plants with increased iron and vitamins could decrease malnutrition.

41. Section 2
Genetics and Biotechnology
DNA Technology
Restriction enzymes recognize and bind to specific DNA sequences and cleave the DNA within the sequence.
Scientists use restriction enzymes as powerful tools for isolating specific genes or regions of the genome.

42. Section 2
Genetics and Biotechnology
DNA Technology
The newly generated DNA molecule with DNA from different sources is called recombinant DNA.

43. An organism’s genome is the total DNA in the nucleus of each cell.
Section 2
Genetics and Biotechnology
DNA Technology
DNA Tools
An organism’s genome is the total DNA in the nucleus of each cell.
DNA tools can be used to manipulate DNA and to isolate genes from the rest of the genome.

44. The Human Genome Project
Section 3
Genetics and Biotechnology
The Human Genome
The Human Genome Project
The goal of the Human Genome Project (HGP) was to determine the sequence of the approximately three billion nucleotides that make up human DNA and to identify all of the approximately 20,000–25,000 human genes.

45. Section 2
Genetics and Biotechnology
DNA Technology
An electric current is used to separate DNA fragments according to the size of the fragments in a process called gel electrophoresis.

46. Gel electrophoresis Used to: To get a DNA Fingerprint for forensics
To get a DNA fingerprint for paternity testing
To get a DNA fingerprint so that you can look for evolutionary relationships among organisms
To check a PCR reaction.
To test for genes associated with a particular disease.

47. Section 2
Genetics and Biotechnology
DNA Technology
A technique called the polymerase chain reaction (PCR) can be used to make millions of copies of a specific region of a DNA fragment.

48. Section 2
Genetics and Biotechnology
DNA Technology