1. MOLECULAR GENETICS
CHAPTER
10 and 13

2. The Blue People of Troublesome Creek

3. Analysis Questions for The Blue People of Troublesome Creek
What physical TRAIT did Martin Fugate and his wife pass on to their many generations of offspring?
What physical VARIATION of this trait did Martin Fugate and his wife pass on to their many generations of offspring?
Why did this condition occur?
What role did genes play in both the appearance of the trait and the passing on of the trait?
Based on this reading and your responses to the above questions, how might you begin to define the term “genetics”?
Based on this reading and your responses to the above questions, how might you begin to define the term “trait”?
Based on this reading and your responses to the above questions, describe the relationship between enzymes (proteins) and traits.

4. CENTRAL DOGMA OF MOLECULAR BIOLOGY
DNA
Transcription
RNA
Translation
Protein
Trait
Replication
CENTRAL DOGMA OF MOLECULAR BIOLOGY

5. On the road to discovery of DNA….
Hershey and Chase 1952
worked with viruses that infect bacteria called bacteriophages and E. Coli bacteria
Found DNA, not protein, is the hereditary molecule.
Chargaff 1947
For all organisms, adenine = thymine and cytosine = guanine
Wilkins and Rosalind Franklin, early 1950’s
studied the structure of DNA crystals using X-rays.
Found double helix with equal subunits
Watson and Crick, 1953
Used Chargaff's base data and Franklin’s X-ray diffraction data to construct a model of DNA.

6. DNA Deoxyribonucleic acid
A large polymer used to carry the genetic code of all living organisms

7. DNA bound protein is called CHROMATIN
DNA is found packed in the nucleus of eukaryotic organisms; it is found in the cytoplasm of prokaryotic organisms
DNA is packed together and wrapped around special proteins called HISTONES
DNA bound protein is called CHROMATIN
When chromatin condenses (gets thicker) it forms CHROMOSOMES
Gene  DNA  Chromatin  Chromosomes

8. DNA structure Double Helix - twisted ladder
Made of monomers called nucleotides
Nucleotides are composed of:
Deoxyribose: 5 carbon sugar (side of helix)
Phosphate group (side of helix)
Purine and Pyrimidine Base (steps ladder)
Hydrogen bonds hold sides together

9. Nucleotide

10. Nitrogenous Bases Two types: Purines (2 RINGS) Pyrimidines (1 RING)
Purines (two rings) larger bases
Pyrimidines (one ring) smaller bases
Purines (2 RINGS)
Adenine and Guanine
Pyrimidines (1 RING)
Thymine and Cytosine
Purines
Adenine Guanine
Pyrimidines
Cytosine Thymine
Deoxyribose
Phosphate group

11. Chargaff’s rules: Base pairing rule is A-T and G-C
Thymine is replaced by Uracil in RNA
Bases are bonded to each other by weak hydrogen bonds
Discovered because of the relative percent of each base; (notice that A-T is similar and C-G are similar) there was complementary base pairing of a purine with a pyrimidine
The paired bases can occur in any order, giving an overwhelming diversity of sequences

12. DNA REPLICATION Making a complete copy of an entire length of DNA
Occurs in S phase of cell cycle for both Mitosis and Meiosis
Occurs in the nucleus of the cell
Complimentary sides are formed due to nitrogenous base pairing joined by hydrogen bond

13. Semi Conservative Model
Explains process of replication
1 original DNA serves as template (guide) for making another DNA side
Replication will work in opposite directions on both sides at same time

14. How Does Replication Start?
an enzyme called helicase “unzips” the DNA to create a replicating bubble.
Single stranded binding proteins keep 2 sides apart and stable
Another enzyme, DNA polymerase, moves along the bases on each side and connects complementary nucleotides.

15. Anti Parallel Strand DNA runs in opposite directions
It is read in a 5  3 direction
5’Carbon of Deoxyribose has phosphate attached to it
1’ Carbon of sugar has nitrogen base attached to it
3’ Carbon of sugar has an open bond (connector site for next nucleotide)

17. Leading vs. Lagging Strand in replication fork
Runs in a continuous 5’  3’ direction as it opens
Lagging
Doesn’t run in 5’  3’ direction
Slower, works backward making Okazaki fragment

18. How does DNA get the genetic code out of the nucleus???
Transcription and Translation with RNA

19. RNA Ribonucleic acid Single-stranded Sugar is ribose
Thymine is replaced by URACIL

20. Differences between DNA & RNA
Structure:
Double stranded
Sugar
Deoxyribose
Bases:
Adenine
Guanine
Cytosine
Thymine
RNA
Structure:
Single stranded
Sugar
Ribose
Bases:
Adenine
Guanine
Cytosine
Uracil

21. Transcription- how RNA is made
Occurs in Nucleus
Makes a disposable copy of DNA, just in form of RNA
RNA polymerase temporarily separates the strands of a small section of the DNA molecule exposing some of the bases of the DNA molecule.
Along one strand, the RNA polymerase binds complementary RNA nucleotides to the exposed DNA bases.
As the RNA polymerase moves along, it makes a strand of messenger RNA (mRNA). It carries DNA’s message out of the nucleus and into the cytoplasm.

22. Types of RNA: Messenger RNA (mRNA) Ribosomal RNA (rRNA)
carries information from DNA to ribosome
Ribosomal RNA (rRNA)
Combines with proteins that makes up ribosomes
Transfer RNA (tRNA)
Carries amino acids to ribosome

23. PROTEIN SYNTHESIS TRANSCRIPTION – the synthesis of RNA
under the direction of DNA
TRANSLATION – the actual synthesis of a protein, which occurs under the direction of mRNA

25. Codons
a sequence of 3 nitrogen bases on mRNA that code for 1 amino acid, it’s a triplet code; Universal with all life.
61 of 64 codons code for 20 amino acids on earth
Codons match up with anticodons to create a protein

27. The Genetic Code The Messenger RNA Genetic Code Second Letter U C A G
First Letter
Third Letter
Second Letter U C A G U
Phenylalanine (UUU)
Serine (UCU)
Tyrosine (UAU)
Cysteine (UGU) U
Phenylalanine (UUC)
Serine (UCC)
Tyrosine (UAC)
Cysteine (UGC) C
Leucine (UUA)
Serine (UCA)
Stop (UAA)
Stop (UGA) A
Leucine (UUG)
Serine (UCG)
Stop (UAG)
Tryptophan (UGG) G C
Leucine (CUU)
Proline (CCU)
Histadine (CAU)
Arginine (CGU) U
Leucine (CUC)
Proline (CCC)
Histadine (CAC)
Arginine (CGC) C
Leucine (CUA)
Proline (CCA)
Glutamine (CAA)
Arginine (CGA) A
Leucine (CUG)
Proline (CCG)
Glutamine (CAG)
Arginine (CGG) G A
Isoleucine (AUU)
Threonine (ACU)
Asparagine (AAU)
Serine (AGU) U
Isoleucine (AUC)
Threonine (ACC)
Asparagine (AAC)
Serine (AGC) C
Isoleucine (AUA)
Threonine (ACA)
Lysine (AAA)
Arginine (AGA) A
Methionine;Start (AUG)
Threonine (ACG)
Lysine (AAG)
Arginine (AGG) G G
Valine (GUU)
Alanine (GCU)
Aspartate (GAU)
Glycine (GGU) U
Valine (GUC)
Alanine (GCC)
Aspartate (GAC)
Glycine (GGC)
Glycine (GGC) C
Valine (GUA)
Alanine (GCA)
Glutamate (GAA)
Glycine (GGA) A
Valine (GUG)
Alanine (GCG)
Glutamate (GAG)
Glycine (GGG) G

28. Translation Occurs in cytoplasm
mRNA combines with a ribosome mRNA carries the codon
tRNA carries the anticodon which pairs up with the codon
These amino acid links form a protein

29. SO: Say the mRNA strand reads: tRNA would bring the amino acids:
mRNA (codon) AUG–GAC–CAG-UGA
tRNA (anticodon) UAC-CUG-GUC-ACU
tRNA would bring the amino acids:
Methionine-Aspartic acid-Glutamine-stop

31. TRANSCRIPTION AND TRANSLATION

32. MUTATION
Change in nucleotide sequence of DNA or mRNA that code for a protein
Caused by mutagens (physical or chemical interactions that change the nucleotide sequence of DNA)

33. 2 types of mutations Point mutations
Single nucleotide mutates and affects a single codon
Reading Frameshift
Alter codon sequence
Insertion: adding nucleotides to the sequence
Deletion: taking out nucleotides from the sequence

34. GENETIC ENGINEERING
A new form of manipulation that biologists created where they can engineer a set of genetic changes directly into an organisms DNA

35. BIOTECHNOLOGY
Computers and other devices used to help in performing science
DNA gene cloning is an example

36. POLYMERASE CHAIN REACTION
Requires no organism in the production of new DNA molecules
Turns a single molecule of DNA into a large, identical DNA molecules
Used in forensics

37. Recombinant DNA Major focus of genetic engineering
The sequence of nucleotides in the gene being manipulated are read
Desired gene is cut from surrounding genes
DNA from 2 different sources is joined into one molecule (hybrid)

38. Plasmids
molecules of DNA found in bacteria separate from the bacterial chromosome.
small (a few thousand base pairs) and circular
usually carry only one or a few genes

39. TRANSFORMATION
Genetic alteration of a cell that is caused from directly taking in DNA from outside the cell membrane.
It can occur naturally in some species of bacteria, but it can also be effected by artificial means in other cells

40. DNA Fingerprinting
Pattern of bands made up of specific fragments from an individuals DNA
Restriction enzymes can cut the DNA at specific sites with “sticky ends”
DNA Ligase can join DNA at specific sites
The DNA created artificially is called recombinant DNA

41. Gel Electrophoresis Creates a DNA fingerprint
Different DNA samples are exposed to the SAME restriction enzyme creating RFLP (fragments of different lengths of DNA)
Those fragments are loaded into agarose gel and electric currents are used
RFLP’s will separate according to length/size of the fragments which create a unique fingerprint

42. Transgenic Organisms
Recombined DNA from 2 different organisms to make 1 organism that has traits from BOTH parents.
These traits will then be carried on to offspring

43. Human Genome Project Began 1990 ended in 2003
Mapped out entire DNA genome nucleotide sequences for all humans as a species
Contains approximately 40,000 different genes

44. What is DNA technology used for?
Gene therapy
Pharmaceuticals
Criminal Forensics
Environmental Clean-up
Agriculture
Livestock