The how and why of information flow in living things. Microbial Genetics The how and why of information flow in living things. What exactly is living? http://www.nature.com/news/2010/100407/full/news.2010.169.html Interesting argicle on the results of transformation. Nick

Genetics Terms Genome: Chromosome Gene Base pair Genetic code Genotype Phenotype The sum total of information carried by a cell, consists of chromosomes and extra chromosomal information Chromosome: The large DNA molecule of a bacterial cell that contains all the information/plans for the cell. Gene: a segment of DNA and its sequence of nucleotides that codes for a functional product, usually but not always a protein. Base pair: In the double helix structure each rung of this twisted latter is made of 2 nucleotides either AT or GC, These complementary base pairs make the replication of DNA possible. Each strand serves as a template for the other strand. Genetic code: the linear sequence of nucleotides that codes for specific RNA’s and proteins. For proteins each set of 3 nucleotides codes for a specific amino acid within the protein. Genotype: the genetic composition of an organism, its entire complement of DNA. Phenotype: the expression of an organisms genes: the protein of the cell and the properties they confer on the organism.

The Polymers of life Define Polymer Define Monomer What are the polymers of life? Why use polymers? Polymer: a molecule consisting of a sequence of similar molecules, or monomers. Monomer: One of something, molecules of similar structure that are combined together to make a polymer. Polymers of life are: Proteins, Nucleic acids, Carbohydrates and lipids Why use polymers? The use of polymers allows cells to create incredibly complex molecules with complex functions with out having to create a multitude of different materials. Like the English language that is made up of about 26 sounds (Yes I know there are more). But the amount of information that is contained in our language and our communication is generated by those 26 sound.

Determine Relatedness Clinical Focus, p. 223 4

Determine Relatedness Which strain is more closely related to the Uganda strain? Strain % Similar to Uganda Kenya 71% U.S. 51% 5

The genetic Code Name the monomers that make up the genetic code. Name the monomers that make up Proteins A,G,T,C 20 amino acids make up the proteins

What is the flow of genetic information in the bacterial cell? Verb Enzyme Substrate Product Replication: DNA Polymerase: DNA: DNA Transcription: RNA polymerase: DNA: RNA Translation: Ribosome's and various: RNA: Protein Reverse transcription: reverse transcriptase: RNA: DNA

Genetic Map of the Chromosome of E. coli Figure 8.1b 8

The Flow of Genetic Information Figure 8.2 9

DNA Replication The double strand of DNA is separated. DNA polymerase reads the DNA strand and creates another. The newly synthesized DNA contains an old strand and a new strand. The two new strands are then separated into the two new daughter cells.

Semiconservative Replication Figure 8.3a 11

DNA Synthesis Figure 8.4 12

DNA Synthesis DNA is copied by DNA polymerase In the 5'  3' direction Initiated by an RNA primer Leading strand is synthesized continuously Lagging strand is synthesized discontinuously Okazaki fragments RNA primers are removed and Okazaki fragments joined by a DNA polymerase and DNA ligase 13

Transcription A sequence of DNA is relaxed and opened up. RNA polymerase synthesizes a strand of RNA RNA uses ACGU Starting point is a promoter

Transcription Figure 8.7 15

The Process of Transcription Figure 8.7 16

Translation mRNA associates with ribosome's (rRNA and protein) 3-base segments of mRNA specify amino acids and are called codons. Genetic code: relationship among nucleotide sequence and corresponding DNA sequence.

Degenerate: Most amino acids are code for by more than one codon. 64 codons 3 are nonsense Start codon Aug is for methionine. See the codon sequence.

The Genetic Code Figure 8.8 19

Simultaneous Transcription & Translation Figure 8.10 20

The Process of Translation Figure 8.9 21

The Process of Translation Figure 8.9 22

The Process of Translation Figure 8.9 23

The Process of Translation Figure 8.9 24

The Process of Translation Figure 8.9 25

The Process of Translation Figure 8.9 26

The Process of Translation Figure 8.9 27

The Process of Translation Figure 8.9 28

Info From information storage to reality. What determines what info is used What determines how information is moved about.

Regulation Constitutive genes are expressed at a fixed rate Other genes are expressed only as needed Repressible genes Inducible genes Catabolite repression 30

Operon ANIMATION Operons: Overview Figure 8.12 31

Induction Figure 8.12 32

Induction Figure 8.12 33

Repression Figure 8.13 34

Repression ANIMATION Operons: Induction ANIMATION Operons: Repression Figure 8.13 35

Catabolite Repression (a) Growth on glucose or lactose alone (b) Growth on glucose and lactose combined Figure 8.14 36

Lactose present, no glucose Lactose + glucose present Figure 8.15 37

Types of Bacterial sex Name Process What it is Comments What is sex and why is it important? Transformation: naked DNA is transferred between cells. Conjugation: F+ and f- cells. Transduction: phage used to move DNA about. Plasmids and Transposes.

Genetic Recombination The rearrangement of genes. Crossing over is where genes are recombined within a chromosome.

Transformation Naked DNA is transferred from one bacteria to another. Was the first experiment that showed DNA was the genetic information

Genetic Recombination Figure 8.25 42

Genetic Transformation ANIMATION Transformation Figure 8.24 43

Conjugation DNA transferred from one bacteria to another by a sex pillus. Information of transfer coded by a plasmid called F+ Hfr cells occur when F+ plasmid goes into the host chromosome and recombines, it will then draw across the DNA.

Bacterial Conjugation Figure 8.26 45

Conjugation in E. coli Figure 8.27a 46

Conjugation in E. coli Figure 8.27b 47

Conjugation in E. coli Figure 8.27c 48

Transduction DNA is passed from one bacterium to another in a bacteriophage and put into recipients DNA.

Transduction by a Bacteriophage Figure 8.28 50

Alternate forms of the chromosome format. Plasmids: self replicating circular molecules of NDA Transposes: small segments of DNA that can move into different parts of the genome. Can these have an effect on Evolution?

Control of gene expression Repression Induction

The Operon Model of gene expression Repression: regulatory mechanism inhibits gene expression Induction: a process that turn on gene expression

Repressible Operon

Inducible operon

Where are the points of control

If a cell has all the genes that are needed then why are they not expressed at one time?

Mutations What are they?

Mutations What can they do

Mutation A change in the genetic material Mutations may be neutral, beneficial, or harmful Mutagen: Agent that causes mutations Spontaneous mutations: Occur in the absence of a mutagen 62

Mutation Base substitution (point mutation) Change in one base Missense mutation Change in one base Result in change in amino acid Figure 8.17a, b 63

Mutation Nonsense mutation Results in a nonsense codon Figure 8.17a, c 64

Mutation Frameshift mutation Insertion or deletion of one or more nucleotide pairs Figure 8.17a, d 65

The Frequency of Mutation 66

Chemical Mutagens Figure 8.19a 67

Radiation Ionizing radiation (X rays and gamma rays) causes the formation of ions that can react with nucleotides and the deoxyribose-phosphate backbone 68

Radiation UV radiation causes thymine dimers Figure 8.20 69

Repair Photolyases separate thymine dimers Nucleotide excision repair Figure 8.20 70

Selection Positive (direct) selection detects mutant cells because they grow or appear different Negative (indirect) selection detects mutant cells because they do not grow Replica plating 71

Replica Plating Figure 8.21 72

Ames Test for Chemical Carcinogens Figure 8.22 73

The old and new genetics Screening and selection of mutants

What do you think we would call the new genetics?