Microbial Genetics

1
Microbial Genetics

• Heredity
• Chromosomes
• DNA proteins
• Bacterial
• Human

• Genes
• Alleles
• Mutations

2
Genetic Information Storage

• DNA/Base sequences
• Genetic information transfer

3
DNA Replication

• DNA structure
• 5 and 3 ends
• Antiparallel strand orientation
• Strand unwinding

4
DNA Polymerase

• Leading strand synthesis
• Lagging strand synthesis
• Need for DNA Ligase

5
RNA Synthesis

• RNA Polymerase
• Promoter sequence
• Terminator sequence
• 3 RNA types
• rRNA
• mRNA
• tRNA

6
Gene Complexity Compared

• Eukaryotic
• Introns transcribed then spliced out
• Exon shuffling can occur
• Prokaryotic
• No introns
• Operons

7
Genetic Code

• mRNA codons

8
Protein Synthesis

• tRNA anticodons
• Amino acid links
• Role of ribosomes

9
Coupling of Transcription/Translation

• Prokaryotic streamlining of gene expression

10
Regulation of Metabolism

• Enzyme Inhibition
• Enzyme Induction
• Enzyme Repression

11
Mutations

• Genotype
• Phenotype

12
Mutation Types - Substitutions

• Point mutations
• Silent
• Missense
• Nonsense

13
Mutation Types

• Frameshift
• Rearrangements

14
Causes of Mutation

• Spontaneous
• Fragility
• Errors in replication
• Chemical mutagens

• Radiation (Physical mutagens)

15
Mutation Studies

• Genetic diseases
• Xeroderma pigmentosum
• Werners syndrome
• Blooms syndrome
• Progerias
• Accelerated aging
• Mental retardation
• Damage to early neurons

16
Ames Test Detects Mutagens

• Salmonella typhimurium (his-)
• Mutation reverts phenotype to ability to
  biosynthesize histidine
• Rat liver extract added to simulate mammalian
  enzymes
• Bacteria grown with many controls