ch 7: microbial genetics. nucleotide (2.27) (2.25)
TRANSCRIPT
Ch 7: Microbial Genetics
Nucleotide (2.27)
(2.25)
(2.26)
antiparallel
Base-pairs
Theory
Idea
Prokaryotic chromosome(s)
Eukaryotic chromosomes - condensation
gene or group of genes
Bacterial chromosome map
DNA replication
DNA replication
3’
DNA replication
5’
Replication of a prokaryotic chromosome
Replication of a eukaryotic chromosome
Where the energy comes from
genotype
phenotype
Serratia at 25 & 37 oC
Transcription
3 kinds of RNA
5’3’
5’3’
3’
3’5’
5’
5’
terminator
Eukaryotic transcription
mRNA modification
Cap
Tail
Edit
Translation: Universal Genetic Code
41
42
43
5’3’
ribosomes
large
large
small
small
Flattened (2D) view
more 3D view
Where amino acid binds
Where it binds to mRNA
tRNAs
Translation: initiation
Peptidyl Amino-acyl
exit
Translation: elongation
Translation: termination
Translation differences
Control of gene expression
Prokaryotic genes
lac operon: makes enzymes for lactose catabolism
inducible
more usual
more unusual
trp operon: makes enzymes for tryptophan synthesis
repressible
more usual
more unusual
Mutations: point
5’ 3’
Nitrous acid
Mutagens
Mutagens
Non-ionizing radiation
4 kinds of DNA repair
Positive selection
rare
see more
replica plating
Negative selection
Ames Test for mutagens
(or a little)
Vertical transfer = between generations {from parent(s) to offspring}
Horizontal transfer = between contemporaries (sometimes different species)
Usual genetic recombination mechanisms in eukaryotes
sex
crossing-over during meiosis
Transformation: DNA from the environment
Transduction
Bacterial conjugation
Producing an Hfr cell
Transposons
aka. “jumping genes”
McClintock (NP 1983)
Ultimate source of Human Genetic information:
Online Mendelian Inheritance in Man (OMIM)
(at the National Library of medicine website)
http://www.ncbi.nlm.nih.gov/