basic genetics, common to all living things
DESCRIPTION
BASIC GENETICS, COMMON TO ALL LIVING THINGS. CHROMOSOME. GENOME. GENE. DNA. NUCLEOTIDES. MUTATION. NATURAL SELECTION. DNA PART I: STRUCTURE, REPLICATION. GENOME: SUM TOTAL OF ALL HERITABLE DNA IN CELL GENOME SIZE: E. coli genome: 4 million base pairs, 1mm in length. - PowerPoint PPT PresentationTRANSCRIPT
BASIC GENETICS, COMMON TO ALL LIVING THINGS
GENOME
NUCLEOTIDES
CHROMOSOME
GENE
DNA
MUTATION
NATURAL SELECTION
DNA PART I:
STRUCTURE, REPLICATION
GENOME: SUM TOTAL OF ALL HERITABLE DNA IN CELL
GENOME SIZE: E. coli genome: 4 million base pairs, 1mm in length
Human: closer to 4 billion base pairs.
ChromosomeA single molecule of DNA
The single molecule of DNA is always double stranded
In bacteria - the chromosome is circular! And there is only 1
What is the difference between chromosome and genome?
GENE
Segment of DNA that encodes 1 protein
Usually several hundred base pairs in length
E. coli genome, with some important genes named (not all!)
DNAName of the chemical that makes up the chromosomes in all living things
All DNA shares some important chemical characteristics
Made up of 4 kinds of nucleotides (ACTG), double stranded
All DNA differs slightly in the way that it’s put together that makes each living thing unique
One of 4 bases in DNA:
Adenosine
Guanine
Cytosine
Thymine
Structure of a nucleotide, the building block of DNA chains
DNA BASE PAIRING: A with T, C with G
REPLICATION
DNA DNA
Requires:
Nucleotides (raw material)
DNA polymerase (enzyme)
DNA template
GENOTYPE vs. PHENOTYPEPotential vs. actual or 'expressed' properties
The genotype of an individual refers to the information encoded by all the genes, which are all present in duplicate
The phenotype refers to how the genes are expressed as physical traits in the individual or bacterial cell.
DNA PART II:
TRANSCRIPTION,
TRANSLATION,
MUTATION,
Control of gene expression
FLOW OF GENETIC INFORMATION:
DNA DNA replication
DNA RNA PROTEIN transcription translation
1 GENE 1 PROTEINThe Central Dogma
Transcription:Produces an mRNA molecule that matches the sequence of the gene
DNA RNA
Requires:
DNA template
Nucleotides (raw material)
RNA polymerase (enzyme)
gene
mRNA molecule
Translation:Convert the mRNA information into
a protein molecule
RNA PROTEIN
Requires:
mRNA, Ribosomes,
tRNA molecules carrying amino acids
mRNA
tRNA molecules carrying each amino acid
Ribosome
Protein
TRANSCRIPTION and TRANSLATION ANIMATIONS
Transcription:http://www.fed.cuhk.edu.hk/~johnson/teaching/genetics/animations/transcription.htm
McGraw Hillhttp://highered.mcgraw-hill.com/sites/0072437316/student_view0/chapter15/animations.html
Very nice animated exercisehttp://gslc.genetics.utah.edu/units/basics/transcribe/
Very simple and nice cartoon of transcription and translationhttp://www.lewport.wnyric.org/jwanamaker/animations/Protein%20Synthesis%20-%20long.html
Another nice simple animation of bothhhttp://www.wisc-online.com/objects/index_tj.asp?objid=AP1302
Others + games at: http://science.nhmccd.edu/biol/ap1int.htm
Noncoding DNA, sequence between genes
Introns
Exons Eukaryotes only
INTRONS, EXONS, NON-CODING DNA
MUTATION
RECIPE
DNA
PROTEIN
RNA
MUTATION
Change in genetic material (base sequence of the DNA)
TYPES OF MUTATION
Base substitution
(May or may not be Missense)
Nonsense
Frameshift
BACTERIAL GENETICS, CONTINUED
A TG CG CT A T CCA
A TG C CC A T CCA A
T A TG C A T CCA
C TG CG CT A T CCA
HOW DOES MUTATION OCCUR??
Mistakes in replication - chemical mutagens - radiation
Compounds that cause mutation are called mutagens
Mutations that occur without seeming cause are ‘spontaneous’
MUTATIONS CAN BE BENEFICIAL!
Cells have safeguards and repair mechanisms
THE ONE BIG FLY HAD ONE RED EYETHE ONE BIG FLY HAD ONE RED EYETHE ONE BIG FLY HAD ONE RED EYETHQ ONE BIG FLY HAD ONE RED EYE
THE ONE BIG FLY HAD ONE RED EYETHE ONE BIG FLY HAD ONE RED EYETHE ONE BIG FLY HAD ONE RED EYETHE ONE QBI GFL YHA DON ERE DEY E
Point mutation, missense
THE ONE BIG FLY HAD ONE RED EYETHE ONE BIG FLY HAD ONE RED EYETHE ONE BIG FLY HAD ONE RED EYETHE ONE BIG
Frameshift, insertion
Nonsense
MUTATION???Mutation = alteration in DNA base pair sequence
Mutation sometimes occurs naturally - mistakes during DNA replication
Mutation may also occur because of environmental exposure to chemicals, UV light, radiation, etc.
Consequences of mutation??
There may be none
Protein may be altered
Protein may be non-functional or not made at all