basic genetics, common to all living things

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

RECIPE

DNA

PROTEIN

RNA

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