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.

Chromosome A 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!)

DNA Name 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 Requires: Nucleotides (raw material) DNA polymerase (enzyme) DNA template

GENOTYPE vs. PHENOTYPE Potential 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 replication DNARNAPROTEIN transcriptiontranslation 1 GENE 1 PROTEIN The 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: McGraw Hill Very nice animated exercise Very simple and nice cartoon of transcription and translation Another nice simple animation of both hhttp:// Others + games at:

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 ATGCGCTATCCA ATGCCCATCCAA TATGCATCCA CTGCGCTATCCA

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 EYE THQ ONE BIG FLY HAD ONE RED EYE THE ONE BIG FLY HAD ONE RED EYE THE ONE QBI GFL YHA DON ERE DEY E Point mutation, missense THE ONE BIG FLY HAD ONE RED EYE THE 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