Brief Introduction to Biology and Genetics Ryan McConnell STAT 499 September 17, 2004

All information can be found at: (pictures)

Cells – Fundamental Units of Life Take in nutrients Convert nutrients into energy Reproduce Information storage (DNA) 100,000,000,000,000 cells in humans

Cell Organization 10 times larger Organelles Organizational complexity Unicellular Lack nucleus Bacteria

Macromolecules in Cells Cells are primarily filled with water

Basic Cell Structures Plasma Membrane – comprised of proteins and lipids, separates internal and external environments Cytoplasm – the cell’s fluid-filled inner space Nucleus – contains genetic material Mitochondria – perform respiration to generate energy, replicate independently, contain their own DNA Ribosomes – site of protein synthesis, attached to ER or free-floating

Deoxyribonucleic Acid - DNA Double helix, 4 nitrogenous bases

Ribonucleic Acid - RNA RNA is single-stranded Uracil replaces Thymine Many kinds of RNA: –Messenger RNA (mRNA) –Transfer RNA (tRNA) –Ribosomal RNA (rRNA)

DNA Replication is Semiconservative

Transcription (making a portable copy) DNA mRNA

Translation – portable copy directs protein synthesis mRNAprotein

Ribosomes – physical site of protein synthesis

Mechanism of Translation

Proteins – The Final Product

What’s in a Genome?

DNA Packaging DNA from a single human cell is over 1 meter long when stretched out How does it fit in a cell? –Several layers of packaging result in structures called chromosomes

Chromosomes

What is a Gene? Humans are predicted to have up to 30,000 genes

Terminology You’re Likely to Encounter Locus – The position at which a gene is located on a chromosome Alleles – Different versions of a gene at the same locus ex. Locus for pea plant size has either “tall” allele or “short” allele Mitochondrial Genes – mitochondria have their own DNA separate from the nucleus endosymbiont theory, maternal inheritance (sperm lack mitochondria) Genome – the full set of chromosomes and DNA contained within an organism (organism-specific)

Control of Gene Expression Regulation can occur at any of the multiple steps from DNA protein Every cell contains the complete genome Kidney cells have all of the genes expressed in heart cells, etc.

Control of Gene Expression, Cont. Regulatory proteins bind to control regions in the DNA this regulates the rate of transcription to mRNA

Mechanisms of Genetic Variation Why are we all different? Phenotype – Traits that are expressed Genotype – Genetic composition underlying the phenotype Recombination – a.k.a. “crossing over” Mutations Environment ≠

Meiosis – Production of Gametes

Recombination During Meiosis

Overview of Mutations

Inheritance of Genes

Molecular Genetics The Study of Heredity, Genes, and DNA

Obtaining DNA

Isolating mRNA

DNA Hybridization

FISH

Microarrays – This is Us! For a great demo, check out:

Building a Genomic Library

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Questions?