Brief Introduction to Biology and Genetics

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Brief Introduction to Biology and Genetics
Ryan McConnell STAT 499 September 17, 2004
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All information can be found at

• http//www.ncbi.nlm.nih.gov/About/primer/genetics.
  html

http//www.accessexcellence.org/RC/VL/GG/
(pictures)
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Cells Fundamental Units of Life

• Take in nutrients
• Convert nutrients into energy
• Reproduce
• Information storage (DNA)
• 100,000,000,000,000 cells in humans

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Cell Organization

• 10 times larger
• Organelles
• Organizational complexity

• Unicellular
• Lack nucleus
• Bacteria

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Macromolecules in Cells
Cells are primarily filled with water
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Basic Cell Structures

• Plasma Membrane comprised of proteins and
  lipids, separates internal and external
  environments
• Cytoplasm the cells 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

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Deoxyribonucleic Acid - DNA
Double helix, 4 nitrogenous bases
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Ribonucleic Acid - RNA

• RNA is single-stranded
• Uracil replaces Thymine
• Many kinds of RNA
• Messenger RNA (mRNA)
• Transfer RNA (tRNA)
• Ribosomal RNA (rRNA)

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(No Transcript)
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DNA Replication is Semiconservative
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Transcription (making a portable copy)
mRNA

• DNA

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Translation portable copy directs protein
synthesis
mRNA
protein
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Ribosomes physical site of protein synthesis
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Mechanism of Translation
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Proteins The Final Product
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Whats in a Genome?
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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

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Chromosomes
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What is a Gene?
Humans are predicted to have up to 30,000 genes
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Terminology Youre 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)

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Control of Gene Expression
Every cell contains the complete genome Kidney
cells have all of the genes expressed in heart
cells, etc.
Regulation can occur at any of the multiple steps
from DNA protein
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Control of Gene Expression, Cont.
Regulatory proteins bind to control regions in
the DNA this regulates the rate of transcription
to mRNA
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Mechanisms of Genetic VariationWhy are we all
different?

• Phenotype Traits that are expressed
• Genotype Genetic composition underlying the
  phenotype
• Recombination a.k.a. crossing over
• Mutations
• Environment

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Meiosis Production of Gametes
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Recombination During Meiosis
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Overview of Mutations
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Inheritance of Genes
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Molecular GeneticsThe Study of Heredity, Genes,
and DNA
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Obtaining DNA
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Isolating mRNA
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DNA Hybridization
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FISH
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Microarrays This is Us!
For a great demo, check out http//www.bio.davids
on.edu/courses/genomics/chip/chip.html
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Building a Genomic Library
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All graphics appear courtesy of the following
websites

• http//www.accessexcellence.org/
• http//www.ncbi.nlm.nih.gov/About/primer/genetics.
  html

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Questions?