Special Topics. Review of Gene Expression Outline Definition of gene expression Proteins- the end product of gene expression Polymers of monomers Joined by peptide bond C. Denaturing of proteins leads to loss of function i. Ways to denature protiens
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Special Topics Review of Gene Expression Outline Definition of gene expression Proteins- the end product of gene expression Polymers of monomers Joined by peptide bond C. Denaturing of proteins leads to loss of function i. Ways to denature protiens D. Genes code for proteins i. Genome vs. gene ii. Polymer of monomers (nucleic acid vs. nucleotide) Transcription – DNA to RNA A. Where does this occur? Translation –RNA to protein A. Where does this occur? Why do we care about gene expression as allied health students? Terminology to be aware of throughout the semester
Structural molecules • Enzymes • Receptors for signals and hormones • Adhesion molecules • Recognition markers Gene Expression- the process that makes a heart a heart, a brain a brain, and you different from me. The final end result is the synthesis of a protein. DNA RNA Protein The physiology comes from protein functions!
R R R R Proteins are chains of amino acids linked by the Peptide Bond Primary structure
Essential 20: central carbon, hydrogen, amine group and carboxyl group....different R groups Glycine Alanine Valine Leucine Isoleucine Serine Threonine Cysteine Methionine Glutamic acid
Aspartic acid Lysine Arginine Asparagine Glutamine Phenylalanine Tyrosine Histidine Tryptophan Proline
Denaturing proteins: loss of structure leads to loss of function Heat pH high salt What is another way to change a protein’s conformation?
R R Folding and coiling is stabilized by bonds formed between the “R groups” of amino acids. First, understand this:
Changing a single amino acid can change the shape of the protein Can result in loss of protein function
Genes code for proteins A gene is a code which determines the sequence of amino acids in a protein DNA RNA Protein So changes in a gene can result in changes in protein structure (and the protein’s ability to function)
Genome vs gene? • Genome: like a cookbook • Gene: single recipe • How are recipes written? • Ingredient list • Order of adding ingredients • The gene= the recipe for a protein. • Which amino acids to link together • Order of linking them together • Mutation= heritable change
April 2003- Human Genome Project was completed.What do we know • Haploid genome is a little over 3 billion base pairs. • 20-25,000 protein-encoding genes • What’s the rest? • RNA genes (tRNA, rRNA, RNAi/ RNAa’s, too) • “junk DNA” (pseudogenes) • Repeating elements, transposons, etc.
DNA is • Macromolecule made by dehydration synthesis • Double stranded • Antiparallel • 5’ end to 3’end • has base-pairing rules: • A-T • C-G
transcription Transcription: Making a “working copy” of a gene. This process occurs in the nucleus of a cell DNA RNA Protein RNA: • Is a macromolecule • is single stranded • It contains the sugar ribose (rather than deoxyribose) • It lacks T, uses U instead (uracil rather than thymine)
Translation: the ribosome makes a protein using the code in the mRNA molecule and this occurs in the cytoplasm
Summary Interactive Workshop Activity on Protein Synthesis http://www.pbs.org/wgbh/aso/tryit/dna/index.html#
Why do we care about gene expression? • Drug reaction due to expression of “alternate” forms of genes. (Personalized medicine is coming! NewScientist 27 Oct 2007) • Some people are more susceptible to disease states or infection (HIV/ Alzheimer’s / Diabetes/ obesity) • Your feelings can alter gene expression! (September 2007 issue of Genome Biology) loneliness desensitizes the glucocorticoid receptor and cuts off immune control and anti-inflammatory effects of cortisol. • Massage/hugging/gentle touch increases the synthesis and release of oxytocin (a protein hormone). More oxytocin means better social bonds. • The smell of coffee upregulates gene expression of nine different genes • Just to name a few......
Terminology • Mutation vs. DNA damage • Pluripotent vs. unipotent stem cells • Determined vs. Differentiated