Happy Thursday! Submit Reading Guide for Essay, Replication Errors and Mutation A few announcements –Videos posted online –Are you doing a type of cancer for your disease project? –Disease Project

Gene Expression: How do genotypes become phenotypes? From mom From Dad

Before these two cells form a zygote (YOU!), how much genetic information do each of them have? Hint: A zygote has 46 chromosomes. One gamete (sex cell) Another gamete

Chromosome: –Structure found in the nucleus of all* cells –Made of DNA and protein, compacted DNA: –Hereditary material “given” to us by our parents –Double helix shape –Stores genetic “gene” information –Self-replicates to produce 2 exact copies of itself

Gene: –A segment of DNA that serves as a code for a specific product. Ex: presence of dimples, curly hair, blood type A, etc. Gene for hitch- hikers thumb

The Big Picture Gene for hitch- hikers thumb

GenotypePhenotype inherit Propose how this occurs. What other factors might be included “within” the blue arrow? How do you go from alleles (A, a) to an actual phenotype that is noticeable?

The Central Dogma DNA RNA Protein

DNA  RNA  Protein TranscriptionTranslation Replication

DNA Structure Nucleotides (monomers) along one strand of DNA are represented by the bases A, T, C, G

DNA Replication DNA, must be copied accurately to preserve an organism’s genotype Occurs before a cell divides so the new cells will have identical DNA Occurs before meiosis and before mitosis. Takes place in the nucleus. Enzymes used: –Helicase: Unwinds double helix –DNA Polymerase: Creates new strand

DNA Replication Complimentary base pairing rules : A  T C  G Make a complimentary strand of DNA 5’ CGTGGTTAAATCTGA 3’

After DNA replication, there’s enough DNA to go around (in each cell)…you can now begin to process/use it! Gene Expression

What does this look like in the cell?

Transcription The assembly of an RNA molecule from a DNA template RNA = Ribonucleic Acid. Single strand. Uses complimentary base pairing* Takes place in nucleus Enzyme that does this? RNA polymerase Possible outcomes mRNA, tRNA, rRNA

Transcription New Rules: DNA 5’ GTACGTCTCCTCTAATT 3’ mRNA C  G G  C T  A A  U

Translation The assembly of polypeptides (which become proteins) using the information from mRNA Enzyme* that does this? tRNA mRNA is “read” in triplets called codons Codons code for amino acids Chains of amino acids make up proteins Takes place in cytoplasm

DNA AGGTACTCCTCTA ATT RNA UCCAUGAGGAGAUUAA Polypeptide The Genetic Code 

The Genetic Code

Translation Alanine Threonine Glutamate Leucine Arginine Serine Stop!

Where to start / stop? Translation begins –When enzyme spots AUG on mRNA –AUG = “start codon” –AUG translates to Methionine Translation stops –3 different stop codons: UAA, UAG, UGA

Some smaller details DNA 5’ AGGCTATGGGATAC 3’  “Gene”/sense strand 3’ TCCGATACCCTATG 5’ template strand mRNA5’ AGGCUAUGGGAUAC 3’ tRNA reads 5’  3’ Polypeptide

Once your amino acid sequence is complete, it folds along itself and becomes a protein! Helps you express your phenotype

Discuss with your neighbors: 1.Where does DNA Replication take place? 2.Where does Transcription take place? 3.What does Transcription produce? 4.Where does Translation take place? 5.What does Translation produce? 6.The Genetic Code is used to figure out what amino acids are assembled based on the strand created from the strand

Your Task Work on Gene Expression Practice Problems