Agenda 4/23 and 4/24 DNA replication and protein synthesis review Central Dogma Posters Homework 1. DNA replication video and notes 2. Protein Synthesis Video and Notes

Central Dogma

DNA Replication DNA replication is used to create new DNA before cell division Semi-conservative replication is used One side of ‘old’ DNA is used to create the ‘new’ side of DNA DNA replication depends on complementary base pairing Guanine-Cytosine Thymine-Adenine

Meselson and Stahl Experiment

Enzymes of DNA Replication 1. Helicase- unwinds the double helix by breaking the hydrogen bonds between two bases 2. DNA polymerase- links nucleotides together to form a new strand using the pre-existing strand as a template

Transcription Transcription is the synthesis of mRNA copied from a DNA template RNA Polymerase ‘reads’ the DNA and pairs mRNA nucleotides using base pair rules Adenine-Uracil Guanine-Cytosine Thymine-Adenine Occurs in the nucleus of eukaryotic cells

Translation Synthesis of polypeptides on ribosomes Amino acid sequence is determined by mRNA sequence Codons of 3 bases of mRNA code for 1 amino acid The tRNA carries the correct amino acid and will base pair with mRNA to create the polypeptide chain

Use of a codon chart If the DNA sequence is ATGCCCGGA, what would the mRNA sequence be? What would the amino acid sequence be?

Overview Posters 1. DNA replication 2. Transcription 3. Translation Sample DNA sequence (at least 15 letters) Semi-conservative nature Helicase DNA polymerase Hydrogen bonds, anti-parallel structure, sugar-phosphate backbone, nitrogen bases Complementary base pairing 2. Transcription Location RNA polymerase Sugar-phosphate backbone 3. Translation Location in cell mRNA codon tRNA anticodon Peptide Bonds Ribosome Amino acids