1. Replication, Transcription & Translation Notes Unit 3

2. Step 1: Replication • Replication: the process of DNA copying itself • DNA needs to replicate before the cell can reproduce Animation: http://www.hhmi.org/biointeractive/dna/animations.html

3. Replication steps • First step: enzymes “unzip” DNA into two separate strands • Each strand serves as a pattern to make new DNA molecules • Second step: free nucleotides join onto strands to form two new strands of DNA, aided by enzymes • Two complete strands will result, these will be exactly alike • Each resulting strand has one “old” half and one “new” half Animation: http://www.johnkyrk.com/DNAreplication.html

4. Animation: http://www.johnkyrk.com/DNAtranscription.html Step 2: Transcription • produces RNA from DNA • Genetic code from DNA is transferred to mRNA to form protein • Segment of DNA separates in nucleus, one segment serves as pattern for RNA • The code obtained from DNA lets the mRNA know which amino acids to pick up • Code is set of 3 nitrogen bases (called codon)

5. Step 3: Translation • Conversion of RNA into amino acid sequence that makes a protein • The mRNA leaves the nucleus and enters the cytoplasm • Ribosomes attach to mRNA • tRNA picks up the correct amino acids and carries them to the mRNA strand forming the protein Animation: http://www.johnkyrk.com/DNAtranslation.html

6. Review of Process (Animation) • http://www.johnkyrk.com/er.html