Replication Transcription Translation Notes Unit 3 Replication the

Replication, Transcription & Translation Notes Unit 3

Replication: the process of DNA copying itself DNA needs to replicate before the cell can reproduce Animation: http: //www. hhmi. org/biointeractive/dn a/animations. html

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/DNArepli cation. html

DNA Replication Occurs during S phase of Cell Cycle Must occur prior to cell dividing

Helicase unzips double helix DNA polymerase joins nucleotides

Resulting daughter cells (at conclusion of mitosis and cytokinesis) each have identical DNA

Transcription DNA has specific instructions for making proteins (base sequence) Protein synthesis happens at the ribosome DNA cannot leave nucleus DNA will unwind at particular area with specific protein instructions m. RNA will form with these instructions (this is transcription)

Transcription Produces m. RNA from DNA Genetic code (instructions from DNA) which will ultimately form specific protein Segment of DNA unwinds & separates, revealing pattern for m. RNA The code obtained from DNA dictates which amino acids are needed Codon= trio of nitrogen bases (1 codon 1 amino acid) Protein = chain of amino acids

m. RNA leaves nucleus Travels to ribosome with “message” (instructions) for protein synthesis

m. RNA arrives at ribosome with a series of codons (protein assembly instructions)

t. RNA will respond with specific “anticodons” (complementary base pair rules apply), bringing the corresponding amino acid to the ribosome

Translation Conversion of RNA into amino acid sequence that makes a protein The m. RNA leaves the nucleus and enters the cytoplasm Ribosomes attach to m. RNA t. RNA picks up the correct amino acids and carries them to the m. RNA strand forming the protein Animation: http: //www. johnkyrk. com/DNAtransl ation. html

Translation Process by which protein is actually formed as per original instructions from DNA Occurs at the ribosome Amino acids = building blocks of proteins Proteins = polypeptides(macromolecules) Sequence of aa determines protein

The Genetic Code

4 Bases 64 possible combinations (codons) 20 amino acids

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