DNA Replication & Protein Synthesis

DNA may go through 1 of 2 processes DNA Replication Protein Synthesis

DNA Replication Replication: Mitosis & Meisosis Steps Find origin of replication (replication fork) DNA unwinds  reveal nitrogenous base Floating nitrogenous bases attach to open segments Identical strand formed that is complementary Rewinds into double helix C-- T -- A -- G--

HONORS EXTENSION: DNA Replication New DNA replicates in the 5’  3’ direction DNA replication is anti-parallel- 2 new strands replicating in opposite directions Leading strand- copied directly the entire length Okazaki Fragments- lagging strand- copied in short fragments Discontinuous

HONORS EXTENSION: Enzymes Involved in DNA Replication Helicase- unwinds DNA Creates replication fork DNA polymerase- joins nucleotides Only works if there is a nucleotide before it on the new strand RNA polymerase/primer- starts nucleotide attachment Does not need an existing nucleotide on the new strand to join

Central Dogma: Protein Synthesis: Step 1 Occurs in nucleus Transcription- re-write DNA onto RNA strand Isolate segment of DNA to transcribe Enzyme reads DNA Attach bases according to base pair rules A pairs with U Product: mRNA (messenger RNA) 1.

Protein Synthesis: Step 2 mRNA leaves nucleus Goes to ribosome in cytoplasm for the remainder of protein synthesis DNA winds back up in the nucleus 2. Ribosome

Protein Synthesis: Step 3 Translation- make an amino acid chain 3. Anti-codon- Compliments mRNA codon tRNA- Carries needed amino acid mRNA- threads through ribosome Ribosome Codon- 3 nitrogenous bases- tell ribosome which amino acid to make

Protein Synthesis: Step 3 Cont’d Complementary tRNA attaches to mRNA codon via dehydration synthesis Amino acids link tRNA floats away

Protein Synthesis DNA & RNA codon sequences control the production of protein Sequence of amino acids determines the shape of the protein that is made

AUG UCG GCA