1. DNA Replication & Protein Synthesis

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

3. 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--

4. 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

5. 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

6. 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.

7. 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

8. 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

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

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

11. AUG UCG GCA