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Transcription. The Central Dogma. DNA Transcription RNA Translation Proteins. replication. transcription. translation. GOAL. Use DNA to make a Protein Step 1: Replicate DNA Step 2: Transcribe DNA into RNA Step 3: Translate RNA into a protein Where does this happen? Step 1: Nucleus
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The Central Dogma • DNA • Transcription • RNA • Translation • Proteins
replication transcription translation GOAL • Use DNA to make a Protein • Step 1: Replicate DNA • Step 2: Transcribe DNA into RNA • Step 3: Translate RNA into a protein • Where does this happen? • Step 1: Nucleus • Step 2: Nucleus • Step 3: Cytoplasm Ribosomes
RNA vs. DNA DNA RNA Sugar: Ribose Bases: A,U,C,G Single Stranded • Sugar: Deoxyribose • Bases: A,T,C,G • Double Stranded
RNA • Stands for: Ribonucleic Acid • Three Types: • mRNA • Carries the message from the DNA to the ribosome • tRNA • Brings amino acids from the cytoplasm to the ribosome • rRNA • Makes up part of the ribosome
Transcription Basics • Process of taking DNA and turning it into RNA • Uses enzymes: Chemical Reaction • Happens in the nucleus
RNA Polymerase start site nucleotides Transcription • Starts because of an enzyme called RNA polymerase • This enzyme starts to unwind the DNA at the start of a gene • Nucleotides pair with ONE strand of DNA • RNA Polymerase (enzyme) bonds them together DNA molecule
mRNA Transcription • DNA winds back up • mRNA detaches and leaves the nucleus
Transcription vs Replication Similarities • Both involve enzymes • Both pair the matching bases together • Happens in the nucleus
Transcription Only copies ONE gene Only copies ONE side A will match with U instead of T Final Product: mRNA Replication Copies the ENTIRE strand Copies BOTH sides A will match with T Final Product: Same thing you started with (DNA) Transcription vs Replication Differences
Goal of Translation • Convert mRNA into amino acids that will end up building a protein • Proteins are polymers of amino acids
codon for methionine (Met) codon for leucine (Leu) Amino acids are coded by mRNA base sequences. • Codons are three letters words • There are 64 different codons • Each word means (translates) into ONE of the AMINO ACIDS
Codons Review: Codon=3 nucleotides that are read together. If this is the strand of mRNA: UCGCACGGU The codons are: UCG-CAC-GGU How many codons are there? 3
The genetic code matches each codon to its amino acid or function. • There are 20 Amino Acids
Amino acids are linked to become a protein • An anticodon is a set of three nucleotides that is complementary to an mRNA codon. • An anticodon is carried by a tRNA.
Your Turn Strand of mRNA: AUGCGUACCUUAUAA What are the codons? AUG-CGU-ACC-UUA-UAA What are the anticodons? UAC-GCA-UGG-AAU-AUU
tRNA carries amino acid to ribosome • ribosome forms bonds between the amino acids.
Important Notes • Start: ALWAYS start with codon AUG • What amino acid will you always start with? • Methionine (AUG) • End: ALWAYS end with a STOP • Which codons will that be? • UAA, UAG, UGA