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Presentation on theme: "Transcription."— Presentation transcript:

1 Transcription

2 The Central Dogma DNA Transcription RNA Translation Proteins

3 GOAL Use DNA to make a Protein Where does this happen?
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 replication transcription translation

4 RNA vs. DNA DNA RNA Sugar: Deoxyribose Bases: A,T,C,G Double Stranded
Sugar: Ribose Bases: A,U,C,G Single Stranded

5 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

6 Transcription Basics Process of taking DNA and turning it into RNA
Uses enzymes: Chemical Reaction Happens in the nucleus

7 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 start site nucleotides RNA Polymerase DNA molecule

8 Transcription DNA winds back up mRNA detaches and leaves the nucleus

9 Transcription vs Replication Similarities
Both involve enzymes Both pair the matching bases together Happens in the nucleus

10 Transcription vs Replication Differences
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)

11 Translation

12 Goal of Translation Convert mRNA into amino acids that will end up building a protein Proteins are polymers of amino acids

13 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 codon for methionine (Met) leucine (Leu)

14 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

15 The genetic code matches each codon to its amino acid or function.
There are 20 Amino Acids

16 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.

17 Your Turn Strand of mRNA: AUGCGUACCUUAUAA What are the codons?
What are the anticodons? UAC-GCA-UGG-AAU-AUU

18 tRNA carries amino acid to ribosome
ribosome forms bonds between the amino acids.

19 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

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