Genetics Lecture 3: Translation of mRNA - Protein Synthesis Flashcards
Structure of Eukaryotic Genes
- Promotor (includes TATA Box and Start Codon)
- Terminator Sequence followed by Stop Codon
- Three Exons
- Each Exon is divided by Introns
- Message Structure runs as:
Start - Information - End
Where is the Genetic Information Stored?
In the Codons.
What is a Codon?
It’s a set of 3 Bases.
What is the start Codon?
AUG.
What are the stop Codons?
UAA, UAG, UGA.
How many Amino Acids are there?
20 Amino Acids.
How many Codons are there?
61 Codons.
What is the Amino Acid/Codon relationship?
Degenerate but not ambiguous
Lots of different codons code for the same amino acid but the cell is never confused because it’s always the same.
Where does Protein assemble take place?
In the Ribosome.
What determines the amino acid sequence?
The mRNA Sequence.
Describe the process of Translation in basic terms.
- Initiation
- Binding of the 2nd tRNA
- Peptide bond formation
- Release of initial tRNA
- Binding of next tRNA
- Termination
- Peptide release
Describe the process of Translation in more detailed terms.
- The next complementary amino-acyl - tRNA binds at A site
- A New Peptide Bone is Formed
- The Previous tRNA is released from the P site
- The Ribosome moves by one codon
- The process repeats unit stop codon is reached
Where does TRANSCRIPTION take place?
Nucleus
Where does TRANSLATION take place?
Cytoplasm
APPLICATION QUESTION: Explain what is meant by a gene at the molecular level.
A molecular definition of a gene is an organized unit of DNA sequences that enables a segment of DNA to be transcribed into RNA and ultimately results in the formation of a functional product
