Gene Expression 2 (Genetics 5) Flashcards
Translation
during translation only mRNA is translated
Translation: Overview
DNA in nucleus serves as a
template
2. mRNA is processed before leaving
the nucleus
3. When mRNA is formed it has
codons
4. mRNA moves into cytoplasm and
becomes associated with ribosomes
5. tRNA with anticodon carries amino
acid to mRNA
6. Anticodon-codon complementary
base pairing occurs
7. Peptide chain is transferred from
resident tRNA to incoming tRNA
8. tRNA departs and will soon pick up
another amino acid
Codon
a sequence of three nucleotides on the mRNA
Initiation
Assembly of three components that carry out the process; Ribosome, tRNA and mRNA
Elongation
Stepwise addition of amino acids to the growing protein chain
Termination
stop codon is encountered, triggering dissociation of the complex
Structure of the ribosome
Large ribosomal sub-unit contains three slots for tRNA and the small ribosomal sub-unit contains the mRNA binding site
How many units do ribosomes have?
two
Wobble position
The third nucleotide in a codon it is at the 5’ end of the anticodon, the identify of this base is not as important if the first two have matched up (may result in Watson-Crick Base pairing)
aminoacyl-tRNA synthetases
specific for each amino acid, helps find the right tRNA molecule and use ATP
What is the size of the large ribosomal sub-unit?
50s
What is the size of the small ribosomal sub-unit?
30s
What does the small ribosomal sub-unit contain?
the mRNA binding site
What does the ribosome contain structurally?
Proteins, rRNA and an active site
What does wobble pairing allow for?
lets the same tRNA recognize multiple codons for the amino acid it carries
