Translation Flashcards
why is the central dogma a simplification
- Central dogma is a simplification due to the regulatory links which can pass information back, where proteins and RNA interact of DNA and control information
just after transcription takes place what is happening
- RNA has left the nucleus with PolyA tail and 5’cap
- Genetic data is transcribed to a readable format
- And now it can be translated to a useable format
where does translation occur
occurs on large complexes called the ribosome
what does translation use
Translation involves 4 things
- MRNA
- TRNA
- Ribosome 30S and 50s
- RRNA – ribosomal RNA
what does tRNA do
tRNA coverts mRNA to amino acids
what does rRNA do
rRNA catalyses the attachment of each new amino acid to the growing chain
what is the ribosome made out of
ribosome is made out of..
- 60% RNA
- 40% protein
A codon is …
three bases pairs that code for one amino acid
where do you start the reading frame
- you start the reading frame from the first codon this is AUG
- this defines the sequence that is read and the protein that is made
how many possible reading frames are there
- there are 6 possible reading frames – there are 3 on one strand and 3 on the other strand
what is a frame shift mutations
- frame shifting mutations – any mutation that removes 1 or 2 bases leads to frame shift
what direction do you read protein sequences from
- protein sequences always written from N terminal, analogous to 5’- with a protein sequence you start with the N terminal – always read from N-terminus to C terminius (5’-3’)
what are degerneacy
this is the fact that there is more than one codon per amino acid
what is a codon usage bias
- there is a codon usage basis – certain codons that are used for one amino acid that are more common than other
what are the stop codons and what do they do
- some are STOP codons these mark the end of a protein
- these are UAA, UGA, UAG
why are there 64 possible combinations but only 20 amino acids
because of the degenerative nature of the genetic code - wobbling in tRNA allows degeneracy to happen
what shape does tRNA have
has an l shaped 3D fold
what are the different ends of a tRNA molecule
- one end is of the molecule is attached to a specific amino acid –this is catalysed by aminoacyl tRNA transferase
- the other end has three exposed bases – the anti-codon this is the loop at the bottom, this is complementary to one codon
what does aminoacyl tRNA do
- aminoacyl tRNA synthetase catalyses and error checks
how is the tRNA held together
shape of tRNA held together by hydrogen bonds between complimentary pairs