Protein Synthesis Flashcards
What are UTRs?
UTRs stand for untranslated regions and there can be either a 5’ UTR or 3’UTR.
UTRs do not code for anything but are still very important as the 5’ UTR determines the rate at which the protein is synthesised and the 3’ UTR determines how stable the RNA is (before degradation).
What is the coding region?
The coding region is the area which is translated.
In the coding region, the bases are read in triplet code, the start codon always being AUG (methionine).
These codons are recognised by the standard base pairing with the tRNA- the anticodon being complementary to the codon, bringing the specific amino acid.
How are amino acids degenerate?
As triplet codes are used and four types of bases, its means 64 codons are possible. However there are only 20 amino acids that can be created which means that one amino acid can be coded for by more than one triplet code.
How doe being degenerate help the genes?
It can help protect the genes from deleterious effects of mutations so results in silent mutations.
What is it about the genetic code that helps support the theory of evolution?
There is a great amount of generality within the genetic code (with a few noble variations) -the genetic code is also used by majority of biological organisms.
LOOK OVER THE POSTER FOR THE STEP IN PROTEIN SYNTHESIS.
LOOK OVER THE POSTER FOR THE STEP IN PROTEIN SYNTHESIS.
Where can the two populations of ribosomes that can carry out protein synthesis be found?
Bound to the endoplasmic reticulum or free ones that can be found in the cytosol.
Where does the protein translation occur in the ribosome?
In the cleft between ribosomal units.
What a eukaryotic ribosomes made out of?
They are composed of two subunits which are made from multiple ribosomal RNA and proteins.
What is the three reading frames in mRNA?
Codons are read in a continuous batch so there are three separate reading frames and each reading frame translates to a completely different peptide sequence.
There is only one frame for each mRNA and this is determined by the location of the AUG start codon.
If there is a deletion or insertion of amino acids, then the reading frame will be changed e.g. in frame 2, one nucleotide is deleted and in frame 3 two nucleotides are therefore deleted, and this could cause a completely different sequence of amino acids (this can occur if there are mutations).
What are the differences between the size of the ribosomes between bacterial and mammalian ribosomes?
Bacteria have 70s
Eukaryotes have 80s
What are the differences between the sizes of the large and subunit sizes between bacterial and mammalian ribosomes?
Bacteria have 50s & 30s
Eukaryotic have 60s & 40s
*the reason why the Eukaryotic ribosome adds up to 80s and not 100s is because when the subunits are added together, the volume and size of the subunits become smaller.
What are the differences in the components present in large subunits between bacterial and mammalian ribosomes?
Bacteria have 23S & 5S RNA and 31 proteins
Eukaryotic have 28S, 5.8S & 5S RNA and 49 proteins.
What are the differences in the components present in small subunits between bacterial and mammalian ribosomes?
Bacteria have 16S RNA and 21 proteins
Eukaryotic have 18S RNA and 33 proteins.
What is the benefit of having these differences between bacterial and mammalian ribosomes?
It allows us to use certain chemicals/substances to target certain ribosomes such a bacterial ones in order to destroy or stop the reproduction of more bacteria.
