Protein Synthesis - Translation Flashcards
What is the third process in Protein Synthesis called?
Translation
What does the mature mRNA do once it’s in the cytoplasm?
It finds and binds to a ribsosome
Which end of the mature mRNA enters the ribosome?
the 5’ end with the start codon
How many bases/codons can you fit in a ribosome?
You can fit 6 bases or in other words, 2 codons
What happens to the first codon in the ribosome?
A tRNA molecule carrying an the complementary base pairs for the start codon enters the ribosome
Where do the tRNA molecules entering ribosome come from?
They are floating around in cytosol
What is the full-form of tRNA
Transfer RNA
What is tRNA’s specific structure?
- Made froma single stranded RNA molecule containing 76 nucleotides
- Strand coils and forms complementary base pairing with itself
- There are 3 haipin loop structures, one is the anti-codon loop
- 4th end of tRNA is acceptor stem wheer amino acid is joined
What does the tRNA do once it enters the ribosome?
The complementary base pairs bond to the mRNA base pairs
What important structure does the tRNA carry at the top of the molecule?
Amino Acid
What is special about the first tRNA molecule to bind to the first mRNA codon?
It is always the same tRNA molecule carrying the same amino acid methionine, as every mRNA starts with the same start codon and will have the same tRNA with complementary base pairs bond to it.
How many different amino acids are there?
20
What happens when the first tRNA molecule finished binding?
It leaves the ribosome, leaving the amino acid behind, and the mRNA moves along 3 bases at a time in a 5’ to 3’ direction. A new tRNA molecule follows the same process.
What happens to all the amino acids left behind?
The amino acids left behind bond to each other, forming a polypeptide chain
When does Translation stop?
When the stop codon is reached, ribosome falls off, as there is no tRNA molecule for the stop codon.
What is left behind after Translation?
The final protein is made by the chained amino acids
What is function of mRNA
Carry genetic message from DNA in nucleus to ribosomes in cytoplasm to be translated into protein.
What is function of rRNA?
Helps make the structure of ribosome with help of other proteins
What is function of tRNA
Molecules that carry specific amino acids based on their anticodons which bind to complementary mRNA codons. Taken to ribsome to help construct proetins.
Where is Rough Endoplasmic Reticulum found?
Near nucleus
What is role of Rough Endoplasmic Reticulum?
- Folding of polypeptide
- Sometimes modification of polypeptide
- Packaged into vesicles to be transported to golgi apparatus
Where is Golgi Apparatus found?
Near cell wall/membrane
What is role of Golgi apparatus?
- Further modification of protein
- If necessary glycoproteins are formed (sugar added to protein)
- Packaged into scretory vesicle to be exocytosed out of cell (exported)
