Consider a single murine hepatocyte at homeostasis with its surrounding environm
ID: 266466 • Letter: C
Question
Consider a single murine hepatocyte at homeostasis with its surrounding environment, which includes other neighboring hepatocytes and extra-hepatic tissues. Due to changes in the organism’s activity, this hepatocyte receives signals that trigger the need to synthesize exactly 20 copies of a protein required for altered amino acid metabolism.
1.) How many equivalents of ATP are required to synthesize these 20 protein molecules?
Use the following assumptions/constraints when determining your answers:
All of the necessary catalytic complexes have already been synthesized within the cell
Nucleotides used for transcription must be accounted for
A single transcript is sufficient for translation of all 20 polypeptides
The primary transcript contains 400 nucleotides that are not translated. This includes the stop codon and a single intron that must be removed by the spliceosome prior to translation
The poly-A tail contains an additional 210 nucleotides
Amino acids and tRNA’s are readily available, energy required for their synthesis/replacement does not need to be accounted for
Each of the 20 protein molecules to be synthesized are identical, and contains 613 amino acids
Once translated, no further processing of the 20 molecules occurs, they fold spontaneously and do not require other post-translational modifications
Do not account for waste products
Explanation / Answer
Answer : in the translation process it takes approximately
4n-1 ATP where n= number of amino acid in the protein.
One of the protein molecule contains 613 amino acid so
20 contains 613*20=12260 amino acids
So number if ATP required= 12260*4-1= 49040