Question

1.The same amino acid sequence protein produced in bacteria can have different bioactivity than when produced in mammalian cells. Explain why.

2.Carbohydrate conversion to energy that cells can use has a component that occurs in the cell cytoplasm and a part that occurs in the mitochondria. In cancer cells, how does this get altered?

Answer 1

Ans 1:- Even the polypeptide sequence is same but the bioactivity changes when protein is expressed in mammalian cells than E.coli. Because, mammalian cells containing various post translation modification like glycosylation, phosphorylation, disulfide bond formation. These post translational modification may change the bioactivity of protein in mammalian cells. In contrast bacterial cells don't have these modifications thus bioactivity is different even if the amino acid sequence remain same.

Ans 2:- The cancer cell have altered metabolism, which cancer cells only uses glycolysis for the production of ATP. These are known as aerobic fermentation or Warburg effect. This effect state that cancer cells alter the metabolism and glycolysis is favored over oxidation phosphorylation. And NADH is regenerated via lactate production. This allow the cancer cell to use a lot of glucose and channelize the pathway towards increased cell mass.

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