Concept explainers
(a)
To explain: The discrepancy between the normal length of prolactin and length of the polypeptide synthesized containing 277 amino acids.
Introduction: Prolactin is a type of hormone present in the pituitary gland. It is a 199 amino acids long sequence. This hormone is required to stimulate the production of milk in females.
(b)
To explain: The result that on adding SRP to a cell-free protein-synthesizing system and found that the translation has stopped after a polypeptide about 70 amino acid long has been produced whereas in the first experiment the polypeptide synthesized is of 277 amino acids. Also, explain the purpose it serves for the cell.
Introduction: Prolactin is a type of hormone present in the pituitary gland. It is a 199 amino acids long sequence. This hormone is required to stimulate the production of milk in females.
(c)
To explain: The result that on adding both SRP and ER membrane vesicles to the protein-synthesizing system the translation of prolactin mRNA produces a polypeptide 199 amino acid long whereas in the first experiment the polypeptide synthesized is of 277 amino acids. Also, determine the location of such polypeptides.
Introduction: Prolactin is a type of hormone present in the pituitary gland. It is a 199 amino acids long sequence. This hormone is required to stimulate the production of milk in females.
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Becker's World of the Cell (9th Edition)
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