BIOMOLECULES AND ENZYMES

BIOLOGY

PROTEINS

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Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]

An internal signal sequence tells the cell to put the protein where?

A	Import into the ER
B	Import into the nucleus
C	Retention of the protein in the ER lumen
D	Transport to the membrane

Explanation:

Detailed explanation-1: -Entering the nucleus. Entry of large proteins into the nucleus requires: Nuclear Localization Signal (NLS) lys-lys-lys-arg-lys.

Detailed explanation-2: -A signal sequence is a protein region with which a protein can be directed to the appropriate cellular compartment within a cell; they initiate co-translational transfer through the membrane of the endoplasmic reticulum (ER).

Detailed explanation-3: -(a) Signals for import into nucleus and import into ER. ER. The signal for import into the ER is located at the N-terminus of the protein and functions before the protein is fully synthesized, whereas the signal for nuclear import is internal and functions after the protein has been released from the ribosome.

Detailed explanation-4: -Secretory proteins are targeted to the ER by a signal sequence at their amino (N) terminus, which is removed during incorporation of the growing polypeptide chain into the ER.

There is 1 question to complete.