17) Which of the following steps is not required for signal-based targeting of p

Question

17) Which of the following steps is not required for signal-based targeting of proteins to the nucleus?

a) Translation occurs using ribosomes

b) The newly synthesized protein contains a nuclear localization sequence that directs it to the nucleus.

c) The protein is converted to a linear form using heat shock proteins.

d) importin binds to the protein and together they pass through the nuclear pore complex.

e) All the above steps are required for protein targeting to the nucleus.

35) Which of the following statements regarding humoral immune represents correct?

a) Humoral immune responses are carried out by cytotoxic T cells and macrophages.

b) Humoral immune responses are mediated by plasma cells that secrete antibodies.

c) Humoral immune responses are carried out by cell of the innate immune system.

d) Humoral immune responses primarily function to eliminate cancer cells and virally infection.

Explanation / Answer

Ans 1 (Q-17) Translation of the proteins occurs with the help of ribisome. Ribosome is the complex molecular machine serve as the site of biological protein synthesis.  

A nuclear localization signal or NLS directs a protein for import into the cell nucleus by nuclear transport.

Heat shock protein or HSPs function as chaperons of nuclear transport help in the movememnt of protein across the nuclear membrane

Importin is a type of karyopherin (karyopherins are group of proteins invovled in transporting macromolecules between the cytoplasm and nucleus in eukaryotic cell) that transport protein molecules into the nucleus by binding to nuclear localization signal.

Therefore option e " All the above steps are required for protein targeting to the nucleus" is correct.

Ans 2( Q-35) Innate immune system consists of cells and proteins that are always present and ready to mobilize and fight microbes at the site of infection. On the other hand, adaptive immune system is the second line of defense system, fight against those pathogens which are able to evade or overcome innate immunity defense. Adaptive immune response are of two types: a) humoral immunity mediated by antibody produced by B lymphocites and b) cell mediated immunity mediated by T lymphocites.

Therefore the option b) " Humoral immune responses are mediated by plasma cells that secrete antibodies" is correct.

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