This set of Life Sciences Multiple Choice Questions & Answers (MCQs) focuses on “Cell Signaling”.
1. Which of the following signal molecule is NOT used for extracellular signaling?
a) Autocrine
b) Endocrine
c) Paracrine
d) Cyclic AMP
View Answer
Explanation: Extracellular signaling in animals is carried out by four categories of signal molecules endocrine, paracrine, autocrine, and juxtacrine signaling. Cyclic AMP is a secondary messenger used for intracellular signaling.
2. In endocrine signaling, the signal molecule act on target cell only in close proximity.
a) True
b) False
View Answer
Explanation: Endocrine signaling always acts on the distant target cell or that cell which located distantly from their site of synthesis while paracrine signaling is used for the cells which are located in close proximity.
3. Arrange the following sequence of extracellular signaling in the correct order?
1) Transport of signal to a target
2) Start of signal transduction pathways
3) Signaling cell synthesize and release signaling molecules
4) Binding of the signal to the specific receptor
a) 2, 3, 4, 1
b) 3, 1, 4, 2
c) 1, 2, 3, 4
d) 1, 3, 4, 2
View Answer
Explanation: Specific extracellular signaling molecules are defined for each cell. Extracellular signaling involves the synthesis and release of signal molecules, which bind to the specific receptor and initiate signal transduction pathway.
4. Which of the following signaling pathway is followed by T-lymphocytes in response to antigenic stimulation?
a) Autocrine signaling
b) Juxtacrine signaling
c) Paracrine signaling
d) Endocrine signaling
View Answer
Explanation: Signaling pathway in which signal molecules affect the same cell that produces it is called autocrine signaling. In response to antigenic stimulation, T-lymphocytes synthesize a growth factor which derives its own proliferation and amplifies the immune response.
5. Name the signaling which requires physical contacts between the cells involved.
a) Paracrine signaling
b) Intracellular signaling
c) Autocrine signaling
d) Juxtacrine signaling
View Answer
Explanation: Juxtracrine signaling is different from another signaling as it requires physical contact between the cells, these signals neither travel to distant target nor act on the same cell.
6. Mark the signal molecule which does not interact with cell surface receptor.
a) Insulin
b) Glucagon
c) Testosterone
d) Gastrin
View Answer
Explanation: Testosterone is a steroid hormone which can easily traverse cytosolic membrane and interact with a nuclear receptor or cytosolic receptor.
7. Name the largest family of cell surface receptor?
a) GPCR
b) Ion-channel receptor
c) Enzyme-linked receptor
d) Nuclear receptor
View Answer
Explanation: GPCR is a G-protein coupled receptor; it requires G-protein for transmission of signals to the intracellular receptor. It is present in all eukaryotes and it includes receptors which are responsible for smell, light, and taste.
8. Which of the following G-protein takes part in the regulation of vision?
a) Gs family
b) Gi family
c) Gq family
d) Golf
View Answer
Explanation: G-protein which takes part in vision is Gt or transducin. Transducin is GTP-binding protein and is trimeric in nature.
9. Name the family of monomeric G-protein which regulates the growth of the cell?
a) Ras
b) Rab
c) Ran
d) Rho
View Answer
Explanation: Ras is a monomeric G-protein which controls the growth of the cell through serine-threonine protein kinases. Ras works in a cyclic manner from inactive GDP-bound form to active GTP-bound form.
Sanfoundry Global Education & Learning Series – Life Sciences.
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