Cell Signalling and Transduction

Q1: Which of the following is a hormone whose action requires a cell surface receptor?

A Nitric oxide

B Progesterone

C Adrenaline

D Growth factors

ANS:C - Adrenaline

The growth factors, which are all proteins,have the hormone-like effects and need to receptors for their functions. So the D response is the correct one.

Q2: Which of the following is not a type of signaling molecule?

A Testosterone

B Insulin

C Thyroxin

D Adenylate cyclase

ANS:D - Adenylate cyclase

It is a effector molecule present on p.m. which convert GTP in to cAMP.

Q3: Which of the following statement is correct?

A Cell communicate with one another in multicellular organisms using extracellular signaling molecules or hormones

B Cell communicate with one another in unicellular organisms using extracellular signaling antigen and antibody

C Cell communicate with one another in multicellular organisms using intracellular signaling molecules only

D Cell communicate with one another in unicellular organisms using intracellular signaling antigen and antibody

ANS:A - Cell communicate with one another in multicellular organisms using extracellular signaling molecules or hormones

No answer description is available.

Q4: Two key organizing principles for large multicellular organisms are

A prokaryotic cell structure and cell specialization

B cell specialization and communication between cells

C communication between cells and simple nerve reflexes

D simple nerve reflexes and cell specialization

ANS:B - cell specialization and communication between cells

No answer description is available.

Q5: When a __________ reaches its __________ , there is a specific means of receiving it and acting on the message. This task is the responsibility of specialized proteins called __________ .

A signaling molecule; receptor; G proteins

B signaling molecule; target cell; G proteins

C signaling molecule; target cell; receptors

D kinase; receptor; proteases

ANS:C - signaling molecule; target cell; receptors

No answer description is available.

Q6: In terms of cell communication, what do bacterial pathogens such as cholera and anthrax have in common?

A They destroy the receptors for key signaling molecules

B They prevent the production of key signaling molecules

C They alter the chemical structure of key signaling molecules

D They block the normal functioning of signal transduction mechanisms

ANS:D - They block the normal functioning of signal transduction mechanisms

No answer description is available.

Q7: In vasodilation, proper nerve signals sent to blood vessels cause

A the release of nitric oxide from endothelial cells

B relaxation of smooth muscle cells

C reduced blood pressure

D All of the above

ANS:D - All of the above

No answer description is available.

Q8: cAMP and cGMP are derived from

A ATP and GTP by the actions of adenylate cyclase and guanylate cyclase respectively

B GTP and ATP by the actions of adenylate cyclase and guanylate cyclase respectively

C ATP and GTP by the actions of guanylate cyclase and adenylate cyclase respectively

D none of the above

ANS:A - ATP and GTP by the actions of adenylate cyclase and guanylate cyclase respectively

No answer description is available.

Q9: SH2 domains specifically bind to

A phosphorylated serine residues

B phosphorylated tyrosine residues

C GDP

D Ca2+

ANS:B - phosphorylated tyrosine residues

From signalling, molecule sh2 bind always phosphorylated tyrosine residue and sh3 bind PPP domain.

Q10: A signal cascade induced by adrenaline or thyroxine

A must begin with receipt of the signal molecule by a surface receptor

B involves the activation of a G protein

C results in the activation of a sequence of enzymes needed for the cell effect

D all of the above

ANS:D - all of the above

No answer description is available.

Q11: Why is it that inhaling nitric oxide reduces blood pressure only in the lung tissue and not elsewhere in the body*?

A Because other body tissues use a different signaling molecule

B Because nitric oxide cannot cross cell membranes and enter the blood

C Because nitric oxide breaks down quickly and thus cannot travel far

D None of the above

ANS:C - Because nitric oxide breaks down quickly and thus cannot travel far

Because NO has tendency to get converted into nitrates and nitrites rapidly.

Q12: Which of the following processes involve the combining of a message from one signaling molecule with that of another to either enhance or inhibit a cellular effect?

A Signal transduction

B Signal reception

C Signal integration

D Signal amplification

ANS:C - Signal integration

No answer description is available.

Q13: Which of the following statement is incorrect?

A The principal lipophilic hormones that binds to receptors located in the plasma membranes are prostaglandins

B Prostaglandins are synthesized from arachidonic acid

C Prostaglandins act as paracrine signaling molecules

D None of the above

ANS:D - None of the above

No answer description is available.

Q14: A cell is known to respond to a particular signaling molecule. Which of the following must be true of this cell?

A It is in the heart muscle

B It is also the site of production for the signaling molecule

C It contains the receptor for the signaling molecule

D It is incapable of signal transduction

ANS:C - It contains the receptor for the signaling molecule

In order to a cell communicate it must have a receptor which is specific to the messenger (ligand).

Q15: Which of the following is a second messenger?

A lnositol 1,4,5-triphosphate

B Diacyl glycerol

C Phospholipase C

D Both (a) and (b)

ANS:D - Both (a) and (b)

No answer description is available.

Q16: In paracrine signaling, the signaling molecules affects only

A target cells close to the cell from which it was secreted

B target cells distant from its site of synthesis in cells of an endocrine organ

C both (a) and (b)

D none of the above

ANS:A - target cells close to the cell from which it was secreted

Answer: D.

Because paracrine signalling depends on the signal that are released into the extracellular space and act locally on neighboring cells.

Q17: Simple nerve reflexes use signaling molecules called

A neurotransmitters

B nitric oxides

C G proteins

D proteases

ANS:A - neurotransmitters

No answer description is available.

Q18: The major second messengers are

A cAMP

B cGMP

C DAG

D All of these

ANS:D - All of these

No answer description is available.

Q19: Which of the following is true about a hydrophilic signaling molecule?

A Its receptor is located in the cytosol of the target cell

B It might trigger a signal cascade that causes some effect in a cell

C Since it can enter the cell, it directly affects some specific cell process

D It is a steroid

ANS:B - It might trigger a signal cascade that causes some effect in a cell

No answer description is available.

Q20: Which of the following statements about G proteins is false?

A They are involved in signal cascades

B They bind to and are regulated by guanine nucleotides

C They become activated when bound to GDP

D They must be active before the cell can make needed cAMP

ANS:C - They become activated when bound to GDP

G protein gets activated when they are bound to to GTP not GDP. Gprotein activate when they bound to GTP.

Q21: What is the name of the protein signaling molecule that alters glucose uptake, and where would its receptors be located?

A Insulin; many different cell types that use glucose for fuel

B Insulin; beta cells of the pancreas

C PDGF; the blood

D NGF; the nerves involved in simple reflexes

ANS:A - Insulin; many different cell types that use glucose for fuel

No answer description is available.

Q22: The signaling molecules called steroid hormones

A are made in one location of the body but have their effects some distance away

B are hydrophilic and so cannot penetrate the plasma membrane

C bind to cell surface receptors to trigger chemical cascades

D never enter the blood of humans

ANS:A - are made in one location of the body but have their effects some distance away

Steroid hormones are also synthesized in gonads.

Q23: The enzyme that catalyzes the splitting of PIP2 into two molecules of inositol triphosphate (IP3) and diacylglycerol in cell signaling, is

A phosphokinase C

B phospholipase C

C phosphodiesterase C

D lipokinase

ANS:B - phospholipase C

No answer description is available.

Q24: Self-phosphorylation is an excellent mechanism for triggering specific catalytic function of the proteins involved in signal cascades because it

A changes the shape and thus the enzymatic activity of the proteins involved

B makes the receptor more likely to capture the signaling, molecule

C allows hydrophilic signaling molecules to cross the plasma membrane

D None of the above

ANS:A - changes the shape and thus the enzymatic activity of the proteins involved

Best example is RTK receptor which by autophosphorylation create site for docking which lead signal proceed.

Q25: Nitroglycerin has long been administered to human patients suffering from chronic chest pain (angina). This medication works because it

A mimics the action of signal receptors

B is broken down into hormones that affect the heart

C interferes with chemical cascades that trigger contraction of heart muscle

D breaks down into nitric oxide, which increases blood flow to the heart

ANS:D - breaks down into nitric oxide, which increases blood flow to the heart

No answer description is available.

Q26: Cell signaling can be classified into

A three distinct types based on the distance over which the signaling molecules act

B two distinct types based on the distance over which the signaling molecules act

C three distinct types based on the signaling molecules

D none of the above

ANS:A - three distinct types based on the distance over which the signaling molecules act

Autocrine: Acts on own cell.

Paracrine: Acts on nearby cell (mostly of different type cell which secrets it).

Endocrine: Which acts on distance cell by circulation (Hormone).

Q27: If a disease of the blood vessels caused the endothelial cells of the vessel to die, what effect would that have on the cellular activities associated with vasodilation?

A Nitric oxide would no longer be produced

B Smooth muscle cells could not be made to relax

C It would be more difficult to increase blood flow and reduce blood pressure

D All of the above

ANS:D - All of the above

No answer description is available.

Q28: The hormone or ligand can be considered as

A first messenger

B second messenger

C both (a) and (b)

D none of these

ANS:A - first messenger

No answer description is available.

Q29: Which of the following comes under the category of cell surface receptor?

A Enzyme linked receptors

B Ion-channel linked receptors

C G protein linked receptors

D All of these

ANS:D - All of these

No answer description is available.

Q30: Small charged molecules, often biogenic amines function as

A hormones

B neurotransmitters

C both (a) and (b)

D none of these

ANS:C - both (a) and (b)

Small molecules we say here is simply an organic biomolecule. Like (acetylcholine, neurotransmitter).

Q31: The binding of ligands to many G-proteins linked receptors leads to shortlived

A increase in the concentration of certain intracellular signaling molecules called second messenger

B decrease in the concentration of certain intracellular signaling molecules called second messenger

C increase in the concentration of certain extracellular signaling molecules called first messenger

D decrease in the concentration of certain extracellular signaling molecules called first messenger

ANS:A - increase in the concentration of certain intracellular signaling molecules called second messenger

No answer description is available.

Q32: In the signal transduction mechanism known as protein phosphorylation

A the signaling molecule binds to a surface receptor

B receptor kinases play a key role in triggering the signal cascade

C phosphorylated proteins act with enzymes to trigger the signal cascade

D All of the above

ANS:D - All of the above

No answer description is available.



img not found
img

For help Students Orientation
Mcqs Questions

One stop destination for examination, preparation, recruitment, and more. Specially designed online test to solve all your preparation worries. Go wherever you want to and practice whenever you want, using the online test platform.