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Cell Signalling And Transduction Online Exam Quiz

Important questions about Cell Signalling And Transduction. Cell Signalling And Transduction MCQ questions with answers. Cell Signalling And Transduction exam questions and answers for students and interviews.

1. The binding of ligands to many G-proteins linked receptors leads to shortlived

Options

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

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

Options

A : phosphokinase C

B : phospholipase C

C : phosphodiesterase C

D : lipokinase

3. Which of the following statement is incorrect?

Options

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

4. In paracrine signaling, the signaling molecules affects only

Options

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

5. A signal cascade induced by adrenaline or thyroxine

Options

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

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

Options

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

7. Which of the following is not a type of signaling molecule?

Options

A : Testosterone

B : Insulin

C : Thyroxin

D : Adenylate cyclase

8. 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 __________ .

Options

A : signaling molecule; receptor; G proteins

B : signaling molecule; target cell; G proteins

C : signaling molecule; target cell; receptors

D : kinase; receptor; proteases

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

Options

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

10. cAMP and cGMP are derived from

Options

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

1. 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?

Options

A : Signal transduction

B : Signal reception

C : Signal integration

D : Signal amplification

2. Which of the following statements about G proteins is false?

Options

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

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

Options

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

4. The signaling molecules called steroid hormones

Options

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

5. In the signal transduction mechanism known as protein phosphorylation

Options

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

6. Which of the following is a hormone whose action requires a cell surface receptor?

Options

A : Nitric oxide

B : Progesterone

C : Adrenaline

D : Growth factors

7. Small charged molecules, often biogenic amines function as

Options

A : hormones

B : neurotransmitters

C : both (a) and (b)

D : none of these

8. Which of the following comes under the category of cell surface receptor?

Options

A : Enzyme linked receptors

B : Ion-channel linked receptors

C : G protein linked receptors

D : All of these

9. Which of the following statement is correct?

Options

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

10. In vasodilation, proper nerve signals sent to blood vessels cause

Options

A : the release of nitric oxide from endothelial cells

B : relaxation of smooth muscle cells

C : reduced blood pressure

D : All of the above

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