The signaling molecules called steroid hormones

are hydrophilic and so cannot penetrate the plasma membrane

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

are hydrophilic and so cannot penetrate the plasma membrane

bind to cell surface receptors to trigger chemical cascades

never enter the blood of humans

Two key organizing principles for large multicellular organisms are

communication between cells and simple nerve reflexes

prokaryotic cell structure and cell specialization

cell specialization and communication between cells

communication between cells and simple nerve reflexes

simple nerve reflexes and cell specialization

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

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

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

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

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

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

In the signal transduction mechanism known as protein phosphorylation

the signaling molecule binds to a surface receptor

receptor kinases play a key role in triggering the signal cascade

phosphorylated proteins act with enzymes to trigger the signal cascade

A signal cascade induced by adrenaline or thyroxine

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

involves the activation of a G protein

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

Cell signaling can be classified into

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

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

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

three distinct types based on the signaling molecules

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

Insulin; beta cells of the pancreas

Insulin; many different cell types that use glucose for fuel

Insulin; beta cells of the pancreas

NGF; the nerves involved in simple reflexes

In vasodilation, proper nerve signals sent to blood vessels cause

the release of nitric oxide from endothelial cells

relaxation of smooth muscle cells

Which of the following statements about G proteins is false?

They must be active before the cell can make needed cAMP

They are involved in signal cascades

They bind to and are regulated by guanine nucleotides

They become activated when bound to GDP

They must be active before the cell can make needed cAMP

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 __________ .

signaling molecule; receptor; G proteins

signaling molecule; target cell; G proteins

signaling molecule; target cell; receptors

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

Because other body tissues use a different signaling molecule

Because nitric oxide cannot cross cell membranes and enter the blood

Because nitric oxide breaks down quickly and thus cannot travel far

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

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

Its receptor is located in the cytosol of the target cell

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

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

cAMP and cGMP are derived from

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

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

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

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

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

mimics the action of signal receptors

is broken down into hormones that affect the heart

interferes with chemical cascades that trigger contraction of heart muscle

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

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?

Nitric oxide would no longer be produced

Smooth muscle cells could not be made to relax

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

SH2 domains specifically bind to

phosphorylated tyrosine residues

In paracrine signaling, the signaling molecules affects only

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

target cells close to the cell from which it was secreted

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

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

makes the receptor more likely to capture the signaling, molecule

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

makes the receptor more likely to capture the signaling, molecule

allows hydrophilic signaling molecules to cross the plasma membrane

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

They destroy the receptors for key signaling molecules

They prevent the production of key signaling molecules

They alter the chemical structure of key signaling molecules

They block the normal functioning of signal transduction mechanisms

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

It is incapable of signal transduction

It is also the site of production for the signaling molecule

It contains the receptor for the signaling molecule

It is incapable of signal transduction

30 + Mcqs in Cell Signalling and Transduction in Biochemistry Page 1 McqOptions

1.	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
Answer» B. are hydrophilic and so cannot penetrate the plasma membrane

Discussion

2.	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)
Answer» E.

Discussion

3.	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
Answer» C. communication between cells and simple nerve reflexes

Discussion

4.	Which of the following is a hormone whose action requires a cell surface receptor?
A.	Nitric oxide
B.	Progesterone
C.	Adrenaline
D.	Growth factors
Answer» D. Growth factors

Discussion

5.	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
Answer» C. phosphodiesterase C

Discussion

6.	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
Answer» B. decrease in the concentration of certain intracellular signaling molecules called second messenger

Discussion

7.	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
Answer» D. Signal amplification

Discussion

8.	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
Answer» E.

Discussion

9.	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
Answer» E.

Discussion

10.	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
Answer» B. two distinct types based on the distance over which the signaling molecules act

Discussion

11.	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
Answer» B. Insulin; beta cells of the pancreas

Discussion

12.	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
Answer» E.

Discussion

13.	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
Answer» D. They must be active before the cell can make needed cAMP

Discussion

14.	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
Answer» D. kinase; receptor; proteases

Discussion

15.	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
Answer» D. None of the above

Discussion

16.	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
Answer» E.

Discussion

17.	The hormone or ligand can be considered as
A.	first messenger
B.	second messenger
C.	both (a) and (b)
D.	none of these
Answer» B. second messenger

Discussion

18.	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
Answer» C. Since it can enter the cell, it directly affects some specific cell process

Discussion

19.	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
Answer» B. GTP and ATP by the actions of adenylate cyclase and guanylate cyclase respectively

Discussion

20.	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
Answer» E.

Discussion

21.	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
Answer» E.

Discussion

22.	Which of the following is not a type of signaling molecule?
A.	Testosterone
B.	Insulin
C.	Thyroxin
D.	Adenylate cyclase
Answer» E.

Discussion

23.	SH₂ domains specifically bind to
A.	phosphorylated serine residues
B.	phosphorylated tyrosine residues
C.	GDP
D.	Ca
E.	<sup>2+</sup>
Answer» C. GDP

Discussion

24.	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
Answer» B. target cells distant from its site of synthesis in cells of an endocrine organ

Discussion

25.	Simple nerve reflexes use signaling molecules called
A.	neurotransmitters
B.	nitric oxides
C.	G proteins
D.	proteases
Answer» B. nitric oxides

Discussion

26.	Small charged molecules, often biogenic amines function as
A.	hormones
B.	neurotransmitters
C.	both (a) and (b)
D.	none of these
Answer» D. none of these

Discussion

27.	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
Answer» B. makes the receptor more likely to capture the signaling, molecule

Discussion

28.	The major second messengers are
A.	cAMP
B.	cGMP
C.	DAG
D.	All of these
Answer» E.

Discussion

29.	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
Answer» E.

Discussion

30.	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
Answer» D. It is incapable of signal transduction

Discussion

Explore topic-wise MCQs in Biochemistry.

The signaling molecules called steroid hormones

Which of the following is a second messenger?

Two key organizing principles for large multicellular organisms are

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

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

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

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?

In the signal transduction mechanism known as protein phosphorylation

A signal cascade induced by adrenaline or thyroxine

Cell signaling can be classified into

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

In vasodilation, proper nerve signals sent to blood vessels cause

Which of the following statements about G proteins is false?

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 __ .

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

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

The hormone or ligand can be considered as

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

cAMP and cGMP are derived from

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

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?

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

SH₂ domains specifically bind to

In paracrine signaling, the signaling molecules affects only

Simple nerve reflexes use signaling molecules called

Small charged molecules, often biogenic amines function as

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

The major second messengers are

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

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