54 + Mcqs in Cell Signalling and Transduction Page 1 McqOptions

1.	SH domains specifically bind to
A.	phosphorylated serine residues
B.	phosphorylated tyrosine residues
C.	GDP
D.	Ca
Answer» C. GDP

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.	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

4.	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

5.	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

6.	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

7.	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

8.	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

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.	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

11.	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

12.	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

13.	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

14.	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

15.	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

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.	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

18.	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

19.	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

20.	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

21.	SH2 domains specifically bind to
A.	phosphorylated serine residues
B.	phosphorylated tyrosine residues
C.	GDP
D.	Ca2+
Answer» C. GDP

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.	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

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

Discussion

25.	The highly folded membranes found in such eukaryotic organelles as mitochondria and chloroplasts
A.	increase the surface area where key chemical processes can occur
B.	help the cell against physical damage
C.	make it possible to package large amounts of DNA within the cell
D.	assist with cell movement
Answer» B. help the cell against physical damage

Discussion

26.	Lysosomes are specialized vesicles in __________ that contain digestive enzymes for the breakdown of food. A related organalle known as a vacuole, which is found in __________ , also contains enzymes but in addition may act as a storage organelle for nutrients or water.
A.	animals; plants and fungi
B.	plants; animals and fungi
C.	plants and fungi; animals
D.	animals and plants; fungi
Answer» B. plants; animals and fungi

Discussion

27.	The simplest way to differentiate a prokaryotic cell from a eukaryotic one is to
A.	look for a plasma membrane
B.	see if a nucleus is present
C.	check for the presence of DNA
D.	determine if the cell is an entire organism or not
Answer» C. check for the presence of DNA

Discussion

28.	Which of the following is the best criterion for deciding whether a cell is prokaryotic or eukaryotic?
A.	The cell came from a single-celled or multicelled organism
B.	The cell has a nucleus or not
C.	The cell has cytosol or not
D.	DNA is present in the cell or not
Answer» C. The cell has cytosol or not

Discussion

29.	According to the fluid mosaic model of cell membranes,
A.	the most common type of molecules in the membrane are proteins
B.	basic membrane structure results from how the proteins interact with water
C.	the membrane is a highly mobile mixture of phospholipids and proteins
D.	the unique properties of cell types are determined by their phospholipids
Answer» D. the unique properties of cell types are determined by their phospholipids

Discussion

30.	In terms of basic cell structure, what do an elephant and an oak tree have in common?
A.	They both are eukaryotes
B.	They both have a cell nucleus
C.	They both have mitochondria
D.	All of the above
Answer» E.

Discussion

31.	Where in a eukaryotic cell, DNA can be found?
A.	Nucleus
B.	Mitochondrion
C.	Vacuole
D.	Both (a) and (b)
Answer» E.

Discussion

32.	Which of the following two organelles look most alike structurally?
A.	Nucleus and vesicle
B.	Golgi apparatus and smooth endoplasmic reticulum ER
C.	Vacuole and cytoskeleton
D.	Lysosome and chloroplast
Answer» C. Vacuole and cytoskeleton

Discussion

33.	Which of the following structures is expected in a bacterium?
A.	Nucleus
B.	Plasma membrane
C.	Golgi apparatus
D.	Endoplasmic reticulum
Answer» C. Golgi apparatus

Discussion

34.	Which of the following organelles is directly connected to the outer membrane of the nucleus in a eukaryotic cell?
A.	Mitochondrion
B.	Lysosome
C.	Golgi apparatus
D.	Endoplasmic reticulum
Answer» E.

Discussion

35.	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

36.	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

37.	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

38.	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

39.	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

40.	Eukaryotic cells are more efficient than prokaryotes because their internal compartmentalization
A.	makes each compartment nutritionally independent of all others
B.	allows for specialization through the subdivision of particular tasks
C.	allows for specialization through merging of different tasks
D.	reduces overall cell size
Answer» C. allows for specialization through merging of different tasks

Discussion

41.	An organism's first line of defense against attack by an invader such as a virus or bacterium is usually
A.	to flee or hide
B.	its body wall
C.	a specific immune response
D.	a nonspecific immune response
Answer» C. a specific immune response

Discussion

42.	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

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

Discussion

44.	Which of the following cell organelles are expected to be associated with motor proteins?
A.	Smooth ER
B.	Vesicles
C.	Plasma membrane
D.	Chloroplasts
Answer» C. Plasma membrane

Discussion

45.	Which of the following are responsible causing the diseases?
A.	Pathogens
B.	T cells
C.	Lymphocytes
D.	Macrophages
Answer» B. T cells

Discussion

46.	In which of the following cell types more cellular detail can be observed using an electron microscope compared to a light microscope?
A.	Animal
B.	Bacterial
C.	Protist
D.	All of these
Answer» E.

Discussion

47.	Which of the following is present in both prokaryotes and eukaryotes?
A.	Lysosome
B.	Chloroplast
C.	Plasma membrane
D.	Vacuole
Answer» D. Vacuole

Discussion

48.	A certain cell organelle which is made of a double phospholipid bilayer that has many large pores in it, is most likely
A.	the nuclear envelope
B.	the plasma membrane
C.	the mitochondrion
D.	the cytoskeleton
Answer» B. the plasma membrane

Discussion

49.	Microtubules, motor proteins, and actin filaments are all part of
A.	the mechanism of photosynthesis that occurs in chloroplasts
B.	the rough ER (endoplasmic reticulum) in prokaryotic cells
C.	the cytoskeleton of eukaryotic cells
D.	the process that moves small molecules across cell membranes
Answer» D. the process that moves small molecules across cell membranes

Discussion

50.	Clearly defined nucleus, mitochondria in a large central vacuole and chloroplasts, indicate the group of organisms from
A.	bacteria
B.	fungi
C.	plants
D.	animals
Answer» D. animals

Discussion

Explore topic-wise MCQs in Biochemistry.

SH domains specifically bind to

Which of the following is a second messenger?

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*?

In the signal transduction mechanism known as protein phosphorylation

Cell signaling can be classified into

In vasodilation, proper nerve signals sent to blood vessels cause

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

A signal cascade induced by adrenaline or thyroxine

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

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

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

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

Two key organizing principles for large multicellular organisms are

The hormone or ligand can be considered as

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

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?

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

Which of the following statements about G proteins is false?

In paracrine signaling, the signaling molecules affects only

SH2 domains specifically bind to

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

Small charged molecules, often biogenic amines function as

Simple nerve reflexes use signaling molecules called

The highly folded membranes found in such eukaryotic organelles as mitochondria and chloroplasts

Lysosomes are specialized vesicles in __________ that contain digestive enzymes for the breakdown of food. A related organalle known as a vacuole, which is found in __________ , also contains enzymes but in addition may act as a storage organelle for nutrients or water.

The simplest way to differentiate a prokaryotic cell from a eukaryotic one is to

Which of the following is the best criterion for deciding whether a cell is prokaryotic or eukaryotic?

According to the fluid mosaic model of cell membranes,

In terms of basic cell structure, what do an elephant and an oak tree have in common?

Where in a eukaryotic cell, DNA can be found?

Which of the following two organelles look most alike structurally?

Which of the following structures is expected in a bacterium?

Which of the following organelles is directly connected to the outer membrane of the nucleus in a eukaryotic cell?

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

cAMP and cGMP are derived from

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

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 true about a hydrophilic signaling molecule?

Eukaryotic cells are more efficient than prokaryotes because their internal compartmentalization

An organism's first line of defense against attack by an invader such as a virus or bacterium is usually

The signaling molecules called steroid hormones

The major second messengers are

Which of the following cell organelles are expected to be associated with motor proteins?

Which of the following are responsible causing the diseases?

In which of the following cell types more cellular detail can be observed using an electron microscope compared to a light microscope?

Which of the following is present in both prokaryotes and eukaryotes?

A certain cell organelle which is made of a double phospholipid bilayer that has many large pores in it, is most likely

Microtubules, motor proteins, and actin filaments are all part of

Clearly defined nucleus, mitochondria in a large central vacuole and chloroplasts, indicate the group of organisms from

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 __ .

Lysosomes are specialized vesicles in that contain digestive enzymes for the breakdown of food. A related organalle known as a vacuole, which is found in , also contains enzymes but in addition may act as a storage organelle for nutrients or water.