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There are 58 questions tagged under Membrane Transport and Signalling.

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1 Go

Q:

Which of the following is not true of a micelle?

A

A micelle will spontaneously form through phospholipids in an aqueous solution.

B

A micelle is simply a cellular membrane with a vacuous interior.

C

The hydrophobic effect is the driving force for the formation of a micelle.

D

When a micelle forms, there is an overall decrease in Gibbs free energy.

Tags: Membrane Transport and Signalling |

2 Go

Q:

What is the action of the sodium-potassium pump?

A

Allows 2Na+ in, pumps 3K+ out

B

Allows 3Na+ in, pumps 2K+ out

C

Allows 2K+ in, pumps 3Na+ out

D

Allows 3K+ in, pumps 2Na+ out

Tags: Membrane Transport and Signalling | Eukaryotic Cells |

3 Go

Q:

Detergents are efficient emulsifiers particularly because of their

A

amphoteric properties

B

amphipathic properties

C

aliphatic properties

D

aromatic proprties

Tags: Membrane Transport and Signalling |

4 Go

Q:

A kidney cell contains a cytosolic protein that has great binding affinity for ATP, and thus serves as a sensor for a buildup of ATP within the cell. It is noted that at the current state of the kidney cell, almost all of these sensor proteins are in the bound state. If the sodium-potassium pump is the only mechanism for the cell to equilibrate to a lower level of ATP, what chemical change can be expected within the cell?

A

Large influx of Na+ ions

B

Increase in the hypertonicity of the cell with respect to its surroundings

C

Loss of K+ ions

D

Lower ion concentration within the cell

Tags: Membrane Transport and Signalling |

5 Go

Q:

Which of the following properties can be expected in an transmembrane protein?

A

Large amount of hydrophilic residues

B

Mostly beta-sheet structures

C

Large amount of hydrophobic residues

D

A disproportionate amount of histidine

Tags: Protein Structure and Function | Membrane Transport and Signalling |

6 Go

Q:

Crystallography is a visualization technique to determine the arrangement of atoms in solids. It has been incredibly useful in discovering the structures of many proteins, such as hemoglobin. Difficulties arise when crystallography is attempted on non-polar molecules, such as proteins high in valine or alanine. Using this information, which of the following would be most difficult to visualize using crystallography?

A

A ribosome

B

A viral protein from HIV

C

A trans-membrane protein

D

A digestive protease

Tags: Membrane Transport and Signalling | Eukaryotic Cells |

7 Go

Q:

To regulate osmotic balance, a cell loses 50 mM of sodium and gains 50 mM of potassium. Is the cell hypotonic, hypertonic, or isotonic to its surroundings?

A

Hypotonic

B

Isotonic

C

Hypertonic

D

Not enough information.

Tags: Membrane Transport and Signalling | Solutions |

8 Go

Q:

The sodium-potassium pump does which of the following?

A

Pumps in two Na+ and pumps out three K+

B

Pumps in three Na+ and pumps out two K+

C

Pumps in two K+ and pumps out three Na+

D

Pumps in three K+ and pumps out two Na+

Tags: Membrane Transport and Signalling |

9 Go

Q:

Detergents are efficient emulsifiers particularly because of their

A

amphoteric properties

B

amphipathic properties

C

aliphatic properties

D

aromatic proprties

Tags: Membrane Transport and Signalling |

10 Go

Q:

Biologists often view the membrane of a neuron as a capacitor, because it separates charged ions inside and outside the membrane. Which of the following changes to the membrane would allow for increased ability of the membrane to separate charge?

A

Longer fatty acid chains in the phospholipid membrane.

B

Shortening the fatty acid chains in the phospholipid membrane.

C

Inserting magnesium ion symporters in the membrane.

D

None of the above

Tags: Membrane Transport and Signalling | Circuits |

11 Go

Q:

Which of the following is not a function of cholesterol?

A

Precursor for bile salts

B

Helps to maintain cell fluidity

C

A cofactor in the beta oxidation of fatty acids

D

Precursor for steroid hormones

Tags: Membrane Transport and Signalling | Endocrine System | Digestive System |

12 Go

Q:

Regulation of osmotic pressure is essential for organisms. Substantially higher concentrations of extracellular solutes like salts and glucose can be extremely inhibitory to normal metabolic functions by withdrawing water from cells. To manage osmotic pressure, which of the following strategies is least likely to be effective for a cell?

A

for managing extracellular glucose, assembling glycogen inside the cell

B

for managing extracellular sodium chloride, importing salt into the cell

C

for managing extracellular sucrose, producing a different solute like glycerol inside the cell

D

for managing extracellular glucose, degrading the cell's starch into glucose

Tags: Membrane Transport and Signalling |

13 Go

Q:

Which process requires ATP?

A

Diffusion

B

Passive transport

C

Osmosis

D

Active transport

Tags: Membrane Transport and Signalling |

14 Go

Q:

ATP can be generated by oxidative phosphorylation in the mitochondria via the electron transport chain, which comprises of a series of hydrogen pumps, electron carriers and ATP synthase. An electrochemical H+ gradient is produced across the inner mitochondrial membrane when H+ is pumped (driven by redox reactions within the proton pump complexes) from the matrix into the intermembrane space. The return of H+ into the matrix through ATP synthase drives the synthesis of ATP. Oligomycin is a macrolide (type of antibiotic) that inhibits the proton channel (F0 subunit) of ATP synthase. What can we expect to happen to the H+ electrochemical gradient with the introduction of oligomyciin?

A

The buildup of H+ in the intermembrane space would eventually overcome oligomycin and ATP would continue to be generated.

B

H+ would begin to flow from the intermembrane space into the matrix back through the proton pump complexes of the ETC.

C

The H+ gradient would be unaffected.

D

H+ would stop being pumped from the matrix into the intermembrane space.

Tags: Oxidative Phosphorylation | Membrane Transport and Signalling |

15 Go

Q:

ATP can be generated by oxidative phosphorylation in the mitochondria via the electron transport chain, which comprises of a series of hydrogen pumps, electron carriers and ATP synthase. An electrochemical H+ gradient is produced across the inner mitochondrial membrane when H+ is pumped (driven by redox reactions within the proton pump complexes) from the matrix into the intermembrane space. The return of H+ into the matrix through ATP synthase drives the synthesis of ATP. Oligomycin is a macrolide (type of antibiotic) that inhibits the proton channel (F0 subunit) of ATP synthase. Dinitrophenol (DNP) is a known metabolic poison that uncouples oxidative phosphorylation by carrying protons across the inner mitochondrial membrane from the intermembrane space to the matrix. What is an expected result when both oligomycin and DNP are present in mitochondria?

A

The actions of oligomycin and DNP cancel each other out. There is no net effect on regular oxidative phosphorylatiive ATP generation. ATP is produced as normal.

B

ATP is not produced but a lot of heat is generated.

C

ATP is generated, but less than normal.

D

ATP is not produced and the proton pumps of the ETC stop pumping protons from the matrix to the intermembrane space.

Tags: Oxidative Phosphorylation | Membrane Transport and Signalling |

16 Go

Q:

The useful property of plasma membranes, which allows them to create relatively impermeable layers, is facilitated by the fact that the phospholipids are

A

nonpolar

B

zwitterionic

C

amphoteric

D

amphipathic

Tags: Membrane Transport and Signalling |

17 Go

Q:

Which of the following is false regarding desmosomes?

A

they contain protein structures

B

they allow tissues to resist shear forces, as in the epithelium

C

they contain pores for direct cell-to-cell communication through cytoplasm

D

they can be found in epithelial tissues

Tags: Membrane Transport and Signalling |

18 Go

Q:

Muscle cells rely on changes in membrane potential in order to initiate contraction. Which of the following is incorrect regarding muscle cells and their membrane potential dynamics?

A

Depolarization of the muscle membrane results in an influx of calcium

B

Contraction is induced directly by calcium influx from outside the cell as well as efflux from the sarcoplasmic reticulum

C

Efflux of calcium ions from the sarcoplasmic reticulum initiates hyperpolarization of the cell, resulting in the contraction of the cell

D

Muscle contraction is an active process

Tags: Membrane Transport and Signalling | Musculoskeletal System |

19 Go

Q:

Two solutions are separated by a semipermeable membrane which freely allows water to pass through but prevents ion passage. Solution X is 30 mOsm while Solution Y is 60 mOsm. A force is applied to Solution X solution such that it exerts a hydrostatic force on the membrane separating it from Solution Y. Which of the following is true?

A

Osmotic hydrostatic forces are opposed

B

The system will equilibrate when both solutions have the same osmolarity

C

Osmotic pressure is acting to increase the volume of Solution Y

D

Osmolarity of Solution Y can be expected to increase

Tags: Membrane Transport and Signalling |

20 Go

Q:

Cholesterol is a compound within membranes which acts to increase fluidity under low temperatures and decrease fluidity during high temperatures. If the membrane is composed of phospholipids with higher melting points, the membrane will be less fluid. Which of the following may act to increase the fluidity of a membrane?

A

Increasing cholesterol concentration in the membrane

B

Increasing intracellular calcium concentrations

C

Increasing the average length of the phospholipids

D

Increasing desaturation within the membrane

Tags: Membrane Transport and Signalling |

21 Go

Q:

A micelle of a phospholipid forming in a solution of BF3 would be expected to have

A

its polar heads on the inside of the complex

B

its polar heads on the outside of the complex

C

a mixed arrangement of heads and tails

D

a complete dissociation of the micelle phospholipids

Tags: Membrane Transport and Signalling | Lipids |

22 Go

Q:

Gap junctions in cardiac myocytes are quite important for heart function. Their main purpose is for

A

allowing for propagation of action potentials

B

structural stability

C

nutrient transport between cells

D

all of the above

Tags: Membrane Transport and Signalling | Circulatory System |

23 Go

Q:



The compound above can act as a hormone. Its method of sending its signal to cells is most probably:

A

binding to membrane-bound hormone receptors on cell surfaces.

B

traversing the cell membrane and binding to cytosolic hormone receptors.

C

binding to extracellular hormone receptors which cleave the molecule and allow it traverse the cell membrane and stimulate its response.

D

traversing the cell membrane and binding to membrane-bound hormone receptors on the inner cell surface.

Tags: Membrane Transport and Signalling | Endocrine System |

24 Go

Q:

In studying how a novel compound enters cells, researchers notice the compound moves against its concentration gradient across the cell membrane. Which of the following can be concluded about the mechanism of transport?

A

The transport is active unless the compound is small and nonpolar in which case it is moving via simple diffusion.

B

The transport is passive unless it is large and polar in which case it is moving via active transport.

C

The transport is passive regardless of the size and charge of the compound.

D

The transport is active regardless of the size and charge of the compound.

Tags: Membrane Transport and Signalling |

25 Go

Q:

Which of the following hormones can be expected to have a receptor in the cytosol of the target cell rather than on the membrane of the target cell?

A

growth hormone

B

insulin

C

testosterone

D

ACTH (adrenocorticotropic hormone)

Tags: Membrane Transport and Signalling |

26 Go

Q:


The graph above depicts the rate of transport of two compounds across a membrane. Which of the following best predicts the identity of each molecule?

A

Molecule A is glycine (NH2CH2COOH); Molecule B is testosterone

B

Molecule A is O2; Molecule B is propanol

C

Molecule A is CO2; Molecule B is acetate (CH3COO-)

D

Molecule A is a bile salt; Molecule B is chloride

Tags: Membrane Transport and Signalling |

27 Go

Q:

The steroid hormones produced by the smooth endoplasmic reticulum would be stored in which of the following ways?

A

Peroxisomes, so the hormones could aid in lipid breakdown.

B

Steroid hormones are not stored; because they are lipophilic they are able to diffuse through lipid bilayers.

C

Secretory vesicles, so the hormones could be released when needed.

D

Lysosomes, so the hormone could aid in the breakdown and destruction of excess secretory products.

Tags: Membrane Transport and Signalling | Lipids |

28 Go

Q:

Ergosterol is a steroid compound found in fungi which serves a similar function to cholesterol in animal cells. Ergosterol is also often detected in samples of various grasses. Which of the following experiments would best identify whether ergosterol is produced by the plants or is a contaminant in the plant samples?

A

Compare ergosterol levels in fungus-contaminated seeds versus fresh seeds with no visible contamination.

B

Harvest seeds at various time points throughout the season and measure changes in ergosterol over time.

C

Transform fungal ergosterol-producing genes into plants and compare their ergosterol levels to the levels of unmodified plants.

D

Supply plants with Amphotericin B, an antifungal which targets ergosterol in membranes.

Tags: Membrane Transport and Signalling | Prokaryotes |

29 Go

Q:

Which of the following intercellular attachment structures are used to prevent shearing forces between cells?

A

Desmosomes

B

Gap junctions

C

Tight junctions

D

Anti-tear junctions

Tags: Membrane Transport and Signalling |

30 Go

Q:

A colligative property is one that:

A

will not affect freezing point of solutions but will affect boiling point.

B

depends only on the total number of molecules in a solution.

C

has no in the properties of liquids.

D

depends on the ratio of the number of solute molecules to solvent molecules.

Tags: Membrane Transport and Signalling |

31 Go

Q:

Which of the following is incorrect regarding the sodium potassium pump?

A

It requires ATP to function

B

It contributes to the resting potential of cells

C

It is located on the plasma membrane of cells

D

It pumps 3 sodium ions out and 3 potassium ions in

Tags: Membrane Transport and Signalling |

32 Go

Q:

α-helices are integral to which of the following structures within the body?

A

Cytosolic proteins involved in degradation of genomic material

B

Cytosolic, non-enzymatic proteins

C

The support structure around DNA

D

Specialized proteins fixed within the cell membrane

Tags: Protein Structure and Function | Membrane Transport and Signalling |

33 Go

Q:

Integral membrane proteins are permanently embedded in the cell membrane. Which of the following is NOT a function of integral membrane proteins?

A

Hormone reception

B

Protein synthesis

C

Cell adhesion

D

Cytoskeleton attachment

Tags: Protein Structure and Function | Membrane Transport and Signalling |

34 Go

Q:

Nucleic acids are used for all of the following except:

A

Storing genetic information

B

Intracellular signaling

C

Component of membranes

D

Energy

Tags: Nucleic Acid Structure and Function | Membrane Transport and Signalling |

35 Go

Q:

Which of the following choices does NOT directly affect the rate of diffusion of a substance across a membrane?

A

Concentration gradient

B

Permeability of the membrane to the diffusing substance

C

Cellular volume

D

Surface area across which diffusion is taking place

Tags: Membrane Transport and Signalling |

36 Go

Q:

The kidneys normally do a very good job at ensuring glucose is not lost in urine. Which of the following best describes this process?

A

Facilitated diffusion with a glucose carrier

B

Active transport using a glucose pump

C

Glucose is selectively retained and not filtered into urine

D

By using a symporter to carry glucose with Na+

Tags: Renal System | Membrane Transport and Signalling |

37 Go

Q:

lf ATP synthesis was inhibited in the nervous system of an animal, which of the following best describes the major effect on neural function?

A

The cell could not generate an action potential

B

The cell could not propagate action potentials throughout its membrane

C

The cell could not open voltage-gated channels

D

The cell could not maintain its resting potential

Tags: Nervous System | Membrane Transport and Signalling |

38 Go

Q:

Which of the following best describes the effect of insulin secretion from the pancreas immediately after a meal?

A

A decreased rate of glucose transport into the target cell

B

An increased rate of glucose transport into the target cell

C

A decreased rate of glucose utilization and ATP generation

D

A decreased conversion of glucose to glycogen in liver and skeletal muscle

Tags: Glycolysis, Gluconeogenesis, PPP | Membrane Transport and Signalling |

39 Go

Q:

Which of the following molecules are NOT structural parts of the cell membrane?

A

Lipids

B

Proteins

C

Nucleic acids

D

Steroids

Tags: Membrane Transport and Signalling | Nucleic Acid Structure and Function |

40 Go

Q:

Which of the following is true of carrier proteins that are used in facilitated diffusion?

A

Carrier proteins used in facilitated diffusion are usually coupled to ATP hydrolysis

B

Carrier proteins used in facilitated diffusion are specific for a specific type of molecule

C

Carrier proteins used in facilitated diffusion are located in the nuclear membrane

D

Carrier proteins used in facilitated diffusion work against concentration gradients

Tags: Protein Structure and Function | Membrane Transport and Signalling |

41 Go

Q:

Which of the following best describes the situation where membrane transport does NOT require a transporter?

A

The molecule to be transported is a small ion

B

The molecule to be transported is large and polar

C

The molecule to be transported is moved from a low to a high concentration

D

The molecule to be transported is small and non-polar

Tags: Membrane Transport and Signalling |

42 Go

Q:

Which of the following is NOT true of carrier proteins which facilitate active transport?

A

Carrier proteins facilitating active transport are integral membrane proteins

B

Carrier proteins facilitating active transport show specificity for a specific type of molecule

C

Carrier proteins facilitating active transport can be characterized by saturable transport

D

Carrier proteins facilitating active transport is down concentration gradients

Tags: Membrane Transport and Signalling |

43 Go

Q:

Phospholipids and fatty acids, and their degree of saturation, have far-reaching implications for membrane transport and fluidity. Which of the following is a correct statement?

A

A saturated fatty acid has more double bonds than an unsaturated fatty acid

B

A species in a cold environment will tend to have more double bonds in the fatty acids of their phospholipids compared to a species in a warm environment

C

A species in a cold environment will tend to have less double bonds in the fatty acids of their phospholipids compared to a species in a warm environment

D

If the proportion of double bonds in a phospholipid increases, the fluidity of the membrane will decrease

Tags: Membrane Transport and Signalling | Lipids |

44 Go

Q:

Signal transduction describes the process of extracellular signalling molecules and ligands binding to cell-surface receptors which triggers events inside the cell. Which of the following best describes an event NOT typically associated with signal transduction started by extracellular signals?

A

The binding of epinephrine to adrenergic receptors

B

Protein phosphorylation

C

A steroid hormone binding to its receptor

D

Activation of secondary messenger molecules

Tags: Membrane Transport and Signalling | Hormonal Regulation |

45 Go

Q:

Which of the following best describes the concept of an amphipathic molecule?

A

An amphipathic molecule has one positively charged region and one negatively charged region

B

An amphipathic molecule is branched, and with at least two branch points

C

An amphipathic molecule has one polar region and one nonpolar region

D

An amphipathic molecule has two different types of bonds

Tags: Protein Structure and Function | Lipids | Membrane Transport and Signalling |

46 Go

Q:

In untreated diabetics, excess glucose in the blood is due to incomplete reabsorption (normally done by transporters present in the nephrons of the kidney) and subsequent excretion in the urine. Which of the following best describes this effect?

A

The transporters are inhibited by high levels of glucose

B

The Vmax of the transporter is reached at lower blood glucose levels

C

The binding affinity of these transporters is increased in diabetics

D

The binding capacity of the transporters has been exceeded

Tags: Membrane Transport and Signalling | Renal System | Protein Structure and Function | Carbohydrates |

47 Go

Q:

Which of the following is NOT a physiological role for nucleotides?

A

As components of the coenzymes NAD and FAD

B

Intracellular signalling

C

As components of many proteins

D

As intermediates for biosynthetic processes

Tags: Enzyme Structure and Function | Nucleic Acid Structure and Function | Membrane Transport and Signalling | Protein Structure and Function |

48 Go

Q:

Which of the following is NOT a transmembrane protein?

A

Phospholipase C

B

NADH dehydrogenase complex

C

Cytochrome oxidase

D

Cytochrome bc1 complex

Tags: Oxidative Phosphorylation | Protein Structure and Function | Membrane Transport and Signalling |

49 Go

Q:

Which of the following would NOT support the chemiosmotic-based model of oxidative phosphorylation?

A

The transfer of electrons through the electron transport chain results in the formation of a proton gradient across the inner mitochondrial membrane

B

Oxidative phosphorylation cannot occur in cells with breached mitochondrial membranes

C

Raising the pH of the fluid in the intermembrane space results in ATP synthesis

D

The order of the enzyme complexes in the electron transport chain results in proton flow in one direction

Tags: Oxidative Phosphorylation | Membrane Transport and Signalling |

50 Go

Q:

Which of the following is NOT correct in regard to fatty acid transport into the mitochondrial matrix?

A

Fatty acid transport into the mitochondrial matrix is the rate-limiting step in beta oxidation.

B

The inner mitochondrial membrane is impermeable to fatty acyl CoA.

C

A specialized carrier system transports activated fatty acids from the cytosol to mitochondria.

D

Fatty acyl groups that enter the matrix are not committed to oxidation to acetyl-CoA.

Tags: Citric Acid Cycle | Metabolism of Fatty Acids and Proteins | Membrane Transport and Signalling |

51 Go

Q:

Which of the following is NOT correct about carbohydrates in cells?

A

They are involved in cell-to-cell recognition

B

They can be organic catalysts

C

They can act as binding sites for proteins

D

They can serve as energy stores in animal cells

Tags: Carbohydrates | Membrane Transport and Signalling |

52 Go

Q:

Which of the following is TRUE of diffusion across a membrane?

A

Diffusion is characterized by unidirectional motion

B

Diffusion involves hydrophobic and small, uncharged molecules

C

Diffusion is a form of energy-requiring transport

D

Organisms only using diffusion localize their cellular functions to specific regions

Tags: Membrane Transport and Signalling |

53 Go

Q:

In skeletal muscle contraction, which of the following provides the most important source of calcium ions?

A

Triphosphate binding to a receptor on the sarcoplasmic reticulum membrane.

B

The opening of calcium channels in the sarcoplasmic reticulum.

C

The calcium ATPase in the sarcoplasm.

D

Voltage-gated calcium channels in the muscle fiber plasma membrane.

Tags: Protein Structure and Function | Musculoskeletal System | Membrane Transport and Signalling |

54 Go

Q:

Which of the following is FALSE about the sarcoplasmic reticulum?

A

The sarcoplasmic reticulum stores calcium ions.

B

The sarcoplasmic reticulum transports calcium ions into the sarcoplasm when the muscle fiber is stimulated.

C

The sarcoplasmic reticulum contributes to the generation of the muscular action potential.

D

The sarcoplasmic reticulum is a specialized type of endoplasmic reticulum.

Tags: Musculoskeletal System | Membrane Transport and Signalling |

55 Go

Q:

Which of the following is true of the major histocompatibility complex (MHC)?

A

Four classes of the major histocompatibility complex exist.

B

T cells do not detect infections through MHC.

C

MHC I acts as a signal for viruses.

D

MHC molecules display protein fragments from a pathogen for recognition by B cells.

Tags: Protein Structure and Function | Immune System | Membrane Transport and Signalling |

56 Go

Q:

In general, steroid molecules can be expected to traverse the cellular membrane via:

A

passive diffusion

B

facilitated diffusion

C

active transport

D

ion exchange

Tags: Membrane Transport and Signalling |

57 Go

Q:

The spreading of action potentials of adjacent cardiomyocytes takes place through:

A

desmosomes.

B

gap junctions.

C

tight junctions.

D

pinocytotic junctions.

Tags: Membrane Transport and Signalling |

58 Go

Q:

Facilitated diffusion:
I. requires channels to allow molcules in or out.
II. uses ATP.
III. is an example of passive transport.

A

I only only

B

I and II only

C

I and III only

D

III only

Tags: Membrane Transport and Signalling |

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