Berne & Levy Physiology, 7th Edition, Bruce M. Koeppen, Bruce A. Stanton Questions and Answers

25 July 2023

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Koeppen: Berne and Levy Physiology, 7th Edition

Chapter 01: Principles of Cell Function

Multiple Choice Questions and Answers

1. The subcellular structure that degrades proteins is called the:

A. Tight junction

B. Mitochondria

C. Lysosome

D. Plasma membrane

E. Ribosome

ANS: C

2. An experiment is done to measure the uptake of an amino acid into a cell. The following data are obtained:

If Na+ is removed from the extracellular bathing solution, or if a drug is added that prevents the cell from making adenosine triphosphate (ATP), the uptake of amino acid into the cell is markedly reduced. According to this information, which of the following mechanisms is probably responsible for the transport of the amino acid into the cell?

A. Passive diffusion through the lipid bilayer

B. Uniporter

C. Transport ATPase

D. Na+ symporter

E. Na+ antiporter

ANS: D

3. A membrane permeable by only Na+ separates two compartments containing Na2SO4, shown as follows:

Electrodes are placed in both compartments, and a voltage is applied (that of compartment A is held at 0 mV). What voltage applied to compartment B would result in no net movement of Na+ across the membrane separating the compartments?

A. –60 mV

B. –30 mV

C. 0 mV

D. +30 mV

E. +60 mV

ANS: E

4. The resting membrane potential of a cell is –85 mV. The intracellular and extracellular concentrations of several ions are indicated in the following table, as is the calculated Nernst equilibrium potential (Ei) for each of these ions:

Ion	Concentration Inside Cell	Concentration Outside Cell	Ei
Na+	12 mEq/L	145 mEq/L	66 mV
K+	150 mEq/L	4 mEq/L	–96 mV
Cl–	30 mEq/L	105 mEq/L	–33 mV
Ca++	0.0001 mmol/dL	1 mmol/dL	122 mV

The membrane has channels for Na+, K+, Cl–, and Ca++. The conductance of the membrane is the greatest for which ion?

A. Na+

B. K+

C. Cl–

D. Ca++

ANS: B

5. A cell contains the following membrane transporters:

Na+ channel

K+ channel

Na+,K+-ATPase

The resting membrane voltage of the cell is –80 mV, and the intracellular and extracellular ion concentrations are as follows:

Ion	Intracellular Concentration	Extracellular Concentration
Na+	10 mEq/L	145 mEq/L
K+	120 mEq/L	4 mEq/L

The cell is treated with a drug to inhibit the Na+,K+-ATPase. What would be the effect of this drug on the following parameters?

	Intracellular [Na+]	Intracellular [K+]	Cell Volume	Membrane Voltage
A.	Decrease	Decrease	Decrease	Depolarize
B.	Increase	Decrease	Increase	Depolarize
C.	Increase	Increase	Increase	No change
D.	Decrease	Increase	Decrease	Hyperpolarize
E.	Increase	Increase	Decrease	Hyperpolarize

ANS: B

6. Which of the labeled proteins (shaded) is attached to the membrane by a glycosylphosphatidylinositol (GPI) anchor?

ANS: E

7. A cell has channels for Na+, K+, and Cl– in its plasma membrane. The resting membrane potential is –60 mV (cell interior negative). The intracellular and extracellular concentrations for these ions, as well as the calculated Nernst potentials, are listed as follows:

Ion	Intracellular Concentration	Extracellular Concentration	Ei
Na+	14 mEq/L	140 mEq/L	60 mV
K+	150 mEq/L	5 mEq/L	–89 mV
Cl–	10 mEq/L	100 mEq/L	–60 mV

A drug is applied to the cell that increases the permeability of the cell by Cl– (i.e., it opens Cl– channels). What effect will this drug have on the net movement of Cl– across the plasma membrane?

A. Net Cl– movement out of the cell will be increased.

B. Net Cl– movement into the cell will be increased.

C. There will be no change in the net movement of Cl–.

ANS: C

8. Reducing the extracellular [K+] would be expected to have which of the following effects on the resting membrane potential and on the excitability of ventricular myocytes?

	Membrane Potential	Excitability
A.	Unchanged	Unchanged
B.	Hyperpolarized	Decreased
C.	Hyperpolarized	Increased
D.	Depolarized	Decreased
E.	Depolarized	Increased

ANS: B

9. A cell is bathed in an isotonic NaCl solution that contains 5 mmol/L of glucose. The intracellular concentration of glucose is 10 mmol/L. What is the most likely mechanism for the transport of glucose across the plasma membrane into this cell?

A. Glucose uniporter

B. Na+-glucose symporter

C. Na+-glucose antiporter

D. Diffusion of glucose through the lipid bilayer of the membrane

ANS: B

10. A blood sample is taken from an individual whose blood osmolality is 295 mOsm per kilogram of water. Red blood cells from this sample are then placed in the following solutions:

Solution	Osmolality (mOsm/kg H2O)	Reflection Coefficient (s) of Solute
1. NaCl	300	1
2. Fructose	300	0.5
3. Urea	300	0
4. CaCl2	100	1
5. KCl	150	1

The red blood cells in which of these solutions will swell to the greatest degree?

A. 1

B. 2

C. 3

D. 4

E. 5

ANS: C

11. A solution that causes a cell to shrink is:

A. Isotonic

B. Hypotonic

C. Hypertonic

ANS: C

12. Osmosis is:

A. The active transport of water

B. The number of solute particles in 1 kg of water

C. The diffusion of water across cell membranes

D. The defined as the weight of a volume of a solution divided by the weight of an equivalent volume of distilled water

E. The amount of a substance relative to its molecular weight

ANS: C

More Questions and Answers from Berne & Levy Physiology

What separates the intracellular contents from the extracellular environment?

Plasma membrane

How are eukaryotic cells distinguished from prokaryotic cells?

Presence of membrane-delimited nucleus in eukaryotic cells

Name Important cellular functions of plasma membrane (6)

Selective transport (carried out by membrane transport proteins)
Cell recognition (through cell surface antigens)
Cell communication (through neurotransmitter and hormone receptors and through signal transduction pathways)
Tissue organization
Membrane-dependent enzymatic activity
Determination of cell shape by linkage of cytoskeleton to the plasma membrane

What are the Examples of cells within the human body without nucleus?

Mature human red blood cells and cells within the lens of the eye

An aqueous solution containing numerous organic molecules, ions, cytoskeletal elements, and a number of organelles

Cytoplasm

The plasma membrane of eukaryotic cells consists of a...

5-nm-thick lipid bilayer with associated proteins

7. Primary function of cytosol: Metabolism, protein synthesis (free ribosomes)

8. Primary function of cytoskeleton: Cell shape and movement, intracellular transport

9. Primary function of nucleus: Genome (22 autosomes and 2 sex chromo- somes), DNA and RNA synthesis

10. Primary function of mitochondria: ATP synthesis by oxidative phosphoryla- tion, calcium storage

11. Primary function of smooth endoplasmic reticulum: Synthesis of lipids, cal- cium storage

12. Primary function of free ribosomes: Translation of mRNA into cytosolic pro- teins

13. Primary function of Rough endoplasmic reticulum: Translation of mRNA into membrane associated proteins or for secretion out of the cell

14. Primary function of lysosome: Intracellular degradation

15. Primary function of endosome: Cellular uptake of cholesterol, removal of receptors from the plasma membrane, uptake of small molecules and water into the cell, internalization of large particles (e.g., bacteria, cell debris)

16. Primary function of golgi apparatus: Modification, sorting, and packaging of proteins and lipids for delivery to other organelles within the cell or for secretion out of the cell

17. Primary function of proteosome: Degradation of intracellular proteins

18. Primary function of peroxisome: Detoxification of substance

19. Major lipids of the plasma membrane: Phospholipids and phosphoglycerides

20. Amphipathic molecules that contain a charged (or polar) hydrophilic head and two (nonpolar) hydrophobic fatty acyl chains: Phospholipids

21. The amphipathic nature of phospholipid molecule is critical for...: The formation of bilayer

22. The form the core of the bilayer, and the are exposed on the surface: hydrophobic fatty acyl chains, polar head groups

23. The presence of a produces a "kink" in the fatty acyl chain, which prevents tight packing of membrane lipids and increases membrane fluidity.: Double bond

24. The majority of membrane phospholipids have a "backbone" to which are attached the , and an is linked to via a .: Glycerol, fatty acyl chains, alcohol, glycerol, phosphate group

25. Common alcohols: Choline, ethanolamine, serine, inositol, and glycerol

26. Another important phospholipid which has the amino alcohol sphingosine as its "backbone" instead of glycerol: Sphingomyelin

27. Usual length of fatty acyl chains: 14 to 20 carbons, may be saturated or unsaturated (i.e., contain one or more double bonds)

28. 5 common phospholipids: OUTER LEAFLET:

- Phosphatidylcholine

- Shingomyelin

INNER LEAFLET:

- Phosphatidylethanolamine

- Phosphatidylserine

- Phosphatidylinositol (involved in signal transduction)

29. Found in both leaflets and serves to stabilize the membrane at normal body temperature (37 degrees C): Cholesterol

30. Minor lipid component of the plasma membrane: Glycolipids

31. Consist of two fatty acyl chains linked to polar head groups that consist of carbohydrates: Glycolipids

32. A glycolipid that plays an important role in anchoring proteins to the outer leaflet of the membrane: Glycosylphosphatylinositol (GPI)

33. True or False: Both cholesterol and glycolipids, like the phospholipids, are amphipathic.: True

34. As temperature increases, the fluidity of the membrane .: In- creases

35. The presence of unsaturated fatty acyl chains in the phospholipids and glycolipids (increases/decreases) membrane fluidity.: Increases

36. True or False: Although the lipid bilayer is "fluid," movement of proteins in the membrane can be constrained or limited.: True. For example, membrane proteins can be anchored to components of the intracellular cytoskeleton, which limits their movement.

37. Describe the plasma membrane of epithelial cells.: Junctional complexes (e.g., tight junctions) separate the plasma membrane of epithelial cells into two domains: apical and basolateral

38. Crucial for functioning of several organ systems (e.g., the gastrointestinal tract and kidneys): Vectorial transport

39. One important function is to segregate signaling molecules.: Lipid rafts

40. Classifications of membrane proteins: Integral, lipid-anchored, peripheral

41. Embedded in the lipid bilayer, where hydrophobic amino acid residues are associated with the hydrophobic fatty acyl chains of the membrane lipids.: - Integral membrane proteins

42. Integral membrane proteins that span the bilayer: Transmembrane proteins

43. Transmembrane proteins have both hydrophobic and hydrophilic regions. The hydrophobic region, often in the form of , spans the mem- brane. Hydrophilic amino acid residues are then exposed to the aqueous environment on either side of the membrane.: Alpha helix

44. A superfamily of membrane proteins that serve as receptors for many hor- mones, neurotransmitters, and numerous drugs.: G protein-coupled receptors

45. G protein-coupled receptors are coupled to .: Heterotrimeric G

proteins

46. G protein-coupled receptors span the membrane with how many alpha-he- lical domains?: Seven

47. The binding site of each ligand of the superfamily of membrane proteins is either on the extracellular portion of the protein ( ) or in the mem- brane-spanning portion ( ), whereas the cytoplasmic portion binds to the

.: Large ligands, small ligands, G protein

48. Makes up the third largest family of genes in humans: Superfamily of mem- brane proteins

49. Nearly half of all nonantibiotic prescription drugs are targeted toward...: G

protein-coupled receptors

50. A protein can also be attached to the membrane via . The protein is covalently attached to a lipid molecule, which is then embedded in one leaflet of the bilayer.: Lipid anchors

51. anchors protein to the outer leaflet of the membrane.: Glycosylphos- phatidylinositol (GPI)

52. Proteins can be attached to the inner leaflet via their or via their

.: Amino terminus by fatty acids (e.g., myristate or palmitate), carboxyl-terminus by prenyl anchors (e.g., farnesyl or geranylgeranyl)

53. May be associated with the polar head groups of the membrane lipids, bu they more commonly bind to integral or lipid anchored proteins: Peripheral proteins

54. In many cells, some of the outer leaflet lipids, as well as many of the proteins exposed on the outer surface of the membrane are .: Glycosylated