Deck 12: Biological Membranes

Question 1

The sodium-potassium ATPase is one of the major energy consumers in the human body.Which other active transport process in the human body uses a mechanism similar to that of the sodium-potassium ATPase?

A)The reabsorption of amino acids in the renal tubules.
B)Uptake of amino acids into the brain through the blood-brain barrier.
C)Transport of calcium into the sarcoplasmic reticulum.
D)Glucose uptake by erythrocytes.
E)Absorption of chloroform by the lung alveoli.

Answer 1

Transport of calcium into the sarcoplasmic reticulum.

Question 2

Most sphingolipids are glycolipids.However, there is one sphingolipid that contains phosphate but no carbohydrate.This lipid is:

A)Ceramide.
B)Sphingomyelin.
C)Ganglioside.
D)Sphingosine.
E)Cerebroside.

Answer 2

Sphingomyelin.

Question 3

The mechanism that absorbs glucose from the intestinal lumen can be characterized as:

A)Electroneutral.
B)Facilitated diffusion.
C)Secondary active transport.
D)Antiport.
E)Passive diffusion.

Answer 3

Secondary active transport.

Question 4

The fluidity of biological membranes depends on temperature and lipid composition.Because membrane fluidity has to be maintained in an optimal range, you can expect that, in comparison with tropical fish, the biological membranes of cold-water fish have:

A)A higher proportion of polyunsaturated fatty acids.
B)A higher sphingomyelin/lecithin ratio.
C)A higher cholesterol content.
D)A higher content of saturated fatty acids.
E)A higher glycolipid content.

Question 5

Of the following compounds, the one that is most likely to diffuse across a lipid bilayer by passive diffusion is:

A)Ethanol.
B)Serum albumin.
C)Glucose.
D)Glycine.
E)Sodium ions.

Question 6

How do most integral membrane proteins interact with the lipid bilayer?

A)By covalent attachment to a glycosylphosphatidylinositol anchor.
B)Through covalently bound fatty acids.
C)By electrostatic interactions with the head groups of membrane lipids.
D)By a little piece of hydrophobic a helix that traverses the lipid bilayer.
E)By hydrogen bonds with the head groups of membrane lipids.