Biology

Robert J. Brooker

Chapter 5

Membrane Structure, Synthesis, and Transport - all with Video Answers

Educators

Chapter Questions

Problem 1

Which of the following statements best describes the chemical composition of biological membranes?
a. Biological membranes are bilayers of proteins with associated lipids
and carbohydrates.
b. Biological membranes are composed of two layers—one layer of
phospholipids and one layer of proteins.
c. Biological membranes are bilayers of phospholipids with associated
proteins and carbohydrates.
d. Biological membranes are composed of equal numbers of
phospholipids, proteins, and carbohydrates.
e. Biological membranes are composed of lipids with proteins attached
to the outer surface.

Norma Kimmel

Norma Kimmel

Numerade Educator

Problem 2

Which of the following events can never be energetically favorable in a biological membrane and therefore will not occur spontaneously?
a. the rotation of phospholipids
b. the lateral movement of phospholipids
c. the flip-flop of phospholipids to the opposite leaflet
d. the rotation of membrane proteins
e. the lateral movement of membrane proteins

Norma Kimmel

Numerade Educator

Problem 3

Let’s suppose an insect, which doesn’t maintain a constant body temperature, was exposed to a shift in temperature from 60°F to 80°F. Which of the following types of membrane changes would be the most beneficial in helping the insect cope with the temperature shift?
a. increase the number of double bonds in the lipid tails of
phospholipids
b. increase the length of the lipid tails of phospholipids
c. decrease the amount of cholesterol in the membrane
d. decrease the amount of carbohydrate attached to membrane
proteins
e. decrease the amount of carbohydrate attached to phospholipids

Norma Kimmel

Numerade Educator

Problem 4

Carbohydrates of the plasma membrane
a. are bonded to a protein or lipid.
b. are located on the outer surface of the plasma membrane.
c. can function as cell markers for recognition by other cells.
d. All of the above are true of the carbohydrates.
e. Only a and c are true

Norma Kimmel

Numerade Educator

Problem 5

A transmembrane protein in the plasma membrane is glycosylated at two sites in the polypeptide sequence. Where in this protein would you expect these two sites to be?
a. in transmembrane segments
b. in hydrophilic regions that project into the extracellular environment
c. in hydrophilic regions that project into the cytosol
d. could be anywhere
e. b and c only

Norma Kimmel

Numerade Educator

Problem 6

The tendency for Na+ to move into the cell can be due to
a. the higher numbers of Na+ outside the cell, resulting in a chemical
concentration gradient.
b. the net negative charge inside the cell attracting the positively
charged Na+.
c. the attractive force of K+ inside the cell pulling Na+ into the cell.
d. all of the above.
e. a and b only.

Christina Sorrentino

Christina Sorrentino

Numerade Educator

Problem 7

Let’s suppose the solute concentration inside the cells of a plant is 0.3 M and the concentration outside is 0.2 M. If we assume that the solute does not readily cross the membrane, which of the following statements best
describes what will happen?
a. The plant cells will lose water, and the plasma membrane will push
against the cell wall.
b. The plant cells will lose water, and the plasma membrane will pull
away from the cell wall (plasmolysis).
c. The plant cells will take up a lot of water and undergo osmotic lysis.
d. The plant cells will take up a little water, and the plasma membrane
will push against the cell wall.
e. both a and b.

Norma Kimmel

Numerade Educator

Problem 8

What features of a biological membrane are major contributors to its selective permeability?
a. phospholipid bilayer
b. transport proteins
c. glycolipids on the outer surface of the membrane
d. peripheral membrane proteins
e. both a and b

Norma Kimmel

Numerade Educator

Problem 9

What is the name given to the process in which solutes are moved across
a membrane against their concentration gradient?
a. simple diffusion
b. facilitated diffusion
c. osmosis
d. passive diffusion
e. active transport

Christina Sorrentino

Christina Sorrentino

Numerade Educator

Problem 10

Large particles or large volumes of fluid can be brought into the cell by
a. facilitated diffusion.
b. active transport.
c. endocytosis.
d. exocytosis.
e. all of the above.

Christina Sorrentino

Christina Sorrentino

Numerade Educator