BCMB 311 Exam 2 Questions with Verified Correct
Answer
The shape of a cell and the mechanical properties of its plasma membrane are determined
by a meshwork of fibrous proteins called what?
a) basal lamina
b) tight junction
c) cell cortex made largely of spectrin
d) glycocalyx
c) cell cortex made largely of spectrin
Micelles are:
a) hydrophilic head groups are wider than the hydrophobic tails
b) hydrophobic and hydrophilic domains are of equal width
c) hydrophobic tails are wider than the hydrophilic head groups
a) hydrophilic head groups are wider than the hydrophobic tails
The bilayer is:
a) hydrophilic head groups are wider than the hydrophobic tails
b) hydrophobic and hydrophilic domains are of equal width
c) hydrophobic tails are wider than the hydrophilic head groups
b) hydrophobic and hydrophilic domains are of equal width
Inverted micelles are:
a) hydrophilic head groups are wider than the hydrophobic tails
,b) hydrophobic and hydrophilic domains are of equal width
c) hydrophobic tails are wider than the hydrophilic head groups
c) hydrophobic tails are wider than the hydrophilic head groups
Which of the following would produce the most fluid lipid bilayer?
a) phospholipids with tails of 18 carbon atoms and two double bonds
b) phospholipids with fully saturated tails of 20 carbon atoms
c) phospholipids with tails of 20 carbon atoms and two double bonds
d) phospholipids with fully saturated tails of 18 carbon atoms
a) phospholipids with tails of 18 carbon atoms and two double bonds
In the α helices of transmembrane proteins, the hydrophobic side chains face which
direction?
a) the external or lumenal side of the membrane
b) the outside of the membrane-spanning helix
c) the cytosolic side of the membrane
d) the inside of the membrane-spanning helix
b) the outside of the membrane-spanning helix
Which characteristic describes the tails of phospholipids?
a) coated with sugars
b) amphipathic
c) hydrophobic
d) hydrophilic
, c) hydrophobic
Why do phospholipids form bilayers in water?
a) The hydrophilic head is attracted to water, while the hydrophobic tail shuns water.
b) The hydrophilic head is insoluble in water.
c) The hydrophobic head is attracted to water, while the hydrophilic tail shuns water.
d) The hydrophobic tail is attracted to water, while the hydrophilic head shuns water.
a) The hydrophilic head is attracted to water, while the hydrophobic tail shuns water.
Which of the following best explains why lipids very rarely "flip" from one monolayer to
the other within a lipid bilayer?
a) The lateral pressure of lipid head groups pushing against each other within a monolayer
prevents any lipids from moving to the other monolayer.
b) The energy required to desolvate the head group is too high.
c) The head group is too hydrophilic to pass through the acyl chain regions of the bilayer.
b) The energy required to desolvate the head group is too high.
Triacylglycerols ____________.
a) are completely hydrophilic.
b) are amphipathic.
c) have two hydrophobic tails and one hydrophilic tail.
d) are completely hydrophobic.
d) are completely hydrophobic.
Answer
The shape of a cell and the mechanical properties of its plasma membrane are determined
by a meshwork of fibrous proteins called what?
a) basal lamina
b) tight junction
c) cell cortex made largely of spectrin
d) glycocalyx
c) cell cortex made largely of spectrin
Micelles are:
a) hydrophilic head groups are wider than the hydrophobic tails
b) hydrophobic and hydrophilic domains are of equal width
c) hydrophobic tails are wider than the hydrophilic head groups
a) hydrophilic head groups are wider than the hydrophobic tails
The bilayer is:
a) hydrophilic head groups are wider than the hydrophobic tails
b) hydrophobic and hydrophilic domains are of equal width
c) hydrophobic tails are wider than the hydrophilic head groups
b) hydrophobic and hydrophilic domains are of equal width
Inverted micelles are:
a) hydrophilic head groups are wider than the hydrophobic tails
,b) hydrophobic and hydrophilic domains are of equal width
c) hydrophobic tails are wider than the hydrophilic head groups
c) hydrophobic tails are wider than the hydrophilic head groups
Which of the following would produce the most fluid lipid bilayer?
a) phospholipids with tails of 18 carbon atoms and two double bonds
b) phospholipids with fully saturated tails of 20 carbon atoms
c) phospholipids with tails of 20 carbon atoms and two double bonds
d) phospholipids with fully saturated tails of 18 carbon atoms
a) phospholipids with tails of 18 carbon atoms and two double bonds
In the α helices of transmembrane proteins, the hydrophobic side chains face which
direction?
a) the external or lumenal side of the membrane
b) the outside of the membrane-spanning helix
c) the cytosolic side of the membrane
d) the inside of the membrane-spanning helix
b) the outside of the membrane-spanning helix
Which characteristic describes the tails of phospholipids?
a) coated with sugars
b) amphipathic
c) hydrophobic
d) hydrophilic
, c) hydrophobic
Why do phospholipids form bilayers in water?
a) The hydrophilic head is attracted to water, while the hydrophobic tail shuns water.
b) The hydrophilic head is insoluble in water.
c) The hydrophobic head is attracted to water, while the hydrophilic tail shuns water.
d) The hydrophobic tail is attracted to water, while the hydrophilic head shuns water.
a) The hydrophilic head is attracted to water, while the hydrophobic tail shuns water.
Which of the following best explains why lipids very rarely "flip" from one monolayer to
the other within a lipid bilayer?
a) The lateral pressure of lipid head groups pushing against each other within a monolayer
prevents any lipids from moving to the other monolayer.
b) The energy required to desolvate the head group is too high.
c) The head group is too hydrophilic to pass through the acyl chain regions of the bilayer.
b) The energy required to desolvate the head group is too high.
Triacylglycerols ____________.
a) are completely hydrophilic.
b) are amphipathic.
c) have two hydrophobic tails and one hydrophilic tail.
d) are completely hydrophobic.
d) are completely hydrophobic.
