Question 1

An increase in the ratio of saturated to unsaturated fatty acid chains in a membrane _______________ the fluidity of the membrane.

Accepted Answer

decreases

Question 2

The temperature at which a phospholipid membrane transitions from a rigid to a fluid state is referred to as _______________.

Accepted Answer

Tm, or melting temperature

Question 3

Membranes are said to be ____________ because their two faces always differ from each other.

Accepted Answer

asymmetric

Question 4

The _______________ of small molecules is correlated with their relative solubilities in water and nonpolar solvents.

Accepted Answer

The answer of The _______________ of small molecules is correlated...

Question 5

_______________ membrane proteins are bound primarily by electrostatic and hydrogen-bond interactions with the head groups of lipids.

Accepted Answer

The answer of _______________ membrane proteins are bound primarily by...

Question 6

Choose the correct answer from the list below. Not all of the answers will be used.
-____________ membrane proteins are embedded in the hydrocarbon chains of membrane lipids.

Accepted Answer

Integral membrane proteins are the ones that are embedded in the hydrocarbon chains of membrane lipids, distinguishing them from peripheral membrane proteins, which are not embedded in the lipid bilayer.

Question 7

Choose the correct answer from the list below. Not all of the answers will be used.
-Lipid biolayers spontaneously form ____________.

Accepted Answer

Lipid bilayers spontaneously form closed biomolecular sheets due to the hydrophobic effect, which drives the hydrophobic tails of lipids to avoid water, resulting in a stable, enclosed structure.

Question 8

_______________ are bilayer lipid vesicles with an aqueous compartment.

Accepted Answer

The answer of _______________ are bilayer lipid vesicles with an...

Question 9

Choose the correct answer from the list below. Not all of the answers will be used.
-The driving force for the formation of membrane bilayers is/are the:

Accepted Answer

The hydrophobic effect, which is the tendency of nonpolar substances to aggregate in aqueous solutions and exclude water molecules, is the primary driving force for the formation of membrane bilayers. This effect causes the hydrophobic tails of phospholipids to face inward, away from water, while the hydrophilic heads face outward, interacting with water.

Question 10

The rate of lateral diffusion is such that a phospholipid molecule can travel from one end of a bacterium to the other in _______________ of time.

Accepted Answer

The answer of The rate of lateral diffusion is such...

Question 11

Choose the correct answer from the list below. Not all of the answers will be used.
-____________: This substance inhibits prostaglandin H2 synthase-1 by blocking the channel through which the substrate, arachidonate, travels.

Accepted Answer

Acetylsalicylic acid (aspirin) inhibits prostaglandin H2 synthase-1 (also known as cyclooxygenase-1, or COX-1) by acetylating a serine residue in the enzyme, which blocks the access of arachidonic acid to the active site, thus preventing the synthesis of prostaglandins.

Question 12

Choose the correct answer from the list below. Not all of the answers will be used.
-____________: The type of amino acid found in the transmembrane helix of an integral protein.

Accepted Answer

The transmembrane helices of integral proteins are typically composed of hydrophobic amino acids, which allow the protein to stably interact with the hydrophobic core of the lipid bilayer.

Question 13

Choose the correct answer from the list below. Not all of the answers will be used.
-____________: A complex between cholesterol and membrane phospholipids.

Accepted Answer

Lipid rafts are specialized microdomains in cell membranes, characterized by their composition of cholesterol, sphingolipids, and certain proteins, forming a more ordered structure compared to the surrounding membrane. These rafts are involved in various cellular processes, including signal transduction and membrane trafficking.

Question 14

_______________ inserts into lipid bilayers, disrupting interactions between fatty acids, thereby helping to maintain membrane fluidity.

Accepted Answer

The answer of _______________ inserts into lipid bilayers, disrupting interactions...

Question 15

Choose the correct answer from the list below. Not all of the answers will be used.
-____________ has a high permeability through lipid bilayers.

Accepted Answer

Water has a high permeability through lipid bilayers because it is a small, polar molecule that can easily pass through the hydrophobic core of the bilayer.

Question 16

Most cell membranes are electrically polarized, the inside being _______________ relative to the outside.

Accepted Answer

The answer of Most cell membranes are electrically polarized, the...

Question 17

Choose the correct answer from the list below. Not all of the answers will be used.
-Cells maintain a ____________ concentration of intracellular potassium as compared to the extracellular concentration.

Accepted Answer

Cells maintain a high concentration of intracellular potassium compared to the extracellular concentration, which is crucial for various cellular functions including maintaining the resting membrane potential and cell volume.

Question 18

Choose the correct answer from the list below. Not all of the answers will be used.
-____________: These membrane components contain carbohydrates.

Accepted Answer

Glycolipids are membrane components that contain carbohydrates attached to lipids.

Question 19

________________ is the noncovalent force which favors close packing of the tails of the lipids in a membrane.

Accepted Answer

The answer of ________________ is the noncovalent force which favors...

Question 20

Choose the correct answer from the list below. Not all of the answers will be used.
-____________: The process by which lipids and proteins move in the membrane bilayer.

Accepted Answer

Lateral diffusion is the process by which lipids and proteins move within the plane of the membrane bilayer.

Quiz 12: Membrane Structure and Function

An increase in the ratio of saturated to unsaturated fatty acid chains in a membrane _______________ the fluidity of the membrane.

The temperature at which a phospholipid membrane transitions from a rigid to a fluid state is referred to as _______________.

Membranes are said to be ____________ because their two faces always differ from each other.

The _______________ of small molecules is correlated with their relative solubilities in water and nonpolar solvents.

_______________ membrane proteins are bound primarily by electrostatic and hydrogen-bond interactions with the head groups of lipids.

Choose the correct answer from the list below. Not all of the answers will be used. -____________ membrane proteins are embedded in the hydrocarbon chains of membrane lipids.

Choose the correct answer from the list below. Not all of the answers will be used. -Lipid biolayers spontaneously form ____________.

_______________ are bilayer lipid vesicles with an aqueous compartment.

Choose the correct answer from the list below. Not all of the answers will be used. -The driving force for the formation of membrane bilayers is/are the:

The rate of lateral diffusion is such that a phospholipid molecule can travel from one end of a bacterium to the other in _______________ of time.

Choose the correct answer from the list below. Not all of the answers will be used. -____________: This substance inhibits prostaglandin H2 synthase-1 by blocking the channel through which the substrate, arachidonate, travels.

Choose the correct answer from the list below. Not all of the answers will be used. -____________: The type of amino acid found in the transmembrane helix of an integral protein.

Choose the correct answer from the list below. Not all of the answers will be used. -____________: A complex between cholesterol and membrane phospholipids.

_______________ inserts into lipid bilayers, disrupting interactions between fatty acids, thereby helping to maintain membrane fluidity.

Choose the correct answer from the list below. Not all of the answers will be used. -____________ has a high permeability through lipid bilayers.

Most cell membranes are electrically polarized, the inside being _______________ relative to the outside.

Choose the correct answer from the list below. Not all of the answers will be used. -Cells maintain a ____________ concentration of intracellular potassium as compared to the extracellular concentration.

Choose the correct answer from the list below. Not all of the answers will be used. -____________: These membrane components contain carbohydrates.

________________ is the noncovalent force which favors close packing of the tails of the lipids in a membrane.

Choose the correct answer from the list below. Not all of the answers will be used. -____________: The process by which lipids and proteins move in the membrane bilayer.