CELS-4-revision2

The plasma membrane contains amphipathic phospholipids with ______ heads that interact with water and ______ tails that form the hydrophobic interior.

Hydrophilic; non-polar

Lipid; protein

Hydrophobic; charged

Non-polar; polar

None

The ______ allows eukaryotic cells to maintain compartmentalization, while the ______ regulates the passage of genetic information.

Cytoskeleton; plasma membrane

Plasma membrane; nuclear envelope

Endoplasmic reticulum; Golgi apparatus

Mitochondrion; ribosome

None

Which of the following best explains why small, non-polar molecules can pass through the membrane without assistance?

They are actively transported using ATP-driven pumps designed for these types of molecules

Their properties allow them to dissolve in the hydrophobic membrane interior

They are small enough to diffuse through membrane channels

The hydrophilic lipid tails allow their passage through the bilayer

None

Which of the following statements is false?

Cholesterol disrupts membrane integrity, increasing permeability to all molecules

Membrane proteins facilitate both passive and active transport processes

The fluidity of the membrane is influenced by temperature, cholesterol, and fatty acid composition

The phospholipid bilayer restricts charged molecules from freely passing

None

Which of the following is true regarding membrane fluidity?

It is maintained by cholesterol

It depends solely on protein concentration rather than lipid composition

It remains constant regardless of temperature or lipid composition

It decreases when the proportion of unsaturated fatty acids increases

None

Which of the following statements about membrane proteins is false?

Transport proteins can be involved in both passive and active transport mechanisms

Signal transduction proteins relay messages from the extracellular environment into the cell, influencing cellular functions like growth and division

The primary function of intercellular joining proteins is to anchor the cell to the extracellular matrix

Glycoproteins play a role in cell-cell recognition, often binding to molecules on neighboring cells

None

Membrane proteins play a crucial role in:

Preventing molecular movement across the bilayer entirely

Facilitating transport and signaling transduction

Forming a static structure and facilitative transportation

Generating ATP from phospholipid metabolism

None

The plasma membrane maintains homeostasis by:

Allowing hydrophilic molecules to diffuse freely while restricting hydrophobic molecules

Using selective permeability and dynamic protein interactions

Preventing all molecules from crossing to preserve internal conditions

Utilizing membrane proteins exclusively for active transport processes

None

Passive transport moves molecules ______ their gradient, while active transport moves molecules ______, requiring the direct use of ______.

Against; against; ATP

Against; along; ATP

Along; along; energy

Along; against; ATP

None

10.

The sodium-potassium pump helps maintain cellular electrochemical gradients by:

Pumping equal amounts of sodium and potassium ions across the membrane

Using ATP to move sodium out of the cell and potassium into the cell

Allowing sodium into the cell via passive diffusion

Transporting both ions down their respective concentration gradients

None