Phospolipids/membrane structure and function

Which of the following is responsible for getting large or charged (polar) molecules across the cell membrane?

• E
• B
• C
• D

Hydrophilic portion of cell membrane?

• A
• C
• D
• E 

Hydrophobic region of the cell membrane?

• E
• B
• C
• A 

Look at the cross section of a cell membrane of a eukaryotic cell. H+ ions are being pumped from a low concentration to a high concentration. How do you describe this type of transport across the cell membrane?

• active transport
• passive transport
• facilitated diffusion
• co-transport

The function of the plasma membrane is to:

• A.Serve as a highly selective barrier and allow cells to accumulate materials and energy

• B.Completely isolate the cell from the external environment.

• C. Equalize the chemical composition inside and outside the cell.

• D.None of the above.

Phospholipids can form bilayer structures because of their:

• A. Rectangular shapes

• B. Amphipathic nature.

• C. Ability to dissolve well in water.

• D. Inability to associate with other phospholipids.

Cholesterol within membranes functions as a(an) ____________ through its interactions with both hydrophobic and hydrophilic parts of phospholipids.

• A. Stabilize the membrane structure

• B. pH buffer

• C. Energy source

• D. Temperature controller

In a lipid bilayer, ___________ fatty acid tails face each other within the bilayer and form a region that excludes water.

• A. Hypotonic

• B. Hypertonic

• C. Hydrophilic

• D. Hydrophobic

Which of the following statements best describes the chemical composition of cell membranes?

• A. Cell membranes are bilayers of proteins with associated lipids and carbohydrates.

• B. Cell membranes are composed of two layers, one layer of phospholipids and one layer of proteins.

• C. Cell membranes are bilayers of phospholipids with associated proteins and carbohydrates.

• D. Cell membranes are composed of equal numbers of phospholipids, proteins, and carbohydrate.

Based on the diagram, name the molecule labelled F?

• A. Transmembrane protein

• B. Integral protein

• C. Peripheral protein

• D. Cytoskeleton