Plasma Membrane Review

What type(s) of cells have a plasma membrane?

• Plants only

• Eukaryotes only

• Prokaryotes only

• All cells

Answer explanation

The plasma membrane surrounds the outside of the cell. All cells have a plasma membrane.

Match the following parts of the plasma membrane to their pictures:

• Phospholipids

• 
• Proteins

• 
• Cholesterol

• 
• Carbohydrates

• 

What macromolecule are the phospholipids that make up the majority of the plasma membrane?

• Lipids

• Carbohydrates

• Proteins

• Nucleic acids

Answer explanation

Phospholipids are lipids. They have 2 fatty acid tails.

The plasma membrane is made primarily of ​ (a)   that have a polar head and nonpolar tails. Embedded in the membrane are transport ​ (b)   . On the outside of the membrane there are ​ (c)   chains.

• phospholipids
• proteins
• carbohydrate
• nucleic acids

The phospholipids that form the bilayer of the plasma membrane have polar and nonpolar regions. What is the nonpolar portion of the phospholipid made of?

• monosaccharides

• nucleic acids

• fatty acids

• amino acids

Answer explanation

Fatty acids are the building bock of lipids. They are hydrocarbons, and they are nonpolar.

Match the following functions to the parts of the cell membrane:

• Cholesterol

• Transport molecules through

• Phospholipids

• Forms a bilayer

• Carbohydrate chains

• Strengthens the membrane

• Proteins

• Used in cell signaling

Why is the plasma membrane called a "fluid mosaic model"?

Answer explanation

The fluid mosaic model is used to dscribe the plasma membrane because it is made up of many different components, like a mosaic and they can all move around fluidly.

Which of the following parts of the plasma membrane is important for strengthening the membrane and stopping the phospholipid tails from sticking together?

• proteins

• hydrophillic heads

• cholesterol

• carbohydrate chains

Answer explanation

The cholesterol is embedded in the membrane where it provides stability to the phospholipid tails.

What does "bi" mean in phospholipid bilayer?

• flat

• two

• cell

• polar

Answer explanation

Bi = 2

Bicycle = two wheels

Binomial = two names

Bilayer = two layers

Phopholipids have a polar head which is ​ (a)   and nonpolar tails which are ​ (b)  

• hydrophillic
• hydrophobic

Answer explanation

Hydrophobic means "afriad of water." Fatty acid tails are hydrophobic meaning they repel water.

Hydrophillic is the opposite - the polar heads are attraced to water.