The video provides an introduction to the plasma membrane, focusing on its composition and structure. It explains the phospholipid bilayer, highlighting the hydrophilic and hydrophobic properties of phospholipids. The fluid mosaic model is discussed, emphasizing the movement of phospholipids and proteins within the membrane. The video also covers the role of cholesterol in maintaining membrane fluidity under varying temperatures.

What are the main components of a phospholipid?

• A phosphate group, a glycerol molecule, and two fatty acid tails

• A carbohydrate, a glycerol molecule, and two fatty acid tails

• A phosphate group, a protein, and two fatty acid tails

• A carbohydrate, a protein, and two fatty acid tails

Why are the tails of phospholipids oriented away from water?

• Because they are charged

• Because they are polar

• Because they are hydrophobic

• Because they are hydrophilic

What distinguishes a saturated fatty acid from an unsaturated one?

• Presence of a triple bond in unsaturated fatty acids

• Absence of a double bond in saturated fatty acids

• Presence of a double bond in saturated fatty acids

• Absence of a triple bond in unsaturated fatty acids

What is the role of integral proteins in the cell membrane?

• They are embedded within the membrane

• They are attached to carbohydrates

• They lie on the surface of the membrane

• They are only found outside the cell

What is a glycoprotein?

• A protein attached to a lipid

• A carbohydrate attached to a protein

• A protein attached to a phosphate group

• A lipid attached to a carbohydrate

What is the fluid mosaic model?

• A model describing the rigidity of the cell membrane

• A model describing the crystalline structure of the cell membrane

• A model describing the static nature of the cell membrane

• A model describing the dynamic nature of the cell membrane

What is a glycolipid?

• A lipid attached to a phosphate group

• A carbohydrate attached to a lipid

• A lipid attached to a protein

• A protein attached to a carbohydrate

How does cholesterol affect membrane fluidity at low temperatures?

• It decreases membrane fluidity

• It makes the membrane more rigid

• It increases membrane fluidity

• It has no effect on membrane fluidity

What happens to the phospholipids in the membrane when the temperature rises?

• They stop moving

• They become more rigid

• They move further apart

• They move closer together

What is the primary function of cholesterol in the cell membrane?

• To form the phospholipid bilayer

• To attach to proteins

• To maintain membrane fluidity

• To increase membrane rigidity