Cholesterol Structure (Part 2 2)

The video explores cholesterol's role in stabilizing cell and organelle membranes. It details the structure of phospholipids, highlighting ester linkages and negative charges. Cholesterol's hydrophobic interactions with phospholipid tails and hydrogen bonding with polar heads are explained, emphasizing their contribution to membrane stability. The video also illustrates cholesterol's position in membrane bilayers, showing its presence in both inner and outer leaflets.

What is the primary role of cholesterol in cell membranes?

• To decrease membrane thickness

• To stabilize cell membranes

• To facilitate protein synthesis

• To increase membrane fluidity

What is the significance of the phosphate group in phospholipids at physiological pH?

• It is protonated and positively charged

• It is deprotonated and negatively charged

• It is neutral

• It is positively charged

How does cholesterol interact with phospholipid tails?

• Through hydrogen bonds

• Through Vander Waals attractions

• Through covalent bonds

• Through ionic bonds

What is the role of the A ring hydroxyl group in cholesterol?

• It forms ionic bonds with the phospholipid tails

• It forms covalent bonds with the phospholipid head

• It forms hydrogen bonds with the phospholipid head

• It forms Vander Waals attractions with the phospholipid tails

What effect does cholesterol have on membrane entropy?

• It has no effect on membrane entropy

• It fluctuates membrane entropy

• It decreases membrane entropy

• It increases membrane entropy

Where can cholesterol be found in the membrane?

• Only in the inner leaflet

• Only in the outer leaflet

• In both the inner and outer leaflets

• Only at the membrane surface

How does cholesterol affect the rigidity of the membrane?

• It decreases membrane rigidity

• It makes the membrane more flexible

• It increases membrane rigidity

• It has no effect on membrane rigidity