Cell Membrane Structure and Function

This video tutorial explains the role of phospholipids in cell membranes and describes the fluid mosaic model. It compares triglycerides and phospholipids, highlighting their hydrophobic and hydrophilic properties. The formation of the phospholipid bilayer and its function as the basis of cell membranes are discussed. The video also covers the various functions of membranes, including acting as barriers, locations for chemical reactions, and involvement in cell signaling. The structure and properties of the cell surface membrane, including the role of cholesterol in membrane stability and fluidity, are explained. Finally, the fluid mosaic model is described, emphasizing the movement of phospholipids and the arrangement of protein molecules.

What is the primary role of phospholipids in cell membranes?

• To form a barrier between the cell and its environment

• To facilitate cell division

• To store genetic information

• To provide energy for the cell

How do triglycerides differ from phospholipids in terms of structure?

• Triglycerides have two fatty acids, while phospholipids have three

• Triglycerides contain a phosphate group, while phospholipids do not

• Triglycerides are polar, while phospholipids are nonpolar

• Triglycerides have three fatty acids, while phospholipids have two

What happens when phospholipids are placed in water?

• They dissolve completely

• They form a single layer

• They arrange into a bilayer

• They repel each other

What is the significance of the hydrophilic and hydrophobic regions in phospholipids?

• They enable the formation of a bilayer structure

• They allow phospholipids to dissolve in water

• They make phospholipids rigid

• They prevent phospholipids from interacting with proteins

Which of the following is NOT a function of cell membranes?

• Facilitating cell signaling

• Acting as a barrier

• Storing genetic information

• Providing a location for chemical reactions

Why can hydrophobic molecules easily pass through the cell membrane?

• Because they are nonpolar

• Because they are water-soluble

• Because they are small

• Because they are charged

What role does cholesterol play in the cell membrane?

• It acts as a receptor for hormones

• It increases the membrane's fluidity

• It stabilizes the membrane structure

• It makes the membrane more permeable

What does the 'fluid' aspect of the fluid mosaic model refer to?

• The movement of ions through the membrane

• The movement of water across the membrane

• The movement of phospholipids within each layer

• The movement of proteins within the membrane

Why is the cell membrane described as a 'mosaic'?

• Because it is colorful

• Because it contains a variety of proteins embedded within it

• Because it is composed of repeating patterns

• Because it is made of a single type of molecule

How does cholesterol affect the fluidity of the cell membrane?

• It has no effect on fluidity

• It decreases fluidity in warm conditions

• It increases fluidity in warm conditions

• It only affects fluidity in cold conditions