BIO 150 Phospholipid Bilayer

2 key properties of a cell membrane

they can function as a physical and a chemical barrier for the cell

Proteins and lipids

are embedded in the bilayer and facilitate the passage of molecules into and out of the cell

The morphology of the saturated and unsaturated fats in the lipid bilayer

Maintains the proper fluidity and function of the cell membrane

Allows organisms to regulate membrane flexibility in response to different environmental temperatures

Key characteristics of the lipid bilayer

Lipid bilayer is semipermeable and is approximately 50% lipids/50% proteins

Why is the lipid bilayer also called "the Fluid Mosaic"?

The lipid bilayer is called the fluid mosaic because there are lots of diverse components that support the cell and are always in motion

What role does cholesterol play in the lipid bilayer?

Facilitates the movement, and also keeps the phospholipids from pulling apart or from clustering too closely together

Difference between Integral membrane proteins and peripheral membrane proteins

Integral are exposed to both sides of the cell and are used to transport molecules across the membrane; peripheral are located on the surface of the membrane

Diffusion

the net movement of molecules from an area of greater concentration to an area of lesser concentration

Osmosis

Movement of water molecules through a semipermeable membrane from a low solute concentration to a high solute concentration

Does passive transport require energy?

No, passive transport doesn’t require energy

Define active transport; is energy required for it?

Cells use energy to move molecules across the cellular membrane (utilize membrane proteins); yes

Define bulk transport & give an example

large particles (or large quantities of smaller particles) are moved across the cell membrane; exocytosis/endocytosis

What is the key function of phagocytosis

Takes in larger substances like bacteria

We had a discussion in class about a key example of when bulk transport of Dopamine occurs due to hijacking of endocytosis into the neuronal synapse. What drug does this?

Methamphetamine

What is a thermophile and what type of environment do these types of bacteria live in?

Thermophiles are archaea that exist in extreme temperatures

Organelles

Specialized small organs within a cell