AP Biology Cell Membranes & Diffusion!

Front

What is the primary function of the plasma membrane?

Back

The plasma membrane regulates the movement of substances in and out of the cell, maintaining homeostasis.

Front

What are phospholipids and their role in cell membranes?

Back

Phospholipids are molecules with a hydrophilic (water-attracting) head and two hydrophobic (water-repelling) tails, forming a bilayer that makes up the cell membrane.

Front

Define diffusion in the context of cell membranes.

Back

Diffusion is the passive movement of molecules from an area of higher concentration to an area of lower concentration across a membrane.

Front

What is the difference between active transport and passive transport?

Back

Active transport requires energy to move substances against their concentration gradient, while passive transport does not require energy and moves substances along their concentration gradient.

Front

Explain the role of cholesterol in the plasma membrane.

Back

Cholesterol helps to stabilize the fluidity of the plasma membrane, making it less permeable to very small water-soluble molecules that might otherwise pass freely through.

Front

What are integral membrane proteins?

Back

Integral membrane proteins are proteins that are embedded within the lipid bilayer and can span across the membrane, playing roles in transport and communication.

Front

What are peripheral membrane proteins?

Back

Peripheral membrane proteins are proteins that are loosely attached to the exterior or interior surfaces of the membrane and can be easily removed.

Front

What is facilitated diffusion?

Back

Facilitated diffusion is the process by which substances move across a membrane with the help of transport proteins, without the use of energy.

Front

Define glycoproteins and their function in cell membranes.

Back

Glycoproteins are proteins with carbohydrate chains attached that function as recognition sites for cell interactions and signaling.

Front

What is the significance of unsaturated fatty acids in membrane fluidity?

Back

Unsaturated fatty acids prevent tight packing of lipids, increasing membrane fluidity, especially in cold temperatures.