Lecture 4: Membrane Transport

Flashcards about Membrane Transport

What is a concentration gradient?

The movement of molecules from an area of high concentration to an area of low concentration.

What are the different ways molecules move across the cell membrane?

Simple diffusion, facilitated diffusion, osmosis, active transport, exocytosis, and endocytosis.

What are the three types of tonicity?

Isotonic, hypertonic, and hypotonic.

What are the two main types of cell transport?

Passive and active transport.

What is the function of the cell membrane?

Surrounds the entire cell and cell organelles and is fluid in nature.

What are the two parts of a phospholipid?

Polar/hydrophilic head and nonpolar/hydrophobic tail.

What are the two types of proteins in the cell membrane?

Integral and peripheral proteins.

What are the two types of Integral proteins?

Carrier and channel proteins.

What are the two types of Peripheral proteins?

Receptors and antigens.

What is one of the most important functions of the cell membrane?

Facilitating the transport of materials between the outside and the inside of the cells.

What are the three types of passive transport?

Simple diffusion, facilitated diffusion, and osmosis.

What is passive transport?

The movement of materials across the cell membrane without using cellular energy.

What is simple diffusion?

Transport across a membrane without the help of membrane proteins.

What are two small molecules that use simple diffusion?

Oxygen and carbon dioxide.

What are the factors affecting rate of diffusion?

Concentration gradient, surface area, and number and size of pores.

What is facilitated diffusion?

For larger, water-soluble molecules that move along the concentration gradient.

What are the two distinct types of transport proteins that mediate facilitated diffusion?

Channel and carrier proteins.

What are the three types of carrier proteins?

Uniporters, symporters, and antiporters.

What do uniporters do?

Transports a single solute from one side of the membrane to the other.

What do symporters do?

Transports two different solute molecules simultaneously in the same direction.

What do antiporters do?

Transports two different solute molecules in opposite directions.

What is osmosis?

The diffusion of water molecules from a dilute solution to a more concentrated solution across a selectively permeable membrane.

What are the three types of solutions related to osmosis and tonicity?

Hypertonic, hypotonic, and isotonic.

What is a hypertonic solution?

Contains a high concentration of solute relative to another solution, causing cells to shrivel.

What is a hypotonic solution?

Contains a low concentration of solute relative to another solution, causing cells to swell and possibly burst.

What is an isotonic solution?

Contains the same concentration of solute as another solution, with water diffusing into and out of the cell at the same rate.

What is active transport?

Carrier-mediated transport that takes place against concentration gradient and requires energy.

What is the purpose of the Sodium/Potassium Pump (Na+/K+ ATPase)?

Maintains the resting potential of the cell.

What are the two types of vesicular transport?

Exocytosis and endocytosis.

What are the three types of endocytosis?

Pinocytosis, phagocytosis, and receptor-mediated endocytosis.