BIOS 3755: Human Physiology - Membrane Transport

A collection of flashcards covering key concepts related to membrane transport mechanisms, diffusion, active transport, osmolarity, tonicity, and diseases affecting transport systems.

What is diffusion?

The passive movement of particles from an area of high concentration to low concentration.

What limits the efficiency of diffusion over large distances?

Distance and the hydrophobic interior of the lipid bilayer of membranes.

What are the basic types of membrane transport?

1. Simple diffusion 2. Facilitated diffusion 3. Active transport.

What is facilitated diffusion?

A type of mediated transport that requires a carrier molecule and occurs down the electrochemical gradient without energy input.

What is active transport?

A process that requires energy to move solutes against their electrochemical gradient.

What are the three types of facilitated diffusion?

1. Channels (always open) 2. Pores (intermittently open) 3. Carriers (never open at both ends simultaneously).

What is osmolarity?

The total solute concentration of a solution.

What is tonicity?

The ability of an extracellular solution to make water move into or out of a cell by osmosis.

What happens to red blood cells in hypotonic solutions?

They swell as water moves into them.

What is the role of aquaporins?

Channels that facilitate the rapid movement of water across cell membranes.

What does the sodium-potassium pump do?

Exports 3 Na+ ions out of the cell and imports 2 K+ ions into the cell for each ATP molecule hydrolyzed.

How does cystic fibrosis affect transport processes?

It results from mutations in the CFTR chloride channel, leading to thick and viscous mucus that clogs airways and affects nutrient absorption.