Lecture 7

Question 1

What is diffusion?

Answer 1

Movement of molecules from high to low conc. to reach equal concentration through barriers

Question 2

What is osmosis?

Answer 2

Movement of water across membrane to equalise solute conc.

Question 3

What are the 3 states of solute concentration and how does this impact human cell health?

Answer 3

Isotonic = the same conc. + healthy cells. Hypertonic = higher conc. for extracellular fluid, water tries to leave cells, causing them to shrivel. Hypotonic = lower conc. for extracellular fluid, water tries to enter cell, causes it to swell and possibly lyse.

Question 4

What are the two types of gradients and what are their purposes?

Answer 4

Chemical and electrical gradients. This means that there are different concentrations of the substance on the two sides. By having a chemical gradient, it allows rapid signalling in excitable cells e.g calcium ions.

Question 5

What is the resting membrane potential?

Answer 5

The electrical potential difference (electrical gradient) at rest. Intracellular is more negative and extracellular is more positve.

Question 6

What is depolarization and repolarization?

Answer 6

Depolarization is when the chemical gradient is lost during a signalling event. Repolarization is when the chemical gradient is created again after a signalling event has occurred.

Question 7

What is an excitable cell?

Answer 7

A cell which makes the body do things.