Osmosis & Aquaporins Presentation

Types of Aquaporins

Osmosis Video Quiz

Video Quiz Answers

Cell Membrane

Channels Discovery

Importance of Osmosis

in Plants & Animals

Aquaporins

2003 Nobel Prize Winners for Chemistry

Peter Agre

Osmosis

• discovered water channels
• Johns Hopkins University
• President of American Association for Science Advancement

1.) Osmosis is best defined as the movement of

A) molecules from an area of high concentration to an area of lower concentration.

B) molecules from an area of low concentration to an area of higher concentration.

C) water molecules across a membrane from an area of low water to an area of higher concentration.

D) water molecules across a membrane from an area of high water concentration to an area of lower concentration.

E) water molecules inside a container.

2.) Which of the following will pass through a cell membrane most easily?

A) small polar molecules

B) small nonpolar molecules

C) large polar molecules

D) large nonpolar molecules

E) large neutral molecules

3.) A red blood cell placed in a hypertonic medium will

A) expand.

B) burst.

C) shrink.

D) have no change in shape.

E) become a white blood cell.

4.) A 5% urea solution is hypotonic to a 10% urea solution.

A) True

B) False

5.) If a cell is placed in an isotonic medium, there will be no net movement of water.

A) True

B) False

Animals

Reactions when blood Cells [or other cells] is in contact with:

• isotonic solution: they will neither shrink nor swell.

• hypertonic solution: cells will lose water and shrink (plasmolyze).

ex: Saltwater from the ocean is hypertonic to our cells, drinking it dehydrates body tissues

• hypotonic solution (or if pure solvent is used): cells will swell (the osmotic pressure may rupture the cell membrane if great enough)

Plants

osmosis is at least partially responsible for the absorption of soil water by root hairs and for the elevation of the liquid to the leaves of the plant.

Osmosis influence the distribution of nutrients and the release of metabolic waste products.

• are membrane proteins that facilitates water transport in and out of the cell

• affects the rate of water transport across membranes

• essential to life b/c if it dysfunctions it may cause and contribute to disease

linked diseases:

• diabetes insipidus
• salivary gland dysfunction
• cataracts

Roderick MacKinnon

diffusion which involves movement of water molecules through a selective permeable membrane

• discovered structural and mechanistic studies of ion channels
• Rockefeller University

• driven by a difference in solute concentrations
• water flows from the solution with the lower solute
• size of solute particles DOES NOT influence osmosis

Resources

Notes

• AP Biology Ms. Foglia Handout

Book

• AP Biology Seventh Edition

Website

• highered.mcgraw-hill.com
• www.infoplease.com
• arbl.cumbs.colostate.edu
• osmosi.html
• asmena.ethz.ch
• www.aquaporins.org
• www.nobelprize.org
• vivo.colostate.edu