Monday, December 23, 2013

Diffusion and Osmosis

Part A

Correct
Phospholipids contain both a polar head and a nonpolar hydrocarbon tail, both of which are necessary for their ability to form membrane bilayers.
Part B

Correct
Lipids are nonpolar molecules, whereas sugars are polar.
Part C

Correct
Osmosis is the diffusion of water across a selectively permeable membrane.
Part D

Correct
Detergents form micelles around the grease, which are then washed away because the polar head groups facing outward on the micelle are water-soluble.
Part E

Correct
Small nonpolar molecules such as oxygen can diffuse across cell membranes.
Part F

Correct
The hydrophilic, or water-loving, portion of a phospholipid is the polar head, whereas the hydrophobic portion is the nonpolar tail.
Part G

Correct
The salt concentration in the solution is lower than it is in the cell, so water enters the cell, causing it to burst.

3 comments: