Chapter 8 Flashcards
What are membranes composed mainly of.
They are composed mainly of phospholipid bilayer. It also contains some other lipids, proteins and carbohydrates.
Substances that contain a hydrophobic and hydrophilic region are called…
Amphipathic
The fact that phospholipids are amphipathic gives rise to what property.
Self-assembly in water. Meaning they form two layers (a bi layer)
Properties of a Phospholipid Bilayer
Self assembly in water
Individual molecules are not static
They are semipermeable
What are the functions of the proteins that make up a membrane.
Enzyme function, Signal carrying, Transport, Cell recognition, Attachment to the cytoskelenton.
What does Isotonic mean
When a cell and its surrounding have the same salt concentration.
When a cell has a higher salt concentration than the sorroundings
Hypertonic
When a cell has a lower salt concentration than the sorroundings
Hypotonic
when things move from an area of high concentration to an area of lower concentration.
Diffusion
When water moves from an area of high concentration to an area of low concentration across a semi-permeable membrane
Osmosis
The movement of substances from regions of lower concentrations to regions of higher concentrations using energy
Active transport
Diffusion, Osmosis and Active transport are…
Ways things move across a membrane
What does the rate of diffusion depend on
The temperature, concentration gradient and ability to pass through a membrane
The rate of diffusion would be faster when
The temperature or/and the concentration gradient is high.
What is energy
The ability to do work
