Cell Physiology Flashcards
Selective Permeability
Excludes:
- Proteins, nucleic acids, large molecules, structural molecules
Allows:
- Small molecules, lipid soluble substances
- Ions and water via channels
Simple Diffusion
-water via water channels, small uncharged molecules, lipid-soluble substances
Ex: Osmosis
movement of water
Carrier Mediated Transport
-Active Transport
-Facilitated Diffusion
Passive Processes
-Move down the gradient
-No ATP/energy needed
-ex: diffusion, osmosis, facilitated diffusion
Active Processes
-against gradient
-requires energy/ATP
-carrier proteins
Which of the following processes requires ATP?
a. simple diffusion
b. facilitated diffusion
c. active transport
d. more than one of the above
c. active transport
Which of the following is a passive process?
a. diffusion
b. facilitated diffusion
c. osmosis
d. all of the above
d. all of the above
Characteristics that affect diffusion rate
temperature
concentration gradient
molecular weight
surface area
membrane permeability
How does Temperature affect diffusion rate?
Temperature increase = diffusion rate increases
How does molecular weight affect diffusion rate?
Molecular weight increase = diffusion weight decrease
How does membrane permeability affect diffusion rate?
Membrane permeability increase = diffusion rate increase
How does membrane surface area affect diffusion rate?
Membrane surface area increase = diffusion rate increase
How does concentration gradient affect diffusion rate?
Concentration gradient increase = diffusion rate increase
What makes up a solution?
A mixture of solute and solvent
What is the universal solvent?
Water
What is a solute?
Whatever dissolves in the solvent (water)
A solute is always in….
constant motion and the rate depends on heat
The goal of a concentration is….
-Equilibrium
-Net diffusion/Net movement
-Moves from high to low
What makes an area in the body made for diffusion?
often folded or contain microvilli
All of the following increase the rate of diffusion EXCEPT
a. increasing the concentration gradient
b. increasing the temperature
c. increasing the membrane surface area
d. increasing the diffusion distance or barrier
d. increasing the diffusion distance or barrier
What molecules does the Lipid Bilayer diffuse?
- oxygen, CO2, steroid hormones, alcohol, some drugs and water via aquaporins
How do molecules that cannot diffuse get across?
-Carrier Proteins
-Ion Channels
What are Gated Channels?
Certain stimuli regulate opening of the channels
What stimuli opens the Gated Channels?
Ligand binding, mechanical stretch, change in membrane voltage
