High Confidence - Biological Membranes Flashcards
What factors affect membrane permeability?
Solvents
Temperature
How would you increase the permeability of a membrane with a solvent?
Increase its concentration.
What type of molecule is a messenger molecule and how does it travel?
Hormone.
Blood.
The path from an area of high concentration to an area of low concentration is called what?
Down the concentration gradient
What sort of process is diffusion?
Passive - no energy is needed for it to happen.
What is the water potential of pure water?
Zero.
Name three types of solutions in relation to water potential and cells.
Isotonic
Hypotonic
Hypertonic
Diffusion using carrier and channel proteins is called what?
What type of process is it?
Facilitated diffusion.
Passive.
How does a carrier protein work?
A large molecule attaches to a carrier protein in the membrane.
The protein changes shape and releases the molecule on the opposite side
Define active transport.
Movement of molecules against a concentration gradient.
What proteins does active transport use and what is important about the process?
Carrier proteins.
Requires energy (ATP)
What does the outer membrane do for mitochondria?
The outer membrane keeps substances (enzymes) needed for respiration together.
How could you investigate the effect of temperature on membrane permeability?
Cut 5 equal-sized pieces of beetroot.
Rinse to remove any pigment released during cutting.
Add each piece to a separate test tube with 5cm3 of water in each.
Put each test tube in a water bath of varying temperatures for the same amount of time.
Remove the pieces, leaving just the liquid.
Colorimeter…
