Cell Membranes and Movement Flashcards
What part of the cell membrane is part A?
Phospholipid Bilayer
What part of the cell membrane is part B?
Hydrophobic Tail
What part of the cell membrane is part C?
Hydrophillic Head
What can a cell membrane carry?
Hormones
Different Types of Proteins:
Protein Channels
Protein Carriers
Protein channels
A channel protein is a protein that allows the transport of specific substances across a cell membrane.
Carrier Proteins
carrier proteins can transport ions and molecules either passively through facilitated diffusion, or via secondary active transport.
What does Cholesterol do?
Gives membrane stability
What does Glycoproteins do?
Strucutural support and forms connective tissues
What does Glycolipids do?
Contribute energy and act as a marker for cellular recognition
The Fluid Mosaic Model
Phospholipids are a continuous double bilayer, which is described as fluid because it continually moves.
Proteins are scattered through the bilayer like tiles in a mosaic.
Flexible and proteins
Types of Movement
Diffusion
Facilitated Diffusion
Osmosis
Active Transport
Diffusion
The net movement of particles (molecules or ions) from a higher concentration to a lower concentration. e.g. oxygen
High - Low
A passive process so does not require energy.
Known as simple diffusion
Facilitated Diffusion
Larger molecules e.g. glucose cannot diffuse simply
Molar molecules would also diffuse protein inside the cell membrane
Protein carriers - a large molecule attaches to the carrier protein
The protein changes shape
Releases molecule to opposite side
What protein channels do
form pores in the membrane for charged particles.
Moves down the concentration gradient
Osmosis
H2O like a magnet.
Dipolar molecule +ve/-ve end
Most biological reactions are ionic.
Because H2O is dipolar it can surround +ve / -ve
Dissolving = easier transport
Osmosis and H2O
Same diffusion with water
Solute - soluble
Pure water - 0 water potential
Osmosis
Isotonic
Isotonic - place cell in isotonic solution = there will be no net movement.
Hypertonic - cell net movement out of the cell (shrivel) dehydrates
Hypotonic - cell net movement will be into cell (cell bursts)
Active Transport
ATP uses energy to move molecule ions across a cell membrane.
AT similar to facilitated diffusion.
Uses protein
Low - High / High - Low
Push against and can push things out
