Cell Membrane
Help with membrane shape and fluidity
Name the two kinds of passive transport.
Diffusion and facilitated diffusion
What is osmosis?
The diffusion of water
What is the flow of molecules in active transport?
Why does a cell want to have small volume?
Quicker transport of molecules to the centre of the cell
Describe what semi-permeable means.
Barrier that only allows certain things through.
What is the flow of molecules in passive transport
High to low concentration
What is the flow of water in osmosis?
High to low water concentration (low to high solute concentration)
Where does the energy for active transport come from?
ATP, synthesized in the mitochondria
In the surface area to volume ratio which is minimized and which is maximized?
Maximized = SA
Minimized = volume
What are the four criteria for the cell membrane to consider when letting molecules through?
Size, shape, electrical charge, fat/lipid solubility
What is the difference in molecules that can use diffusion vs. facilitated diffusion?
Diffusion: molecules must be small and uncharged
Facilitated: polar, charged, and/or larger molecules
The concentration of solute in a cell is the same as the concentration outside. This is known as what?
Isotonic
What is the difference between endo and exocytosis?
Endo = brings items into the cell
Exo = sends materials out of the cell
Direction of transport is different.
Describe what happens as a cell increases in size.
Increases the volume at a faster rate than the surface area.
List all the components of the cell membrane
Phospholipid bilayer, proteins (channel, pump, other), cholesterol, carbohydrates.
Describe how facilitated diffusion is different from diffusion.
Facilitated is controlled by channel proteins that select for certain molecules using a specific shape
A cell is placed in a solution and shrinks. What kind of solution is it?
Hypertonic
What is common between endo and exocytosis?
The membrane changes shape and both require ATP.
How does the mitochondria increase surface area?
Using cristae (folded membrane) to increase SA without increasing volume.
List three molecules that are transported in to the cell, and two that are transported out.
Any 2 of the following (OUT): water, urea, proteins, hormones, CO2, lactic acid
What type of diffusion would glucose undergo?
Facilitated using the glucose-carrier protein.
What happens to a cell in a hypotonic solution?
the cell gets bigger due to water moving in
Nerve cells use what kind of transport?
Pump proteins via the sodium-potassium pump.
Why would a large cell die before a small cell?
It is too difficult and takes too long to transport nutrients in and out of the cell to support demand.