Membrane Basics
What is the function of the cell membrane?
Controls what enters and leaves the cell
What does a cell recognition protein do?
recognize self vs foreign cells, typically glycoproteins.
What are the three ways small molecules move across the membraen?
Diffusion, Facilitated transport, Active transport
What is osmosis?
A type of facilitated transport that moves water.
low to high
What are the main components of the cell membrane? Name 3
Phospholipid bilayer, proteins, cholesterol
What does a channel protein do?
allow substances to move through the membrane via a passageway or tunnel
During diffusion, what direction in terms of concentration do substances move?
From high to low concentrations, so no protein or energy is required.
What are aquaporins?
Protein channels in cell memrane that allow water to move from one side of the membrane to another
What are the two ways substances move in bulk?
Exocytosis and endocytosis
What is the model used to describe the cell membrane? Define it
Fluid-mosaic model: a combination of phospholipids, cholesterol, and proteins that move positions and can change composition.
What does a carrier protein look like and what does it do?
allow substances to move through the membrane via a protein that changes shape.
During facilitated transport, substances move from ___ to ___ concentrations.
high to low.
What does a cell do when it is placed in an isotonic solution?
No change in the cell. Water moves in and out equally, because their is equal solute/water concentration inside and outside of the cell.
What is required for active transport?
Carrier proteins and ATP is required
Name the five types of membrane proteins:
Channel, Carrier, receptor, enzymatic, cell recognition
What does a receptor protein look like and what does it do?
Binds substances and causes a response in the cell. Draw
A ____two choices____ protein is required for facilitated transport to occur. Energy (is/isn't) required.
channel or carrier, energy isn't required.
What happens to a cell in hypertonic solutions?
The cell shrivels because water moves out since there is higher solute/lower water outside of the cell.
Exocytosis is the mass _____ of contents. ____ is required to make the vesicles.
release. ATP
Because the cell is _______ it only allows certain substances to move in or out of the cell.
selectively permeable
What is an enzymatic protein? What does it do and what does it look like? Draw
Speed up chemical reactions.
Name an example of a substance that moves via diffusion
Non polar molecules- have no charge or have an equal charge. inert gases (oxygen, CO2) and lipid soluble compounds
What does a cell do when it is placed in a hypotonic solution?
The cell expands and possibly bursts because water moves in since there is lower solute/higher water outside of the cell
What is endocytosis and what is an example of a substance that moves via endocytosis.
mass intake of contents: ATP is required to make and move vesicles.
proteins and sugars that need to be taken into the cell