cell membrane Flashcards
what does the cell membrane do
The cell membrane provides protection for the cell from neighbouring cells and the external environment. The membrane provides support for the shape of the cell and controls what enters and exits it.
what does selectively permeable mean
only certain substances can pass through
what organisms have a cell wall
plant and fungi
where is the cell wall located
outside the cell membrane
what does the cell wall do
provides structure and support
is the cell wall permeable or selectively permeable
permeable
what is the cell membrane responsible for
- taking in nutrients for the cells
- excreting waste products
- ensuring toxic substances don’t enter the cell
describe the internal environment inside the cell
There is a multitude of different enzymes working in the cell to carry out our different cellular processes. Enzymes only work under specific conditions.
what is the fluid mosaic model?
the fluid mosaic model describes the membranes as lipid bilayers that can flow and change shape with proteins embedded in various patterns
what does the phospholipid bilayer consist of
Contains hydrophilic heads which means they love water, and two hydrophobic tails meaning they hate water.
where is cholesterol found
it is found dispersed throughout the cell
what does cholesterol do
It interacts and disrupts boundaries between the tails, allowing the membrane to maintain flexibility.
what are the different proteins found in the membrane
- adhesion proteins
- transport proteins
- receptor proteins
- glycoproteins (recognition proteins)
what are adhesion proteins
A membrane protein that helps link cells together to form tissues to allow communication
what are transport proteins
A protein that carries molecules across the membrane
what are the different transport proteins
- carrier proteins
- channel proteins
what are channel proteins
They have narrow passageways through the membrane, allowing small particles to pass through. Channel proteins rely on the concentration gradients
what are carrier proteins
Will bind to specific molecules on one side of the membrane and change shape to release the molecules on the other side.
what is a receptor protein
A protein in a cell membrane that binds hormones and other signal molecules
what is an example of a receptor protein
When a brain releases a hormone it will not enter the cell it affects. Instead, it binds to a receptor protein in the membrane of the cell causing a reaction that will lead to a change
what are recognition proteins
A protein that acts as a marker on membranes. This allows immune cells to differentiate between host cells and foreign cells.
describe recognition proteins in the blood
Blood type A has a particular glycoprotein (antigen). If they receive blood with B antigens the immune system will not recognise it and target it to be destroyed resulting in clumping
