Plasma membrane Flashcards
What is the plasma membrane?
The plasma membrane is the active boundary of a cells.
Describe the structure of the plasma membrane.
2D fluid composed of a phospholipid bilayer with embedded proteins.
What force allows phospholipids to move freely?
Weak dispersion forces allows the phospholipids to move freely, like a fluid.
Describe structure of phospholipid. (4)
- phosphate head: hydrophilic (polar)
- Fatty acid tail: hydrophobic tail (non polar)
What is the difference between the two hydrophobic tails in a phospholipid?
One is saturated (single bonds) and one is unsaturated (double bond present)
What is a glycocalyx?
Coating of outer layer of PM with carbohydrate chains.
Gives cell identity by contributing to communication, cell to cell recognition, adhesion and protects from damage.
What are the two types of proteins found in plasma membrane?
- intergral: embedded into membrane, penetrate hydrophobic region
- peripheral: anchored to exterior, don’t penetrate hydrophobic region
What are the functions of the plasma membrane? (4)
- protective boundary providing selective permeability
- separates internal contents from external contents of cell
- glycoproteins allow for cell identity
- communicates and interacts with external environment and other cells to maintain and balance internal conditions
Want is the function of cholesterol in the plasma membrane?
Stabilises the plasma membrane by loosening membrane and reducing movement.
Assists with temp fluctuations.
What are the functions of peripheral proteins? (2)
- cellular communication
- ancor cells
What are the functions of integral proteins? (3)
- transport of materials across PM
- regulate movement of substance
- performs functions in and out of the cell
What are the 4 types of proteins found in the plasma membrane?
- receptor
- recognition
- transport
- adhesion
What are lipids responsible for in the plasma membrane? (4)
- flexibility
- repair
- shape change
growth
What factors allow some substances to cross the PM? (4)
- size
- charge
- solubility in lipid solvents (polarity)
- direction of concentration gradient
What is simple diffusion?
Movement of a substance from an area of high conc. to an area of low conc.