Cell Membrane Flashcards
Know all components of the plasma membrane
What is the purpose of the plasma membrane?
To surround and separates the cell from the environment.
What are the key features of plasma membrane?
- Composed of mostly lipids and proteins
- Controls movement in + out of the cell
- Provides structural support
- Interacts with the environment
- Separates fluids into separate compartments (Extracellular fluid + intracellular fluid)
ECF
Extracellular Fluid:
Composed of water and dissolved chemicals outside of the cell
Blood, lymph & interstitial fluid
high in Na+, Ca++, Cl- (salt, calcium, chlorine)
ICF
Intracellular Fluid= fluid inside cells –> Cytosol
- high in K+ (potassium), amino acids + nucleic acids
usually negative in charge to ECT
What is the Endomembrane system?
ECF + ICF
Membranes within the cell to separate it into different parts.
Components of Plasma Membrane
Phospholipid Bilayer
brief summary
- 2 layers of phospholipids
- 40% of the biological membrane
Most important structural part
Is amphilic
Components of Plasma Membrane
Amphilic
definition, components, placement
=hydrophillic + hydrophobic
1 hydrophillic head w/ phosphorus
- inside layer sticks in to tough water inside the cell
- outside layer sticks out to touch water ouside the cell
2 hydrophobic tails
- attracts hydrophonoc
- faces towards the other layers hydrophobic tails
- between the 2 bilayers
Components of Plasma Membrane
Cholesterol facts
=Steroid
* 10% of the plasma membrane
* % varries between cells
* +makes the membrane more rigid, - makes it less permeable to water
Components of Plasma Membrane
Pollysaccarides
Types of them.
What is it?
Pollysaccarides stick out of cells acting as a signal to other cells for indentification.
1. Glycolipids
2. Glycoproteins
3. Glycolax
Components of Plasma Membrane
Glycolipids
- pollysaccharide
- lipids bound to carbs
Components of Plasma Membrane
Glycoproteins
- pollysaccaride
- proteins bound to carbs
Components of Plasma Membrane
Glycolax
A layer of pollysaccharides on the outside of the cell
Components of Plasma Membrane
Proteins
Name the proteins in the plasma membrane
- peripherial membrane proteins
- integral membrane proteins
- transmembrane proteins
- receptor proteins
- structural proteins
Proteins in the plasma membrane make up 50%
Peripherial Membrane Proteins
Not in the phospholipid bilayer - Attached to the edge
Integral Membrane Proteins
Partially penetrate or span across
Transmembrane Proteins
Touches the ECF + ICF by going through the membrane
extracellular fluid + intracellular fluid
Receptor Proteins
Direct elements outside the cell
Transport Proteins
Move things between the ECT + ICF
Structural Proteins
Connects to the cytoskeleton inside the cell + extracellular matrix inside the cell
Diffusion
What is it? What does it do?
Diffusion moves solutes from high to low concentrations
* doesn’t need energy - actually releases
* happens naturally + spontaneously
* leads to equillibrium
* solutes move with gradient
Solute
chemical disolved in water
Concentration
amount of solute disolved in a given amount of water
Dilute
Lower concentration
Concentration Gradient
definition + attributes
The concentration between inside and outside of the cell
* happens across the plasma membrane
* has energy
* bigger difference in solutes leads to more energy
Homeostasis
definition + attributes
Homeosasis maintains the difference in concentration between the inside + outside of the cell
* NOT equilibrium = death for living cells
* Requires energy
What affects the rate of diffusion in the plasma membrane?
and how do they affect the membrane?
- +concentration gradient = +rate
- +membrane thickness = -rate
- +surface area = +rate
- +temp = +rate
- +molecules = -rate
- +permeability = +rate
Osmosis
How water moves across membranes following salt.
* diffusion of water
* only way the body can move water across membranes
* the body uses energy to move salt from one side of membrane