Membranes
Cards (13)
- Colorimetry: used to measure the concentration of a solution.
- What model is used to describe cell membranes?Fluid mosaic model
- Cholesterol is responsible for regulating the fluidity of the cell membrane by getting in between phospholipid molecules and making the membrane more rigid
- The membrane consists of a phospholipid bilayer with a hydrophilic head and hydrophobic tail
- Factors affecting membrane structure:temperature -> phospholipids have more kinetic energy and move around more which increases membrane permeabilitypolarity of solvent: polar solvent can form hydrogen bonds with the hydrophilic heads of the phospholipids membrane and cause the structure to break down
- Different types of lipids found in the cell membrane:
- phospholipids
- cholesterol - regulates membrane fluidity
- glycolipids - Antigens or cell marker
- Different type of proteins found in the cell membrane:
- surface proteins - provide mechanical support
- Glycoproteins - recognition sites for foreign cells or chemicals
- Transport proteins - Transport proteins that transport substances across the membrane
- different type of transport proteins:channel proteins - transport ionscarrier proteins - transports large substances using ATPco-transport proteins - transports 2 molecules at once
- facilitated diffusion is the movement of molecules across a membrane from a region of high concentration to a region of low concentration using transport proteins
- diffusion is the movement of particles from an area of high concentration to an area of low concentration
- Exocytosis is when materials are released out of the cell through fusion of vesicles with the plasma membrane.
- active transport is the movement of molecules against their concentration gradient, requiring energy (ATP)
- Adaptations for simple and facilitated diffusion:
- large surface area to volume ratio
- Maintaining a steep concentration gradient
- short diffusion distance
- Large number of transport proteins (facilitated diffusion)