Zusammenfassung der Ressource
Cell Membranes
- Structure
- Role
- Barrier between the
cell & the
environment
- Controls what enters & leaves
- Partially permeable
- Fluid mosaic
- Phospholipids are
constantly moving
- Proteins are scattered throughout the bilayer
- Bilayer
- Phospholipids
- Head
- Hydrophilic
- Attracts water
- Tail
- Hydrophobic
- Repel water
- Doesn't allow
water-soluble
substances through
- Cholersterol
- Helps maintain shape
- Increasing temp increases permiability
- Diffusion
- Passive
- Simple
- Diffuse simply across the
membrane
- Depends on
concentration
gradient
- Depends on thickness
- Depends on surface area
- Facilitated
- Carrier proteins & channels
- Larger molecules
- Charged molecules
- Depends on concentration gradient
- Depends on the number of channels / carrier
proteins
- Down concentration gradient
- Osmosis
- Diffusion of water molecules
- Partially permeable membrane
- High to low water potential
- Water has 0
- The more solute then the lower the
water potential
- Conditions same
as diffusion
- Active Transport
- Active process
- Against concentration
gradient
- Carrier proteins
- ATP
- Source of energy
- Hydrolysed to ADP & P
- Releases energy
- Conditions
- Speed of proteins
- Number of proteins
- Rate of respiration
- Co-transport