Plasma Membrane Flashcards
Hydrophobic
Repelled by water, non-polar, allows small hydrophobic & polar molecules to pass through
Hydrophilic
Attracted by water, polar
Phospholipid Bilayer
Acts as a barrier between intracellular and extracellular environments.
Phospholipid
Hydrophilic polar phosphate head
Hydrophobic non-polar fatty acid tail
Fluid Mosaic Model
Fluid - Fatty acid tails
Mosaic - appearance of proteins on external surface
Phospholipid Bilayer
Functions of Plasma Membrane
Receives external signals, active boundary - only allows specific substances to pass, cell identity, transport
Proteins
recognises, transports and receives molecules
Glycoproteins
markers for cell-cell communication
Carbohydrate chains
attached to glycoproteins to help receive and recognise, enabling specific functions to occur
Glycolipid
maintain the stability of the cell and assists cellular recognition
Cholesterol
substance found in cell membranes. Makes PM more fluid and vice versa during hot temp
Method of Transport depends on
size - bigger is harder, charge - charged is harder, polarity, concentration gradient
Simple Diffusion
Passive net movement of a solute from a region of high solute concentration to low solute concentration. Small, lipid soluble (non-polar), uncharged molecules.
Facilitated Diffusion
Passive net movement of substance from an area of high concentration to an area of low concentration via a membrane protein. Bigger molecules than simple diffusion
Protein Carriers
molecule binds, protein carrier changes shape, moves the substance down and out
Protein Channels
doesn’t change shape, acts like a pore. Transports faster than diffusion
Active Transport
movement of molecules from a region of low concentration to high concentration, requiring use of energy, ATP. Goes against concentration gradient.
Osmosis
Net movement of water across membrane from area of low solute to high solute concentration
Cytosol
liquid part of the cell that suspends organelles
Cystoplasm
contains molecules such as enzymes which are responsible for breaking down waste.
Mitochondria
generates most of the chemical energy needed to power the cell’s biochemical reactions.
Ribosome
links amino acids together in messenger RNA molecules to form polypeptide chains.
Endoplasmic Reticulum
membrane-bound. Has ribosomes attached and is involved in protein and lipid synthesis.
Golgi Apparatus
proteins are packaged into secretory vesicles ready for export from the cell
Vesicles
small sac made of phospholipid bilayer in the Golgi
