Transport And Membranes Flashcards
What does the cell membrane contain?
Phospholipid bilayer, intrinsic proteins, extrinsic proteins, cholesterol and glycolipids
What is an intrinsic protein?
Span the full membrane
What are extrinsic proteins?
Surface proteins
What is cholesterol used for in cell membranes?
Stability
What are glycolipids in cell membranes?
Recognition site
What are phospholipids made of?
2 fatty acids, glycerol and phosphate
What is the structure of a phospholipid?
Hydrophobic tail and hydrophilic head
What do phospholipids form?
Phospholipid bilayer
What does it mean to be lipid soluble?
Water and other small substances can diffuse through but larger molecules and water soluble ones can’t
What is diffusion?
The net movement of particles from an area of high to low concentration
What kind of process is diffusion?
Passive process down a concentration gradient
How can you speed up diffusion?
Bigger surface area, short diffusion pathway, higher temp (gives kinetic energy to move faster) and bigger concentration gradient
What is facilitated diffusion?
When a molecule is too large to diffuse across the membrane so can go via carrier proteins. It involves proteins which are specific to the substance crossing
Why might carrier proteins become a limiting factor in facilitated diffusion?
Because they may become fully saturated with molecules so can’t take anymore across
What is osmosis?
Net movement of water molecules from an area of Hugh to low concentration across a partially permeable membrane
