Unit 1 Flashcards
(122 cards)
Structure of phospholipid bilayer
Phospholipids form a bilayer with the hydrophobic and polar tails of the lipid facing the middle of the membrane and the hydrophilic and non-polar head of the membrane towards the watery contents of the cell
Channel proteins
Hydrophilic, passes through centre of integral membrane. Transports Polar molecules through the membrane (example water) channels are water field pause or tunnels. Used in facilitated diffusion. Transport large and polar molecules. 
Phospholipids
Paula/hydrophilic head. Nonpolar/hydrophobic tail
Cholesterol
Regulate fluidity, neither tooth fluid or too firm
Glycoprotein
Have branching carbohydrates on surface, recognition and adhesion between cells and in the recognition of antibodies, hormones and viruses
 how does the cell membrane maintain homeostasis
By controlling the movement of substances across the cell membrane
Diffusion
Molecules move from an area of high solute concentration to an area of low solute concentration
Passive transport
Move down a concentration gradient no energy required
Simple diffusion
Solute molecules move across the membrane if they are permeable (for example oxygen and carbon dioxide)
Facilitated diffusion
Charged particles, large molecules carried across using transport proteins, protein channels (for example potassium, glucose)
Osmosis
Movement of water molecules from high to low water concentration until it comes to an equilibrium
Active transport
Against concentration gradient and uses energy powered by ATP
Active transport through carrier proteins
Carry ions in large polar molecules for example glucose through the membrane by changing the shape of the molecule
Exocytosis
Type of active transport, moves materials out of cell
Endocytosis 
Moves large polar molecules that cannot pass through the hydrophobic cell membrane
Phagocytosis
Forms of vesicle in the cytoplasm to engulf large molecules
Pinocytosis
Forms vacuoles in the cytoplasm to take in fluid along with dissolved small molecules
How does temperature affect the rate of diffusion
As temperature increases the rate increases
How does concentration affect the rate of diffusion
As concentration increases rate increases
How does particle size affect rate of diffusion
As particle size increases the rate decreases
How does surface area to volume ratio affect rate of diffusion
The bigger the surface area to volume ratio the faster the rate of diffusion
How are charged particles moved
Channel protein
How are small molecules moved
Simple diffusion
How are large molecules moved
Carrier protein