Cell Membrane Flashcards
Describe cell membrane structure
Phospholipid bilayer with hydrophobicends facing away it is selectively permeable
Cholesterol throughout
Trans membrane proteins
Functions of cell membrane 5-6
Regulate movement of molecules
① transport raw materials into cell
② remove waste from cell(exocytosis)
③ transfer materials produced in cellto outside the cell
④ prevent entry of unwanted molecules
⑤ prevent escape of needed molecules
Is water passable?
Water can pass passively and slowly
Uses aquaporins
What can pass through hydrophobic part of cell membrane?
Small nonpolar molecules
Oxygen and Carbon dioxide
Types of cell membrane protein?
Carrier channel aquaporins
Carrier proteins
Transmembrane (integral) protein to help move neutral water soluble molecules
Eg-glucose
From outside to inside
Specific to larger molecules
Active or passive
Channel proteins
Transmembrane (integral) and allows ions to pass through membrane
Less selective
Passive
Aquaporins
Special (integral) proteins that help water pass through cell membrane
Passive
Glycoproteins
Carbohydrates bonded to proteins serve as markers for attachment to cytoskeleton
Glycolipids
Recognition site for molecules to help join cells together to form tissue
What is the purpose to have a carbohydrate attached to cell membrane?
Recognition sites for molecules attaching to cell membrane
What are solutions made up of?
Solute dissolved in solvent
In cell solvent is always water
Cell solutes are sugars, salts, ions (Na, chloride ion and k or ATP
Concentration gradient
Meaning cells do work to ensure more solute On one side of cell membrane
Not always even
Diffusion
High to low concentration
Which factors affect solute movement (4)
① size
② charge and polarity
③ concentration gradient
④ distance
What are the 3 transport methods?
Passive
Active
Bulk membrane
Passive transport
No energy
① Simple diffusion from high to low until equilibrium reached
② osmosis - movement of water muleules from high to low across semi-permable
How is water flow or osmosis determined?
Relative water concentration on both sides of thembrune and inability of solute molecules to pass membrane
Types of solutions (2)
Hypotonic and hypertonic
Hypertonic
Shrivel and shrink or plasmolysis which shrinks vacuole
Higher concentration of solutes outside
High osmotic pressure
Hypotonic
Water flows into cell higher solute concentration in cell has low osmotic pressure
Lyse batin plants its turgid
Types of passive transport
Simple diffusion
Osmosis
Facilitated diffusion (passive)
The cell membrane is
Flexible, fluid and dynamic
Cholesterol allows flexibility to allow high and low temps
Explain facilities diffusion: carrier and channel protein
Carrier: glucose permease, diffusion of glucose
Ion Channel: diffusion of ions
