Membrane Flashcards
What is the fluid mosaic model
Proteins move through mosaic like structure (membrane) components are free to move indedently from eachother,
Hydrophilic heads create mosaic like image from above and below.
What three factors effect the permeability of a membrane
Heat, Ethanol, pH
what is a solute
dissolved molecules
what is a solvent
the liquid the molecules are dissolved in
what is a soloution
it is the solute and the solvent
what is a hypertonic
higher concentration then cell fluid
what is hypotonic
lower concentartion then cell fluid
what is isotonic
same concertation then cell fluid
why can steroid-hormones, Co2 and O2 pass through a membrane
They are non-polar so they can pass through the membrane
What is ficks law
Surface area x concentration difference / Length of diffusion path
What is simple diffusion
When a molecule passes through a membrane wihtout a chemical process being undergone, it may travel through the gaps within the phospholipid bilayer or through a protein channel
What is facilitated diffusion
This is when a carrier protein embedded within the phospholipid bilayer makes a chemical bond with the molecule. This happens at the binding site and protein changes shape and carries the molecule across the membrane, moving it from an area of high concentration to an area of low concentration.
What is water potential
The ‘Potential’ for water to move from one area of high water potential to another area of low water potential through a membrane.
What is cytosis
a form of active transport where parts of the plasma membrane infold or outfold to take in other cells. It can lead to the transport of materials into the cell (endocytosis) or outside the cell (exocytosis)
What is phagocytosis
Solid substances like whole organisms are taken into a cell through folds of the surface membrane, this is usually performed by white blood cells.
What is pinocytosis
Liquids, large molecules and/or intracellular fluids are taken in through small vesicles.
What is the type of movement and direction of diffusion
passive, higher to lower concentration
What is the type of movement and direction of facilitated diffusion
passive, higher to lower concentration
What is the type of movement and direction of osmosis
passive, higher to lower concentration
What is the type of movement and direction of active transport
active, lower to higher
What are the conditions needed and examples of diffusion
concentration gradient,
examples include O2, CO2 and steroid hormones
What are the conditions needed and examples of facilitated diffusion
concentration gradient (channel/carrier)
Examples include water and glucose
What are the conditions needed and examples of osmosis
concentration gradient, channel proteins optional
Examples include water only
What are the conditions needed and examples of active transport
ATP +carrier protein/ protein pump
Examples include ions, sugars and amino acids
What state is an animal cell in when in a hypertonic solution
shrivelled
What state is an animal cell in when in a hypotonic solution
lyses
What state is an animal cell in when in a isotonic solution
normal
What state is an plant cell in when in a hypertonic solution
plasmolysed
What state is an plant cell in when in a hypotonic solution
turgid (normal)
What state is an plant cell in when in a isotonic solution
flaccid
What is osmosis in animal cells like?
If placed in hypertonic, then it shrinks and becomes wrinkled, if placed in hypotonic it lyses
What is osmosis in plant cells like?
Plant cells have a cell wall which provides structure,
Hypotonic = water enters, fills vaculoues, plasma membrane pushes against cell wall making it inflexible/turgid
Hypertonic = flaccid, water is lost stops pushing against cell wall.
Why is it normal for plant cells to be Turgid
Plants use the cell walls of their cells for structure, a turgid cell allows for the cell wall to become even more inflexible and strong, giving the plant more structure.
Roles of memebranes
Cell recognition
Cell compartmentalization
Cell communication
