plasma membrane Flashcards
Diffusion
A net movement of substances travelling down its concentration gradient
-high concentration to low concentration
dynamic equilibrium
When the distribution of particles are equally distributed
Simple diffusion
When molecules directly go through the cell membrane phospholipid bilayer they are usually small molecules or nonpolar eg carbon dioxide and oxygen passive transport=no energy
passive transport
Input energy is not needed (ATP)
concentration gradient
moving with the flow (high concentration to low concentration)
Facilitated diffusion
Transport protein(carrier and channel proteins) helps molecules that are too big or polar to pass through,eg glucose
Cholesterol
Stabilizes membrane what keeps structure so not over crowded or far away making it better at what what passes through it
Protein channels (integral)
Help transport material through the cell membrane especially when they have a hard time passing through
Peripheral proteins:
Act at enzymes speed up reactions attracting cytoskeleton structure to help with cell shape
Carbohydrates
Helps with cell identification
Osmotic pressure:
Pressure created by water moving across the membrane due to osmosis
More water moving=higher osmotic pressure
Things that affect the rate of diffusion
-distance the greater distance need to be travelled the slower diffusion rate
- higher temp more movement of molecules therefore diffusion faster
- particle size smaller particles faster rate of diffusion
Osmosis
Movement of water through a semipermeable membrane(high concentration to low )
Water molecules can travel through cell membrane or through protein channels in larger quantities
Low water= high solute concentration(eg sugar)
-water loves to move towards solute
hypertonic
Hypotonic
-higher solute(sugar, salt) concentration, less water
-lower solute concentration, more water
Active transport
Opposite of diffusion goes against concentration gradient so low to high concentration atp is needed
Polar vs non polar
Some molecules have positive and negative ends too, and when they do, we call them polar. If they don’t, we call them non-polar.
findings:
The potato cylinders placed in pure water or weak sucrose solutions will gain mass as water will have moved from an area of high concentration (outside the potato cells) to an area of lower concentration (inside the potato cells)
The potato cylinders placed in strong sucrose solutions will lose mass/length as water will have moved from an area of high concentration (inside the potato cells) to an area of lower concentration (outside the potato cells).
plasma membrane
-Outer boundary of cell
-Protects the cell
-Composed of lipid molecules that are interspersed with tiny protein channels.
-Controls what enters and leaves the cell.
things that may affect ability to pass through
-size
-chemical formula
-charge