f4 chap 3: movement of substances across plasma membrane Flashcards
what does each phospholipid moelcule consisit of?
polar head (hydrophilic), nonpolar tail (hydrophobic)
what are the 2 protein molecules?
channel protein, carrier protein
whats the function of glycoprotein and glycolipid?
act as receptors to hormones such as insulin, stabilise the membrane by forming hydrogen bonds with water and act as antigens for cell identification.
function of cholesterol?
make the phospholipid bilayer
stronger, more flexible and less permeable to water-soluble substances
what are the characteristics of lipid soluble substances that enables it to move across plasma membrane?
its nonpolar molecules
examples of lipid soluble substances?
fatty acid, glycerol, fat soluble vitamins, steroid compunds
what are the characteristics of small molecules and ions that enables it to move across plasma membrane?
polar molecules, ions, nonpolar molecules
example of large molecules that can go through plasma membrane?
glucose, amino acid
examples of passive transport?
Simple diffusion, osmosis and facilitated diffusion
whats simple diffusion?
Simple diffusion is the movement of molecules
or ions from an area of high concentration to an
area of low concentration.
example of substances that diffuses through phospholipid bilayer by simple diffusion ?
fatty acids and glycerol, oxygen and carbon
dioxide
whats osmosis?
net movement of water molecules from area of high water potential to area of low water potential randomly through a selectively permeable membrane.
channel protein characteristics?
Channels have specific internal characteristics that only allow specific ions to pass
through it.
example of lipid insoluble molecules?
ions, large molecules(amino acid, glucose)
can lipid insoluble molecules pass through the phospholipid bilayer?
no dawg
are amino acid, and glucose able to pass though the phospholipid bilayer?
no
how do lipid insoluble molecules move past the membrane?
through facilitated diffusion
does facilitated diffusion require energy?
no
why doesnt facilitated diffusion require energy?
bc transport proteins transport molecules down a concentration gradient
explain the process of the movement of glucose molecules across a plasma membrane through facilitated diffusion if extracellular glucose concentrations are higher than in cytoplasm.
i) extracellular glucose binds with the specific site of the carrier proteins.
ii) carrier proteins change shape to allow glucose molecules to pass through the carrier proteins and to enter
the cell.
iii) carrier proteins return to their original shape
types of transport protein?
carrier protein, channel protein
what does active transport result in?
accumulation or excretion of molecules or ions in the cell.
characteristics of active transport?
i) movement of molecule or ion substances across a plasma membrane occurs against a concentration gradient.
ii) requires energy from ATP molecules generated during cellular
respiration.
iii) requires specific carrier protein with specific sites to bind with certain molecules or ions.
explain how sodium-potassium pump transports sodium ions into extracellular and potassium ions into cell
i) three sodium ions bind to the carrier protein.
ii) ATP molecules decompose into ADP and P. The
phosphate group is bound to the carrier protein.
iii) phosphate bond provides energy and changes the shape of the carrier protein, then sodium ion is transported through the
carrier protein out of a cell.
iv) two potassium ions from outside the cell bind with a carrier protein. the phosphate group leaves the carrier protein.
v) loss of the phosphate group restores original shape of the carrier protein.
vi) Potassium ion is transported through the carrier protein into the cell.
