ch. 4 | membrane structure & function Flashcards
(from 4.1)
what are integrated proteins?
proteins embedded in the plasma membrane of a cell
(from 4.1)
what is the role of cholesterol (and other steroids) in a cell’s membrane?
stiffen & strengthen membrane
(from 4.1)
what are peripheral proteins? what is one of their functions?
proteins on the inside of the plasma membrane; structural + help stabilize & shape membrane + help signal pathways btwn cells
(from 4.1)
these integral proteins help molecules pass through the membrane via a channel which allows this to occur
channel proteins
(from 4.1)
________ proteins help molecules pass through the plasma membrane via combining with a substance
carrier
(from 4.1)
what are cell recognition proteins and what function do they carry out?
integral glycoproteins which help cells recognize and alert the body to pathogens (helps stimulate immune response)
(from 4.1)
what are receptor proteins? what feauture of receptor proteins helps them carry out this function?
(what is a well-known example of a receptor protein?)
integral proteins which alert the cell to carry out certain functions; its shape after being binded with a specific molecule
(ans: insulin)
(from 4.1)
which integral proteins carry out direct metabolic reactions within a cell?
enzymatic protein
from 4.1
what are the respective cellular responses of these activated proteins:
a. structural protein
b. enzyme
c. gene regulatory protein
a. altered shape or movement of cell
b. altered metabolism or a function of cell
c. altered gene expression & amnt of a cell protein
(from 4.2)
what are the special channel proteins which allow water to diffuse across the plasma membrane called?
aquaporins
(from 4.2)
what is the difference between active and passive transport?
active = requires energy; passive = does not require energy
(from 4.2)
what is the difference between diffusion and active transport of molecules into a cell’s membrane?
diffusion needs a concentration gradient & features molecules dispersing from a high concentration to a lower concentration; active transport requires a carrier protien + energy to move molecules from areas of low concentration to high concentration
(from 4.2)
what is a isotonic solution? what happens due to the presence of this type of solution?
a solution cotaining an equal solute concentration to that of the cytoplasm of the cell; causes cells to neither gain nor lose water
(from 4.2)
this type of solution contains a lower solute concentration than the cytoplasm of a cell
(also causes the cell to GAIN water via osmosis)
hypotonic solution
this type of solution has a higher solute concentration than that within a cell’s cytoplasm
(causes a cell to LOSE water via osmosis)
hypertonic solution
(from 4.2)
what happens during facilitated transport?
a carrier protein speeds the rate at which a solute crosses the plasma membrane toward the lower concentration within the cell’s cytoplasm
(from 4.2)
what is the sodium-potassium pump? how does it affect the relationship of the inside of a cell to the outside of a cell?
a carrier protein that transports 3 sodium (Na+) ions outside of the cell and 2 potassium (K+) ions to the inside of the cell; causes the inside of the cell to be more negatively (less positively) charged than the outside
(from 4.2)
how are macromolecules transported into and out of a cell? why?
via vesicle formation (also called bulk transport); too large for carrier proteins
(from 4.2)
what do vesicles do during exocytosis?
(what also happens when the vesicle fuses with the plasma membrane?)
vesicles fuse w/ the plasma membrane to secrete hormones, neurotransmitters, & digestive enzymes
(vesicle membrane fuses permanently w/ plasma membrane–cell grows)
(from 4.2)
when a large material is taken in by endocytosis (process of things entering the cell), this is called ____________.
(why is this important to an organism’s health?)
phagocytosis
ans: important in the development of immunity to bacterial diseases
(from 4.2)
what occurs when vesicles (such as lysosomes) form around a liquid or very small particles?
(what is a function of this process?)
pinocytosis
(from 4.2)
what happens during receptor-mediated endocytosis?
(why is this more effiicient than regular endocytosis?)
specific molecules bind to receptor proteins, shaped specific to the molecules that are then selectively taken into a cell via vacuole formation
ans: is involved both in the uptake & transfer/exchange of substances
(from 4.3)
what is the extracellular matrix? (ECM)
(from 4.3)
list the 3 types of cell junctions and their respective functions
- adhesion juntions = mechanically attach cells via filaments
- tight junctions = junctions between cells which bring them tighter, connecting plama membranes
- gap junctions = allow comm btwn cells
