5.5-5.11 Quiz/Vocab Flashcards
what do membrane proteins do?
specialize
in what ways to membrane proteins specialize?
anchor cells to substrates
transport molecules
catalyze enzymatic reactions
receive information
identification tags
what does it mean for biological membranes to be selectively permeable?
for membranes to allow some but not all substances to pass
what is the membrane permeable to?
small non polar molecules and some small polar molecules; water is small enough to pass through gaps slowly
what is the bilayer impermeable to?
to charged ions and most large polar molecules
are gases such as N2, O2, and CO2 permeable?
yes
are hydrophobic non polar molecules permeable?
yes
are small polar molecules such as H2O, glycerol, and urea permeable?
yes
are large polar molecules such as glucose and uncharged mono & disaccharides permeable?
NO
are ions and electorally charged molecules permeable?
NO
How do impermeable substances cross the membrane?
via transport proteins (carrier and channel)
what are carrier proteins?
proteins that change shape and transfer molecules
What does carrier mediated transport transfer?
solutes
what are the two forms of carrier-mediated transport?
active and passive transport
what do transfer proteins do?
form pores in the membranes that allow passive transport (diffusion) of water and ions
what is diffusion?
the movement of ions and small molecules down a concentration gradient and through the membrane (simples and facilitated)
what is concentration gradient?
when particles in a liquid or gas are unevenly distributed
how does diffusion move across concentrations?
from an area of high concentration to an area of low concentration
what is a membrane gradient?
potential energy capable of doing work
how is the rate of diffusion determined?
by size, shape, and the charge of particles as well as temperature