GENE EXPRESSION, AND MUTATION SUMMARY
2026
◉ diffusion.
Answer: movement of molecules from high to low concentration
◉ equilibrium.
Answer: solute concentration is equal throughout
◉ solution.
Answer: fluid (solvent) containing a dissolved substance (solute)
◉ osmosis.
Answer: diffusion of water across a semipermeable membrane from
high to low concentrations
◉ tonicity.
Answer: strength of a solution
◉ isotonic solution.
,Answer: the concentration of the solute is equal on both sides of
membrane; there is no net movement of water
◉ hypotonic solution.
Answer: the concentration of the solute outside the cell is lower than
inside the cell; water moves into the cell and cells will swell
◉ hypertonic solution.
Answer: the concentration of the solute outside the cell is higher
than inside the cell; water moves out of the cell and the cell shrivels
◉ why does tonicity matter in human health?.
Answer: different types of dehydration -> you have to give them the
right treatment or you might give them something that has the
wrong tonicity and it might make them more dehydrated
◉ cell signaling.
Answer: cell communication within or between cells
◉ what are the 3 main steps of cell signaling?.
Answer: reception, transduction, and response
◉ reception.
, Answer: getting the message; signaling molecule (message) binds to
a receptor protein
◉ transduction.
Answer: transporting the message; series of relay proteins inside the
cell (biochemical relay)
◉ response.
Answer: change in cell behavior; targeted proteins bring about a
specific cellular response
◉ fluid-mosaic model.
Answer: phospholipid bulgar is fluid - at room temp, consistency of
olive oil; cholesterol (steroid) -> regulates membrane fluidity, at high
temps: stiffens membrane and makes it less fluid & at low temps:
prevents freezing by blocking contact between certain phospholipid
tails; considered a mosaic because of the presence of many proteins
that can move around if not anchored
◉ selectively permeable plasma membrane.
Answer: allows some substances to move across but not others
◉ what can move across the plasma membrane freely?.