Unit 5: Enzymes Flashcards
Osmosis
movement of water across selectively permeable membrane
Tonicity
relative solute concentrations of two environments separately by a semipermeable membrane
simple diffusion
molecules move directly through the plasma membrane without assistance
facilitated diffusion w/ carrier proteins
carrier proteins in the membrane allow large lipid-insoluable molecules that cannot cross the membrane by simple diffusion to be transported into the cell
facilitated diffusion involving channel proteins
channel proteins in the plasma membrane allow inorganic ions to pass through
water potential
gives tendency for water molecules to enter or leave a solution by osmosis
plasmolysis
complete loss of turgor from a cell; plasma membrane shrinks (flaccid) turgor provides support for the plant body
active transport
the movement of molecules or ions from the regions of low concentration to regions of high concentration across the cellular membrane by a transport protein
Primary transport
directly uses ATP for the energy to transport molecules
Secondary transport
energy is stored in a concentration gradient; ATP not directly involved
entropy
a system can be thought of as a measurement of the amount of disorder in the molecules to make up the system
exocytosis
vesicles merge with the plasma membrane to export material from the cell
endocytosis
a general term for engulfing of material by infolding of the plasma membrane
denaturation
change in shape with associated loss of function; can occur when environmental factors disrupt the chemical bonds between amino acids
optimum temperature
temperature at which an enzyme works at its maximum rate
