5 Written questions
5 Matching questions
- receptor-mediated endocytosis
- energy coupling
- second law of thermodynamics
- a The principle whereby every energy conversion reduces the order of the universe, increasing its entropy. Ordered forms of energy are at least partly converted to heat.
- b A nonprotein molecule or ion that is required for the proper functioning of an enzyme. See also coenzyme.
- c The movement of specific molecules into a cell by the inward budding of membranous vesicles. The vesicles contain proteins with receptor sites specific to the molecules being taken in.
- d In cellular metabolism, the use of energy released from an exergonic reaction to drive an endergonic reaction.
- e A measure of disorder. One form of disorder is heat, which is random molecular motion.
5 Multiple choice questions
- An energy-releasing chemical reaction in which the reactants contain more potential energy than the products. The reaction releases an amount of energy equal to the difference in potential energy between the reactants and the products.
- (1) A specific substance (reactant) on which an enzyme acts. Each enzyme recognizes only the specific substrate or substrates of the reaction it catalyzes. (2) A surface in or on which an organism lives.
- A property of biological membranes that allows some substances to cross more easily than others and blocks the passage of other substances altogether.
- Cellular "drinking"; a type of endocytosis in which the cell takes fluid and dissolved solutes into small membranous vesicles.
- The transfer of a phosphate group, usually from ATP, to a molecule. Nearly all cellular work depends on ATP energizing other molecules by phosphorylation.
5 True/False questions
thermodynamics → The movement of materials out of the cytoplasm of a cell by the fusion of vesicles with the plasma membrane.
hypertonic solution → Referring to a solution that, when surrounding a cell, will cause the cell to take up water.
active site → The part of an enzyme molecule where a substrate molecule attaches (by means of weak chemical bonds); typically, a pocket or groove on the enzyme's surface.
aquaporin → A transport protein in the plasma membrane of some plant or animal cells that facilitates the diffusion of water across the membrane (osmosis).
active transport → The diffusion of a substance across a biological membrane, without any input of energy.