5 Written Questions
5 Matching Questions
- fluid mosaic
- a The capacity to perform work, or to rearrange matter.
- b A description of membrane structure, depicting a cellular membrane as a mosaic of diverse protein molecules embedded in a fluid bilayer made of phospholipid molecules.
- c An organic molecule serving as a cofactor. Most vitamins function as coenzymes in important metabolic reactions.
- d The diffusion of water across a selectively permeable membrane.
- e The spontaneous tendency of a substance to move down its concentration gradient from where it is more concentrated to where it is less concentrated.
5 Multiple Choice Questions
- A substance that reduces the activity of an enzyme by binding to the enzyme's active site in place of the substrate. A competitive inhibitor's structure mimics that of the enzyme's substrate.
- A nonprotein molecule or ion that is required for the proper functioning of an enzyme. See also coenzyme.
- Cellular "eating"; a type of endocytosis whereby a cell engulfs macromolecules, other cells, or particles into its cytoplasm.
- (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.
5 True/False Questions
entropy → A measure of disorder. One form of disorder is heat, which is random molecular motion.
enzyme → An organic molecule serving as a cofactor. Most vitamins function as coenzymes in important metabolic reactions.
concentration gradient → An increase or decrease in the density of a chemical substance in an area. Cells often maintain concentration gradients of ions across their membranes. When a gradient exists, substances tend to move from where they are more concentrated to where they are less concentrated.
kinetic energy → The energy of motion; the energy of a mass of matter that is moving. Moving matter does work by imparting motion to other matter.
hypertonic solution → Referring to a solution that, when surrounding a cell, will cause the cell to lose water.