| A | B |
|---|
| atom | the smallest unit of an element that maintains the properties of that element |
| element | a substance that cannot be separated or broken down into simpler substances by chemical means |
| cell theory | the theory that states that all living things are made up of cells that cells are the basic units of organisms, that each cell in a multicellular organism has a specific job, and that cells come only from existing cells |
| organic compound | a covalently bonded compound that contains carbon |
| protein | a molecule that is made up of amino acids and that is needed to build and repair body structures and to regulate processes in the body |
| carbohydrate | a class of molecules that includes sugars, starches and fiber: contains carbon, hydrogen ,and oxygen |
| lipid | a fat molecule or a molecule that has similar properties: examples include oils, waxes, and steroids |
| nucleic acid | a molecule made up of subunits called nucleotides |
| organism | a living thing: anything that can carry out life processes independently |
| structure | the arrangement of parts in an organism |
| function | the special, normal, or proper activity of an organ or part |
| homeostasis | the maintenance of a constant internal state in a changing environment |
| photosynthesis | the process by which plants, algae, and some bacteria use sunlight , carbon dioxide, and water to make food |
| cellular respiration | the process by which cells use oxygen to produce energy from food |
| mitosis | in eukaryotic cells, a process of cell division that forms two new nuclei, each of which has the same number of chromosomes |
| passive transport | the movement of substances across a cell membrane without the use of energy by the cell |
| diffusion | the movement of particles from regions of higher density to regions of lower density |
| osmosis | the diffusion of water through a semipermeable membrane |
| active transport | the movement of substances across the cell membrane that requires the cell to use energy |
| endocytosis | the process by which a cell membrane surrounds a particle and encloses the particle into the cell |
| exocytosis | the process in which a cell releases a particle by enclosing the particle in a vesicle that then moves to the cell surface and fuses with the cell membrane |
