| A | B |
|---|
| cell membrane | flexible barrier around a cell that regulates what enters and leaves a cell |
| organelle | specialized structure in the cell that performs the functions required for life in the cell |
| lipid | macromolecule made mainly from hydrogen and carbon including fats, oils and waxes |
| ion | an atom that has a positive or negative charge |
| covalent bond | formed by the sharing of electrons between atoms |
| cytoplasm | material inside the cell membrane - not including the nucleus |
| nucleolus | dense region in the nucleus where protein production is initiated |
| endoplasmic reticulum | internal membrane system in cells which lipid and some protein components of cell membranes are modified |
| mitochondria | converts food into usable energy for the cell |
| lysosome | enzyme-filled sac in the cell that assists with digestion in the cell |
| cell wall | strong supporting layer around the cell membrane in plants, fungi, algae and some bacteria |
| semipermeable membrane | allows selective substances in or out of the cell |
| diffusion | movement from a high concentration to a low concentration |
| endocytosis | process by which a cell takes material into the cell |
| hydrogen bonding | the attraction between slightly positive hydrogen atoms and slightly negative atoms |
| solute | the substance dissolved in a solution |
| activation energy | energy needed to get a reaction started |
| spontaneous generation | a disproven hypothesis that life could arise from nonliving matter |
| stimulus | a signal to which an organism responds |
| independent variable | the factor in an experiment that an experimentor purposely changes |
| science | an organized way of using evidence to learn about the natural world |
| solvent | the substance a solute is dissolved into to make a solution |
| flagella | long, whiplike projections that allow a cell to move |
| cell | the basic unit of life |
| isotopes | atoms of the same element that have different numbers of neutrons |
| ionic bond | bond in which electrons are transferred from one atom to another |
| compound | a substance formed by the chemical combination of two or more elements in definite proportions |
| element | a pure substance that consists of entirely one type of atom |
| solution | a type of mixture in which all the components are evenly distributed |
| pH | a measure of the concentration of hydrogen ions in a solution |
| acid | a solution with a higher concentration of H+ ions and a pH below 7 |
| base | a solution with a low concentration of H+ ions and a pH above 7 |
| atom | the basic unit of matter |
| carbohydrate | compounds made up of carbon, hydrogen and oxygen atoms and are the main source of energy for living things |
| monosaccharide | single-sugar molecules which include glucose, galactose and fructose |
| disaccharide | a two-part sugar molecule |
| polysaccharide | a multi-unit sugar molecule |
| protein | macromolecules made up of amino acids |
| nucleic acid | a macromolecule made up of repeating units called nucleotides |
| enzyme | a protein that acts as a catalyst in biological reactions |
| monomers | small, repeating units that make up a large molecule |
| cytoskeleton | internal framework that helps a cell maintain its shape and aids in cell division |
| nucleus | an organelle that contains nearly all of a cell's DNA |
| chromosomes | structures found within a nucleus that are made up of DNA and protein |
| ribosome | organelle where protein synthesis occurs |
| rough ER | site where membrane proteins are made in a cell |
| smooth ER | site where membrane lipids are made and detoxification of drugs occurs in a cell |
| golgi apparatus | organelle that modifies, sorts and packages products from the endoplasmic reticulum |
| cilia | short, hairlike projections used for movement by some cells |
| chloroplast | organelle found in plants, algae and some bacteria that use photosynthesis to capture the Sun's energy |
| vacuole | structures in cells that store materials |
| mitochondrion | organelle found in eukaryotic cells that convert food energy into usable ATP energy for the cell |
| active transport | transport across a cell membrane that requires energy |
| passive transport | transport across a cell membrane that does not require energy |
