| A | B |
|---|
| cell | collection of living matter enclosed by a barrier that separates the cell from its surroundings; basic unit of all forms of life |
| eukaryotes | cells that do contain a nuclei |
| cell membrane | a thin flexible barrier around the cell |
| protein | needed by the body for growth and repair and to make up enzymes |
| nucleus | the center of the atom which contains the protons and neutrons; controls most cell processes |
| selective permeability | property of biological membranes that allows only certain substances to pass through them |
| carbohydrates | major source of energy for the human body |
| homeostasis | process by which organisms maintain a relatively stable internal environment |
| equilibrium | balance |
| organelle | specialized structure that performs inportant cellular functions within a eukaryotic cell |
| ribosomes | small particle in the cell on which proteins are assembled; made of RNA and protein |
| mitochondria | cell organelle that releases energy from stored food molecules |
| choloroplast | organelle found in cells of plants and some other organisms that uses energy from sunlight to make energy-rich food molecules by photosynthesis |
| vacuole | cell organelle that stores materials such as water, salts, proteins, and carbohydrates |
| diffusion | process by which molecules tend to move from an area where they are more concentrated to an area where they are less concentrated |
| osmosis | diffusion of water through a selectively permeable membrane |
| facillitated diffusion | movement of specific molecules across cell membranes through protein channels |
| active transport | energy-requiring process that moves material across a cell membrane against a concentration difference |
| cell wall | provide support and protection for the cell |
| cytoplasm | the material inside the cell membrane - not including nucleus |
| prokaryotes | has cell membrane and cytoplasm but do not contain nuclei |
| cell theory | idea that all living things are composed of cells; cells are the baisc units of life; new cells are produced from existing cells |
