Science Vocabulary

the smallest structural and functional unit of an organism, typically microscopic and consisting of cytoplasm and a nucleus enclosed in a membrane a protective layer surrounding the cell on the outside the semipermeable surrounding the cytoplasm of a cell. comprises cytosol (the gel-like substance enclosed within the cell membrane) and the organelles – the cell's internal sub-structures. All of the contents of the cells of prokaryotic organisms (such as bacteria, which lack a cell nucleus) are contained within the cytoplasm the central and most important part of an object, movement, or group, forming the basis for its activity and growth: a plastid that contains chlorophyll and in which photosynthesis takes place A unicellular organism is an organism that consists of only one cell, unlike a multicellular organism that consists of more than one cell. organisms consisting of more than one cell, and having differentiated cells that perform specialized functions in the cell. a microscopic organism, especially a bacterium, virus, or fungus. causing or likely to cause harm favorable or advantageous; resulting in good: a disorder of structure or function in a human, animal, or plant, especially one that produces specific signs or symptoms or that affects a specific location and is not simply a direct result of physical injury: a member of a large group of unicellular microorganisms that have cell walls but lack organelles and an organized nucleus, including some that can cause disease. an infective agent that typically consists of a nucleic acid molecule in a protein coat, is too small to be seen by light microscopy, and is able to multiply only within the living cells of a host: an organelle found in large numbers in most cells, in which the biochemical processes of respiration and energy production occur. It has a double membrane, the inner layer being folded inward to form layers (cristae). a space or vesicle within the cytoplasm of a cell, enclosed by a membrane and typically containing fluid. any of a number of organized or specialized structures within a living cell.