cell
Basic unit of life
cell theory
..., idea that all living things are composed of cells, cells are the basic units of structure and function in living things, and new cells are produced from existing cells*
cell membrane
A thin, flexible barrier around a cell; regulates what enters and leaves the cell; Made of phospholipid bilayer
nucleus
Control center of the cell. Contains DNA.
eukaryote
A cell that contains a nucleus and membrane bound organelles; An organism with cells characteristic of all life forms except primitive microorganisms such as bacteria
prokaryote
A microscopic single-celled organism, including bacteria and cyanobacteria; does not have a nucleus with a membrane or other specialized organelles; considered to have evolved before Eukaryotes.
cytoplasm
A jellylike fluid inside the cell in which the organelles are suspended.
organelle
A tiny cell structure that carries out a specific function within the cell
vacuole
Cell organelle that stores materials such as water, salts, proteins, and carbohydrates
lysosome
A small, round cell structure containing chemicals that break down large food particles into smaller ones.
cytoskeleton
A network of microtubules, microfilaments, and intermediate filaments that branch throughout the cytoplasm and serve a variety of mechanical and transport functions.
centriole
Cell organelle that aids in cell division in animal cells only
ribosome
A cell organelle composed of RNA and protein; the site of protein synthesis.
endoplasmic reticulum
A system of membranes that is found in a cell's cytoplasm and that assists in the production, processing, and transport of proteins and in the production of lipids
Golgi apparatus
A system of membranes that modifies and packages proteins for export by the cell
chloroplast
An organelle found in plant and algae cells where photosynthesis occurs
mitochondrion
Cell organelle that breaks down lipids and carbohydrates and releases energy. (has remnants of its own DNA so it may have been "on its own" in the past.)
cell wall
A rigid layer of nonliving material that surrounds the cells of plants and some other organisms.
lipid bilayer
A double layer of fat that makes up the cell membrane (like two layers of a "ball crawl" that surround the cell.
selectively permeable
A property of cell membranes that allows some substances to pass through, while others cannot
diffusion
Movement of molecules from an area of higher concentration to an area of lower concentration.
facilitated diffusion
Movement of specific molecules across cell membranes THROUGH PROTEIN CHANNELS
aquaporin
Allows water to cross membranes by facilitated diffusion which is faster than simple diffusion., - water channel proteins
osmosis
Diffusion of water through a selectively permeable membrane
isotonic
All materials in/out of the cell are at equilibrium
hypertonic
Having a higher concentration of solute than another solution.
hypotonic
Having a lower concentration of solute than another solution
osmotic pressure
Force produced by the pressure of water diffusing through a semipermeable membrane; the greater the difference in water concentration on either side of the membrane, the greater the osmotic pressure
homeostasis
Process by which organisms maintain a relatively stable internal environment; A tendency to maintain a balanced or constant internal state; the regulation of any aspect of body chemistry, such as blood glucose, around a particular level
tissue
A group of similar cells that are organized to do a specific job.
organ
A collection of tissues that carry out a specialized function of the body
organ system
A group of organs that work together in performing vital body functions.
receptor
A protein that detects a signal molecule and performs an action in response.
atoms*
There are approximately 100 trillion of these in one human cell.