capsule
a polysaccharide layer tightly adhered to the outside of the cell wall that prevents cell dehydration and helps the cell to stick to surfaces
cell membrane
the structure that encloses the cell, made of the phospholipid bilayer
cell wall
a rigid carbohydrate structure that provides overall support and protection for the cell
centrosome
a structure in the cytoplasm of animal cells that coordinates the formation of microtubules, which allow cell division to proceed during reproduction
chloroplast
a membrane-bound organelle found in plants and some other organisms that captures energy from light and converts it into chemical energy
chromosome
a structure that contains DNA, the genetic material that is passed from one generation to the next
cytoplasm
a combination of cytosol, a jellylike fluid primarily made up of water and dissolved substances that fill the spaces around the internal cell structures, and organelles (excluding the nucleus)
cytoskeleton
a network of filaments that gives the cell its shape and forms the support network for cell functions, such as cell division
deoxyribonucleic acid (DNA)
an organic molecule containing coded instructions for the life processes of an organism, which consists of nucleotides bonded together in the form of a double helix
endomembrane system
a system of membranes suspended within eukaryotic cells to partition the cells into functional compartments, such as the Golgi apparatus and endoplasmic reticulum
endoplasmic reticulum (ER)
a network of membranes that helps process molecules in a cell and transports cell materials; may be rough (with ribosomes attached) or smooth (without ribosomes attached)
eukaryote
an organism characterized by membrane-bound organelles, such as the nucleus
flagellum (plural, flagella)
threadlike tail that allows some cells to move; structure differs between prokaryotes and eukaryotes
Golgi apparatus
an organelle that attaches chemical markers to molecules produced in the endoplasmic reticulum in order to transport the molecules to their places inside or outside a cell
junction
a point at which cells are bound together
lysosome
an organelle that digests bacteria that enter a cell, eliminates toxins, and recycles unneeded cell materials
mitochondrion (plural, mitochondria)
an organelle that changes energy from food into energy a cell can use
nucleoid
the area inside a prokaryotic cell where genetic material (DNA) is found
nucleolus (plural, nucleoli)
a site within the nucleus where ribosomal subunits are assembled before export to the cytoplasm
nucleus (plural, nuclei)
a membrane-bound organelle that contains most of the genetic material (DNA); this structure directs a cell's growth, division, and death
organelle
a structure in a cell that has a specific task, such as a mitochondrion or Golgi apparatus
peroxisome
a structure in eukaryotes that transforms fatty acids into sugars and aids chloroplasts in oxidizing plant sugars
pilus (plural, pili)
short, hairlike projection found on the surface of many bacteria that helps cells stick together; longer pili can transfer DNA from cell to cell
prokaryote
a unicellular organism with no internal membrane-bound structures
ribosome
a structure composed of RNA and protein that constructs proteins based on the instructions provided by DNA; may be free-floating in cytoplasm or attached to form rough endoplasmic reticulum