Cell Structure
Kathleen & Josiah
" Cells "
cell membrane
thin, flexible barrier around a cell; regulates what enters and leaves the cell
cell wall
strong layer around the cell membrane in plant, algae, and some bacteria
nucleus
in cells, large structure inside some cells that contains the cell's genetic material, DNA, and controls the cell's activities
cytoplasm
materials inside the cell membrane- but not including the nucleus
chromatin
granular material visible within the nucleus; consists of DNA tightly coiled around proteins
chromosomes
thread like structure within the nucleus containing the genetic information that is passed from one generation of cells to the next
cytoskeleton
network of protein filaments within some cells that helps the cell maintain its shape and is involved in many forms of cell movement
ribosomes
small particle in the cell on which proteins are assembled; made of RNA and protein
endoplasmic reticulum
internal membrane system in cells in which components of the cell membrane are assembled and some proteins are modified
golgi appratus
stack of membranes in the cell in which enzymes attach carbohydrates and lipids to proteins
lysosomes
cell organelle filled with enzymes needed to break down certain materials in the cell
vacuoles
cell organelle that stores materials such as water, salts, proteins, and carbohydrates
chloroplasts
organelle found in cells of plants and some other organisms that uses energy from sunlight to make energy- rich food molecules by photosynthesis
mitochondria
cell organelle that releases energy from stored food molecules
lipid bilayer
double-layered sheet that forms the core of nearly all cell membranes
concentration
the mass of a solute in a given volume of solution, or mass/ volume
diffusion
process by which molecules tend to move from an area where they are more concentrated to an area where they are less concentrated
selectively permeable
property of biological membranes that allows only certain substances to pass through them
osmosis
diffusion of water through a selectively permeable membrane
isotonic
noting or pertaining to a solution containing the same salt concentration as mammalian blood.
hypertonic
noting a solution of higher osmotic pressure than another solution with which it is compared
hypotinic
noting a solution of lower osmotic pressure than another solution with which it is compared
facilitated 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