Cytology

Cell Theory All living things are made up of at least one cell Cells are the basic units of structure and function in an organism Cells only come from the reproduction of other cells

Prokaryotic Cells Bacteria Extremely tiny (1-5 m) Contain DNA, but lack nucleus Only has a cell membrane-- no membrane bound organelles

Eukaryotic Cell Separate Domain than prokaryotes Most fundamental difference in classification Contain many membrane bound organelles 10-100x larger than prokaryotes Plants, Animals Fungi, Protists

Cytoplasm Portion of the cell outside the nucleus Fluid inside of the cell Water based solution Nutrients needed for life dissolved inside cell Includes organelles

Nucleus—Control Center Contains the cell’s DNA—genetic code DNA bound in chromatin Chromatin: thread like structure of Protein and DNA Instructs cell how to make proteins Enclosed by Nuclear Envelope-- a membrane Contain nuclear pores-- allow certain materials to pass in and out of nucleus Nucleolus—dense structure where ribosomes are assembled

Ribosomes Where proteins are assembled No membrane (also found in prokaryotes) Made of RNA (ribose) and protein Can be either free floating or attached to endoplasmic reticulum Extremely tiny

Endoplasmic Reticulum (ER) Transport network Moves molecules to different parts of the cell System of membranes Rough ER-Ribosomes attached Easily transport newly synthesized proteins Smooth ER– no ribosomes Transport of other molecules

Golgi Apparatus Modification and packaging of molecules Helps move materials into and out of cells Works closely with ER Stack-like membranes Form vessicles membrane bound sacs which hold material and move throughout the cell

Lysosome Membranes that contain enzymes that break apart various molecules Digestion or clean up Vessicles that contain enzymes

Vacuole (mostly plants) Large storage sacs for water, salts, proteins, and carbohydrates Pressure of large vacuoles allows plants to support large structures (i.e. leaves, flowers, etc)

Mitochondria Mitochondrion (s.), mitochondria (pl.) Transfer energy stored in carbohydrates (and other organic molecules) into ATP. Contain DNA Bound by double membrane Inner membrane folds to form christae Inherited from mother Likely formed from prokaryotes living within another cell-- endosymbiotic theory

Plastids (mostly plants) Most common is chloroplast Transform solar energy into chemical energy— photosynthesis Contain chlorophyll—green pigment Thylakoid-- flat membranous sac where photosynthesis occurs Contain DNA Bound by a double membrane Likely originally prokaryotic cell that lived within another (eukaryotic) cell

Cytoskeleton Gives cell shape and structure, also allow for movement Network of protein filaments—microtubules Support cell and transport materials Also form cilia and flagella– structures for propulsion Microfilaments Smallest fibers, allow for movement of cell