Levels of Organization Atom Level Tissue Level Ecosystem Level Molecule Level Individual Level Organelle Level Organ System Level Cell Level Community Level Population Level Organ Level Atom Level Molecule Level Organelle Level Cell Level Tissue Level Organ Level Organ System Level Individual Level Population Level Community Level Ecosystem Level
Molecule Combinations of atoms that are bonded together Atom The fundamental unit of all matter Organelle A subcellular membrane- bound compartment
Cell Tissue Organ The basic unit of life Group of similar cells that perform a common function Two or more different tissues that perform a common function
Population All individuals of the same species that occupy a given area Organ System Individual Group of related organs that have a common function A single organism
Community Ecosystem All the species in an ecosystem that can interact A community and its physical environment
The Ingredients of Life Elements- substances composed of only one type of atom. –94 naturally occurring. –Carbon, Nitrogen, Hydrogen, and Oxygen account for 90% of the elements in living things.
Eukaryotic vs. Prokaryotic Cells Feature EukaryoticProkaryotic Organisms Animals, plantsBacteria, Archaea Size 10-100 µm1-10 µm Organelles Yes No DNA form Coiled, linear Circular DNA location NucleusCytoplasm Internal membranes Yes No Cytoskeleton Yes No
Cell Theory CELL THEORY- proposed in 1839 by Schleiden and Schwann. 1.All living things are composed of cells. 2.The cell is the basic unit of life. 3.New cells arise only from preexisting cells. 4.Cells contain hereditary information which is passed from cell to cell during cell division. 5.All cells are similar in chemical composition. 6.All of the energy flow of life occurs within cells.
Invention of the Microscope Invented circa 1595 AD by Zacharias Janssen (1580- 1638), a spectacle maker from Holland.
4 Types of Microscopes Used to Study Cells Dissecting microscope- 4-50X. –Light is passed through or reflected on a specimen. –Focus with a set of glass lenses. Compound light microscope- 1,000X. –Light is passed through a specimen. –Focus with a set of glass lenses. Transmission electron microscope- 50,000X. –Electrons are passed through a specimen. –Focus with a set of magnetic lenses. Scanning electron microscope- 10,000X. –Electrons are scanned over the surface of a specimen that has been coated with a metal. –No Focus, produces a three-dimensional image collected from electrons that are emitted from the metal.
Diffusion Diffusion- the spontaneous tendency of a substance (solute or solvent) to move from a more concentrated to a less concentrated area. –T or F. Diffusion results in the uniform distribution of a substance.
Osmosis Osmosis- the diffusion of water through a selectively permeable membrane from a region of higher concentration to a region of lower concentration.
When referring to two solutions that are separated by a selectively permeable membrane: Isotonic solutions have the same concentration of solute as the cell. Hypotonic solutions have lower solute concentrations than the cell. Hypertonic solutions have higher solute concentration than the cell.