Unit 2

• Organelles

  A tiny cell structure that carries out a specific function within the cell
• Cell membrane


  thin, flexible barrier around a cell; regulates what enters and leaves the cell
• Cell wall


  A rigid layer of nonliving material that surrounds the cells of plants and some other organisms.
• Cytoplasm


  A jellylike fluid inside the cell in which the organelles are suspended
• Cytoskeleton


  A network of fibers that holds the cell together, helps the cell to keep its shape, and aids in movement
• Nucleus


  A part of the cell containing DNA and RNA and responsible for growth and reproduction
• Centriole


  structure in an animal cell that helps to organize cell division
• Vacoule


  a organelle that stores water, food or other substances; plant cells have a large central vacoule
• Vesicles


  small membrane sacs that specialize in moving products into, out of, and within a cell
• Golgi Apparatus


  A system of membranes that modifies and packages proteins for export by the cell
• Endoplasmic Reticulum


  A cell structure that forms a maze of passageways in which proteins and other materials are carried from one part of the cell to another.
• Rough Endoplasmic Reticulum


  Responsible for synthesizing proteins
• Ribsomes


  Makes proteins
• Smooth Endoplasmic Reticulum


  creates lipids or fat
• Lysomes


  Uses chemicals to break down food and worn out cell parts
• Chloroplasts


  Capture energy from sunlight and use it to produce food for the cell
• Mitochondria


  Powerhouse of the cell, organelle that is the site of ATP (energy) production
• Five key differences between plant and animal cells

  Plants have cell walls, chloroplasts and chlorophyl

  Plants store energy as starches and oils instead of fats

  Plants have a big central vacuole

  animal cells have more mitochondria
• Cells are made up of


  Lipids, Carbohydrates, Protein and nucleic acids
• Fluid Mosaic Model


  Structural model of the plasma membrane where molecules are free to move sideways within a lipid bilayer.
• How far particles of a substance move depend on

  concentration of substance on either side of membrane and state of substance
• Properties of solids


  Definite shape and volume, do not compress, least amount of motion only vibrating
• Properties of liquids


  Take shape of container but definite volume, flows readily but doesn't compress readily, has some vibrational, rotational and translational motion
• Properties of gases


  take both shape and volume of their container, highly compressible, has highest level of motion
• Main points on particles of matter


  All matter is made up of particles

  Particles are constantly moving

  Particles pf matter are attracted to one another

  Particles have spaces between them
• Concentration


  A measurement of how much solute exists within a certain volume of solvent
• Concentration gradient


  difference in the concentration of a substance from one location to another
• Semi Permeable Membrane


  A cell membrane that allows some molecules to pass through but not others.
• Diffusion


  Movement of molecules from an area of higher concentration to an area of lower concentration.
• Osmosis


  Diffusion of water through a selectively permeable membrane
• Tonicity


  The ability of a solution surrounding a cell to cause that cell to gain or lose water.
• Isotonic


  Having the same solute concentration as another solution.
• Hypotonic


  lower concentration of solutes outside the cell than inside the cell,water will rush into the cell, and an cause it to burst
• Hypertonic


  Higher concentration of solutes outside the cell than inside the cell
• Facilitated Diffusion


  Movement of specific molecules across cell membranes through protein channels
• Channel Proteins


  provide corridors that allow a specific molecule or ion to cross the membrane
• Carrier proteins


  a protein that transports substances across a cell membrane
• Passive Transport


  the movement of substances across a cell membrane without the use of energy by the cell
• Active Transport


  Energy-requiring process that moves material across a cell membrane against a concentration difference
• Endocytosis


  process by which a cell takes material into the cell by infolding of the cell membrane