1. Cells Jeremy Tague Cara Carlucci Jackie Pariona Period 2 June 7, 2010

2. Robert Hooke(1635-1703): English scientist English scientist He used a compound light microscope to study cork, the dead cells of oak bark. Hooke observed small geometric shapes. He gave the box-shaped structures the name cells. Anton van Leeuwenhoek(1632- 1723): Dutch scientist began grinding lenses and building simple microscopes Each microscope consisted of a flat brass or copper plate in which a small, single glass lens was mounted. lens was held up to the eye, and the object to be studied was placed on the head of a movable pin just on the other side of the lens.

3. Cell Theory 1. All organisms are composed of one or more cells. 2. The cell is the basic unit of structure and organization of organisms. 3. All cells come from preexisting cells. Cara

4. Cell Types Prokaryotes- unicellular organisms that are composed of a prokaryote cell. Prokaryote cells lack internal membrane-bound structures. Example: Bacteria Eukaryotes- unicellular or multi-cellular organisms which are composed of eukaryote cells and contain a true nucleus and membrane-bound organelles. Example: algae Cara

5. Cell Structures Membrane – flexible boundary between the cell and its environment. – Contains phospholipids and carbohydrates and proteins. Nucleus – central membrane-bound organelle that manages cellular functions and contains DNA. Ribosome's – organelles in the nucleus and cytoplasm, where proteins are assembled. (non membrane-bound) Endoplasmic Reticulum(ER) – organelle with a series of highly folded membranes; site of cellulare chemical reactions – Rough ER (with ribosome’s) or Smooth ER(without ribosome’s) Chloroplast – organelles in green plants and some protists that capture light energy and convert it to chemical energy. Mitochondria – eukaryotic membrane- bound organelles that transform energy stored in food molecules.

6. Osmosis Osmosis – the diffusion of water across a selectively permeable membrane. – Example: Putting a limp carrot into water makes it firm again because of osmosis. Passive and Active Transport Passive Transport – movement of particles across cell membranes by diffusion or osmosis, while no energy is used. – Example: Facilitated Diffusion- the passive transport of materials using transport proteins. Active Transport – energy- expending process by which cells transport materials across the cell membrane against a concentration gradient. – Example: occurs in nerve cells. Sodium ions always transport from the cell to the external fluid surrounding the cell, which is an area a high concentration of sodium.

7. Hypertonic, Hypotonic, and Isotonic Solutions Hypertonic Solution – when the concentration of dissolved substances outside the cell is higher than the concentration inside the cell. – Animal cells shrivel & the plant cells’ plasma membrane and cytoplasm shrink away from the cell wall. Hypotonic Solution – when the concentration of dissolved substances is lower in the solution outside the cell than the concentration inside the cell. – Animal cells start to swell and may even burst & plant cells’ plasma membrane do not burst but they do swell and press against the cell wall. Isotonic Solution – the concentration of dissolved substances in the solution is the same as the concentration of dissolved substances inside the cell. – ALL cells retain to their normal shape because there is no osmosis in cells of an isotonic solution.