1. Chapter 7 A View of the Cell I. The Discovery of Cells A. The History of the Cell Theory 1. What are cells? Basic unit of living organisms 2. Anton van Leeuwenhoek developed the first simple light microscope. 3. Compound light microscope uses a series of lenses to magnify objects 4. How did the following scientist contribute to the cell theory? a. Robert Hooke-coined the term cell by looking at cork b. Matthias Schleiden-stated all plants are composed of cells c. Theodore Schwann-stated all animals have cells d. Robert Brown-first observed the nucleus e. Rudolf Virchow-discovered the nucleus

2. 5. The cell theory is made up of three main ideas: a. All organisms are composed of one or more cells 1. unicellular 2. multicellular b. The cell is the basic unit of structure & organization of organisms c. All cells come from preexisting cells 6. Development of electron microscopes (2 basic types): a. SEM (scanning electron microscope)- use electrons to scan the surface of a specimen to give a 3-D shape b. TEM (transmission electron microscope)- use a beam of electrons to pass thru the specimen 2-D B. Two Basic Cell Types 1. Prokaryotes do not have a true nucleus 2. Eukaryotes do have a true nucleus 3. Nucleus is the central membrane-bound organelle that manages cellular functions.

3. II. The Plasma Membrane A. Maintaining a Balance 1. All living cells must maintain a balance regardless of internal and external conditions. 2. Plasma membrane is the boundary between the cell and its environment that allow a steady supply of nutrients to enter and leave the cell. 3. What is homeostasis? the ability to maintain a balance within the cell 4. How does the plasma membrane maintain homeostasis? By allowing some molecules into the cell and keeping others out (selective permeability) B. Structure of the Plasma Membrane 1. Composed of a phospholipid bilayer

4. III. Eukaryotic Cell Structure A. Cellular Boundaries 1. Cell wall is a fairly rigid structure located outside the plasma membrane that provides support and protection; found only in plant cells

5. 2. The phospholipid bilayer is composed of a polar head (hydrophilic head) and 2 fatty acids (hydrophobic tails) a. hydrophilic means water-loving; water soluble b. hydrophobic means hate water; water insoluble 3. Fluid mosaic model (plasma membrane) because it contains lipids and proteins in the membrane that are free moving making a mosaic pattern 4. Transport proteins help aid in the transportation of large molecules across the membrane

6. 2. Chromatin are strands of the genetic material, DNA 3. Nucleolus part of nucleus that makes ribosomes 4. Ribosomes are the site where the cell assembles enzymes and other proteins 5. Cytoplasm is the clear gelatinous fluid inside a cell that house the cell organelles B. Assembly, Transport, and Storage 1. Endoplasmic reticulum (ER)-cite for cellular chemical reactions; (2) types: smooth ER and rough ER (contains ribosomes) 2. Golgi apparatus-modifies & packages proteins 3. Vacuole-temporary storage of materials 4. Lysosomes-contain digestive enzymes; cleanup crew

7. C. Energy Transformers 1. Chloroplasts-capture light energy from the sun; found only in plants 2. Plastids-store starches, lipids, contain pigments; plants only 3. Chlorophyll-traps light energy & gives leaves and stems their green color; pigment 4. Mitochondria-transforms energy for the cell D. Structure for Support & Locomotion 1. Cytoskeleton-provides support for the cell 2. Microtubules-thin hollow cylinders made of protein 3. Microfilaments-thin solid protein fibers 4.Cilia-hairlike projections aide in cellular movement 5. Flagella-longer whiplike projection aide in cellular movement