❧ All cells arise from pre-existing cells ❧ Cells are the basic unit of life ❧ All living things are composed of one or more cells Cell Theory

❧ Robert Hooke: Coined the term “cell” ❧ Antonie van Leeuwenhoek: “Father of Microbiology” ❧ Matthias Schleiden: Botanist ❧ Theodor Schwann: Zoologist ❧ Rudolf Virchow: Physician Contributors to the Cell Theory

❧ ❧ Organisms are generally placed into one of five categories: ❧ Animals: from sponges to worms to insects to fish to humans ❧ Plants: photosynthetic (contain chlorophyll) ❧ Fungus: Molds, Mushrooms ❧ Protists: Amoeba, paramecium ❧ Moneran: bacteria Classification I

❧ In order to be considered alive a “thing” must be able to: ❧ Metabolize ❧ Reproduce (some measure of genetics) ❧ Respond to stimuli ❧ Must be cellular ❧ Growth ❧ Organization ❧ Cells carry out the basic functions of life Alive? Or …..

❧ ❧ There are 2 basic cell types: ❧ Prokaryotic: Monerans (bacteria) ❧ Eukaryotic: Plants, Animals, Fungi, Protists ❧ Prokaryotic: No membrane-bound organelles, DNA is “naked”, DNA is in a region rather than a nucleus. ❧ Eukaryotic: Contains membrane-bound organelles, DNA is wrapped in proteins (“clothed”), DNA is within a nucleus Classification II

❧ Prokaryotic Earthlife.net

❧ Eukaryotic

❧ ❧ With a given image: ❧ 1. Measure the length of the scale bar ❧ 2. Convert this to μm (microns = 1/1000 of a mm) ❧ 3. Divide measured length (in μm) by the number under the scale bar. Calculating Cell Size and magnification

❧

❧ ❧ 1. Measure the length of the specimen (in mm) ❧ 2. Measure the length of the scale bar (in mm) ❧ 3. Divide length of specimen (#1) by length of scale bar (#2). ❧ 4. Calculate the size: Multiply your answer from #3 by the number and units from the scale bar. Calculating specimen size

❧ ❧ 1. Measure the length of the specimen (image/photo) ❧ 2. Convert to microns (x 1000) ❧ 3. Divide the converted number by the magnification. Calculating size with only magnification

❧ ❧ DIY: Using a ruler, measure the field of view under low power in mm. Convert this to microns. OH YEAH, 1 MORE

❧ View specimen under desired magnification and estimate # across diameter

❧ ❧ If the diameter of the field of view is 4.5 mm under low power (40X), ❧ A. What is it in microns? ❧ B. What is the field of view at 100x? (think “backwards”) ❧ C. What is the field of view at 400x? ❧ D. If you estimated 6 cells fitting across the diameter at 400x, what is the size of the cell?

Summary 1.The cell theory states that all cells arise from cells, cells are the basic units of life and all organisms are made of one or more cells. 2.All cells have cytoplasm, a membrane, ribosomes and genetic material. 3.Living things: are cellular, respond to stimuli, have metabolism, reproduce, grow, have organization. 4.Organisms are classified in two broad categories: Prokaryotic and Eukaryotic, their biggest difference are in regard to membranes. 5.Eukaryotes are generally divided into four areas: Animals, Plants, Fungus, and Protists. Monerans are prokaryotic. 6.The cell theory is tied to technology because of the need for better ways to view cells and cell parts.

Organelles: Nucleus: contains DNA/genetic information Mitochondria: Generates ATP, energy molecules Chloroplast: Photosynthesis Cell membrane: Regulates flow of materials in and out. Cytoplasm: chemical reactions Cytoskeleton: Gives structure, pathway for movement. Cell wall: Extracellular material for structure Ribosome: Where polypeptides (think proteins) are linked. Lysosome: digestive enzymes for breakdown of waste

Organelles cont’d: Smooth Endoplasmic reticulum: Make lipids, steroids, releases calcium Rough endoplasmic reticulum: w/ ribosomes, continue protein formation Golgi Apparatus: Packaging of proteins for release from the cell. Vacuole: Storage, waste, water containment (plants)

Protein synthesis The nucleus contains DNA DNA is the code for protein formation Ribosomes translate this code into a polypeptide Ribosomes are on “Rough” ER which can modify the polypeptide The Golgi apparatus can package these polypeptides (proteins) for delivery.

Significant Concept: The shape, structure and size of a given cell or organelle is directly related to its ability to function. This is especially true of the chloroplast and mitochondria.

Cell communication

Diffusion and Osmosis -Diffusion is the movement down a concentration gradient. Material moves from a high concentration to a low concentration. -Osmosis is the diffusion of water based upon the concentration of the solutes. It is sometimes easier to think that water is moving from a high concentration to a low one. -We are interested in the net movement of water. view0/chapter2/animation__how_osmosis_works.html

Cell Size Limitations Cells are limited in size due to the Surface area: Volume ratio As cells grow, their volume increases faster than their surface area. Cells need nutrients and to get rid of waste (diffusion/osmosis). As the volume increases, cell functions decrease because efficiency for the addition or removal of things becomes more difficult (requires more energy). So what does a cell do?

Tonicity Concentrations are relative. Hypertonic v. hypotonic v. isotonic A solution is only hypertonic relative to one that is hypotonic.

Osmotic Pressure or potential: simply put, the ability of water molecules to move across a semi-permeable membrane.

-Facilitated Diffusion: movement of molecules through a specific pathway, such as a protein channel. -Facilitated diffusion, Osmosis and simple diffusion are all forms of Passive Transport, requiring no source of

-Active Transport requires energy. Exocytosis (molecules exiting) and endocytosis (molecules entering) are the two basic forms of active transport.