Do Now What are the three main ways cell communicate? 2. What organelle is most important to cell communication? 3. What is a eukaryote?

Cell Differentiation & Cell Specialization

STEM CELLS

Stem Cells HOW IS THAT POSSIBLE?

Sperm Cell Function: impregnate female egg cell Special structures: flagella, pointy head to break egg membrane, acrosome (packet of enzymes that break down egg membrane), large mitochondria for energy

Skin Cell Function: protect inner organs of organism Special structures: flat, waterproof, different levels of organization- Epidermis Dermis Muscle layer

Red Blood Cells Function: carry oxygen to all tissues in body Special structure: hemoglobin carries four oxygen atoms at once, disc shaped to carry the most oxygen!

Muscle Cell Function: contract and relax for an organism’s movement Special structures: multi fibers to slide along each other for contraction and relaxation of muscle. More mitochondria for more energy

Nerve Cell, Neuron Function: Communicate and control ALL functions in an organism Special structures: Branched dendrites to receive message & long axon to send message, myelin sheath for protection, gaps in myelin (called Nodes of Ranvier) that allow faster nerve conduction

The Microscope Compound Light Microscope Has two lenses – ocular (eyepiece) and objective In order to be viewed, specimen must be thin (so the light may shine through the specimen) and placed on a slide. Specimen may be stained to better see structures

Limitations of microscopes 1. Magnification is limited by the strength of the lens. Calculating magnification: Ocular lens x objective lens = total magnification Example: Ocular (10x) x objective (40x) = 400x 2. As magnification increases resolution (sharpness) decreases, so does Field of vision LOW POWER HIGH POWER

Field of Vision As you increase magnification, you see more details of the specimen, but you see less of the overall specimen. This is called a reduction in the field of vision. LOW POWER HIGH POWER

Upside Down & Backwards?!? The letter "e" is upside down because images under a compound microscope are always reversed and inverted. So when you go to move something to the right, it will be moving to the left. When you go to move something up, it will move down. Its the internal workings of the microscope (lens and mirror) that do this. You put it under the microscope like this But when you look at it… it looks like this?

What would the total magnification be on the microscope to the left? Practice What would the total magnification be on the microscope to the left? Ocular Objective Total Magnification 20X 4X 10X 75X 5X 50X 25X 200X

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