Science 7

• Cells are the most basic unit of life
• Nucleus - contains DNA which controls all activities within the cell
• Cytoplasm - jelly-like substance that holds everything together
• The cell is made up of cytoplasm, nucleus, mitochondria, ribosomes, chloroplast (plant cells), vacuole (plant cells)
• Cytoplasm - where chemical reactions take place, it is made up of water and dissolved substances
• Mitochondria - produces energy through respiration
• Ribosomes - makes proteins
• Chloroplasts - found only in plant cells, where photosynthesis occurs
• Vacuole - stores waste products or excess water
• Cell membrane - regulates what goes into or out of the cell
• Nucleus - contains genetic material called DNA
• Plant cells have chloroplasts which contain chlorophyll that absorbs light to make food during photosynthesis.
• Cytosol - fluid inside the cell that holds organelles together
• Golgi apparatus - modifies and packages proteins for export from the cell
• Endoplasmic reticulum (ER) - network of tubes involved in protein synthesis and transport
• Animal cells do not have chloroplasts because they cannot produce their own food like plants can.
• The nucleolus is responsible for producing ribosomes within the nucleus.
• Endoplasmic reticulum (ER) - transports materials within the cell
• Tube

  - Connects the eyepiece to the objective lenses
• Arm

  -supports the tube and connects it to the base. It is used alongside the base for support.
• Eyepiece Lens: the lens at the top that you look through
• They are usually 10X or 15X power
• Tube: Connects the eyepiece to the objective lenses
• Arm: Supports the tube and connects it to the base
• It is used along with the base to carry the microscope
• Base: The bottom of the microscope, used for support
• Illuminator: A steady light source (110 volts) used in place of a mirror
• Stage: The flat platform where you place your slides
• Stage clips hold the slides in place
• Revolving Nosepiece or Turret: This is the part that holds two or more objective lenses and can be rotated to easily change power
• Objective Lenses: Usually you will find 3 or 4 objective lenses on a microscope
• They almost always consist of 4X, 10X, 40X and 100X powers
• When coupled with a 10X (most common) eyepiece lens, we get total magnifications of 40X (4X times 10X), 100X, 400X, and 1000X
• The shortest lens has the lowest power, and the longest one is the lens with the greatest power
• This means that if they hit a slide, the end of the lens will push in (spring loaded) thereby protecting the lens and the slide
• Rack Stop: This is an adjustment that determines how close the objective lens can get to the slide
• It is set at the factory and keeps students from cranking the high-power objective lens down into the slide and breaking things
• Diaphragm or Iris: Many microscopes have a rotating disk under the stage
• This diaphragm has different-sized holes and is used to vary the intensity and size of the cone of light that is projected upward into the slide.
• There is no set rule regarding which setting to use for a particular power.