General Biology Laboratory Notes

General Biology Laboratory Notes - General Biology...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: General Biology Laboratory Notes Laboratory 1: Cell Structure A. Parts of A Microscope 1. Condenser – located immediately below the stage; focuses the light on the specimen; determines the contrast & resolution of what is seen 2. Objective – located above the stage; projects a real image of the specimen that acts as the object for the ocular lens 3. Eyepiece (Ocular) – located above the objective; further magnifies the object & forms a large virtual image onto the retina of the eye B. Operating the Microscope 1. Always focus with the scanning lens , then switch to higher power if needed 2. With the high power objective in position, focus with the fine adjustment only 3. Never remove a slide from beneath the high power objective; switch back to a lower power first C. Magnification Magnification: Ocular Objective Total Magnification Diameter of field (in micrometers) 10X (scanning) 4X 40X 4,500 μm 10X (low) 10X 100X 1,600 μm 10X (high) 40X 400X 400 μm- “2-D slice of 3- D reality” – sections are thinner than the width of a cell -The field diameters of different lens systems are inversely proportional to their magnifications. -If an object appears to be a small dot with the high power objective, it is approximately 1 μm Fd L /Fd H = M H /M L Fd H = field diameter at higher power Fd L = field diameter at lower power M H = magnification of high power lens M L = magnification of low power lens D. Measurement-(mm) millimeter = 1/1,000 of meter = 10-3 meter - (μm) micrometer = 1/1,000,000 of meter = 10-6 meter -(nm) nanometer = 1/1,000,000,000 of meter = 10-9 meter -(mm) millimeter = 1/1,000 of meter - (μm) micrometer = 1/1,000 of millimeter-(nm) nanometer = 1/1,000 of micrometer E. Image Formation-The lens system both reverses & inverts the image F. Plant Cells a. Elodea : leaf cells- approximate cell length: 100 μm- approximate cell width: 20 μm-organelles seen: vacuole, mitochondria, chloroplast, nucleus (w/ nucleolus) b. Onion: epidermis- approximate cell length: 100 μm- approximate cell width: 20 μm-organelles seen: cell wall, nucleus, mitochondria -Bromphenol Blue used to stain cell -Janus green: stain specific for mitochondria; stains them blue G. Animal Cell a. Human epithelial cell (cheek cell)- approximate cell diameter: 75 μm-organelles seen: plasma membrane, nucleus, mitochondria -Bromphenol Blue & Janus green used to stain cell b. Euglena, Single-celled Eukaryotic Organism- approximate cell length: 50 μm- approximate cell width: 10 μm-organelles seen: cell membrane, mitochondria, nucleus (w/ nucleolus), chloroplasts H. Bacteria: Single-celled Prokaryotic cells-close to the same size as mitochondria & chloroplasts Laboratory 2: Cell Division Mitosis – the division of the cell nucleus resulting in 2 daughter nuclei, each with the same number of chromosomes as the parent nucleus; at the beginning, each chromosome has been duplicated, being composed of 2 sister chromatids Prophase – chromosomes first appear as darkly stained areas & later as distinct entities generally...
View Full Document

Page1 / 24

General Biology Laboratory Notes - General Biology...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online