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Published byJune Cameron Modified over 9 years ago
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Topic: Microscope Aim: How can we measure a cell using a microscope? Do Now: 1. Copy the aim onto your notes sheet. 2. Complete Microscope Check pink sheet 3. Take out a piece of loose-leaf for today’s notes. HW: Cells and Cell Processes Exam Review Sheet (BOTH SIDES)
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1. Where should the microscope be safely placed?
On a tabletop or other flat surface.
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2. Why is the lowest power objective used first?
It provides a larger field of view. LOW HIGH
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Ruler observed under low power Ruler observed under high power
SMALLER FIELD OF VIEW LARGER FIELD OF VIEW
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3. Identify the objective that gives a larger field of view. Low power
HIGH
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4. Identify what occurs to the field of view when switching from low to high power.
The field of view decreases. The amount of light decreases.
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5. Identify the part that used to focus the slide when using the 4x and 10x objectives.
Coarse adjustment
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6. Identify the part that used to focus the slide when using the 40x objective.
Fine adjustment
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The diagram represents a cell in the field of view of a compound light microscope. In which direction should the slide be moved on the microscope stage to center the cell in the field of view? 1. toward A 2. toward B 3. toward C 4. toward D
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Units to measure cells Micrometers/Microns µm 1mm = 1000µm
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Cells are so small that even a cluster of these cells from a mouse only measures 50 microns.
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The human ovum is typically around between 120 to micrometers which is the largest cell in the human body. It is visible to the human eye under a microscope.
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The head of the sperm is on average 5 to 6 micrometers
The head of the sperm is on average 5 to 6 micrometers. The flagellum is up to 50 micrometers long.
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Paper thickness = about 150 µm
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Human hair diameter = µm
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SHRIMP EGGS
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mm um Move decimal three places to the RIGHT 3.2 mm = ? µm 3. 2 3200 µm
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Are there SI units smaller than micro
Are there SI units smaller than micro???? "nano-" = 1/1,000,000,000 (billionth) "pico-" = 1/1,000,000,000,000 (millionth of a millionth, "micro micro-")
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0.7634mm = ? µm 763.4 µm
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um mm Move decimal three places to the LEFT 789 µm = ? mm .789 mm
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53.6 µm = ? mm .0536 mm
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1. 1mm 3.2mm = Field of view = 3200 µm
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2. 500um 1mm = 1000um
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3. 1000um 2000/2 = 1000 2 mm = 2000um
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4. 500um 250um 1000um
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5. 1000um 500um 2000um
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6. 500um 250um 125um 1000um
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7. 2500um 1250um 625um 5mm = 5000um
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8. 1000um 5mm = 5000um
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9. 1000um 7000um
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10. 400um 2000um
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Let’s summarize: Identify the units used to measure cells. Which way do you move the decimal when converting from mm to um? Which way do you move the decimal when converting from um to mm? Describe the two procedures that must be followed before switching to high power. Explain what happens to the amount of light in your field of view when switching from low to high power.
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Determine the length of each cell in um.
Diameter = 1mm Diameter = 2000um 1000um = 500um = 500um
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Determine the length of each cell in um.
Diameter = 1000um Diameter = 2mm 1000/6 = 2000um = 166.7um
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1. Which way should you move the slide to center the cell in the field of view?
Move the slide to the right (towards B) 2. Determine the approximate length of the cell. 300um 500um 700um 1000um 700um 350um 1400um
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