cells and sizes (2.1). can you arrange these items from biggest to smallest? click the next slide to...
TRANSCRIPT
CELLS AND SIZES
(2.1)
Can you arrange these items from biggest to smallest?
Click the next slide to see the answer!
COMPARE THE RELATIVE SIZES OF MOLECULES, CELL MEMBRANE THICKNESS, VIRUSES, BACTERIA, ORGANELLES AND CELLS (2.1.4)
Relative sizes:1. molecules (1 nanometer = 1 nm). 2. cell membrane thickness (10 nm).3. virus (100 nm).4. bacteria (1micrometer or 1 μm).5. organelles (less 10μm).6. cells (<100 μm – plants cells are larger than animal cells)
http://click4biology.info/c4b/2/cell2.1.htm#size
RECAP: SI UNITS OF MEASUREMENT
http://wps.prenhall.com/wps/media/objects/165/169061/GIFS/table1.5.gif
PRACTICE CONVERSIONS!
1. How many millimeters in a meter?2. How many micrometers in a millimeter?3. How many nanometers in a micrometer?4. How many nanometers in a millimeter?5. Convert 50 μm to millimeters.6. Convert 100 nm to micrometers.7. Convert 10 mm to nanometers.8. Convert 20 mm to micrometers.More practice here:
http://www.sciencegeek.net/Chemistry/taters/Unit0Metrics.htm
ANSWERS!
1. How many millimeters in a meter? 10002. How many micrometers in a millimeter? 10003. How many nanometers in a micrometer? 10004. How many nanometers in a millimeter? 1 000
0005. Convert 50 μm to millimeters. 0.05 mm6. Convert 100 nm to micrometers. 0.1 μm 7. Convert 10 mm to nanometers. 10 000 000 nm8. Convert 20 mm to micrometers. 20 000 μm
What is the ACTUAL size of
this stoma?
http://i-biology.net
CALCULATE THE MAGNIFICATION OF DRAWINGS AND THE ACTUAL SIZE OF SPECIMENS IN IMAGES OF KNOWN MAGNIFICATION (2.1.5)
Method #1. Using Scale BarsFirst calculate the scale on the scale bar:
Scale length = 20 μmRuler length 15 mm = 1.33μm per mm
Then measure the image with the ruler:x μm is 60 mm on the imageNow calculate the true length:1.33 x 60 =
80 μm(scale) (image length)
http://i-biology.net
TIP! Always measure in mm – it will make your life easier, trust me!
What is the ACTUAL diameter of this egg cell?
http://i-biology.net
CALCULATE THE MAGNIFICATION OF DRAWINGS AND THE ACTUAL SIZE OF SPECIMENS IN IMAGES OF KNOWN MAGNIFICATION (2.1.5)
What is the ACTUAL size of this bacterial
cell?
http://i-biology.net
Method #2. Using MagnificationMEASURE the length of the cell80 mm (remember always use mm!)
DIVIDE by the magnification given80mm = 0.00089 mm90 000
CONVERT to a whole number = 890 nmRemember to:
MEASURE DIVIDE CONVERT
FIND THE REAL SIZE OF THESE CELLS USING THE MAGNIFICATION:
http://i-biology.net
http://i-biology.net
CALCULATE THE MAGNIFICATION OF DRAWINGS AND THE ACTUAL SIZE OF SPECIMENS IN IMAGES OF KNOWN MAGNIFICATION (2.1.5)
What is the MAGNIFICATION of this plant
cell image?
CALCULATE THE MAGNIFICATION OF DRAWINGS AND THE ACTUAL SIZE OF SPECIMENS IN IMAGES OF KNOWN MAGNIFICATION (2.1.5)
MEASURE the length of the scale bar20 mm (remember always use mm!)
CONVERT to scale bar units1 mm = 20 000 μm DIVIDE by the scale bar label20 000 μm = 2 000 x10 μm
http://i-biology.net
Remember to: MEASURE
CONVERT DIVIDE
http://i-biology.net
More Practice!A student views an image of a cell magnified 350
times. The image is 250 mm long. Calculate the actual length of the sample in the image.
http://i-biology.net
Remember to: MEASURE
DIVIDE CONVERT
MEASURE = 250 mmDIVIDE = 250 mm/350 x = 0.714 mmCONVERT = 714 μm
More Practice!A sperm cell as a tail of 50µm long. A student draws it
75 mm long. Calculate the magnification.
http://i-biology.net
Remember to: MEASURE
CONVERT
DIVIDEMEASURE = 75 mmCONVERT = 75 000 μmDIVIDE = 75 000 μm/ 50 μm = 1 500 x