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Core practicals - Coggle Diagram
Core practicals
Microscopes
Important parts
Stage - where you place the slide, you clip it into place
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Objective lenses - 4x, 10x, 40x
Eye piece - what we look through, has an eye piece lense, 10x
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Viewing a prepare slide
Place the slide on the stage, clip it into place
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Slowly turn the coars adjustment knob, lookig at the microscope from the side while you adjsut the position of the lens
When the objective lense almsot touches the slide, stop turning it
If you look through the eyepiece while positioning the lense, you risk damaging it
Look through th eyepiece lense, and adjust the fine focuisng know until the cells come into focus
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Preparing a slide
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Mount onto the microscope slide with a dro pof water using a pipette, making sure the tissue lies flat
Add 2 drops of iodine solution, which will act as a stain, showing the internal structures
Place a cover slip, make sure there are no are bubbles
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Food tests
Preparing food sample
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Transfer paster to a beaker and add more water, stir it
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Sugars
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Reducing suagrs are present - green, yellow, red
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Lipids
Add food solution, don't filter out as lipid molecules can stick to filter paper
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Culturing microbes
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Avoiding contamination
Sterilise all petri dishes, agar gel to kill unwanted microbes
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Seal the lid loosely using tap to stop unwanted organisms getting in, make sure oxygen can still get in
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Effect of antibiotics
Method
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Open a sterile agar gel plate near a bunsen burner, to kill and airborne bacteria
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Results
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Larger area of zone of inhibiiton, the more effective the anitbiotic
Osmosis in potatoes
Method
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Place the cylinders in a test tube, and add 10cm3 of different concentration solutions to the test tube
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Measure the mass again, and calculate the percentage change
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Results
In water, cylinder gains mass as water move into it by osmosis
In concentrated solution, cylinder loses mass water moves out by osmosis
The point where the line crosses the x axis is where there is no change in mass, concentration outside equals inside
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Photosynthesis
Method
Place a boiling tube 10cm away from an LED, LED doesn't release much heat
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Add agal balls to the boiling tube, you should see bubbles of gas being produced
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Remember to use a control, without the agal balls to show that it is them that cause the change in PH
To measure the pH
See the colour produced of the solution, the pH
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Inverse square law
Doubling the distance, light intensity falls by four times
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Fieldwork
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Distribution
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Place a quadrat along a transect, move the qudrat along the tape measure, record the number of organisms and record light intensity
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