required practical Flashcards
osmosis
-use a cork borer to cut five potato cylinders
-Trim them to all be 3cm using a ruler and a scalpel
-Accurately measure, and record the length of a mass of each cylinder
-Measure 10 cm^3 of this sugar solution and transfer it to the first boiling tube and label
-Repeat for 5 times, but in each boiling tube at a different concentration of the solution and distilled water
-Add one potato cylinder of known Masie and length to each boiling tube
-Leave the cylinders in the boiling tube overnight
-Remove the cylinders from the boiling tube and carefully block them with a paper towel
-Remeasure the length of mass of each cylinder and record it
-Calculate the percentage
-Plot on graph to see the relation between concentration and mass/length
microscopy
-Peel off an epidermal layer of the sample using forceps or tweezers
-And a drop of water using a pet to arthur microscope slide and then place the tissue on top making sure it lies flat
-add two drops of iodine solution
-Play some coverslip on top of the cells slowly, and at an angle
-Remove excess staying with a paper towel
-Place slide on the stage
-Turn, the nose pierced select a low Power objective
-Is a coarse, adjustment knob to raise the stage until the coverslip is close to touching the objective
-Look down the eyepiece and turn the course and fine adjustment knobs to focus the image turn the nose piece to a higher power objective if necessary
-Observe the cell by looking into the eyepiece, and make a labelled drawing of the cells
Microbiology
-disinfect the area with a disinfectant wipes, ensure any product to use it properly. Cleaned off and wipes down.
-label the bottom of all the agar plates
-Wash your hands
-Place different antiseptic’s onto filter paper discs
-lift the lid of the agar plates at an angle, and Catherine quickly using forceps, place, the filter paper discs onto the agar jelly
-take the lead onto the a car plate securely, but loosely
-Incubate at 25° for 48 hours
-Measure the diameter using a ruler
food tests
-Iodide for starch- iodine solution: sample in test tube if starch is present solution will go from Orange/brown to blue/black
-Benedicks test for sugar- Benedicks solution: an equal volume of Benedicks solution and a food sample to a test tube and place in a hot water bath. If sugars are present solution, go from blue to brick red.
-Proteins test- biuret regent: add to the food sample in a test tube and shake the mixture of proteins are present the solution with turn from blue to purple
-lipids test/emulsion test- okay so start a test you just add it sugar test, water bath, proteins shake it ethanol: add a few centimetres cubed of ethanol. Pour. This makes you a test you with equal volumes of distilled water. If the present white emulsion is formed on the surface.
enzymes:
-Measure out the enzyme and substrate into a test tube, using a syringe and place it in a water bath, (along with a buffer solution if measured pH)
-Prepare a spotting tile with iodine, drops and label each tile with a number counting up from 0 to 10
-Mix the enzyme solution together (and buffer) and immediately start a timer
-every 10 seconds, remove a drop of the mixture with a pipette and put it in a dimple of iodine on the spotting tile
-If there was a colour change in starches still present
-Once the colour change stops, stop the timer as it indicates all the starch is broken down
-Repeat this process for different temperatures or different pH buffers and put the time against the pH or temperature on a graph and observe the line of best fit to determine the optimum conditions
photosynthesis:
-Play is a test tube containing a boiling to 10 cm away from the light source and measure this with a ruler
-Fill the boiling tube with a fixed volume of sodium hydrogen carbonate solution
-Play the cup on weed into the boiling tube with the car and at the top and gently push it down with a glass rod
-Leave it for five minutes to rest, and then start a stopwatch and count how many bubbles are produced in one minute
-Record this, and repeat one to 7 times for three more distances increasing by 10 cm each time
