biology paper one core practicals
Cards (4)
- microscopy core practical
- peel off thin layer of onion using forceps
- mount layer onto the microscope slide, make sure the layer lies flat
- add a drop of iodine stain to stain the cells
- place coverslip on slowly, making sure no air bubbles are trapped
- rotate objective lens so that the low power is in line with the stage
- turn the course focus so that the stage is close as close to the objective lens as possible
- place microscope slide in the centre of the stage
- focus slide
- record image then rotate the objective lens so that the high power is in line with the stage
- osmosis core practical
- use a cork borer to cut out 5 identical potato cylinders
- trim the cylinders using a sharp knife and ruler to be same lengths
- measure and record the lengths and mass of each cylinder
- measure equal quantities of the sugar solution and add to the boiling tube making sure to label them
- add a potato cylinder to each tube
- leave cylinders overnight in a test tube rack
- remove cylinders and lightly pat dry
- measure the lengths and mass of each cylinder and calculate the percentage change
- food test core practical
- take a food sample and then crush it diluted water and with a pestle and mortar
- add the paste into a beaker and add more distilled water. stir the solution
- filter it and then add dish soap to solution in order to break down cell walls
- photosynthesis core practical
- take a boiling tube and place it away from a Lightsource e.g. lightbulb
- fill boiling tube with sodium hydrogen carbonate solution - the solution releases carbon dioxide which is needed for photosynthesis
- put a piece of pondweed into boiling tube with the cut end at the top
- leave for 5 minutes to ensure it has acclimated to the conditions in the boiling tube
- start a stopwatch and count the number of bubbles produced in one minute
- repeat 2 more times to calculate a mean
- repeat experiment by increasing distance of boiling tube from light