Methods Flashcards
Give the method for the practical of extracting DNA from fruit
1) peel the skin from half a kiwi fruit and mash it up
2) mix a teaspoon of salt and small volume of washing up liquid into the fruit
3) gently heat up this mixture at about 60^c for 5 mins
4) filter the mixture and retain only the filtrate
5)cool using an ice bath and gently flour chilled ethanol onto the top of the filtrate
Give the method for making a human cheek cells light microscope slide (animal cells)
-small drop of water on the microscope slide
-gently swab the inside of your mouth with a clean cotton bud
-gently rub the cotton bud in the drop of water. You will be able to see the cells with the naked eye
Give the method for making an onion epidermal cell light microscope slide (plant cells)
-Small drop of water on the microscope slide
-peel some onion skin from inside one of the leaves in an onion bulb
-use forceps for transfer to the drop of water
-make sure the onion skin is flat
-put a coverslip over the onion skin-no trapped air bubbles
-Put a drop of the stain on the slide- next to coverslip
- draw the stain under coverslip by putting a piece of filter paper next to it
Give the method for the core practical- investigating the effect of pH on enzyme activity
1) set up a Bunsen burner,heatproof mat, tripod and gauze
2) place a beaker of water on the gauze and adjust the flame to keep the water at about 35’C
3) put two drops of iodine solution into each spot of a spotting tile
4) add 2cm^3 of amylase enzyme solution to a test tube
5) place 2cm^3 of starch solution into the same tube
6) finally, add 1cm^3 of pH solution to the tube-this keeps the pH constant
7) mix the solution in the text tube and place it into the beaker of water on the Bunsen burner.
8) use a pipette to remove a few drops of solution every 20s from the test tube and put them into a different well of the spotting line
9) repeat until the iodine solution stops turning black
10) record the time this takes
11) repeat with different pH solutions
Give the method for the practical investigation the effect of concentration on rate of diffusion
1) cut a 1cm^3 cube of agar. The agar should be make using 0.1M sodium hydroxide and coloured with phenolphthalein indicator to product pink-coloured alkaline agar
2) place a 1cm^3 cube of agar into a 0.5M solution of hydrochloric acid for 2 minutes
3) remove the cube and wash it in water to stop the reaction
4) cut cube in half and measure the distance in mm that the acid has caused the agar to become colourless from the outside, inwards towards the centre
5) repeat experiment 2 more times and calculate the mean value
6) repeat using 1,1.5 and 2M solutions of hydrochloric acid
Name the method for the practical looking for osmosis in potatoes
1) prepare a range of sucrose solutions (20%,40%,100%)
2) set up a series of boiling tubes with each of those solutions
0% sucrose solution is the control in the experiment
3) make a blank table of results. Make sure when weighing the potato cylinders, that their masses are not mixed up when recording them. Each cylinder will have a different mass before+ after the investigation
4)dry the potato strip using a paper towel. Measure the mass of the potato strip
5)place the potato strip into the 0% solution for 20 mins
6) remove the potato strip, dry it using a paper towel. Measure and record the mass of the potato strip
7) repeat for each concentration
8) repeat for several potato cylinders. Calculate a mean
Give the method for the ruler drop test practical
1) get a partner
2) person a holds out their hand with a gap between their thumb and first finger
3) person b holds the ruler with the zero at the top of person a’s thumb
4) person b drops the ruler without telling person a and they must catch it
5) the number level with the top of person a’s thumb is recorded in a suitable table-repeat 5 times
6) swap places
7) you can use the conversation table to help convert your ruler measurement into reaction time or just record the catch distance in mm
