what’s the microscopes core prac?
- take a specimen of cells
- add a drop of water or stain onto the slide
- place specimen on the drop of water/stain
- lower a coverslip on top to hold the specimen in plac
iodine test for starch
benedict’s reducing sugars
add some drops of iodine solution to food and if there’s starch it’ll turn blue-black
when food solution is mixed with an = volume of benedict’s solution and placed in a hot water bath it causes a reduction reaction.
blue = no reducing sugars
green = little
orange = more
red = lots
biuret test for protein?
ethanol emulsion test for fats?
potassium hydroxide is mixed with a solution of the food , then 2 drops of copper sulphate is added
purple indicates protein
food is mixed with ethanol and shaken, fats and oils dissolved in the ethanol float to surface forming a cloudy emulsion.
core prac for osmosis?
- label sep boiling tubes with the sucrose concentrations of each solution u will test.
- cut potato slices the same size using a borer
- blot each potato peice dry. M&R its mass and put it in an empty tube.
- fill each tube with appropriate concentrations, cover potatos w solution
5.leave 15mins, blot, M&R mass again, use formula
why is ethanol used in the core prac?
why is detergent used?
why is salt used?
protease
to cause the DNA to precipitate
it breaks down cell membranes
it makes the DNA more likely to clump together
breaks down proteins
how to extract dna?
-dissolve salt in water and washing up liquid, stir till salt dissolves
-mash strawrberrys and add the solution made
-place in water bath, filter mixture + collect filtrate
-add protease, tilst BT pour in ice cold ethanol slwoly
control variable
independent variable
dependent
doesn’t change
you change
changes because u have changed the independent variable
