Core practicals * Flashcards
What is the equation linking image size, actual size and magnification?
image size = actual size x magnification
I
A M triangle
How do you get from nm to micro metres to mm to m?
divide by 1000
(multiply by 1000 to get from m to mm etc)
What is the food test for starch?
What shows a positive result?
iodine test
turns from orange to blue/black
What is the food test for reducing sugars?
What does it require?
What shows a positive result?
benedicts solution
requires heat (around 70 degrees)
turns brick red (semi quantitative)
What is the food test for protein?
What shows a positive result?
biuret solution
turns from blue to purple
What is the food test for lipids (fat)?
How do you carry it out?
What shows a positive result?
emulsion test
add ethanol, then water and shake
forms a cloudy white emulsion
What is a respirometer used for?
to find the rate of aerobic respiration in living organisms
Explain how a respirometer is used to find the rate of respiration of some maggots
- respirometer is set up with soda lime at the bottom which absorbs CO2, and gauze over it, where the maggots are placed
- the maggots use up the O2 which lowers the pressure
- the red liquid in the tube moves towards the maggots as the volume of O2 decreases
- this is because there is a high pressure in the tube, so the liquid moves from a high to low pressure
- this shows how much O2 is used by the maggots
How do you use a quadrat to find the number of a species in a habitat?
1) Extend a measuring tape from one side of the habitat to another.
2) Place a quadrat at 0m on the tape and count the numbers/estimate percentage cover of each species (use a key to identify each species)
3) Record results in a table.
4) Move the quadrat along the measuring tape and repeat step 3-5 at regular intervals along the measuring tape.
5) Continue until the full length of the measuring tape has been sampled
6) Calculate the average of each species and a bar chart can be drawn to show the data obtained.
