Describing Experiments Flashcards
(20 cards)
what are the 2 ways to investigate how temperature affects enzyme activity?
-measure how fast a product appears
-measure how fast a substrate disappears
measure how fast a product appears
1.the enzyme …….. catalyses the ……… of …….. …….. into ….. and ……
2.you can collect the …… and measure … …. is produces in a … ….
3.use a ……. to add a set amount of …….. …….. to a ……. tube. put the tube into a water …. at 10’C.
4. set up the rest of the apparatus, add a source of …….. (e.g. 1cm^3 of potato) to the …….. …….. and quickly attach the ….
5. record how much …… is produced in the first …… …… 3 times and calculate the ….
6. …… at 20’C, 30’C and 40’C
7. control variables (e.g pH of potatoes)
1.catalase, breakdown, hydrogen peroxide, water, oxygen
2. oxygen, how much, set time
3.pipette, hydrogen peroxide, boiling, bath
4.catalase, hydrogen peroxide, bung
5.oxygen, minute, repeat, mean
6.repeat
measure how fast a substrate disappears
1. the enzyme ……. catalyses the breakdown of …… to …….
2.its easy to …… starch using …… solution, if starch is present the solution will change from ……-….. to ….-…..
3.set up the apparatus and put a …. of iodine solution into each …. on the ……. tile. every 10 seconds drop a sample of the mixture into a well using a …….. when the iodine solution remains ……-…… record the total time taken
4. …… with the water bath at …….. temperatures
5.control variables
1.amylase, starch, maltose
2.detect, iodine, browny-orange, blue-black
3.drop, well, spotting, pipette, browny-orange
4.repeat, different
how to measure how pH effects enzyme activity?
- do the same as temperature but use buffer solution instead of hydrogen peroxide
how to investigate diffusion in a non living system
1. make up some …. jelly with …………… and dilute …… ……… this will make a shade of ….
2.put some dilute ………… …. in a beaker and cut out a few cubes from the jelly and put then in the beaker of ….
3.if you ….. the cubes for a while they will eventually go ………. as the acid ……. into the agar jelly and ………. the sodium hydroxide
- agar, phenolphthalein, sodium hydroxide, pink
- hydrochloric acid, acid
- colourless, diffuses, neutralises
investigate osmosis in a living system (potato)
1.cut open a …… into identical cylinders, and get some beakers with different ….. solutions in them
2.one should be …. water, another should be a very ………… sugar solution, and have a few other concentrations in-between.
3.you measure the …… of the cylinders then leave a few in each beaker for half an …. , then take it out and measure again
4.if the potato have drawn in water by osmosis they’ll be a bit …… but if they have lost water they’ll have ……
5.plot a …..
1.potato, sugar
2.pure, concentrated
3. length, hour
4.longer, shrunk
investigate osmosis in a non-living system (visking tubing)
1.fix some ……. …… over the end of the ……. …… then pour some ….. solution down the glass tube into the thistle funnel
2. put the thistle funnel into a …… of …. water, measure where the ….. solution comes up to on the ….. ….
3.leave the apparatus ………., then measure where the solution is in the glass tube. ….. should be ….. through the visking tube by ……. and this will force the solution .. the glass tube
- visking tubing, thistle funnel, sugar
- beaker, pure, sugar, glass tube
3.overnight, water, drawn, osmosis, up
how do I make a food sample?
- get a piece of food and break it up using a pestle and mortar
2.transfer the group cup food to a beaker and add distilled water
3.give the mistrust a good stir with a glass rod to dissolve some food
4.filter the solution using a funnel lined with filter paper to get rid of the solid bits
describe the Benedict’s test for glucose /4
1.prepare a food sample and transfer 5cm3 to a test tube
2. prepare a water bath and set to 75’c
3.add some Benedict’s solution to the test tube (10 drops) using a pipette
4.place the test tube in the water bath using a test tube holder and leave there for 5 minutes
what is the positive result for glucose?
if the food sample contains glucose, the solution in the test tube will change from its normal blue colour. it will turn either yellow or green in low concentration and brick-red in high concentrations
describe the iodine test for starch /2
1.make a food sample and transfer 5cm3 of the sample into a test tube
2. add a few drops of iodine solution and gently shake
what is the positive result for starch?
if the sample contains starch the colour of the solution will change from browny-orange to black or blue-black
describe the biuret test for proteins /2
1.prepare a sample of your food and transfer 2cm3 of the sample to the test tube.
2.add 2cm3 of biuret solution top the sample and mix the contents of the tube by gently shaking
what is the positive result for protein?
if the food sample contains protein, the solution will change from blue to pink to purple
describe the Sudan III test for lipids /2
1.prepare a sample of food your testing (but you don’t need to filter) use a pipette to add 3 drops of Sudan III stain solution to the east tube and gently shake the tube
what is the positive result for lipids?
the Sudan III solution stains the lipids. if the sample contains lipids the mixture will separate out into two layers, the top layer will be bright red
how can food be burnt to see how much energy it contains?
1.need a food which will …. easily e.g. pasta
2. weigh a small amount of the food and the …… it on a ……. needle
3.add a set volume of ….. to a ……. tube
4. measure the ……….. of the water then set …. to the food using a …… ….. flame.
5. hold the burning food ….. the boiling tube until it goes out. then ……. the food and hold it und the fire again. do this until the food …. relight
6.measure the ……… of the water again
- burn
- skewer, mounted
- water, boiling
- temperature, fire, bunsen burner
- under, relight, won’t
- temperature
how do I calculate the amount of energy in the food in joules?
energy in food = mass of water x temp change of water x 4.2
how do I calculate the amount of energy in joules per gram?
energy per gram of food = energy in food ÷ mass of the food
why would the experiment be inaccurate and how can the accuracy of the energy in food experiment be increased?
-quite a bit of energy related from burning is lost to the surroundings so the energy on the packet might be much higher than your result
-insulating the boiling tube e.g. with foil would minimise heat loss and keep more energy in the water making the result more accurate
