alt Flashcards

Question

investigating gas exchange effect of light

Answer 1

Test tube A - content - leaf conditions - light indicator turns - purple Test tube B - content - leaf conditions - dark indicator turns - yellow Test tube C - content - leaf conditions - light indicator turns - red

Answer 2

add same volume of hydrogen carbonate indicator to 4 boiling tubes put similar sized healthy looking pieces of pondweed into 3 of the test tubes, keep 4th tube empty as control seal with rubber. completely wrap one tube in aliminium foil and 2nd in gauze place all in bright light then check color of indicator

Answer 3

no change in color of the control tube tube w foil will go yellow, respiration will take place but no photosynthesis so co2 will increase gauze tube will stay blue this little photosynthesis means c02 concentration in tube wont change very much the well lit tube will go purple, this will lower the c02 concentration in the tube and lots of photosynthesis

Answer 4

increase in heart rate so that enough blood is taken to the working muscles to provide them with enough nutrients and oxygen for respiration waste products removed faster rate heart beats faster to ensure its removed from muscle cells oxygen debt built up by anaerobically respiring heart then beats faster to ensure extra oxygen which is used to break down the lactic acid in the cells as a result of anaerobic respiration

Answer 5

hold the leaf in boiling water with tweezers this stops inside leaf chemical reactions put leaf in boiling tube with ethanol and heat in an electrical bath until it boils this gets rid of chlorophyll making leaf white rinse the leaf in cold water and add a few drops of iodine solution if starch present, leaf will turn blue-black safety - ethanol is flammable, use tweezers for leaf boiling

Answer 6

cut potato into cylinders weigh the cylinders place them in distilled water and sucrose solutions leave for 30 mins remove them dry them to remove excess liquid plant gains mass - water moved by osmosis meaning solutions is more concentrated than plant tissue plant loses mass - water moved out of plant tissue by osmosis and solution is more concentrated no change - plant tissue is equal to solution surroundings meaning no net movement

Answer 7

place single drops of iodine solution in rows on the tile and label tests with ph to be tested use the syringe to place 2cm3 of amylase in the test tube add 1cm3 of buffer solution using a syringe use test tube to add 2cm3 of starch to the amylase and buffer solution, start stopwatch while mixing using a a pipette after 10 secs use pippette to place drop of iodine which turns blue black then after 10 seconds place another drop repeat every 10 seconds until it remains orange brown the quicker its been digested the better the enzyme works at that ph

Answer 8

starch solution is heated to set temperature iodine is added to wells of a spotting tile amylase is added to the starch solution and mixed well every minute droplets added to a new well of iodine solution continue until iodine stops turning blue black meaning no starch meaning amylase has broken it down calculate time taken and repeat at diff temps the faster the reaction is completed the faster the enzyme works

Answer 9

put 3cm2 hydrogen peroxide in a test tube add fresh potato strips and shake gently keep thumb on test tube to retain gas do the glowing splint test the splint relights positive control - use maganese (iv) oxide bubbles of o2 form negative control - use ptotato strip - high temp causes enzyme to denature negative control - repeat using water nothing happens negative control - in cold environment the effervesance should be slower enzymes are poor in cold

Answer 10

use wood lice to measure uptake of oxygen use sodalime granules to absorb the co2 produced by the respiring woodlice use glass beads with the same mass as the woodlice as control syringe used to set the fluid in the tube to a known level left for a set time decrease in volume of air in testube w woodlice, woodlice uses o2 to respire this decreases pressure in the tube, causing the colored fluid to move toward the test tube containing woodlice use the distance moved by the liquid to calculate the volume of o2 taken in by wood lice