respirometer- experiment 1 Flashcards
what does a respirometer measure?
-the rate of respiration of a living organism
by measuring what how does a respirometer measure the rate of respiration?
-measure the rate of exchange of oxygen and or carbon dioxide
why is a control sometimes used in these experiments?
-it can be used to show how only the living organism is causing the liquid to move
what substance is used to calculate oxygen uptake and why?
-potassium hydroxide
-this absorbs carbon dioxide that is produced
how does the liquid or dye move?
-the reduction of pressure from the absorbed co2 and o2 being used causes the dye to move in the direction of the biological material
what does the distance moved represent?
-the amount of oxygen used in respiration
what does calibrating the respirometer allow?
-it makes it possible to calculate the initial and final levels of the potassium hydroxide
how can the production of carbon dioxide be calculated?
-by replacing KOH with water co2 production can be calculated but the respirometer must be left the same length of time and in the same conditions as that for measuring for oxygen uptake
what does it mean if there is no change in movement?
-the volume of co2 produced is the same as the amount of o2 used in respiration
-the co2 produced exactly replaces the o2 took up
if the liquid moves away from its starting position that means that…
-more co2 was produced than o2 was taken up
if the liquid moves closer to the organism that means that…
-there is less co2 produced than o2 taken up.
what is a dependent variable?
-the variable that is being tested
what is an independent variable?
-the variables that is being changed
what is a control variable?
-variable that is constant in the experiment
what colour is hydrogen carbonate indicator in different light intensities?
-high= purple
-no light= yellow
-low= red
