pag respirometer Flashcards

1
Q

what does respirometer measure

A

rate of oxygen consumption in aerobic respiration

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2
Q

what is the purpose of the soda lime

A

to absorb CO2 produced so volume of O2 absorbed can be measured

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3
Q

why does the apparatus need to be airtight

A

prevent air entering or leaving as this would affect volume and therefore pressure, which would affect movement of coloured liquid

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4
Q

which way does the liquid move and why

A
  • towards experimental tube containing organism
  • organism takes in oxygen for respiration
  • volume decreases in test tube so pressure decreases in test tube
  • pressure in control tube/syringe is comparatively higher
  • liquid moves towards experimental tube
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5
Q

units for respiration rate

A

volume per time

eg cm3 min-1

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6
Q

what is in the control test tube

A

glass beads of same mass as organism in other test tube

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7
Q

limitations

A
  • oxygen uptake may not be a good representation of respiration rate
  • oxygen could leak
  • difficult to read meniscus
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8
Q

control variables

A
  • mass of organisms
  • temperature (use water bath/thermometer)
  • mass of soda lime
  • syringe size if used
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9
Q

describe how you would add the red fluid to the capillary tube at the start of the experiment

A

capillary tube dipped into a small beaker of red fluid and allowed to
run

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10
Q

what info is needed to compare oxygen uptake between organisms

A

mass used

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11
Q

how would the experiment differ using a seed and a small animal

A
  • ethical use of animal eg screen so it cannot touch soda lime
  • bigger syringe needed for animal
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12
Q

what is measured and why

A
  • distance moved by fluid in capillary tube
  • gives rate of oxygen uptake
  • to estimate rate of aerobic respiration
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