Respiration (Cambridge O Level Biology)

Exam Questions

37 mins7 questions
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A student investigated respiration in yeast. They set up the experiment as shown in the diagram below.

061062-may-2018-paper-6-q1-respiration---atp-sq

Every 30 minutes they replaced the water with the same volume but it was 10 oC warmer and counted the bubbles given off in 2 minutes. 

What are the independent and dependent variables in this experiment?

  independent dependent
A number of bubbles time
B time number of bubbles
C water temperature number of bubbles
D water temperature volume of water

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    Which of the following do humans require energy for?

    1. Producing proteins
    2. Cell division
    3. Generation of nerve impulses
    4. Maintaining body temperature
    • 1 & 3

    • 2, 3 & 4

    • 4 only

    • All of the above

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    The graph below shows the results of an investigation into how the rate of respiration of an organism is affected by changing the temperature.

    12--image-2-respiration-rat

    Which of the following statements would explain the difference between the rate of respiration at 10 °C and that at 30 °C?

    • Enzyme activity is higher at 30 °C because more frequent collisions are occurring than at 10 °C.

    • Enzyme activity at 30 °C is lower because the bonds holding an enzyme together are altered at higher temperatures.

    • Enzyme activity is at its optimum at 30 °C, meaning the rate is at its highest.

    • Enzyme activity is lower at 10 °C because the enzymes are denatured and therefore unable to bind to their substrates.

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