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IB Biology HL 1.2.6 Variables affecting rate Question Bank

Practise IB Biology HL 1.2.6 by evaluating how conditions, oxygen supply and apparatus design affect measured respiration or fermentation rates.

Syllabus
First assessment 2025
Course
Biology HL
Level
HL

Exam points

  • Relate temperature, oxygen supply, substrate and apparatus design to measured respiration or fermentation rates.
  • Evaluate rate experiments using sensors, respirometers, controls and data trends under changing conditions.

C1.2.6—Variables affecting rate question 1

[Maximum number: 1]

Proteasomes are a group of proteins that destroy unwanted proteins in the cell, thereby maintaining cell health. However, chemical inhibitors can block the action of proteasomes, resulting in a build up of unwanted proteins with negative consequences for the cell.

Rat heart cells were incubated at different concentrations of a proteasome inhibitor in order to test its toxicity. The bar graph shows the percentage survival of these cells compared to untreated control cells.

Figure for Question C1.2.6—Variables affecting rate question 1 — IB Biology HL

Anticancer Therapeutic Agent Bortezomib', with permission from Elsevier.]

Describe the effect of the two treatments with proteasome inhibitor on mean oxygen consumption.

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