IB Biology HL 1.2.19 Amino acid recycling by proteasomes Question Bank

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.

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

Using the data provided, evaluate the hypothesis that the effects of the proteasome inhibitor on the systolic area are reversible.

Proteasomes are needed to protect mitochondria from unwanted cell proteins. Mean oxygen consumption is a measure of mitochondrial activity. It was recorded in untreated control rats, rats treated for one week and rats treated for three weeks with proteasome inhibitor.

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