Question

Observe the set-up given below and select the correct option.

• A. Yeast undergoes aerobic respiration and resulting carbon dioxide turns lime water milky.
• B. Yeast undergoes anaerobic respiration and resulting carbon dioxide turns lime water milky.
• C. Yeast is unable to respire due to presence of vegetable oil and hence no colour change is observed in lime water.
• D. Yeast is unable to respire due to absence of oxygen and hence no colour change is observed in lime water.

Answer 1

The correct option is B Yeast undergoes anaerobic respiration and resulting carbon dioxide turns lime water milky.

Vegetable oil cuts the air supply and hence yeast switches to anaerobic mode of respiration. Anaerobic respiration takes place in limited air or absence of oxygen and results in production of carbon dioxide. The released carbon dioxide turns the lime water milky.