When making bread with common yeast, the reaction starts as an aerobic process and then becomes an anaerobic process after the oxygen is spent. A baker has created a new strain of yeast which contains no cytochrome c gene and, thus, no cytochrome c protein. This will affect what the yeast strain can do to obtain energy.

Question

When making bread with common yeast, the reaction starts as an aerobic process and then becomes an anaerobic process after the oxygen is spent. A baker has created a new strain of yeast which contains no cytochrome c gene and, thus, no cytochrome c protein. This will affect what the yeast strain can do to obtain energy.

Use the passage to answer the question.

Since the air bubbles in bread are generated by yeast, how will the spaces in this bread compare to those in a loaf made using normal yeast?

more bubbles

differently-shaped bubbles

smaller bubbles

bubbles more on the interior of the loaf

Answer 1

The absence of the cytochrome c gene and protein in the new strain of yeast would impact its ability to carry out aerobic respiration, which is the process responsible for generating the air bubbles in bread. Therefore, without sufficient oxygen supply, the new yeast strain would primarily rely on anaerobic respiration. As a result, the production of carbon dioxide, which creates the air bubbles, may be reduced or altered. This indicates that the spaces in the loaf made with the new yeast strain would likely be smaller or have a different distribution compared to a loaf made using normal yeast. Therefore, the correct answer is smaller bubbles.