Question

Some friends are trying to make wine in their basement. They've added yeast to a sweet grape juice mixture and have allowed the yeast to grow. After several days, they find that sugar levels in the grape juice have dropped, but there's no alcohol in the mixture. The most likely explanation is that ________.

a. the mixture needs more sugar; yeast need a lot of energy before they can begin to produce alcohol the mixture needs less oxygen;
b. yeast only produce alcohol in the absence of oxygen the mixture needs more oxygen;
c. yeast need oxygen to break down sugar to produce alcohol the mixture needs less sugar;
d. high sugar concentrations stimulate cellular respiration, and alcohol is not a by-product of cellular respiration.

Answer 1

D

Step-by-step explanation:

i cAN CONFRIM

Answer 2

The correct answer is d. high sugar concentrations stimulate cellular respiration, and alcohol is not a by-product of cellular respiration.

Step-by-step explanation:

As they added sweet grape juice mixture the amount of sugar increased in the content and it is seen that more than 6 % of sugar decreases the rate of fermentation and alcohol concentration also decreases and a moderate amount of glucose concentration in the anaerobic environment increases the fermentation results in more alcohol production.

High sugar concentration decreases fermentation but increases cellular respiration in the yeast, as a result, it uses more sugar for its growth and produce CO₂ and H₂O so alcohol is not the by-product of cellular respiration. Therefore the correct answer is d. high sugar concentrations stimulate cellular respiration, and alcohol is not a by-product of cellular respiration.