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In yeast, ethanol is produced from glucose under anaerobic conditions. What is t

ID: 970003 • Letter: I

Question

In yeast, ethanol is produced from glucose under anaerobic conditions. What is the maximum amount of ethanol (in millimoles) that could theoretically be produced under the following conditions? A cell-free yeast extract is placed in a solution that contains 2.50 × 102 mmol glucose, 0.40 mmol ADP, 0.40 mmol Pi, 0.80 mmol ATP, 0.20 mmol NAD , and 0.20 mmol NADH. It is kept under anaerobic conditions. Under the same conditions, what is the theoretical minimum amount of glucose (in millimoles) required in the solution to form the maximum amount of ethanol?

In yeast, ethanol is produced from glucose under anaerobic conditions. What is the maximum amount of ethanol (in millimoles) that could theoretically be produced under the following conditions? A cell-free yeast extract is placed in a solution that contains 2.50 x102 mmol glucose, 0.40 mmol ADP, 0.40 mmol Pt, 0.80 mmol ATP, 0.20 mmol NAD, and 0.20 mmol NADH. It is kept under anaerobic conditions Number mmol Under the same conditions, what is the theoretical minimum amount of glucose (in millimoles) required in the solution to form the maximum amount of ethanol? Number mmol

Explanation / Answer

Each glucose molecule is broken down into two pyruvate molecules in a process known as glycolysis.Glycolysis is summarized by the equation:

C6H12O6 + 2 ADP + 2 Pi + 2 NAD+ ---> 2 CH3COCOO- + 2 ATP + 2 NADH + 2 H2O + 2 H+

Again this CH3COCOO- reacts to form ethanol according to the following reaction-

2 CH3COCOO- --->2CH3CHO + 2CO2

2CH3CHO + 2NADH ---> 2 C2H5OH

Combining all, we get,

C6H12O6 + 2 ADP + 2 Pi ---> 2 C2H5OH + 2 ATP + 2 CO2

1                 2             2               2  

250               0.4        0.4           

limiting reagent ADP and Pi

250 mmol glucose = 500 mmol Ethanol

0.40 mmol ADP = 0.40 mmol Ethanol

0.40 mmol Pi = 0.40mmol Ethanol

answer : 0.40 mmol ethanol ------------------------------------------->1

1mole glucose -------------------> 2 mol ethanol

x mole glucose --------------> 0.40 mol ethanol

x = 0.40 / 2 = 0.20

glucose millimoles = 0.20 ---------------------------> answer