BOTANY Higher Secondary Second Year - Textbooks Online

In fermentation process, if glucose is converted into ethanol then it is
called ethanolic fermentation.
Yeast
Glucose Ethanol
Bacillus acidilacti
When glucose is converted into organic acids such as lactic acid, then
this type of fermentation is known as lactic acid fermentation. It is carried
out by the bacterium Bacillus acidilacti.
Kuhne’s fermentation tube experiment
Lactic acid
Kuhne’s fermentation tube consists of an upright glass tube and a side
tube with a bulb. 10 per cent glucose solution mixed with baker’s yeast is
taken in the Kuhne’s tube and the tube is completely filled. After some
time, the glucose solution is fermented and gives out an alcoholic smell.
The level in the upright tube will fall due to the accumulation of CO 2 gas.
It is because yeast contains the enzyme zymase which converts glucose
solution into alcohol and CO 2. When a crystal of KOH is introduced into
the tube, the KOH will absorb CO 2 and the level of the solution will rise
in the upright tube.
Self evaluation
I . Choose and write the correct options.
1. Which of the following is the common respiratory substrate?
a. Proteins b. Lipids
c. Carbohydrates d. Vitamins
2. The number of high energy terminal bonds present in ATP is
a. one b. two
c. three d. four
3. The first step in aerobic respiration is
a. glycolysis b. Krebs cycle
c. terminal oxidation d. cyclic photophosphorylation
4. Glucose is phosphorylated to glucose-6-phosphate by the enzyme
a. aldolase b. enolase
c. pyruvic kinase d. hexokinase
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