- Which of the following microorganisms is used for producing acetic acid (vinegar)?
A. Acetobacter aceti
B. Saccharomyces cerevisiae
C. Penicillium notatum
D. Lactobacillus bulgaricus
Answer: A. Acetobacter aceti
Explanation:
Acetobacter aceti is used in the fermentation process that converts ethanol into acetic acid, which is the key component of vinegar.
- Which of the following is responsible for the formation of biofertilizer in rice fields?
A. Azospirillum
B. Anabaena
C. Rhizobium
D. Pseudomonas
Answer: B. Anabaena
Explanation:
Anabaena is a nitrogen-fixing cyanobacterium that forms a symbiotic association with aquatic plants like Azolla, enhancing soil fertility in rice fields.
- The organism used for the large-scale production of ethanol from molasses is:
A. Clostridium butylicum
B. Saccharomyces cerevisiae
C. Lactobacillus acidophilus
D. Streptococcus lactis
Answer: B. Saccharomyces cerevisiae
Explanation:
Molasses, a by-product of sugar production, is fermented by Saccharomyces cerevisiae (yeast) to produce ethanol on an industrial scale.
- Rhizobium is associated with which part of leguminous plants?
A. Roots
B. Stem
C. Leaves
D. Flowers
Answer: A. Roots
Explanation:
Rhizobium forms nodules on the roots of leguminous plants, where they fix atmospheric nitrogen into ammonia, enriching soil nitrogen levels.
- The microorganism used in the production of butyric acid is:
A. Clostridium butylicum
B. Aspergillus niger
C. Saccharomyces cerevisiae
D. Lactobacillus acidophilus
Answer: A. Clostridium butylicum
Explanation:
Clostridium butylicum is involved in the fermentation process that produces butyric acid, a substance used in various industries like plastics and pharmaceuticals.
- In sewage treatment, which of the following is the main process involved in the secondary treatment?
A. Chemical treatment
B. Biological treatment
C. Mechanical filtration
D. Aeration
Answer: B. Biological treatment
Explanation:
The secondary treatment of sewage involves microbial decomposition of organic waste. This is primarily done by aerobic bacteria in the activated sludge process.
- The microbe used for the production of biogas from cattle dung is:
A. Methanobacterium
B. Azotobacter
C. Lactobacillus
D. Saccharomyces cerevisiae
Answer: A. Methanobacterium
Explanation:
Methanobacterium, an anaerobic microorganism, is used in biogas plants to break down organic matter such as cattle dung to produce methane, the primary component of biogas.
- Which microorganism helps in the ripening of cheese?
A. Lactobacillus acidophilus
B. Penicillium roqueforti
C. Streptococcus thermophilus
D. Saccharomyces cerevisiae
Answer: B. Penicillium roqueforti
Explanation:
Penicillium roqueforti is used in the ripening of blue cheeses, such as Roquefort, where it forms characteristic blue veins that add flavor and texture.
- Which of the following is used in the biological control of plant diseases?
A. Penicillium notatum
B. Trichoderma harzianum
C. Azotobacter
D. Lactobacillus acidophilus
Answer: B. Trichoderma harzianum
Explanation:
Trichoderma harzianum is a fungus used in biological control to protect plants from various fungal pathogens by producing enzymes that break down the cell walls of harmful fungi.
- The role of Lactobacillus in milk fermentation is:
A. To produce carbon dioxide
B. To convert lactose into lactic acid
C. To produce alcohol
D. To convert ethanol into acetic acid
Answer: B. To convert lactose into lactic acid
Explanation:
Lactobacillus bacteria convert lactose (milk sugar) into lactic acid during the fermentation process, leading to the thickening of milk and the production of curd.
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