Give examples to prove that microbes release gases during metabolism.
Solution and Explanation
(a) Bacteria and fungi carry out the process of fermination and during this process they release carbon dioxide. Fermination is the process of converting a complex organic substance into a simpler substance with the action of bacteria or yeast. Fermination of sugar produces alcohol with the release of carbon dioxide and very little energy.
Glucose→without oxygen alcohol+energy+CO2
(b) The dough used for making idli and dosa gives a puffed experience. This is because of the action of bacteria which releases carbon dioxide. This CO2 released from the dough gets trapped in the dough thereby giving it a puffed appearance.
Top Questions on Microbes in human welfare
Answer the following questions:
1. State what do you understand by “MALT”? Where is it located inside our body?
2. Explain cytokine barriers.
3. Name the diagnostic test for AIDS. On what principle does it work?
4. Bone marrow and thymus play an important role in human immune system. Explain how are they able to achieve this.- CBSE CLASS XII - 2025
- Biology
- Microbes in human welfare
Name an alcoholic drink which is produced with the help of microbes:
(1) With distillation
(2) Without distillation- CBSE CLASS XII - 2025
- Biology
- Microbes in human welfare
- Explain how cyanobacteria can be used as bio-fertilizer.
- CBSE CLASS XII - 2025
- Biology
- Microbes in human welfare
Match the items in Column-A with that of Column-B:
- CBSE CLASS XII - 2025
- Biology
- Microbes in human welfare
- Which chemical is obtained from microorganism Aspergillus niger}?
- CBSE Compartment XII - 2025
- Biology
- Microbes in human welfare
Questions Asked in CBSE CLASS XII exam
- Two coils ‘1’ and ‘2’ are placed close to each other as shown in the figure. Find the direction of induced current in coil ‘1’ in each of the following situations, justifying your answers:
(a) Coil ‘2’ is moving towards coil ‘1’.
(b) Coil ‘2’ is moving away from coil ‘1’.
(c) The resistance connected with coil ‘2’ is increased keeping both the coils stationary.
- CBSE CLASS XII - 2025
- Electromagnetic induction
Bittu and Chintu were partners in a firm sharing profit and losses in the ratio of 4 : 3. Their Balance Sheet as at 31st March, 2024 was as follows:
On 1st April, 2024, Diya was admitted in the firm for \( \frac{1}{7} \)th share in the profits on the following terms:- (i) New profit sharing ratio between Bittu, Chintu and Diya was 3 : 3 : 1 .
- (ii) Fixed Assets were found to be overvalued by ₹ 1,40,000.
- (iii) Creditors were paid ₹ 4,20,000 in full settlement.
- (iv) Diya brought proportionate capital and ₹ 5,60,000 as her share of goodwill premium by cheque.
Prepare Revaluation Account and Partners' Capital Accounts.
- CBSE CLASS XII - 2025
- Partnership Accounts
- Pass the necessary journal entries for the following transactions on the dissolution of a partnership firm of Vibha and Ajit after various assets (other than cash) and external liabilities have been transferred to Realisation Account:}
Creditors worth ₹ 46,000 accepted ₹ 9,000 cash and furniture of ₹ 32,000 in full settlement of their claim.
The firm had stock of ₹ 20,000. Ajit took over 40% of the stock at a discount of 10% while the remaining stock was sold for ₹ 18,000.
Vibha was appointed to look after dissolution work for which she was allowed a remuneration of ₹ 16,000. Vibha agreed to bear the dissolution expenses. Actual dissolution expenses ₹ 15,000 were paid by Vibha.
Ajit’s loan of ₹ 45,000 was settled at ₹ 42,000.
A machine which was not recorded in the books was taken over by Vibha at ₹ 23,000, whereas its expected value was ₹ 28,000.
The firm had a debit balance of ₹ 20,000 in the Profit and Loss Account on the date of dissolution.- CBSE CLASS XII - 2025
- Dissolution of Partnership Firms
- How does the process of Natural Selection affect Hardy-Weinberg equilibrium? Explain with the help of graphs.
- CBSE CLASS XII - 2025
- evolution
- A battery of emf \( E \) and internal resistance \( r \) is connected to a rheostat. When a current of 2A is drawn from the battery, the potential difference across the rheostat is 5V. The potential difference becomes 4V when a current of 4A is drawn from the battery. Calculate the value of \( E \) and \( r \).
- CBSE CLASS XII - 2025
- Current electricity
Concepts Used:
Microbes in Human Welfare
There are several valuable microorganisms that are beneficial to humans in various manners such as:
In Household Products
- Fermentation of milk to produce yogurt.
- Milk cuddling to compose curd, cheese, and paneer.
In Industrial Products
- Production of beverages such as wine, beer, whiskey, brandy, or rum.
- Production of antibiotics such as Penicillin and other chemical substances to kill or retard the expansion of disease-causing microbes.
Fermented Beverages
- A fermentor is used to produce microbes on a large scale for industrial purposes.
- The brewer’s yeast (Saccharomyces cerevisiae) is used to make ethanol. At this time, the yeast ferments malted cereals and fruit juices.
Antibiotics
- The term antibiotic means “against life”. These materials can kill or destroy the growth of other microbes.