Chapter 2: Previous Year Paper- 2022

General Instructions:

(i) This question paper contains 13 questions. All questions are compulsory.
(ii) The question paper has three Sections – Section A, B, and C.
(iii) Section – A has 6 questions of 2 marks each. Section – B has 6 questions of 3 marks each, and Section – C has a case-based question of 5 marks.
(iv) There is no overall choice. However, internal choices have been provided in some questions. A candidate has to attempt only one of the alternatives in such questions.
(v) Wherever necessary, neat and properly labelled diagrams should be drawn.

SECTION – A

1. Mention the parts of the human body that get affected by Pneumonia and common cold infections. Write the causative agents of the two diseases.

Answer: Pneumonia affects the lungs, leading to inflammation, fever, chest pain, and difficulty breathing. The causative agents of pneumonia are typically bacteria such asStreptococcus pneumoniae,Haemophilus influenzae, andMycoplasma pneumoniae, as well as viruses such as influenza and respiratory syncytial virus (RSV).

The common cold primarily affects the upper respiratory tract, particularly the nose and throat, causing symptoms such as a runny nose, cough, sore throat, and mild fever. The causative agents of the common cold are mainly rhinoviruses, though other viruses such as coronaviruses and adenoviruses can also cause it.

2. State the impact of constant mechanical agitation and pumping of air in the aeration tank on the sewage during the biological treatment.

Answer: The mechanical agitation and pumping of air in the aeration tank during the biological treatment process help to supply oxygen to aerobic microorganisms. These microorganisms break down organic matter in the sewage, converting it into simpler, non-polluting substances such as carbon dioxide and water. The process aids in reducing the organic load of sewage, improving water quality by removing harmful pollutants. Additionally, the constant agitation prevents the formation of scum and ensures better contact between the microorganisms and the organic matter, making the treatment process more efficient.

OR

(a) Cattle excreta is an important source for producing a domestic fuel. Name the fuel and write its main components.

Answer: The fuel produced from cattle excreta is called biogas. Its main components are methane (CH4), carbon dioxide (CO2), and small amounts of other gases like hydrogen sulfide (H2S). Biogas is produced through anaerobic digestion by microorganisms that break down organic material in the absence of oxygen.

(b) Write the biological process that is responsible for the production of this fuel.
Answer:
The biological process responsible for the production of biogas is anaerobic digestion. In this process, organic matter such as cattle excreta is broken down by microorganisms in the absence of oxygen. This produces methane (CH4) as the primary fuel, along with carbon dioxide (CO2) and small amounts of other gases.

3. (a) Give an example of a viral biocontrol agent.

Answer: An example of a viral biocontrol agent is the