What is the mechanism by which the AIDS virus causes deficiency of immune system of the infected person?
Solution and Explanation
AIDS (Acquired Immuno Deficiency Syndrome) is caused by the Human immunodeficiency virus (HIV) via sexual or blood-blood contact. After entering the human body the HIV virus attacks and enters the macrophages. Inside the macrophages the RNA of the virus replicates with the help of enzyme reverse transcriptase and gives rise to viral DNA. Then this viral DNA incorporates into the host DNA and directs the synthesis of virus particles. At the same time HIV enters helper T-lymphocytes. It replicates and produces viral progeny there. These newly formed progeny viruses get released into the blood attacking other healthy helper T- lymphocytes in the body. As a result the number of T-lymphocytes in the body of an infected person decreases progressively thereby decreasing the immunity of a person.
Top Questions on Human health and disease
Read the following passage and answer the questions that follow. Prevention is the frontline response to drug use. Effective interventions address the underlying conditions contributing to drug use, such as a lack of connection to family or community, instability, insecurity, trauma, mental health issues, etc. When addressed, these factors can effectively prevent the initiation of drug use and the progression to drug use disorders. Study the few key figures of drug use given below and answer the questions that follow.
(a) What do you infer from the figures in Table No. 1 about the people with drug use disorders, 2022 (in million)? State any two of your observations.
(b) How are Hepatitis C and HIV related to drug use disorders by people, as shown in Table No. 2? State the correlation between the two.
(c)
- [(i)] Give the scientific name of (p) shown in Table No. 1.
OR - [(ii)] Give the scientific name of (q) shown in Table No. 1.
- CBSE CLASS XII - 2025
- Biology
- Human health and disease
- [(i)] Give the scientific name of (p) shown in Table No. 1.
- Explain unique features of acquired immunity.
- Maharashtra Class XII - 2025
- Biology
- Human health and disease
- Which of the following is caused by unsterilized needle?
- Maharashtra Class XII - 2025
- Biology
- Human health and disease
- In the life cycle of a {Plasmodium, once the sporozoite enters the blood of the host, it invades the hepatic portal system, resulting in occurrence of change in the host body, leading to malaria
A. Sporozoite enters the hepatocytes and divides by schizogony leading to formation of cryptomerozoites
B. Inside RBCs, the micro-metacryptozoites become rounded and modify into a young trophozoites.
C. As the trophozoite grows in size, a central vacuole is developed so that the nucleus is pushed to one side into the peripheral cytoplasm, leading to amoeboid stage.
D. In Amoeboid stage the small red eosinophils granules appear in the cytoplasm of the host corpulses as Schuffner's granules}
Choose the most appropriate answer from the options given below:- CUET (PG) - 2025
- Zoology
- Human health and disease
- Match LIST-I with LIST-II
\begin{tabularx}{0.8\textwidth}{|l|X|l|X|} \hline \multicolumn{2}{|c|}{LIST-I} & \multicolumn{2}{c|}{LIST-II}
\multicolumn{2}{|c|}{Types Cancer} & \multicolumn{2}{c|}{Tissues involved}
\hline A. & Carcinoma & I. & Muscle
B. & Chondroma & II. & Cartilage
C. & Sarcoma & III. & Blood
D. & Myeloma & IV. & Epithelial Tissue
\hline \end{tabularx}
Choose the most appropriate answer from the options given below:- CUET (PG) - 2025
- Zoology
- Human health and disease
Questions Asked in CBSE CLASS XII exam
- If \( \vec{\alpha} = \hat{i} - 4 \hat{j} + 9 \hat{k} \) and \( \vec{\beta} = 2\hat{i} - \hat{j} + \lambda \hat{k} \) are two mutually parallel vectors, then \( \lambda \) is equal to:
"There is widely spatial variation in different sectors of work participation in India." Evaluate the statement with suitable examples.
- CBSE CLASS XII - 2025
- Population
Alexia Limited invited applications for issuing 1,00,000 equity shares of ₹ 10 each at premium of ₹ 10 per share.
The amount was payable as follows:- On application ₹ 9 per share (Including premium ₹ 6 per share)
- On allotment ₹ 8 per share (Including premium ₹ 4 per share)
- On first and final call ₹ 3 per share.
Applications were received for 1,50,000 equity shares and allotment was made to the applicants as follows:
Category A: Applicants for 90,000 shares were allotted 70,000 shares.
Category B: Applicants for 60,000 shares were allotted 30,000 shares.
Excess money received on application was adjusted towards allotment and first and final call.
Shekhar, who had applied for 1200 shares failed to pay the first and final call. Shekhar belonged to category B.
Pass necessary journal entries for the above transactions in the books of Alexia Limited. Open calls in arrears and calls in advance account, wherever necessary.- Shweta mixed two liquids A and B of 10 mL each. After mixing, the volume of the solution was found to be 20.2 mL.
(i) Why was there a volume change after mixing the liquids?
(ii) Will there be an increase or decrease of temperature after mixing?
(iii) Give one example for this type of solution.- CBSE CLASS XII - 2025
- Solutions
On $31^{\text {st }}$ March, 2024, following is the Balance Sheet of Bhavik Limited :
Bhavik Ltd.
Balance Sheet as at $31^{\text {st }}$ March 2024
I. Equity and Liabilities :
Particulars Note No. $31-3-2024$ (₹) $31-3-2023$ (₹) 1. Shareholders funds (a) Share Capital 12,00,000 10,00,000 (b) Reserves and Surplus 1 4,00,000 3,00,000 2. Non-current liabilities Long-term borrowings 2 6,00,000 10,00,000 3. Current Liabilities 5,00,000 1,00,000 (a) Trade Payables 3 3,00,000 4,00,000 (b) Short-term provisions Total 30,00,000 28,00,000 II. Assets :
1. Non-current Assets (a) Property, Plant and Equipment and Intangible Assets Property plant and equipment 4 19,00,000 15,00,000 (b) Non-current Investments 3,00,000 4,00,000 2. Current Assets (a) Inventories 4,50,000 3,50,000 (b) Trade Receivables 2,50,000 4,50,000 (c) Cash and Cash Equivalents 1,00,000 1,00,000 Total 30,00,000 28,00,000 Notes to Accounts :
Note Particulars $31-3-2024$ (₹) $31-3-2023$ (₹) No. 1. Reserves and Surplus i.e. Balance in Statement of Profit and Loss 4,00,000 3,00,000 2. Long-term borrowings 10% Debentures 6,00,000 10,00,000 3. Short-term provisions Provision for tax 3,00,000 4,00,000 4. Property plant and equipment Plant and Machinery 21,50,000 16,00,000 Less : Accumulated Depreciation 2,50,000 1,00,000 19,00,000 15,00,000 Additional Information :
- During the year, a piece of machinery costing ₹ 8,00,000 with accumulated depreciation of ₹ 50,000 was sold for ₹ 6,50,000.
- Debentures were redeemed on $31^{\text {st }}$ March, 2024.
Calculate :
- Cash flows from Investing Activities
- Cash flows from Financing Activities
- CBSE CLASS XII - 2025
- Balance sheet statement
Concepts Used:
HIV and AIDS
What Is HIV?
HIV is a virus that attacks cells that help the body to fight infection and making a person more vulnerable to other infections and diseases. It is spread by contact with certain bodily fluids of a person with HIV. It is most commonly during the unprotected sex or when share injection or drugs equipment.
What Is AIDS?
It is the late stage of HIV infection that occurs when the body’s immune system is badly damaged because of the virus.