CBSE 2026 · Region 4 · Set 2 · Q28 · 3 marks
Name the cells of the human body attacked by HIV first, when it gains entry into a human body. How does this virus replicate further to cause immunodeficiency in the body ?Show with the help of a flow chart only, the life-cycle of malarial parasite in human.
Name the cells of the human body attacked by HIV first, when it gains entry into a human body. How does this virus replicate further to cause immunodeficiency in the body ?
Show with the help of a flow chart only, the life-cycle of malarial parasite in human.
Marking-scheme solution
-HIV attacks Macrophages first.
-RNA genome starts producing viral DNA by reverse transcriptase.
-The viral DNA gets incorporated into the DNA of host cell and directs the infected
cells to produce viral particles.
-The new viruses are released from the macrophages and they start infecting helper
T lymphocytes (TH).
-Progressive decrease in helper T-lymphocytes takes place.
-So the immune system of infected person becomes weak and start suffering from
infections.
Sporozoites are infected into human body by the bite of female Anopheles.
↓
Sporozoites reach in liver cells through blood.
↓
The parasite reproduces asexually in liver and by bursting the liver cells and new cells are released into blood.
↓
Enter into the RBCs and reproduce asexually
↓
Rupture of RBCs and release of haemozoin
↓
New cells of parasite enter new RBCs and undergo gametogenesis to produce male and female gametocytes.
Human Health and DiseaseAIDSUnderstandshort_answermedium
More from Human Health and Disease
- Name the category of drugs represented by the chemical structure given above. If the methyl group is…2023 · asked 3×
- Lactobacillus that sets milk into curd is categorised as:2024 · asked 3×
- Explain, giving two reasons, how immune response by "vaccine" is different from that by "antitoxin" in humans.2022 · asked 3×
- Student to attempt either option or. Describe any two situations where a medical doctor would recommend…2025 · asked 3×
- (i) Draw the structure of an antibody molecule and label any four of its parts. (ii) Differentiate between…2026 · asked 3×
- Assertion: Virus-infected cells produce interferons. Reason (R): Interferons can cause inflammation of…2024 · asked 3×
- Out of the following, select the correct match:2025 · asked 3×
- Though filariasis is not fatal, but the disease in humans is responsible for considerable suffering, gross…2022 · asked 3×
CBSE Class 12 Biology past-paper question from the 2026board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.