Q.(a)
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🔒 Start your 14-day free trial to unlock the full solution →Part (a)Concept understanding — Biology Disease Control
Biology Disease Control — A First Look
Think of your body as a city. Every day, germs (bacteria, viruses, fungi, parasites) try to enter — through the air you breathe, the food you eat, a cut on your skin. Most of the time, your body's defence systems stop them before you even notice. That's immunity, your natural security force.
But sometimes the invaders break through. You get a fever, a cough, an infection. Now you need disease control — the set of actions that stop the illness from spreading and help you recover.
What exactly is disease control?
In biology, disease control means reducing the incidence (new cases), prevalence (total cases), or transmission of a disease. It's not about wiping out every germ — that's impossible. It's about keeping the disease at a level where it no longer threatens public health.
The NCERT textbook divides disease control into two broad approaches:
1. Preventive measures — stopping the disease before it starts
These are actions taken by individuals, communities, and governments to block the entry of pathogens.
- Vaccination — training your immune system to recognise a germ before it attacks. This is the single most powerful tool in disease control.
- Sanitation and hygiene — clean drinking water, proper sewage disposal, handwashing. Many diseases (cholera, typhoid, hepatitis A) spread through contaminated water or food.
- Vector control — killing or avoiding the organisms that carry disease. Mosquito nets, insect repellents, draining stagnant water — these control malaria, dengue, chikungunya.
- Quarantine and isolation — separating sick people from healthy ones during outbreaks. You saw this during COVID-19.
Prevention is always better than cure. Once a disease spreads in a population, controlling it becomes exponentially harder and more expensive. That's why governments invest heavily in vaccination drives and public sanitation.
2. Curative measures — treating the disease once it occurs
Even with the best prevention, some people will fall ill. Curative measures aim to:
- Reduce the severity of the illness (e.g., antibiotics for bacterial infections, antiviral drugs for flu)
- Shorten the duration of the illness
- Prevent complications and death
- Stop the patient from infecting others
The key point: treatment alone cannot control a disease in a population. If you only treat sick people without preventing new infections, the disease keeps circulating.
Why does disease control matter for society?
A single outbreak can paralyse a city. Schools close, hospitals overflow, businesses shut down. The economic cost is enormous. That's why disease control is not just a medical issue — it's a public health issue.
The NCERT textbook emphasises that disease control requires community participation. No matter how good the doctors or vaccines are, if people refuse to vaccinate their children or ignore hygiene, the disease will keep spreading. …
Part (b)Concept understanding — Cancer Cell Biology
Imagine a city where every cell is a citizen with a specific job. Skin cells form the outer wall, stomach cells digest food, nerve cells carry messages. Each citizen follows a strict rulebook: grow when needed, stop when the job is done, and eventually die to make room for younger replacements. This orderly cycle is what keeps the city healthy.
Now, what happens if one citizen suddenly stops listening to the rules? It starts growing uncontrollably, refuses to die, and begins crowding out its neighbours. Worse, it might break through the city walls and travel to a different district, setting up a new colony there. That rogue citizen is a cancer cell. Cancer cell biology is the study of how normal, well-behaved cells turn into these rebellious, destructive ones.
The core idea: a breakdown of cellular discipline
Every cell in your body contains a complete set of instructions — your DNA. Think of DNA as the city's master blueprint and rulebook. Inside that blueprint are specific genes that act like traffic lights: some tell the cell to grow (these are called proto-oncogenes), and others tell it to stop growing or to self-destruct when damaged (these are called tumour suppressor genes).
Cancer begins when these traffic lights break. A proto-oncogene might get stuck on green, so the cell grows non-stop. Or a tumour suppressor gene might get stuck on red, so the cell never gets the signal to stop or die. Usually, a single broken light isn't enough — the cell has backup systems. But over years, multiple lights break, and the cell loses all control.
Cancer is not one disease but a collection of diseases. All cancers share one fundamental property: uncontrolled cell division caused by accumulated damage to the DNA. The type of cancer depends on which original cell type went rogue (e.g., lung cells → lung cancer, skin cells → skin cancer).
How a normal cell becomes cancerous: a step-by-step intuition
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Initiation — A cell's DNA gets damaged by something (a chemical in cigarette smoke, UV radiation from the sun, a random copying error during cell division). This damage is a mutation. One mutation alone rarely causes cancer, but it's the first crack in the rulebook.
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Promotion — The damaged cell is now slightly more prone to grow. If it encounters more damaging agents (promoters), it accumulates more mutations. Each mutation pushes it further from normal behaviour.
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Progression — After several mutations, the cell now divides rapidly, ignores signals to stop, and refuses to die. It forms a mass of cells called a tumour. Not all tumours are cancerous — benign tumours stay in one place and don't invade neighbours. Malignant tumours are the dangerous ones: they invade nearby tissues and can break off to travel through blood or lymph vessels.
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Metastasis — This is the most dangerous step. A few cancer cells detach from the original tumour, travel through the bloodstream or lymphatic system, and settle in a distant organ (like the liver, lungs, or brain). There, they start a new tumour. This spread is what makes cancer so hard to treat.
Why does this matter for you?
You don't need to memorise gene names or pathways. What matters is understanding the logic behind prevention and treatment:
- Prevention works because most cancers take years to develop. Avoiding known DNA-damaging agents (tobacco, excessive sun, certain viruses like HPV) reduces the chance of those first mutations.
- Early detection works because a small, localised tumour can often be surgically removed before it metastasises. …
Concept: Life cycle of Plasmodium / malaria (a); tumours and cancer diagnostics (b).
Part (a)
(i) In the human body: When an infected female Anopheles bites, it injects sporozoites (the infective stage) with its saliva. These reach the liver, multiply, and then enter the red blood cells (RBCs), where they multiply asexually and rupture the RBCs, releasing a toxin (haemozoin) that causes the recurring high fever and chills. Some parasites in the RBCs form the sexual stages, the male and female gametocytes, which circulate in the blood ready to be picked up by a mosquito.
(ii) Two events inside the female Anopheles:
- Fertilization / fusion of gametes — the gametocytes taken up in the blood meal form gametes that fuse to form a zygote (which develops further in the gut wall). …
Part (a): In humans, Plasmodium sporozoites multiply in the liver, then in RBCs (releasing haemozoin → fever) and form gametocytes; inside the female Anopheles the two events are fertilization (gamete fusion → zygote) and sporogony (formation of sporozoites that reach the salivary glands).
Part (b): Malignant tumours invade tissues and metastasise, unlike localised benign tumours; cancer is detected by biopsy/histopathology, imaging (X-ray/CT/MRI) and antibody/molecular techniques.
Part (a) Life cycle of Plasmodium
(i) In the human body.
- A bite by an infected female Anopheles mosquito injects the infective sporozoites with the mosquito's saliva into the human blood.
- The sporozoites reach the liver cells and multiply there.
- They then enter the red blood cells (RBCs), where they multiply asexually, and the RBCs rupture, releasing more parasites and a toxic substance called haemozoin. Haemozoin is responsible for the characteristic recurring high fever and chills every 3–4 days.
- After several such cycles, some parasites within the RBCs develop into the sexual forms — male and female gametocytes, which circulate in the blood. These are the stages that continue the cycle when a mosquito bites the infected person.
(ii) Two events inside the female Anopheles.
When a female Anopheles bites an infected person, it sucks up blood containing gametocytes; inside the mosquito's gut:
- Fertilization (gametogony): the gametocytes mature into male and female gametes, which fuse to form a zygote (the zygote develops further in the wall of the mosquito's gut). …
Showing the 12 most recent of 19 on this concept.
- AP EAPCET 2026Set ap-2026-05-19-FN1 markMCQQ.Inactivated whole agent vaccines are used in the treatment of (A) Influenza, Rabies (B) Polio, Typhoid (C) Diphtheria, Tetanus (D) Hepatitis-A, Measles
›Reveal solutionSolution
Inactivated whole-agent (killed) vaccines use the entire dead pathogen;
Influenza and Rabies vaccines are the standard textbook examples. Answer: (A).
Concept and Intuition
Vaccines are classified by what they contain:
- Inactivated (killed) whole-agent vaccines: the entire pathogen, chemically or physically killed so it can't cause disease but still triggers immunity — classic examples are Rabies and Influenza (and Salk/IPV polio).
- Live attenuated vaccines: a weakened but still-living pathogen (e.g. Measles, BCG, oral/Sabin polio).
- Toxoid vaccines: an inactivated bacterial toxin, not the whole organism — e.g. Diphtheria and Tetanus.
Step-by-Step Solution
- Check (A) Influenza, Rabies — both are prepared as killed, whole-pathogen vaccines. Matches "inactivated whole agent" cleanly.
- Check (C) Diphtheria, Tetanus — these are toxoid vaccines (inactivated toxin only, not the whole bacterium), so this doesn't fit "whole agent."
- Check (D) Hepatitis-A (inactivated), Measles (live attenuated) — mixed …
- AP EAPCET 2026Set ap-2026-05-20-FN1 markMCQQ.Assertion (A): The p53 gene is often called guardian angel of human genome. Reason (R): It inhibits the development of tumors. (A) Both (A) and (R) are true. (R) is correct explanation for (A) (B) Both (A) and (R) are true. (R) is not correct explanation for (A) (C) (A) is true. But (R) is false (D) (A) is false. But (R) is true
›Reveal solutionSolution
p53's nickname reflects its genuine biological role: it inhibits tumor development, which is precisely why it is regarded as protecting ('guarding') the genome.
Concept and Intuition
p53 is a key tumor-suppressor protein that monitors cells for DNA damage. When damage is detected, p53 can pause the cell cycle to allow repair, or if the damage is too severe, push the cell towards programmed cell death (apoptosis) — preventing a damaged, potentially cancer-prone cell from dividing further. Because this activity actively protects the genome's integrity by stopping tumor-forming cells from propagating, p53 earned its well-known protective nickname.
Step-by-Step Solution
- Confirm the assertion: p53 is indeed widely referred to with a protective, 'guardian'-style nickname reflecting its tumor-suppressing role — TRUE.
- Confirm the reason: p53 inhibits tumor development by halting the cycle or triggering apoptosis of damaged cells — TRUE, and this is a well-established mechanism. …
- AP EAPCET 2026Set ap-2026-05-20-AN1 markMCQQ.Ringworm is caused by (A) Virus (B) Bacteria (C) Fungi (D) Protozoan
›Reveal solutionSolution
This tests a basic infectious-disease fact: ringworm is a fungal (dermatophyte)
skin infection, not viral, bacterial, or protozoan.
Concept and Intuition
"Ringworm" is a common name for dermatophytosis, a superficial infection of
the skin, hair, or nails caused by a group of keratin-digesting fungi collectively
called dermatophytes (genera Trichophyton, Microsporum, Epidermophyton). The
infection produces the classic dry, scaly, circular ("ring-shaped") lesion with a
raised, active, itchy border — the name comes from the ring-like appearance, not
from any actual worm involvement.
Step-by-Step Solution
- Consider the causative-agent categories: virus, bacteria, fungi, protozoan.
- Recall that dermatophyte infections (ringworm, athlete's foot, jock itch) are specifically caused by a group of fungi adapted to digest keratin in skin, hair, and nails. …
- AP EAPCET 2025Set ap-2025-05-20-AN1 markMCQQ.Which one of the following is a liquid tumor ? (A) Carcinoma (B) Sarcoma (C) Leukemia (D) Lymphoma
›Reveal solutionSolution
Leukemia is a cancer of blood cells that proliferates within the blood and bone marrow
without forming a discrete solid mass, earning it the description "liquid tumour,"
unlike carcinoma, sarcoma and lymphoma. Answer: (C).
Concept and Intuition
Tumours/cancers are broadly divided into solid tumours, which form a discrete lump of
abnormal tissue (e.g., carcinomas arising from epithelial tissue, sarcomas from connective
tissue, and lymphomas typically forming solid masses in lymph nodes), and
"liquid tumours," a term specifically used for blood cancers like leukemia, where
malignant white blood cells proliferate and circulate freely within the blood and bone
marrow rather than clumping into a solid mass.
Step-by-Step Solution
- Carcinoma arises from epithelial cells and forms a solid tumour mass — not a liquid tumour.
- Sarcoma arises from connective/mesenchymal tissue and also forms a solid tumour mass — not a liquid tumour.
- Leukemia is a cancer of the blood-forming cells (usually white blood cell precursors) …
- AP EAPCET 2025Set ap-2025-05-20-FN1 markMCQQ.Match the following. List-I - List-II A) Carcinoma - I. Lymphatic system B) Sarcoma - II. Epithelial tissues C) Lymphoma - III. Connective tissues D) Leukemia - IV. Bone marrow
- V. Gonads (A) A-II, B-III, C-I, D-V (B) A-II, B-III, C-I, D-IV (C) A-IV, B-I, C-III, D-II (D) A-V, B-II, C-IV, D-I
›Reveal solutionSolution
Carcinoma = epithelial tissues (II), Sarcoma = connective tissues (III), Lymphoma = lymphatic system (I), Leukemia = bone marrow (IV). Answer: (B).
Concept and Intuition
Cancers are classified by the type of tissue in which they originate, and this classification directly gives their names:
- Carcinomas arise from epithelial tissue (the lining of organs, skin, glands) — the most common category of human cancers (e.g. breast, lung, colon cancers).
- Sarcomas arise from connective and supporting tissues such as bone, cartilage, fat, and muscle.
- Lymphomas arise from cells of the lymphatic system (lymph nodes, lymphoid tissue).
- Leukemias arise from blood-forming (haematopoietic) cells in the bone marrow, leading to abnormal proliferation of white blood cells in the blood.
Step-by-Step Solution
- A) Carcinoma → epithelial tissues, item II.
- B) Sarcoma → connective tissues, item III.
- C) Lymphoma → lymphatic system, item I.
- D) Leukemia → bone marrow, item IV. …
- AP EAPCET 2023Set ap-2023-05-22-AN1 markMCQQ.Mild tertian malaria is caused by (A) Plasmodium vivax (B) Plasmodium ovale (C) Plasmodium falciparum (D) Plasmodium malaria
›Reveal solutionSolution
Straight recall of malaria nomenclature: P. vivax = benign tertian, P. ovale = mild tertian, P. malariae = quartan, P. falciparum = malignant tertian.
Concept and Intuition
Malarial fever is periodic because it is driven by the synchronous rupture of infected RBCs. When a whole cohort of erythrocytic schizonts bursts at once, it releases merozoites together with the toxin haemozoin, which triggers the chill–fever–sweat paroxysm. So the fever interval equals the length of the erythrocytic cycle:
- 48-hour cycle → fever on day 1, day 3, day 5 … Counting inclusively, that is every third day → tertian.
- 72-hour cycle → fever every fourth day → quartan.
Three species run a 48-hour cycle and are therefore all "tertian"; they are then separated by severity, and that adjective is what the question is testing:
- P. falciparum — enormous parasitaemia, sequestration in capillaries, cerebral malaria → malignant tertian, the killer.
- P. vivax — high relapse rate but rarely fatal → benign tertian.
- P. ovale — the least aggressive, geographically restricted species → mild tertian.
- P. malariae — 72-hour cycle → quartan, not tertian at all.
Step-by-Step Solution
- The word tertian eliminates P. malariae (option D), which causes quartan malaria. …
- AP EAPCET 2023Set ap-2023-05-22-FN1 markMCQQ.Among the following mention diseases that have existed in the past but now showing incidence and in new geographical areas. (A) Re-emerging diseases : Tuberculosis (B) Emerging diseases : Cholera (C) Super emerging Diseases : SARS (D) Emerging diseases : Dengue fever
›Reveal solutionSolution
"Existed before, now resurging in new areas" describes re-emerging disease, and tuberculosis is the standard example of one.
Concept and Intuition
Epidemiologists distinguish emerging diseases (newly identified, not previously seen in humans, e.g. many novel viral diseases) from re-emerging diseases (known diseases that had declined in incidence but have reappeared, often in new areas or with new drug-resistant strains). The question's wording — "existed in the past but now showing incidence... in new geographical areas" — matches the re-emerging category exactly.
Step-by-Step Solution
- Parse the definition given: prior existence + renewed incidence + spread to new areas = re-emerging disease.
- Check option (A): Tuberculosis labelled "Re-emerging" — matches; TB had declined with antibiotics but has resurged (including multidrug-resistant TB) and spread into new regions. …
- AP EAPCET 2023Set ap-2023-05-22-FN1 markMCQQ.Reciprocal translocation of chromosomal pieces between 9 & 22 chromosomes leads to (A) Cri-du-chat syndrome (B) Cystic fibrosis (C) Sickle cell anemia (D) Chronic Myelogenous leukemia
›Reveal solutionSolution
Tests the disease linked to the 9;22 chromosomal translocation. Answer: (D) Chronic Myelogenous leukemia.
Concept and Intuition
When a piece of chromosome 9 (carrying the ABL gene) and a piece of chromosome 22 (carrying the BCR gene) are reciprocally exchanged, the resulting abnormally short chromosome 22 is called the Philadelphia chromosome. The fused BCR-ABL gene product is a constitutively active tyrosine kinase that drives uncontrolled proliferation of myeloid blood cells, causing Chronic Myelogenous Leukemia (CML).
Step-by-Step Solution
- Recognize the 9;22 translocation as the classic Philadelphia chromosome abnormality.
- Recall its disease association: CML, a cancer of myeloid blood cell lineage. …
- AP EAPCET 2023Set ap-2023-05-23-AN1 markMCQQ.Father of Bacteriology and link to infectious diseases (A) Ehrenberg and Bacteriology (B) Leeuwenhoek and virology (C) Louis Pasteur and germ theory of diseases (D) Butler and germ theory of diseases
›Reveal solutionSolution
This tests recognition of Louis Pasteur's foundational contribution to microbiology — establishing the germ theory of disease, linking microorganisms to infectious illness.
Concept and Intuition
Several early scientists contributed to the discovery and study of microorganisms, but their specific legacies differ: Antonie van Leeuwenhoek first observed and described microorganisms ("animalcules") under a microscope; Christian Gottfried Ehrenberg named and classified various microbes including "bacterium"; but it was Louis Pasteur who conclusively demonstrated that microorganisms are responsible for causing specific diseases, establishing what is known as the germ theory of disease, and is celebrated as a founding figure of bacteriology/microbiology.
Step-by-Step Solution
- Rule out Ehrenberg — he named organisms and coined terms, but is not specifically credited with germ theory.
- Rule out Leeuwenhoek — he discovered microorganisms via microscopy, a foundational but earlier step, and is not linked to virology or germ theory specifically.
- Rule out Butler — not a recognised founder of germ theory or bacteriology in this context. …
- AP EAPCET 2023Set ap-2023-05-23-FN1 markMCQQ.Identify the fungal disease among the following (A) Common cold (B) Pneumonia (C) Ring worm (D) Typhoid
›Reveal solutionSolution
Among the listed diseases, only ring worm is fungal in origin (caused by dermatophyte fungi such as Microsporum, Trichophyton, Epidermophyton).
Concept and Intuition
Disease causative-agent classification is a staple of the "Human Health and Disease" chapter: common cold is viral (rhinovirus), pneumonia is commonly bacterial (Streptococcus pneumoniae) though it can also be viral, typhoid is bacterial (Salmonella typhi), while ring worm is a classic superficial mycosis caused by keratin-digesting dermatophyte fungi, producing the characteristic ring-shaped lesions on skin.
Step-by-Step Solution
- Common cold → viral. …
- AP EAPCET 2023Set ap-2023-05-23-FN1 markMCQQ.Assertion (A): Dengue fever is caused due to failure of clot reaction Reason (R): The patient of dengue may require transfusion of blood platelets. (A) Both A and R are true and R is the correct explanation of A. (B) Both A and R are true but R is not the correct explanation of A. (C) A is true and R is false. (D) A is wrong and R is true.
›Reveal solutionSolution
Dengue is caused by a viral infection, not by clotting failure — clotting/platelet problems are a downstream effect, not the cause — so the Assertion is false while the Reason (platelet transfusion may be needed) stands true on its own. Answer: (D).
Concept and Intuition
Assertion–Reason questions often hinge on getting causality the right way round. Dengue fever's actual cause is infection by the dengue virus (genus Flavivirus), transmitted through the bite of an infected female Aedes aegypti mosquito. As the disease progresses (particularly in its severe form, dengue haemorrhagic fever/dengue shock syndrome), the virus damages bone marrow megakaryocytes and triggers immune-mediated platelet destruction, causing thrombocytopenia. This low platelet count in turn impairs the body's clotting ability and can cause bleeding manifestations. So "failure of clot reaction" is a symptom/complication that follows from the disease, not the thing that causes the disease in the first place — the Assertion inverts this relationship and is therefore false.
The Reason is a separate, self-contained clinical statement: because platelet counts can fall so low in dengue, transfusion of platelet concentrates is indeed a standard supportive treatment in moderate-to-severe cases. This statement is true regardless of whether the Assertion's causal claim is correct.
Step-by-Step Solution
- Identify the true cause of dengue fever: infection by the dengue virus via mosquito bite — not a primary clotting disorder.
- Recognise that reduced platelets/clotting failure are consequences of the infection (via bone-marrow suppression and immune platelet destruction), not its cause. This makes the Assertion false. …
- AP EAPCET 2022Set ap-2022-07-11-AN1 markMCQQ.What is the name of epithelial cancer? (A) Sarcoma (B) Carcinoma (C) Leukemia (D) Lymphoma
›Reveal solutionSolution
Basic oncology terminology: cancer of epithelial origin is called carcinoma.
Concept and Intuition
Tumour naming in oncology reflects the embryonic/tissue origin of the cancer cells. Epithelial tissues (skin, glandular tissue, linings of organs) give rise to carcinomas — the most common category of human cancers (e.g., lung, breast, colon cancers are mostly carcinomas).
Step-by-Step Solution
- Sarcoma (option A) — arises from mesenchymal/connective tissue (bone, muscle, cartilage) — not epithelial.
- Carcinoma (option B) — arises from epithelial tissue — matches the question. …
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