Maharashtra Board Class 12 Biology Chapter 10 Human Health and Diseases Solutions

Class 12 Biology Chapter 10 Exercise Solutions Maharashtra Board

Biology Class 12 Chapter 10 Exercise Solutions

1. Multiple Choice Questions

 

Question 1. Which of the following is NOT caused by unsterilized needles?
(a) Elephantiasis
(b) AIDS
(e) Malaria
(d) Hepatitis
Answer: (a) Elephantiasis
In simple words: Elephantiasis is caused by parasitic worms transmitted by mosquitoes, not by unsterilized needles. AIDS, Malaria, and Hepatitis can all be transmitted via contaminated needles.

🎯 Exam Tip: Remember common modes of disease transmission for infectious diseases. Identifying what is *not* a cause can be just as important as knowing what is.

 

Question 2. Opium derivative is ........................
(a) Codeine
(b) Caffeine
(c) Heroin
(d) Psilocybin
Answer: (c) Heroin
In simple words: Heroin is a powerful opioid drug synthesized from morphine, which is naturally derived from the opium poppy.

🎯 Exam Tip: Familiarize yourself with common drugs and their origins, especially those derived from plants or used in medicine.

 

Question 3. The stimulant present in tea is ........................
(a) tannin
(b) cocaine
(C) caffeine
(d) crack
Answer: (C) caffeine
In simple words: Caffeine is a natural stimulant found in tea, coffee, and other plants, known for its energizing effects.

🎯 Exam Tip: Understand the active compounds in common beverages and their effects on the human body.

 

Question 4. Which of the following Is caused by smoking?
(a) Liver cirrhosis
(b) Pulmonary tuberculosis
(c) Emphysema
(d) Malaria
Answer: (c) Emphysema
In simple words: Emphysema is a chronic lung disease primarily caused by smoking, leading to damage of the air sacs and breathlessness.

🎯 Exam Tip: Know the major health risks associated with smoking, particularly chronic respiratory diseases.

 

Question 5. An antibody is ........................
(a) molecuic that binds specifically an antigen
(b) WBC which invades bacteria
(c) secretion of mammalian RBC
(d) cellular component of blood
Answer: (a) molecule that binds specifically an antigen
In simple words: An antibody is a protein produced by the immune system that specifically recognizes and binds to a foreign substance called an antigen, helping to neutralize it.

🎯 Exam Tip: Grasp the fundamental definition of an antibody and its role in specific immunity, focusing on its antigen-binding capability.

 

Question 6. The antiviral proteins released by a virus-infected cell are called ........................
(a) histamines
(b) interferons
(c) pyrogens
(d) allergens
Answer: (b) interferons
In simple words: Interferons are signaling proteins released by host cells in response to viral infections, which help to limit the spread of the virus to other cells.

🎯 Exam Tip: Understand the body's innate immune responses, including the function of interferons as antiviral agents.

 

Question 7. Both B-cells and T-cells are derived from ........................
(a) lymph nodes
(b) thymus glands
(c) liver
(d) stem cells in bone marrow
Answer: (d) stem cells in bone marrow
In simple words: Both B-cells and T-cells, crucial components of the adaptive immune system, originate from hematopoietic stem cells found in the bone marrow.

🎯 Exam Tip: Recognize the origin of immune cells (lymphocytes) from bone marrow stem cells, noting their subsequent maturation sites.

 

Question 8. Which of the following diseases can be contracted by droplet infection?
(a) Malaria
(b) Chicken pox
(c) Pneumonia
(d) Rabies
Answer: (c) Pneumonia
In simple words: Pneumonia, a lung infection, can be spread through respiratory droplets released when an infected person coughs or sneezes.

🎯 Exam Tip: Differentiate between various modes of disease transmission, such as droplet, vector-borne, and direct contact, for common illnesses.

 

Question 9. Confirmatory test used for detecting HIV infection is ........................
(a) ELISA
(b) Western blot
(c) Widal test
(d) Eastern blot
Answer: (b) Western blot
In simple words: While ELISA is a common screening test for HIV, the Western blot is used as a confirmatory test to detect specific HIV antibodies.

🎯 Exam Tip: Distinguish between screening and confirmatory tests for important diseases like HIV, understanding the purpose of each.

 

Question 10. Elephantiasis is caused by ........................
(a) W. barterofti
(b) P. vivax
(c) Bedbug
(d) Elephant
Answer: (a) W. bancrofti
In simple words: Elephantiasis, or lymphatic filariasis, is primarily caused by the parasitic worm Wuchereria bancrofti, transmitted by mosquitoes.

🎯 Exam Tip: Learn the specific causative agents for major parasitic diseases, as they are often tested in biology exams.

 

Question 11. Innate immunity is provided by ........................
(a) phagocytes
(b) antibody
(c) T-lymphocytes
(d) B-lymphocytes
Answer: (a) phagocytes
In simple words: Phagocytes, such as macrophages and neutrophils, are part of the innate immune system and provide non-specific defense by engulfing and destroying pathogens.

🎯 Exam Tip: Differentiate between innate and acquired immunity, understanding which cells and mechanisms contribute to each type.

 

2. Short Answer Questions

 

Question 1. What is the source of cocaine?
Answer: Source of cocaine is coca plant - Erythroxylum coca.
In simple words: Cocaine is derived from the leaves of the coca plant, scientifically known as Erythroxylum coca, native to South America.

🎯 Exam Tip: Remember the natural sources of commonly discussed drugs and their scientific names.

 

Question 2. Name one disease caused by smoking.
Answer: Emphysema. (Damaged and enlarged lungs causing breathlessness)
In simple words: Smoking can cause emphysema, a severe lung disease characterized by the destruction of air sacs, leading to chronic shortness of breath.

🎯 Exam Tip: Be able to list at least one specific disease directly linked to harmful habits like smoking.

 

Question 3. Which cells stimulate B-cells to form antibodies ?
Answer: Helper T-cells stimulate B-cells to form antibodies.
In simple words: Helper T-cells activate B-cells, prompting them to differentiate into plasma cells that produce antibodies.

🎯 Exam Tip: Understand the cooperative interaction between T-cells and B-cells in the humoral immune response.

 

Question 4. What does the abbreviation AIDS stand for?
Answer: AIDS stands for Acquired Immuno Deficiency Syndrome.
In simple words: AIDS is an acronym for Acquired Immuno Deficiency Syndrome, a condition caused by HIV that severely weakens the immune system.

🎯 Exam Tip: Know the full forms of important biological abbreviations, especially for diseases and medical conditions.

 

Question 5. Name the causative agent of typhoid fever.
Answer: Salmonella typhi
In simple words: Typhoid fever is caused by the bacterium Salmonella typhi, which is typically spread through contaminated food and water.

🎯 Exam Tip: Memorize the specific pathogens responsible for common infectious diseases.

 

Question 6. What is Rh factor?
Answer: Antigen 'D' present on the surface of RBCs is known as Rh factor.
In simple words: The Rh factor is a specific protein, Antigen D, found on the surface of red blood cells, determining whether a person is Rh-positive or Rh-negative.

🎯 Exam Tip: Focus on understanding the Rh factor's chemical nature (Antigen D) and its location on red blood cells for blood group classification.

 

Question 7 What is schizont?
Answer: Schizont is a ring-like form produced from merozoites inside the erythrocytes of human beings, infected by Plasmodium, which again forms new merozoites.
In simple words: A schizont is a stage in the life cycle of Plasmodium, found within red blood cells, where merozoites multiply asexually before bursting out to infect new cells.

🎯 Exam Tip: Understand the different stages of the Plasmodium life cycle, especially those occurring within the human host, and their significance.

 

Question 8. Name the addicting component found in tobacco.
Answer: Nicotine
In simple words: Nicotine is the highly addictive chemical compound present in tobacco that stimulates the central nervous system.

🎯 Exam Tip: Identify the primary addictive substances in common recreational drugs and their immediate physiological effects.

 

Question 9. Name the pathogen causing Malaria.
Answer: Plasmodium vivax
In simple words: Malaria is caused by protozoan parasites of the genus Plasmodium, with Plasmodium vivax being one of the most common species.

🎯 Exam Tip: Remember the genus and common species names of parasites responsible for major diseases like malaria.

 

Question 10. Name the vector of Filariasis.
Answer: Female Culex mosquito
In simple words: Filariasis, also known as elephantiasis, is transmitted by the bite of infected female Culex mosquitoes.

🎯 Exam Tip: Identify the specific vectors (e.g., mosquito species) involved in the transmission of vector-borne diseases.

 

Question 11. Name of the causative agent of ringworm.
Answer: Trichophyton
In simple words: Ringworm is a fungal infection of the skin caused by dermatophytes, including species from the genus Trichophyton.

🎯 Exam Tip: Know that ringworm is caused by fungi, and be familiar with the common fungal genera involved.

 

Question 12. Health
Answer: Health is defined as the state of complete physical, mental and social well-being and not merely the absence of disease or infirmity.
In simple words: Health is a holistic state encompassing physical, mental, and social well-being, extending beyond just the absence of illness.

🎯 Exam Tip: Memorize the WHO definition of health, as it is a foundational concept in biology and public health.

 

3. Short Answer Questions

 

Question 1. What are acquired diseases?
Answer: Diseases which are developed after the birth of an individual are called acquired diseases. These are of two types, viz. (a) Communicable or infectious diseases and (b) Non- communicable or Non-infectious diseases. Communicable or infectious diseases are transmitted from infected person to another healthy person either directly or indirectly. They are caused due to pathogens like viruses, bacteria, fungi, helminth worms, etc. Non-communicable or Non-infectious diseases cannot be transmitted from infected person to another healthy one either directly or indirectly.
In simple words: Acquired diseases are conditions developed after birth, categorized as either communicable (spread by pathogens) or non-communicable (not spread from person to person).

🎯 Exam Tip: Clearly distinguish between acquired diseases and congenital diseases, and further categorize acquired diseases into communicable and non-communicable types with examples.

 

Question 2. Antigen and antibody.
Answer:

Antigen	Antibody
1. Antigens are foreign proteins which are capable of producing infection.	1. Antibodies are immunoglobulins produced by the body to act against the antigens.
2. The structure of antigens is variable dependent upon the type of pathogen.	2. The structure of antibody is Y-shaped.
3. The antigen is the 'non-self' molecule.	3. The antibody is 'self' molecule.
4. The antigens have epitope sites which bind with the antibody molecule.	4. The antibodies have paratope sites which bind with the antigen molecule.

In simple words: Antigens are foreign substances that trigger an immune response, while antibodies are Y-shaped proteins produced by the body to specifically recognize and neutralize these antigens.

🎯 Exam Tip: Understand the key differences in origin, structure, and function between antigens and antibodies, as this is fundamental to immunology.

 

Question 3. Name the infective stage of Plasmodium. Give Symptoms of malaria
Answer: Sporozoite
I. Symptoms of malaria:
1. Fever accompanied by shivering.
2. Joint pain or arthralgia.
3. Vomiting.
4. Anaemia caused due to rupture of RBCs or haemolysis.
5. Haemoglobinuria.
6. Retinal damage.
7. Convulsions.
8. Cyclical occurrence of sudden coldness followed by rigor and then fever and sweating lasting for four to six hours. This is called a classic symptom of malaria.
9. Splenomegaly or enlarged spleen, severe headache, cerebral ischemia, hepatomegaly, i. e. enlarged liver, hypoglycaemia and haemoglobinuria with renal failure may occur in severe infections.
II. Spread / Transmission of malaria:
1. Malaria parasite is transmitted through the female Anopheles mosquito and hence it is known as mosquito-borne disease. Mosquito acts as a vector.
2. There are four species of Plasmodium, viz., P. vivax, P. falciparum, P. ovale and P. malariae which transmit malaria.
In simple words: The infective stage of Plasmodium is the sporozoite. Malaria symptoms include cyclical fever, shivering, joint pain, and anemia, transmitted by the bite of an infected female Anopheles mosquito.

🎯 Exam Tip: Focus on remembering the infective stage of Plasmodium, the specific vector (female Anopheles mosquito), and the cyclical nature of malaria symptoms.

 

Question 4. Explain the mode of infection and cause of elephantiasis.
Answer: Mode of infection, i.e. transmission:
1. The parasite Wuchereria bancrofti is transmitted from a patient to other normal human being by female Culex mosquito.
2. The filarial larvae leave mosquito body and arrive on the human skin where they penetrate the skin and enter inside.
3. They undergo two moultings to become adults. Later they settle in the lymphatic system. They incubate for about 8-16 months.
4. When they settle in lymphatic system, this infection is called lymphatic filariasis.
5. The worms start infecting lymphatic circulation resulting into enlargement of lymph vessels and lymph nodes. The extremities like legs or limbs become swollen which resembles elephant legs. Therefore it is called elephantiasis.
6. This condition is lymphoedema, i.e. accumulation of lymph fluid in tissue causing swelling.
In simple words: Elephantiasis is caused by Wuchereria bancrofti larvae transmitted by female Culex mosquitoes. The larvae mature and settle in the lymphatic system, causing blockages and severe swelling (lymphoedema), particularly in the limbs.

🎯 Exam Tip: Understand the life cycle and transmission pathway of the Wuchereria bancrofti parasite, highlighting its effect on the lymphatic system and the resulting characteristic swelling.

 

Question 5. Why is smoking a bad habit?
Answer:
1. Smoking involves inhaling the cigarette smoke which contains nicotine and other toxic substances like N-nitrosodimethlene. There is some amount of carbon monoxide.
All these substances affect the normal respiratory health.
2. Smoking invites problems like asthma, hypertension, heart disease, stroke, lung damage.
3. The worst impact is that these substances are carcinogenic and hence can cause cancer of larynx, trachea, lung, etc.
4. Smoking not only affects the smokers but also has bad effect on others due to passive smokers.
5. In women, smoking is still hazardous as their ovaries can undergo mutations due to mutagenic chemicals found in smoke.
6. Therefore, smoking is a very bad habit.
In simple words: Smoking is detrimental because it introduces toxic chemicals like nicotine and carcinogens into the body, leading to severe health issues such as respiratory diseases, heart problems, various cancers, and also harms passive smokers.

🎯 Exam Tip: Be able to articulate multiple reasons why smoking is harmful, covering its effects on various organ systems and its impact on both active and passive smokers.

 

Question 6. What do the abbreviations AMIS and CMIS denote?
Answer: AMIS is Antibody-mediated immune system or humoral immunity and CMIS is cell-mediated immune system.
In simple words: AMIS refers to Antibody-Mediated Immune System, also known as humoral immunity, while CMIS stands for Cell-Mediated Immune System.

🎯 Exam Tip: Know the full forms and basic concepts behind AMIS (humoral immunity via antibodies) and CMIS (cell-mediated immunity via T-cells).

 

Question 7. What is a carcinogen? Name one chemical carcinogen with its target tissue.
Answer:
1. Carcinogen is the substance or agent that causes cancer.
2. Urinary bladder cancer caused by 2-naphthylamine and 4-aminobiphenyl.
In simple words: A carcinogen is any agent that causes cancer. Examples include 2-naphthylamine and 4-aminobiphenyl, which are chemical carcinogens linked to urinary bladder cancer.

🎯 Exam Tip: Define carcinogen and be prepared to provide specific examples of chemical carcinogens and the types of cancer they can cause.

 

Question 8. Active immunity and passive immunity.
Answer:

Active immunity	Passive immunity
1. Active immunity is produced in response to entry of pathogens and their antigenic stimuli.	1. Passive immunity is produced due to antibodies that are transferred to the body.
2. Active immunity is the long lasting immunity.	2. Passive immunity is short-lived immunity.
3. In active immunity, the body produces its own antibodies.	3. In passive immunity, antibodies are given to the body from outside.
4. Natural acquired active immunity is obtained due to infections by pathogens.	4. Natural acquired passive immunity is obtained through antibodies of mother transmitted- to baby by placenta or colostrum.
5. Artificial acquired active immunity is obtained through vaccinations. These vaccines contain dead or live but attenuated pathogens.	5. Artificial acquired passive immunity is also obtained through vaccinations, but here the vaccines contain the readymade antibodies which are prepared with the help of other animals such as horses.

In simple words: Active immunity develops when the body produces its own antibodies in response to an antigen, offering long-lasting protection. Passive immunity involves receiving pre-formed antibodies from an external source, providing immediate but temporary protection.

🎯 Exam Tip: Clearly differentiate between active and passive immunity based on how they are acquired, their duration, and whether the body produces its own antibodies or receives them.

 

4. Short Answer Questions

 

Question 1. B-cells and T-cells.
Answer:

B-cells	T-cells.
1. B-cells are type of lymphocyte whose origin is in bone marrow but maturation is in blood.	1. T-cells are type of lymphocytes which originate in bone marrow but maturation occurs in thymus.
2. B-cells Eire type of lymphocytes which are involved in humoral mediated immunity.	2. T-cells are type of lymphocytes which are involved in cell-mediated immunity.
3. 20% of lymphocytes present in the blood are B-cells.	3. 80% of lymphocytes present in the blood are T-cells.
4. Two types of B-cells are Memory cells and Plasma cells.	4. T-cells are of following subtypes : Cytotoxic T-cells, helper T-cells, suppressor T-cells.
5. They are involved in antibody mediated immunity. (AMI)	5. They are involved in cell-mediated immunity (CMI).
6. B-cells produced antibodies with which they fight against pathogens.	6. T-cells do not produce antibodies.
7. B-cells have membrane bound immunoglobulins located on the surface.	7. There is a presence of T cell receptors on the T-cell surface.

In simple words: B-cells are lymphocytes maturing in bone marrow, primarily responsible for humoral immunity by producing antibodies. T-cells, maturing in the thymus, are responsible for cell-mediated immunity and include various subtypes like helper and cytotoxic T-cells.

🎯 Exam Tip: A comparative understanding of B-cells and T-cells, including their origin, maturation sites, roles in different types of immunity (humoral vs. cell-mediated), and key characteristics, is essential for immunology questions.

 

Question 2. What are the symptoms of malaria? How does malaria spread?
Answer: Symptoms of malaria:
1. Fever accompanied by shivering.
2. Joint pain or arthralgia.
3. Vomiting.
4. Anaemia caused due to rupture of RBCs or haemolysis.
5. Haemoglobinuria.
In simple words: Malaria symptoms include recurrent cycles of fever with shivering, joint pain, vomiting, and anemia from red blood cell destruction. It spreads through the bite of an infected female Anopheles mosquito.

🎯 Exam Tip: Focus on the characteristic cyclical fever and shivering as primary symptoms of malaria, and always remember the vector of transmission.

 

Question 3. AIDS.
Answer:
(1) AIDS or the acquired immuno deficiency syndrome, is fatal viral disease caused by a retrovirus (ss RNA) known as the human immuno deficiency virus (HIV) which weakens the body's immune system. It is called a modern pandemic.
(2) The HIV attacks the immune system which in turn causes many opportunistic infections, neurological disorders and unusual malignancies ultimately leading to death.
(3) AIDS was first noticed in USA in 1981 whereas in India, first confirmed case of AIDS was in April 1986 from Tamil Nadu.
(4) HIV is transmitted through body fluids such as saliva, tears, nervous system tissue, spinal fluid, blood, semen, vaginal fluid and breast milk. However, only blood, semen, vaginal secretions and breast milk generally transmit infection to others.
(5) The transmission of HIV occurs by sexual contact, through blood and blood products and by contaminated syringes, needles, etc. There is also transplacental transmission or through breast milk at the time of nursing.
(6) Accidental needle injury, artificial insemination with infected donated semen and transplantation with infected organs are some of the rare occasions of transmission of HIV.
(7) HIV infection is not spread by casual contact such as hugging, bite of mosquitoes or using other objects touched by a patient.
(8) Acute HIV infection progresses over time to asymptomatic HIV infection and then to early symptomatic HIV infection. Later, it progresses to full blown AIDS when patient shows advanced HIV infection with CD4 T-cell count below 200 cells/mm.
In simple words: AIDS, caused by the HIV retrovirus, is a fatal disease that severely weakens the immune system, leading to opportunistic infections. It is primarily transmitted through sexual contact, contaminated blood, needles, and from mother to child via pregnancy or breastfeeding.

🎯 Exam Tip: Understand AIDS as an immune deficiency syndrome caused by HIV, its modes of transmission, and the types of contact that do not transmit the virus. Note the progression of the disease and its impact on CD4 T-cell count.

 

Question 4. Give the symptoms of cancer.
Answer: Symptoms of cancer:
1. Presence of lump or tumour.
2. White patches in the mouth.
3. Change in a wart or mole on the skin.
4. Swollen or enlarged lymph nodes.
5. Vertigo, headaches or seizures if cancer affect the brain.
6. Coughing and shortness of breath if lungs are affected due to cancer.
In simple words: Common symptoms of cancer include unexplained lumps, persistent white patches in the mouth, changes in skin warts or moles, swollen lymph nodes, and organ-specific symptoms like headaches (brain cancer) or persistent cough (lung cancer).

🎯 Exam Tip: Be able to list and briefly explain several common warning signs and symptoms of cancer, emphasizing both generalized and organ-specific indicators.

 

Question 5. Antigens on blood cells.
Answer:
1. There are about 30 known antigens on the surface of human red blood cells. They decide the type of blood group such as ABO, Rh, Duffy, Kidd, Lewis, P MNS, Bombay.
2. The different blood groups are determined genetically due to presence of a particular antigen.
3. Landsteiner found two antigens or agglutinogens on the surface of human red blood cells which are named as antigen A and antigen B.
4. There is another antigen called Antigen D which decides the Rh status of the blood. If Antigen D is present, the person is said to be RH positive and when it is lacking, the person is Rh negative.
5. These antigens are responsible for types of blood group and the specific transfusions.
6. Antigens present on the RBCs and antibodies present in the serum can cause agglutination reactions if they are non-compatible. Therefore, at the time of transfusion blood groups are checked properly.
In simple words: Antigens on the surface of red blood cells, such as ABO and Rh (Antigen D), determine an individual's blood group. Their presence or absence is genetically determined and crucial for compatible blood transfusions, preventing dangerous agglutination reactions.

🎯 Exam Tip: Understand the role of surface antigens on red blood cells in determining blood groups (ABO, Rh) and their critical importance in ensuring safe blood transfusions to avoid immune reactions.

 

Question 6. Antigen-antibody complex:
ℹ️ चित्र व्याख्या (Diagram Explanation): यह चित्र एक प्रतिजन-प्रतिरक्षी कॉम्प्लेक्स (Antigen-antibody complex) को दर्शाता है। इसमें एक वाई-आकार की प्रतिरक्षी (antibody) अणु को दिखाया गया है जिसके विशिष्ट एंटीजन-बाइंडिंग साइट्स (paratopes) एक विशेष प्रतिजन (antigen) के एपिटोप्स (epitopes) के साथ जुड़े हुए हैं, जैसे एक ताले और चाबी की तरह। यह विशिष्ट बंधन प्रतिरक्षा प्रतिक्रिया की नींव है।
Answer:
1. Between antigen and antibody there is specificity.
2. Each antibody is specific for a particular antigen.
3. On the antigens there are combining sites which are called antigenic determinants or epitopes.
4. Epitopes react with the corresponding antigen binding sites of antibodies which are called paratopes.
5. The antigen binding sites are located on the variable regions of the antibody. Variable regions have small variations which make each antibody highly specific for an particular antigen.
6. Owing to variable region the antibody can recognize the specific antigen.
7. Antibody thus binds to specific antigen in a lock and key manner, forming an antigen- antibody complex.
In simple words: An antigen-antibody complex forms when a specific antibody binds precisely to an antigen, like a lock and key. The antibody's paratopes recognize and attach to the antigen's epitopes, a highly specific interaction critical for immune responses.

🎯 Exam Tip: Emphasize the "lock and key" analogy to explain the high specificity of antigen-antibody binding, and clearly define epitopes (on antigen) and paratopes (on antibody).

 

Question 7. What are the various public health measures, which you would suggest as safeguard against infectious diseases?
Answer: Infectious diseases spread through pathogens, therefore, it is an important duty of each person to decrease the risk of infecting our own self or others. This can be achieved by
1. Washing hands often, especially whenever, we are in contact with food and water. Before and after preparing food, before eating and after using the toilet, hand wash is a must.
2. Vaccinations : Immunization helps us to protect against contracting many diseases. Therefore, timely vaccination should be taken. Especially at the time of epidemic, one must keep distance from infected area or get vaccinated.
3. One must be at home if there are signs and symptoms of an infection. By going out, we may infect other healthy persons.
4. Proper diet and exercise should be followed to improve one's own immunity.
5. Hygiene should be utmost in the kitchen and dining area. One must take care while eating uncovered and leftover food.
6. Bathroom and toilet should be cleaned daily as there can be a high concentration of bacteria or other infectious agents in these areas.
7. One should have responsible sexual behaviour to avoid sexually transmitted diseases.
8. Personal items such as toothbrush, comb, towel, undergarments or razor blade should never be shared.
9. Travelling should be avoided because we may infect other passengers during travel. Moreover, our illness can be aggravated. Some special immunizations are needed during certain travels, such as anti-cholera vaccine while going to Pandharpur during Ashadhi.
In simple words: Public health measures against infectious diseases include frequent handwashing, timely vaccinations, practicing good personal and food hygiene, avoiding contact when sick, and safe sexual practices, all aimed at breaking transmission chains.

🎯 Exam Tip: Focus on a comprehensive list of public health measures, categorizing them into personal hygiene, environmental hygiene, immunization, and behavioral precautions, ensuring a broad understanding of disease prevention.

 

Question 8. How does the transmission of each of the following diseases take place?
(a) Amoebiasis:
Answer: Amoebiasis is usually transmitted by the following ways:
1. The faecal-oral route.
2. Through contact with dirty hands or objects.
3. By anal-oral contact.
4. Through contaminated food and water.
In simple words: Amoebiasis is primarily transmitted via the faecal-oral route, occurring through consumption of contaminated food or water, or direct contact with unhygienic hands/objects.

🎯 Exam Tip: Remember that amoebiasis is a classic example of a disease transmitted through poor sanitation and hygiene, emphasizing the faecal-oral route.

 

(b) Malaria:
Answer: Symptoms of malaria:
1. Fever accompanied by shivering.
2. Joint pain or arthralgia.
3. Vomiting.
4. Anaemia caused due to rupture of RBCs or haemolysis.
5. Haemoglobinuria.
In simple words: Malaria is transmitted through the bite of an infected female Anopheles mosquito, which transfers Plasmodium parasites to humans. Its symptoms include fever, shivering, joint pain, and anemia.

🎯 Exam Tip: Clearly state the vector (female Anopheles mosquito) for malaria transmission and highlight the cyclical fever as a key symptom.

 

(c) Ascariasis:
Answer:
1. Unsafe and unhygienic food and drinks contaminated with the eggs of Ascaris are the main mode of transmission.
2. Eggs hatch inside the intestine of the new host.
3. The larvae pass through various organs and settle as adults in the digestive system.
In simple words: Ascariasis is transmitted when a person ingests food or drink contaminated with Ascaris eggs. The eggs hatch in the intestine, and the larvae migrate through the body before maturing into adult worms in the digestive system.

🎯 Exam Tip: Focus on the transmission route of Ascaris (ingestion of contaminated food/water) and the migratory nature of its larvae within the host body.

 

(d) Pneumonia:
Answer:
1. Pneumonia usually spreads by direct person to person contact.
2. It is also spread via droplet infection, i.e. droplets released by infected person.
3. Using clothes and utensils of the patient.
In simple words: Pneumonia spreads through direct person-to-person contact, via respiratory droplets released during coughing or sneezing, and indirectly through shared contaminated items like clothes or utensils.

🎯 Exam Tip: Understand pneumonia transmission through both direct contact (person-to-person, droplets) and indirect contact (fomites like clothes or utensils).

 

Question 8. How does the transmission of each of the following diseases take place?
(c) Ascariasis:
Answer:
1. Unsafe and unhygienic food and drinks contaminated with the eggs of Ascaris are the main mode of transmission.
2. Eggs hatch inside the intestine of the new host.
3. The larvae pass through various organs and settle as adults in the digestive system.
In simple words: Ascariasis spreads through contaminated food and water containing Ascaris eggs, which hatch in the intestine and develop into adults in the digestive system.

🎯 Exam Tip: Focus on the lifecycle stages and transmission vectors for parasitic diseases; knowing key transmission modes is crucial for prevention questions.

 

Question 8. How does the transmission of each of the following diseases take place?
(d) Pneumonia:
Answer:
1. Pneumonia usually spreads by direct person to person contact.
2. It is also spread via droplet infection, i.e. droplets released by infected person.
3. Using clothes and utensils of the patient.
In simple words: Pneumonia is transmitted through direct contact with an infected person, airborne droplets from coughing or sneezing, and sharing contaminated personal items like clothes and utensils.

🎯 Exam Tip: Understanding droplet infection and direct contact is vital for explaining the spread of respiratory diseases like pneumonia.

 

Question 9. What measures would you take to prevent water-borne diseases?
Answer:
1. To prevent water-borne diseases, use of safe, clean and potable water is a must. Water should be filtered, then boiled and stored in covered container. If possible water purifier systems should be installed at home.
2. One should preferably use bottled water or carry our own water container while travelling.
3. Cleaning of water containers and maintaining personal hygiene near water storage is a must.
4. Megacities offer chlorinated and purified water for citizens. But villages and smaller rural set ups use river water which may be highly contaminated with pathogens. Such water should be purified before consumption to prevent water-borne diseases.
In simple words: Preventing water-borne diseases involves ensuring access to safe, purified drinking water, practicing good personal and storage hygiene, and purifying water sources, especially in rural areas.

🎯 Exam Tip: When answering questions on disease prevention, provide practical and actionable measures, covering both individual hygiene and community-level solutions.

 

Question 10. Typhoid.
Answer:
Typhoid is an infective disease caused by Gram-ve bacterium, Salmonella typhi.
(1) It is food and water-borne infection. In the intestinal lumen of infected person this bacteria is found.
(2) The bacterium has “O” - antigen, which is a lipopolysaccharide (LPS), present on surface coat and its flagella has "H" - antigen. Thus it becomes pathogenic.
(3) Signs and Symptoms of typhoid are as follows:
Prolonged and high fever with nausea, fatigue, headache.
Abdominal pain, constipation or diarrhoea. In severe cases rose-coloured rash is seen in skin. Tongue shows white coating and there is cough. Anorexia or loss of appetite is seen. In chronic cases there is breathlessness, irregular heartbeats and haemorrhage.
(4) Poor hygiene habits and poor sanitation and insects like houseflies and cockroaches spread typhoid.
(5) Typhoid is diagnosed by Widal test.
(6) Antibiotics like Chloromycetin can cure typhoid. Preventive vaccines such as oral Ty21a vaccine and injectable typhim vi and typherix against typhoid are also available. Chronic cases need surgical removal of gall bladder.
In simple words: Typhoid is a food and water-borne bacterial infection caused by Salmonella typhi, characterized by high fever, abdominal pain, and fatigue, diagnosed by the Widal test and preventable by vaccines.

🎯 Exam Tip: For disease-related questions, always mention the causative agent, mode of transmission, key symptoms, diagnosis, and prevention/treatment. Using sub-points helps structure the answer clearly.

5. Match The Following

 

Question. Match the following.
Column I
(a) AIDS
(b) Lysozyme
(c) B-cells
(d) T-helper cells
(e) Antibody
Column II
(i) Antibody production
(ii) Activation of B-cells
(iii) Immunoglobulin
(iv) Tears
(v) Immuno deficiency
Answer: (a) (v), (b) (iv), (c) (i), (d) (ii), (e) (iii)

Column I	Column II
(a) AIDS	(v) Immuno deficiency
(b) Lysozyme	(iv) Tears
(c) B-cells	(i) Antibody production
(d) T-helper cells	(ii) Activation of B-cells
(e) Antibody	(iii) Immunoglobulin

In simple words: This matching exercise connects key immune system components and conditions with their respective functions or characteristics, such as AIDS with immunodeficiency and B-cells with antibody production.

🎯 Exam Tip: For matching questions, understand the core definition or function of each term. Process each pair systematically to avoid errors.

6. Long Answer Questions

 

Question 1. Describe the structure of antibody.
Answer:
ℹ️ चित्र व्याख्या (Diagram Explanation): एक एंटीबॉडी की Y-आकार की संरचना को दर्शाने वाला चित्र, जिसमें दो भारी (H) चेन और दो हल्की (L) चेन होती हैं, जो डाइसल्फ़ाइड बॉन्ड से जुड़ी होती हैं। इसमें विशिष्ट एंटीजन-बाइंडिंग साइट्स (पैराटोप्स) और हिंज क्षेत्र भी दिखाए गए हैं जो लचीलेपन के लिए अनुमति देते हैं।
1. Antibodies are highly specific to specific antigens. They are glycoprotein called immunoglobulins (Igs.).
2. They are produced by plasma cells. Plasma cells are in turn formed by B-lymphocytes.
3. About 2000 molecules of antibodies are formed per second by the plasma cells.
4. Antibody is a 'Y'-shaped molecule. It has four polypeptide chains, two heavy or H-chains and two light or L-chains.
5. Disulfide bonds (-s-s-) hold the polypeptide chains together to form a 'Y'-shaped structure.
6. The region holding arms and stem of antibody is termed as hinge. Each chain of the antibody has two distinct regions, the variable region and the constant region.
7. Variable regions have a paratope which is an antigen-binding site. This part of antibody recognizes and binds to the specific antigen forming an antigen-antibody complex.
8. Antibodies are called bivalent as they carry two antigen binding sites.
In simple words: An antibody is a Y-shaped glycoprotein, an immunoglobulin, made of two heavy and two light polypeptide chains held by disulfide bonds; its variable regions contain paratopes that specifically bind to antigens, forming an antigen-antibody complex.

🎯 Exam Tip: Focus on the Y-shaped structure, the four polypeptide chains (H and L), disulfide bonds, and the specific antigen-binding sites (paratopes) in your description. Mentioning immunoglobulins (Igs) is also important.

 

Question 2. Vaccination.
Answer:
1. Vaccines are prepared from inactivated pathogen, in the form of protein or sugar from pathogen or dead form of pathogen or toxoid from pathogens or attenuated pathogen.
2. These when they are administered to a person to protect against a particular pathogen, it is called vaccination.
3. Vaccination 'teaches' the immune system to recognize and eliminate pathogenic organism. Because, already in the body the vaccine is injected and body has made antibodies in response to it. Thus, body is prepared before the attack, if at all it is exposed to pathogen.
4. Thus, it is an important form of primary prevention, which reduces the chances of illness by protecting people. It works by exposing the pathogen in a safe form.
5. Vaccinations control spread of diseases like measles, polio, tetanus and whooping cough that once threatened many lives.
6. Vaccination controls the epidemic outbreak of diseases, if all the people are pre-vaccinated.
7. Some hazardous diseases like smallpox and polio have been completely eradicated by the vaccination.
In simple words: Vaccination involves administering a safe form of a pathogen (or its components) to stimulate the immune system to produce antibodies, thereby providing protection against future infections and controlling disease outbreaks.

🎯 Exam Tip: Define vaccination clearly, explain how it works (immune memory, antibody production), and provide examples of diseases it has helped control or eradicate. Emphasize its role in primary prevention and public health.

 

Question 3. What is cancer? Differentiate between benign tumour and malignant tumour. The main five types of cancer
Answer:
I. Cancer: Cancer is a disease caused by uncontrolled cell division due to disturbed cell cycle.
II. Difference between benign tumour and malignant tumour:

Benign tumour	Malignant tumour
1. Benign tumour is localized and it does not spread to neighbouring areas.	1. Malignant tumour starts as local but spreads rapidly to neighbouring areas.
2. Benign tumour is enclosed in connective tissue sheath.	2. Malignant tumour is not enclosed in connective tissue sheath.
3. Benign tumour compresses the surrounding normal tissue.	3. Malignant tumour invades and destroys the surrounding tissue.
4. Benign tumours can be removed surgically.	4. Malignant tumours need further treatment after removal.
5. Except for brain tumour, benign tumours are usually not fatal.	5. Malignant tumours are fatal.
6. Benign tumours do not show metastasis.	6. Malignant tumours show metastasis.
7. Benign tumours are well differentiated.	7. Malignant tumours are poorly differentiated.
8. Benign tumours show slow and progressive growth.	8. Malignant tumours show rapid and erratic growth.

III. The main five types of cancer:
Types of Cancer : According to the tissue affected, the cancers are classified into five main types. These are as follows:
1. Carcinoma: Cancer of epithelial tissue covering or lining the body organs is known as carcinoma. E.g. breast cancer, lung cancer, cancer of stomach, skin cancer, etc.
2. Sarcoma : Cancer of connective tissue is called sarcoma. Following are the types of sarcoma osteosarcoma (bone cancer), myosarcoma (muscle cancer),
chondrosarcoma (cancer of cartilage) and liposarcoma (cancer of adipose tissue).
3. Lymphoma : Cancer of lymphatic tissue is called lymphoma. Lymphatic nodes, spleen and tissues of immune system are affected due to lymphoma.
4. Leukaemia : Leukaemia is blood cancer. In this condition, excessive formation of leucocytes take place in the bone marrow. There are millions of abnormal immature leucocytes which cannot fight infections. Monocytic leukaemia, lymphoblastic leukaemia, etc. are the types of leukaemia.
5. Adenocarcinoma : Cancer of glandular tissues such as thyroid, pituitary, adrenal, etc. is called adenocarcinoma.
In simple words: Cancer is a disease of uncontrolled cell growth. Benign tumours are localized and non-spreading, while malignant tumours invade tissues and spread (metastasize), being often fatal. Cancers are classified into types like carcinoma (epithelial), sarcoma (connective tissue), lymphoma (lymphatic), leukaemia (blood), and adenocarcinoma (glandular).

🎯 Exam Tip: Define cancer precisely and provide clear, distinct points of differentiation between benign and malignant tumours, focusing on metastasis, encapsulation, growth rate, and fatality. List and briefly describe the five main types of cancer with examples.

 

Question 4. Describe the different type of immunity.
Answer: There are two basic types of immunity, viz. innate immunity and acquired immunity.
(A) Innate immunity:
1. Innate immunity is natural, inborn immunity, which helps the body to fight against the invasion of microorganisms.
2. Innate immunity is non-specific because it does not depend on previous exposure to foreign substances.
3. Innate immunity mechanisms consist of various types of barriers such as anatomical barriers, physiological barriers, phagocytic barriers and inflammatory barriers. They prevent entry of foreign agents into the body.
(B) Acquired immunity:
1. The immunity that an individual acquires during his life is called acquired immunity or adaptive immunity or specific immunity. It helps the body to adapt by fighting against specific antigens hence it is called adaptive immunity. Since it is produced specifically against an antigen, it is called specific immunity.
2. Acquired immunity takes long time for its activation.
3. This type of immunity is seen only in vertebrates.
4. Due to acquired immunity, the body is able to defend against any invading foreign agent.
In simple words: Immunity is broadly divided into innate immunity, which is an inborn, non-specific defense providing immediate protection, and acquired immunity, which is a specific, adaptive defense developed over a lifetime through exposure to pathogens.

🎯 Exam Tip: Clearly distinguish between innate (non-specific, inborn, immediate) and acquired (specific, adaptive, memory-based) immunity. Mention key characteristics and examples of barriers for each type.

 

Question 5. Describe the ill-effects of alcoholism on health.
Answer:
1. Alcohol in any form is toxic for the body. Hence as soon as alcohol is consumed, the liver tries to detoxify it.
2. In low doses it acts as a stimulant but in high dose, it acts on central nervous system, especially the cerebrum and cerebellum. Still higher dose can induce a comatose condition.
3. Alcohol affect the gastrointestinal tract by causing inflammation and damage to gastric mucosa. Ulceration and painful condition arises in alcoholics.
4. Excessive doses of alcohol induce vomiting.
5. The worst effect of alcohol is on liver causing diseases like cirrhosis.
6. Alcohol induces hypertension and cardiac problems.
7. Apart from physical effect, it causes deterioration of mental health and emotional well-being.
8. Alcoholic person cannot think due to numbness in his/her cerebrum.
9. The social health is greatly affected as the alcoholic can cause problems to his family, friends and society in general.
In simple words: Alcoholism profoundly damages health, leading to liver cirrhosis, cardiovascular issues, gastrointestinal problems, and central nervous system depression, while also impairing mental well-being and causing significant social disruption.

🎯 Exam Tip: Detail the effects of alcoholism across various body systems (liver, nervous, cardiovascular, digestive) and also include mental and social impacts. Focus on specific conditions like cirrhosis and hypertension.

 

Question 6. In your view, what motivates the youngsters to take to alcohol or drugs and how can this be avoided?
Answer:
I. Taking drugs or alcohol:
1. Youngsters are at the vulnerable age, where they lack the planning about their future.
2. If they fall into bad company or are facing parental neglect, they get hooked on to alcohol or drugs.
3. Some common causes for addiction among youngsters are insufficient parental supervision and monitoring or excessive pressure and expectations from them. Lack of communication between an adolescent and parents.
4. Poorly defined rules for the family. Continuous family conflicts.
5. Favourable parental attitudes towards alcohol and drug uses. Many a times, at home children are exposed to such habits.
6. Inability to cope up with present and hence switching to the addictions. Risk taking behaviour which is common among youngsters.
II. Methods/measures to avoid drug abuse:
1. There should be complete acceptance for the child, because the adolescent phase is the most crucial phase when the children should be treated with love, care and respect.
2. Many physical, hormonal and psychological transformations are taking place in this phase. Therefore child suffers from stressful situation.
3. Wrong company and bad influence of peer group can trap the child in bad addictive habits. Thus, family should be supportive and communicative to help such children.
4. The sexual thoughts should be sublimed by channelizing energy into healthy pursuits like sports, reading, music, yoga and other extracurricular activities.
5. Ill-effects of drugs or alcohol should be told to youngsters.
6. Education and counselling can control the children from getting hooked on to the addictions.
In simple words: Youngsters turn to drugs/alcohol due to vulnerability, peer pressure, lack of parental supervision, family conflicts, or inability to cope; this can be avoided through supportive family environments, open communication, healthy diversions, and awareness about ill-effects.

🎯 Exam Tip: Structure your answer into two parts: causes/motivations and prevention/avoidance measures. Provide diverse reasons, including psychological, social, and family factors, and offer practical, holistic solutions.

 

Question 7. Do you think that friends can influence one to take alcohol/drugs? If yes, how may one protect himself/herself from such an influence?
Answer:
Friends can influence one to take alcohol and drugs, if a boy or girl is timid and non-communicative with his or her parents and teachers. It also depends on the personality of the individual. In the adolescent age, many fall in trap due to such peer pressure. The confusion in the mind and role of hormones playing on the psyche and thought process makes one unable to understand the hazards of such habits. Also there is curiosity to do these experimentations due to bad influence of media.
If there is complete trust and friendship with sensible parents, then such influence does not work. One should protect himself or herself by a strong denial. Communicating such incidents to an elder in whom a boy or girl can confide, is very important. One should tell his or her friends about the ill-effects of alcohol and drugs. He should be made aware of these aspects that he or she has learnt in this lesson.
In simple words: Yes, friends can significantly influence drug/alcohol use, especially during adolescence due to peer pressure and developmental changes; protection involves building trust with parents, assertive refusal, confiding in elders, and educating friends about the harmful effects.

🎯 Exam Tip: Acknowledge the role of peer influence, particularly in adolescence. Emphasize the importance of strong family bonds, communication with trusted adults, and assertive communication skills for self-protection against such influences.