Human Health And Disease - Class 12 Medical Biology - Extra Questions

Common cold is a kind of .......... disease. (Infectious, Non-infectious)

The common cold is a viral disease. It is an air-borne disease that spreads from person to person by sneezing, coughing, etc. It affects the upper respiratory system. Hence, it is an infectious disease. 
So, the answer is infectious.


Give any two examples of non-infectious diseases:

Noninfectious diseases cause mostly by physiological conditions. And does not have an infectious agent involved in the cause of dysfunction in the body. Diabetes and goiter are examples of non-infectious diseases.


Define health.

Health is the state of complete physical, mental and social well being.


Give an example of immune deficiency.

Immuno deficiency disease is the AIDS caused by the HIV virus. HIV virus infects the immune cell (T cell) and suppresses its activity.


Why is using tobacco in any form injurious to the health ? Explain.

Major stimulatory component of tobacco is Nicotine. It is highly poisonous. The amount present in one cigar can be fatal, if injected intravenously. Benzpyrene present in tobacco smoke is carcinogenic. Therefore, it is very injurious to health taken in any form. 


Write the scientific names of the causal organisms of elephantiasis and ringworm in humans. Mention the body parts affected by them.

Causative agent of elephantiasis is Wuchereria bancrofti  and the commonly affected body part is genital organs.
Causative agents of ringworm in humans are: Trichophyton which infects the skin, hair and nail, Microsporum which infects skin and hair, Epidermophyton which infects the skin and nail.


State a method of cellular defense which works in plant cell.

The method of cellular defense which works in all eukaryotic organisms is RNA interference - It is a biological process in which the RNA molecule inhibits the gene expression/translation by neutralizing the mRNA molecule which is targeted for inhibiting the expression. This method is useful especially for defense against RNA viruses and transposons in plant cells.


Give any two examples of infectious diseases.

Infectious diseases are those diseases that can be easily transmitted from one person to another. They can be caused by bacteria, viruses, fungi, or protozoans. Examples of infectious diseases include Chickenpox, influenza (common flu), etc.


The health of an organism depends upon the surrounding environmental conditions. Explain giving reasons.

Health depends on three major factors-  physical, social and mental. If the environment is contaminated it adversely affects the physical health of the organism residing in the particular area. For example- if there are unhygienic conditions in surrounding area, it may pose a threat to the inhabitants of the particular area.


Differentiate between chronic disease and acute disease.

Chronic diseaseAcute disease
It lasts for long period of time.It lasts for short period of time.
It develops over a period of time.It develops suddenly and symptoms are intense.
Examples include cancer, heart disease, tuberculosis, arthritis, diabetes. Examples include cold, influenza, cholera, Typhoid, cough. 
They cause severe long term effects.It does not cause long term or ill effects.


Give some basic characteristics of chronic diseases.

The basic characteristics of chronic diseases are:
  • These last for a long time, even as much as a lifetime.
  • These cause drastic long term effects on human health.
  • Patients do not recover completely.
  • Examples include elephantiasis, cardio diseases, tuberculosis, diabetes, arthritis, cancer, etc.


Name the causative organisms for the following diseases.
(i) Elephantiasis
(ii) Ringworm
(iii) Amoebiasis

  1. Elephantiasis refers to a parasitic infection that causes extreme swelling in the arms and legs. The disease is caused by the filarial worm, which is transmitted form human to human via the female mosquito, when it takes a blood meal. The parasite grows into an adult worm that lives in the lymphatic system of humans. Examples of nematode parasites that cause lymphatic filariasis includes Wuchereria bancrofti, Brugia malayi and Brugia timori. The larvae (microfilariae) of the parasite are taken up by the mosquito when it feeds.
  2. Ringworm is a skin infection due to a fungus. Often, there are several patches of ringworm on your skin at once. Ringworm is common, especially among children. However, it may affect people of all ages. It is caused by a fungus, not a worm like the name suggests. Many bacteria and fungi live on your body. Some of these are useful, while others can cause infections. Ringworm occurs when a type of fungus called tinea grows and multiplies on your skin.
          Ringworm can affect the skin on your:
                   Beard -- Tinea barbae
                   Body -- Tinea corporia
                   Feet -- Tinea pedis (also called athlete's foot)
                   Groin area -- Tinea cruris (also called jock itch)
                   Scalp -- Tinea capitis.
    3. Amoebiasis, or amebiasis, refers to infection caused by the amoeba Entamoeba histolytica. The term entamoebiasis is occasionally seen but is no longer in use; it refers to the same infection. A gastrointestinal infection that may or may not be symptomatic and can remain latent in an infected person for several years, amoebiasis is estimated to cause 70,000 deaths per year world wide. Symptoms can range from mild diarrhoea to dysentery with blood and mucus in the stool. E. histolytica is usually a commensal organism.  Severe amoebiasis infections (known as invasive or fulminant amoebiasis) occur in two major forms. Invasion of the intestinal lining causes amoebic dysentery or amoebic colitis.


Differentiate between infectious and non-infectious diseases.

 Infectious diseases
Non-infectious diseases
 
These occur due to external (extrinsic) factors.These generally occur due to internal (intrinsic) factors.
These are cause by the attack of pathogens (viruses, bacteria, fungi, protozoans, worms)These are caused by factors other than living pathogens.
 Infection is transmitted through direct contact (physical contact, sexual contact) or through medium (air, water, food, insects etc.)Infection is not transmitted through direct contact or through medium except in medium hereditary diseases where it occurs from parent offspring.


Explain mode of transmission of Hepatitis

(a) Hepatitis A spreads through contaminated food and water.
(b) Hepatitis B is transmitted by contact with infected person's secretions such as saliva, sweat, tears etc., and also blood.


Classify the following diseases as infectious or non-infectious.
(i)AIDS (ii) Tuberculosis (iii) Cholera (iv)High blood pressure (v) Heart disease (vi) Pneumonia (vii) Cancer

(i) Infectious (ii) Infectious (iii) Infectious (iv) Non-infectious (v) Non-infectious (vi) Infectious (vii) Non-infectious


Name the target organs for the following diseases:
(i)   Hepatitis
(ii)  Pneumonia
(iii) Fungal disease

(i) Hepatitis causes severe damage to the liver. The virus causes inflammation of the liver and yellowing of the skin and sclera of the eye. (ii) Pneumonia is an infection in one or both lungs. It can be caused by fungi, bacteria, or viruses. (iii) Fungal infection targets skin( mainly). nails or lungs.


"Health is wealth". What is the significance of this proverb?

This proverb means that health is the greatest asset for a human being and as such, it is not worth living without good health. It means that even if a person has too much wealth or all different advantages in life, his life will not be worth living if his health is weak. So, this proverb tries to imply the importance of good health.


Mention the modes of transmission of tuberculosis..

Tuberculosis is transmitted directly through sputum of infected person by sneezing, coughing or spitting and indirectly also (air borne disease).


What is poor health?

Poor health is a condition of inability to perform physically, mentally or socially of what is required from a person.


Define acute and chronic diseases.

Acute diseases: These diseases last for only short periods of time and are severe. Acute diseases do not cause long-term bad effects on health. Examples of acute diseases are cold, cough, typhoid, cholera etc.
Chronic diseases: These diseases last for a long time, even can last for a lifetime. Chronic diseases have drastic long-term effects on patient's health. Examples of chronic diseases are arthritis, cancer, AIDS, etc. 


What is a disease? How many types of diseases have you studied? Give examples. 

Any deviation from the normal functioning or state of incomplete physical or mental well being is called disease. Disease is a condition that impairs the proper functioning of the body or one of its parts. The diseases may be of different types, such as :
(a) Acute disease: Which lasts for short duration. Example: Common cold. jaundice
(b) Chronic disease: Which lasts for very long period. Example: Tuberculosis, diabetes. 
(c) Infectious disease: Which can be transmitted from one individual to another directly or indirectly. Example: Influenza, tuberculosis
(d) Non-infectious disease: Which are not transmitted from one individual to another. Example: Cancer, marasmus.


What are the immunisation programmes available at the nearest health centre in your locality? Which of these diseases are the major health problems in your area?

At the nearest health centre in our locality, the following immunisation programmes are available:
(i) For preventing polio.
(ii) For preventing tetanus, diphtheria, and whooping cough
(iii) For preventing tuberculosis
(iv) For preventing measles.
Occasionally, children suffer from measles in our area.


A doctor/nurse/health-worker is exposed to more sick people than others in the community. Find out how she/he avoids getting sick herself/himself.

Explanation-
  • The doctors, nurses, and health workers are exposed to sick people more every day.
  • There are some basic good practices that they follow which keep them away from getting sick.
  • It involves proper sanitization of the hospital, sterilization of equipments, wearing masks and gloves while coming in contact with the patients, proper disposal of the medical wastes are some of the practices that are followed by the medical workers to keep them safe from being getting contamination.


A baby is not able to tell her/his caretakers that she/he is sick. What would help us to find out.
(a) That the baby is sick?
(b) What is the sickness?

Baby is too small to complain on its own. During such cases, following symptoms should be checked for, as this are the common symptoms seen when the baby is ill. They are:
(a) Increase in the body temperature.
(b) Constant crying.
(c) Watering of the eyes.
(d) Not eating food.
(e) Vomiting and diarrhoea.

Sickness is a condition used to refer to physical illness or disease.


Name the plant source of ganja. How does it affect the body of the abuser?

Cannabis (marijuana) is the plant source of ganja. Those who taken large doses of marijuana  may experience an acute psychosis, which include hallucinations, delusions and a loss of sense of personal identity.


 Describe infectious and noninfectious disease.

Infectious diseases-
Infectious diseases are the diseases caused by micro-organisms like bacteria, virus, fungi and protozoa. 
They are spread from one person to another through agents like contaminated air, food, water, vectors etc. are called as communicable diseases.
Non-infectious diseases-
Non-infectious diseases are the diseases caused by genetic abnormalities, malfunctioning of organs, environmental factors etc.
They do not spread from one person to another and are called as non-communicable diseases.


What are the various routes by which transmission of the Human Immunodeficiency Virus takes place?

Human Immunodeficiency Virus (HIV) causes AIDS (Acquired Immuno-Deficiency Syndrome). It is spread via following modes of transmission:
1. From an infected mother to her children via the placenta.
2. Unprotected sex (without the use of condoms etc.) with the infected person.
3. Sharing of syringes, needles, blades etc. of an infected person.
4. Transfusion of infected person's blood to a healthy person.


HIV is dreadful due to the enzyme present in it. Justify.

There is an enzyme in the HIV which is known as reverse transcriptase. The enzyme is responsible for the conversion of the viral RNA to DNA which is then integrated into the human DNA. This integration of the viral DNA in the human DNA prevents the identification of the foreign DNA by the immune cells. Hence, there is no production of antibodies against the foreign DNA material. The persons who are suffering from HIV last stage of infection are said to have the disease AIDS. 


Name the causative agent of Elephantiasis.

Wuchereria bancrofti is the organism which causes filariasis in humans and the parasite completes its life cycle in two host which are humans and culex mosquitoes. 


Describe the structure of HIV with diagram.

HIV is the abbreviation form of the Human immunodeficiency virus, The shape is of the virus is spherical. The virus is composed of a capsid core which contains the genetic material that has been surrounded by a protein envelope. The protein envelope has many spikes of the glycoprotein. The outer part of glycoprotein called gp120 is attached to the gp41 which is the inner part of the glycoprotein. The envelope of HIV also contains other proteins including some HLA antigens (Human Leucocyte Antigen). The genome of HIV contains two helices of RNA molecules in folded form. The enzymes reverse transcriptase is present which is responsible for the conversion of the RNA to form the DNA. There is another enzyme called as integrase which helps the viral genome to incorporate in the host cell.
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Mention the type of immunity acquired by a baby through breast-feeding.

Immunity acquired by a baby through breastfeeding is passive acquired immunity, as already formed antibodies in the mother's body are transferred to the baby through breast milk.


What is an allergy?

Allergies are the reactions or the response given to the antigens which are in the form of particles. Allergy is also termed as hypersensitivity. The substances which can cause allergies are called as allergens. . IgE antibodies are produced and histamine is released by certain cells which causes reddening and inflammation during allergies. 


_________ virus causes AIDS.

Acquired Immunodeficiency syndrome (AIDS) is caused by Human immunodeficiency virus (HIV)


Write the full form of H.I.V.

Human Immuno Deficiency Virus or HIV is the RNA virus that causes AIDS by suppressing the activity of immune cells.


Sketch and label the 'Structure of HIV'.

The image represents the labelled image of structure of HIV. 
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Write the name harmful chemical substances of tobacco.

Nicotine is the harmful chemical present in the tobacco. It is a stimulator of the parasympathetic system and is responsible for addiction. 


Complete the table appropriately.
      Symptoms        Disease        Reason
Pain in lower abdomen, urinary block, back pain, vomiting and giddinessa)                                                        b)                                                              
c)                                            Nephritis                            d)                                                  

SymptomsDiseaseReason
Pain in lower abdomen, urinary block, back pain, vomiting and giddinessa) Kidney Stoneb) Calcium salts such as calcium oxalate and calcium phosphate sediment in the kidney and ureter as grains.
c) Dark colored and turbid urine, back pain and fever, swelling of feet, ankles and faceNephritis       d) Streptococcus infection, autoimmune deficiency syndrome, infection of the urinary bladder


Mention whether the following statements are true (T) or false (F)
AIDS is caused by a bacterium T/F

The given statement is false as AIDS is caused by the human immunodeficiency virus (HIV) and not by bacterium


Find the odd one out:
Proteins, carbohydrates, fats, minerals, cancer.

Cancer is a disease while others are nutrition of the food.
The odd one is Cancer.


Given appropriate biological/ technical terms for the following:
The type of immunity that exists in our body due to our genetic makeup.

Innate immunity exists in our body due to our genetic makeup. It is also called as native immunity.


Describe AIDS disease on the basis of following points -
i) Name of pathogen
ii) Test of confirmation of disease
iii) Main symptoms of disease
iv) Ways of prevention
v) Diagram of replication of retrovirus.

AIDS stands for Acquired Immuno Deficiency Syndrome. It is a deficiency of immune system, acquired during the lifetime of an individual indicating that it is not a congenital disease.
  • Name of pathogen: AIDS is caused by Human Immunodeficiency Virus (HIV). This virus belongs to a group of virus called Retrovirus which have an envelope consisting of a lipid bilayer derived from host cell membrane and projecting knob like glycoprotein spikes with pedicle formed of a virus-coded glycoprotein. This envelope encloses the RNA genome.
  • Test of confirmation of disease: A widely used diagnostic test for AIDS is Enzyme-Linked Immuno-Sorbent Assay (ELISA). The western blotting test is employed for confirmation of ELISA positive cases.
  • Main symptoms of the disease: There is always a time lag between the infection by HIV virus and appearance of AIDS symptoms. This period may vary from a few months to many years (usually 5-10 years). The infected person suffers from fever, diarrhoea and weight loss. A patient becomes so immunodeficient that he/she is unable to protect himself/herself against these infections.
  • Ways of prevention: As AIDS has no cure, prevention is the best option. The following steps may help in preventing the AIDS:
  1. Proper blood testing to make blood safe from HIV.
  2. Ensuring the use of only disposable needles and syringes in public/private hospitals and clinics.
  3. Free distribution of condoms and advocating safe sex.
  4. Controlling drug abuse.
  5. Promoting regular checkup for HIV in the susceptible population.
  6. People should be educated about AIDS.

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Name the following:
A viral disease caused due to unhealthy sexual contact.

Acquired Immuno Deficiency Syndrome (AIDS) is a viral disease which is caused by the Human Immunodeficiency Virus (HIV). This virus affects a person when there is an unhealthy sexual contact.
It can also be caused by the sharing of needles in hospitals or in drug addicts. It's basically spread by sharing body fluids. Having multiple partners for sex also leads to an increased chance of suffering from AIDS.
The immune system of the body is crushed in this disease and the person suffers from many diseases simultaneously.


Define Allergy. Give any two symptoms of Allergic reactions.

The damaging immune response of the body to a certain substance (allergen) due to hypersensitivity is called as an allergy.
The following are the symptoms of allergic reaction:
1. Irritation of eyes and nose
2. Shortness of breath
3. Rashes


Which disease weakens the body's defence system against infections?

HIV is a virus that targets and alters the immune system, increasing the risk and impact of other infections and diseases. The disease caused is AIDS.


How do cytokine barriers provide innate immunity in humans?

Cytokines play an important role in innate immunity after the antigen passes through barrier protection. It can directly block the growth of viruses by the production of interferons or they could activate inflammatory cells (NK cells, phagocytes, etc.) which destroys the antigen 
Thus, the cytokine barriers provide innate immunity in humans by affecting the immuno-modulatory responses of the body and direct interaction with the particles/microbes


Would you predict patients with AIDS to develop fever in response to an infection?

Yes, fever is a very common complaint among HIV patients. It may occur at any point during the viral infection and it also remains as a symptom to identify HIV infection.


Enlist the basic modes of transmission of AIDS

AIDS is a disease caused by HIV infection which damages the immune system of an organism. It is a communicable disease and transmited by following ways:
1. Transfusion (transferring blood from one person to another) of HIV+ blood causes HIV infection to the healthy person.
2. Use of HIV infected instruments like syringes, needles, surgical and dental instruments spread the disease.
3. HIV infected mother spreads the disease to her child during pregnancy.
4. The body fluids like semen, blood, secretion of uterus contains high amount HIV. Direct contact (having sexual relationship) with these fluids causes HIV.


Write very briefly about BCG

Bacillus Calmette-Guérin (BCG) vaccine is vaccine used to treat tuberculosis. The BCG vaccine is an injection given to children who have a higher risk of catching TB. The BCG vaccine helps the human body immune system fight the germs that cause TB and helps stop them from getting serious TB disease. The BCG vaccine is FREE for children under five years of age who have a higher risk of catching TB


Mention whether the following statements are true (T) or false (F)
AIDS is caused by a fungus T/F

Acquired Immunodeficiency Syndrome (AIDS) is a viral infection caused by the human immunodeficiency virus (HIV) and many fungal infections were encountered in this diseased patient
So the given statement is false


Name one plant and the addictive drug extracted from its latex. How does this drug affect the human body?

Heroin, commonly called smack is chemically diacetylmorphine which is a white, odourless, bitter crystalline compound. This is obtained by acetylation of morphine, which is extracted from the latex of poppy plant Papaver somniferum. Generally taken by snorting and injection, heroin is a depressant and slows down body functions.


Application based questions.
Identify A, B, C and Din the following table
Scientific name of the
source plant
DrugHarmful effects/Human 
body part affected
Papaver somniferumADepressant/slows body function
Cannabis sativacarinabinoidsB
Erythroxylum cocaCD

A = Morphine,  B = Affects on the cardiovascular system of the body,  C = Cocaine.D = Potent stimulating effect on the central nervous system, producing a sense of euphoria; excessive dosage causes  hallucinations.


Name the plant source of the drug popularly called smack. How does it affect the body of the abuser?

Heroin, commonly called smack is chemically diacetylmorphine which is a white, odourless, bitter crystalline compound. This is obtained by acetylation of morphine, which is extracted from the latex of poppy plant Papaver somniferum. Generally taken by snorting and injection, heroin is a depressant and slows down body functions.


Write scientific names of the two species of filarial worms causing filariasis. How do they affect the body of infected persons ? How does the disease spread?

  • Lymphatic filariasis is caused by infection with parasites, Wuchereria bancrofti, Brugia malayi.  
  • These worms occupy the lymphatic system, including the lymph nodes; in chronic cases, these worms lead to the syndrome of elephantiasis.
  •  Infection occurs when filarial parasites are transmitted to humans through mosquitoes. 
  • Infection is usually acquired in childhood causing hidden damage to the lymphatic system.


Explain what is meant by metastasis?

A phenomenon in which cancer cells spread to distant sites through body fluids to develop secondary tumor is called metastasis.


Explain the role of innate immunity in protection from infectious diseases.

Innate immunity is the first line of defence of the body against any invading pathogen and provides immediate immunity to the body. It comprises of the physical barriers and their secretions such as the skin and the mucous lining of the gastrointestinal tract and the respiratory tract that prevents any foreign pathogen from invading the body and the cells such as the macrophages, neutrophils, monocytes, mast cells etc. that are involved in phagocytosis of the pathogen, activation of the complement system, secreting cytokines or histamines etc. which in turn help attack or destroy the invading pathogen and initiate repair processes.


What is neoplasm?

Neoplasm is a type of excessive growth, called neoplasia of the tissue. Its growth is excessive, abnormal when compared to the surrounding tissue. Resulting in the formation of tumor which may or may not be malignant.


How does a vaccine affect immunity?

A vaccine helps enhance the immune system of a person by helping them generate antibodies against a disease without actually causing the disease. The process involves injecting the person with an attenuated/ heat killed or modified form of the pathogen which is not capable of causing the disease but generates antibodies in response. This causes the immune system to be active in its response against the pathogen for the disease and the immune system is capable of generating faster responses against the pathogen on subsequent infection by the disease organism.  


How do cellular barriers and cytokine barriers provide innate immunity in humans?

The innate immune system includes:
 Physical Barriers - such as skin, the gastrointestinal tract, the respiratory tract, eyelashes etc whereas Cytokines play an important role in the innate response by acting against the invading agent during the beginning stages of infection in human beings.


Write the scientific names of the two species of fiarial worms causing filariasis.

Filariasis is a disease caused by infection with nematodes (roundworms). Two species of filarial worms causing filariasis are: Wuchereria bancrofti (causes lymphatic filariasis) and Mansonella perstans (causes serous cavity filariasis).


How do macrophages in the human body act as 'HIV factory'?

Macrophages in the human body act a reservoirs of  HIV. HIV infects the cells of the body and replicates in the host cells generating more HIV. However, the macrophages are latent and act as storehouses of HIV that do not replicate in these cells. When HIV are present in the cells in a latent form, the virus in the cells can hide in the cells for a long time(e.g: when a patient is taking medicines to destroy the virus).


Study the diagram showing replication of HIV in humans and answer the following questions accordingly:
Write the chemical nature of the coat $$'A'$$.
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The coat A of HIV is formed of a viral protein called capsid protein. It is in the form of a dimer. So, the chemical nature of the coat 'A' is protein.


Which phylum has a patches of mesodermal cells?

Patches of mesodermal cells are present in pseudocoelomates. They have false coelom or body cavity. In these organisms, the space between body wall and alimentary canal is filled with patches of mesodermal cells. Examples include phylum Aschelminthes.


A person in your colony has recently been diagnosed with AIDS. People/ residents in the colony want him to leave the colony for the fear of spread of AIDS.
Write the symptoms and the causative agent of AIDS.

Causative agent of AIDS is Human Immuno deficiency Virus(HIV).
Symptoms of AIDS appears after incubation period that are :
  • Bouts of fever
  • Diarrhea
  • Weight loss
  • Infections that can be easily overcome in normal condition become fatal for infected person.


Study the diagram showing replication of HIV in humans and answer the following questions accordingly:
Name the two different cells the new viruses $$'E'$$ subsequently attack.
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The new viruses "E" subsequently attacks helper T-lymphocytes or enters into new macrophages.


HIV.

HIV stands for human immunodeficiency virus that causes HIV infection and subsequently, acquired immunodeficiency syndrome or AIDS.


What do you mean by immunization?

Immunization is the process in which either already synthesized immunoglobulins against a specific infection are introduced into the body of a person or when the person develops his/her own immunoglobulins after the process of vaccination. In the process of vaccination, vaccines that are made of the weak or attenuated pathogen or the pathogenic proteins are administered into the body of a person and in response to it, the person develops immunization. 


Explain the principle of immunization. 


 
Immunization is the process whereby a person is made immune or resistant to an infectious disease, typically by the administration of a vaccine. Vaccines stimulate the body’s own immune system to protect the person against subsequent infection or disease.
This happens because when the immune system first sees an infectious microbe, it responds against it and then remembers it specifically. So the next time that particular microbe, or its close relatives enter the body, the immune system responds with even greater vigor. This eliminates the infection even more quickly than the first time around. This is the basis of the principle of immunisation.


What is cancer?

  • Cancer can be described as the uncontrolled growth of abnormal cells in the body which destroys the body tissues.
  • The old cells of the body do not die instead, they grow out of control forming new, abnormal cells. 
  • These abnormal cells form a mass of tissue called a tumor (exception leukemia- no tumour is formed).
  • There are five main categories of cancer:-
1. Carcinomas - develop in the skin or epithelial tissues that line the internal organs.
    2. Sarcomas- develop in the bone, cartilage, fat, muscle or other connective tissues.
      3. Leukemia - develops in the blood and bone marrow.
        4. Lymphomas- develop in the immune system.
        5. Central nervous system cancers develop in the brain and spinal cord


        State any two conditions essential for being free of disease.

        Two main conditions essential for being free of disease-
        1. Personal hygiene and regular exercise.
        2. Drinking clean water and taking balanced diet.


        Anthrax is caused by_______.

        Anthrax is caused by Bacillus anthracis. These bacteria can survive in soil in the form of spores. The symptoms include blisters, skin ulcers, diarrhea etc.



        What is the function of mast cells?

        Mast cells are part of immune system. They play very important role in allergy and anaphylaxis. They are also involved in wound healing, immune tolerance, blood–brain barrier function. They also help to connect innate and adaptive immunity to fight against pathogens.


        Read the following
        i) Common allergens are animal dander, dust, pollen and mites. 
        ii) Allergy reactions are sneezing, watery eyes, running nose and difficulty in breathing.
        iii) For determining cause of allergy very small doses of possible allergens are injected to the patient.
        iv) Symptoms of allergy can be reduced by using drugs like histamine, adrenalin and steroids. 

        All the statements are correct 


        What is immunisation? How do vaccination help in preventing diseases?

        Immunisation is a process of getting immunized against a particular disease, through vaccines made up by using a weak and attenuated form of an immunogen to get protection against a disease, most cost-effective and preventive tool for controlling infectious diseases.
        When B lymphocytes detect the heat killed or an antigen present in the vaccine, two types of cells will form against the  antigen :
            -Plasma B cells
            -Memory B cells
        Plasma B cells produce antibodies which elicit a response against a specific antigen known as the primary response. It takes several days to build the maximum number of antibody in blood around 14 days.
        Memory B cells will form after a couple of weeks which provide a long-term protection to the body.
        Heat-killed antigens in the vaccine are not that much strong to cause disease but strong enough for the immune system to produce antibodies against it and formed memory B cells to develop immunity against future infections.


        Diseases transmitted from an infected person to a healthy person are called ________.

        Diseases transmitted from an infected to a healthy person are called communicable (contagious or non-contagious) diseases.
        These diseases are caused by pathogens (mainly bacteria and viruses) which can be transmitted through physical contact, air, water, food, and vectors. For example, tuberculosis, chickenpox, influenza, etc.


        Why it is difficult to create a vaccine against HIV?

        Vaccines work on memory B cells and T cells which remember the pathogen such as virus and bacteria when they are first given artificially.
        But this is not the case with HIV. HIV is a retrovirus responsible for AIDS and it continuously mutates and changes its structural form so memory immune cells cannot be generated as it appears a new virus every time.
        Hence the vaccine cannot be designed for HIV.


        What is the basis of principal of immunisation?

        The fundamental guideline of immunization is that on the organization of immunization, the body begins creating antibodies against it with the end goal that individual is ensured shape illness. Body recalls the irresistible specialists and memory cells are shaped which can quickly create antibodies on further introduction to the irresistible operators.


        What does a vaccine consist of ? How does a vaccine work?

        Vaccine consist of dead or killed or inactivated or live versions of disease-causing bacteria, virus or toxin. These are also known as a vaccine antigen. Both killed and live vaccines work by stimulating the immune system so it thinks it's being attacked by the active germ. It is a biological preparation that provides active acquired immunity to a particular disease.  White blood cells – APCs, B cells, and T-cells – recognize, destroy and “remember” this version of the pathogen. That way, the immune system can quickly recognize and destroy this harmful microorganism later on. A vaccine is essentially a pathogen-imposter.


        Which disease is more harmful - acute or chronic disease? Why ?

        Chronic disease is more harmful than acute because acute diseases last for very short period of time but chronic diseases is long term illness i.e the disease that last for a long time, even as much as a lifetime. Examples of common chronic diseases are cancer, arthritis, diabetes etc.Chronic diseases  have very drastic long-term effects on people’s health as compared to acute diseases. 


        Write the name of a virus that causes AIDS.

        AIDS stands for acquired immune deficiency syndrome. It is a disorder of the cell-mediated immune system of the body. There is a reduction in the number of helper t cells which stimulate antibody production by b cells. This results in the loss of natural defense against viral infection. This is caused by the HIV virus which stands for Human Immunodeficiency Virus. Once the host is infected with the HIV virus the symptoms may or may not be visible at first but gradually with time the immunity weakens.


        Define allergy.

        • Allergy is a condition of the immune system.
        • It is caused by the hypersensitivity of the immune system to harmless foreign substances as they enter the body.


        Name a disease which are caused by virus, bacteria and protozoa . Any two

         Agents Virus Bacteria Protozoa
         Diseases caused1. HIV/AIDS,
        2.common cold        		 1. Tuberculosis
        2. Typhoid        		 1. Malaria
        2. Dysentery.


        Explain the following statement:
        Being disease free is not the same as being healthy.

        Being healthy means that you are well physically, socially and mentally. Therefore, simply being disease free does not mean that you are healthy, because you may suffer socially e.g. be unwilling to interact with others. Diseases only usually refer to physical health.


        Name the disease caused by Epidermophyton.

        Epidermophyton floccosum is a filamentous fungus that causes skin and nail infections in humans. It can lead to diseases such as tinea pedis (athlete's foot), tinea cruris, and onychomycosis.


        Differentiate between health and disease.

        • Health is referred to as the state of mental, physical, and psychological well-being of an individual.
        • The disease is the condition of abnormal dysfunctioning of the mental and physical states thus, leading to illness in a particular individual and does not take into account the society or community.
        Health differs from disease by the absence of any discomfort in the body which may be because of external or internal factors.


        Suggest two conditions necessary for having good health.

        • Good health can be defined as the absence of disease and infirmity along with a state of complete physical, mental and social well-being of the body and mind.
        • Two conditions necessary for having good health are:-
        1) Having a nutritious and balanced diet.
        2) Relaxation of body and mind by exercising or by doing yoga.


        What is AIDS? Which microbe is responsible for AIDS infection ? State one mode transmission of this disease.Explain in brief one measure for the prevention of AIDS 

        • HIV stands for human immunodeficiency virus. It harms your immune system by destroying the white blood cells that fight infection. AIDS stands for the acquired immunodeficiency syndrome. It is the final stage of infection with HIV. Not everyone with HIV develops AIDS.
        • HIV most often spreads through unprotected sex with an infected person. It may also spread by sharing drug needles or through contact with the blood of an infected person. 
        • Strategies to reduce the risk of HIV infection include , never sharing needles, and using condoms during sexual intercourse



        What questions would you ask the doctor who visited you school on world AIDS day?

        I will ask following questions to doctor visiting our school on world AIDS day:-
        • What is the difference between HIV and AIDS?
        • How is HIV transmitted?
        • What are the ways that HIV cannot be transmitted? 
        • Can a woman living with HIV pass the virus on to her baby?
        • How does HIV testing work?
        • How often should a person be tested?
        • What can we do to reduce stigma against people living with HIV?


        Describe the various type of barriers of immunity.

        • The human immune system includes three lines of defence against foreign invaders: 1) physical and chemical barriers, 2) nonspecific resistance, and 3) specific resistance. 
        • The first line of defence is the physical and chemical barriers, which are considered functions of innate immunity.
        • Physical barriers include skin, the gastrointestinal tract, the respiratory tract, the nasopharynx, cilia, eyelashes and other body hair. 
        • Very few microorganisms can penetrate intact skin; instead, invaders usually enter through wounds or by being injected, such as by mosquito bites. Skin wounds heal rapidly to reestablish the protective barrier.
        • A complex population of normal skin bacteria tends to exclude new invaders, while antimicrobial molecules in sweat can kill many would-be invaders.
        • The defence of the intestine centers largely on the presence of the huge and immensely complex normal commensal microbiota. Potential invaders may be unable to colonize the intestine in the presence of a well-adapted population of commensal microbes. If all else fails, invaders may be rapidly removed from the GI tract by vomiting and diarrhea.
        • Chemical barriers include antimicrobial proteins that harm or destroy invaders, and cells that attack foreign cells and body cells harbouring infectious agents.


        What is Auto-immunity? 

        An autoimmune disease is caused when the immune system of the body cannot recognise the healthy 'self' cells and becomes immune against them. It results in the  nonselective killing of the  body cells by the immune system, giving rise to a disease. Some common autoimmune diseases are SCID, rheumatoid arthritis, Addison's disease, Grave's disease etc.


        Name the enzyme by which the HIV genome replicates in the host cell.

        Answer : 
        i) Reverse transcriptase is the enzyme by which HIV genome replicates in the host cell. 
        ii) Reverse transcriptase catalyzes the formation of DNA from an RNA template. 
        iii) It works completely opposite to transcriptase enzyme.
        iv) It is a type of viral enzyme present in retrovirus.



        Give two examples each of the disease caused by fungus, protozoa, bacteria?

        Diseases caused by fungi:
        i) Candidiasis
        ii) Athlete's foot
        Diseases caused by protozoans:
        i) Malaria
        ii) Trichomoniasis
        Diseases caused by bacteria:
        i) Cholera
        ii) Pneumonia


        Explain why antibiotic do not work against viruses? 

        Antibiotics are not designed to kill viruses because both viruses and bacteria have different mechanisms of survival and replication. Only antiviral medicines can attack a virus but an antibiotic cannot.


        Following a road accident four injured persons were brought to a nearby clinic. The doctor immediately injected them with tetanus antitoxin.
        What is tetanus antitoxin ?


        • Tetanus antitoxin is a sterile, nonpyrogenic solution of the refined and concentrated proteins, chiefly globulins, containing antitoxic antibodies obtained from the blood serum or plasma of healthy horses that have been immunized against tetanus toxin. 
        • Tetanus antitoxin would immediately neutralize the toxins produced by Clostridium tetani. Hence, a doctor administers antitoxin and not a tetanus vaccine to an injured in a roadside accident with a bleeding wound because Clostridium tetani could enter his body through the wound.


        Why family is important?

        Family is important because it provides love, support and a framework of values to each of its members.


        Following a road accident four injured persons were brought to a nearby clinic. The doctor immediately injected them with tetanus antitoxin.
        Name the kind of immunity this injection provided.

        A tetanus vaccine injection would provide active immunity.


        Why there is no use of giving vaccine of hepatitis A virus?

        Hepatitis A causes jaundice and is transmitted by water. In India majority of children gain immunity against this virus by the time they are 5 years old due to exposure through water. So, they already have antibodies against Hepatitis A and therefore vaccination is not required.


        Give reason, majority of children in many parts of India are already immune to Hepatitis A.

        The virus of Hepatitis A spreads through contaminated water and there are many children below the age of 5 who get infected to this disease through the polluted water. The infection of this disease is mild during early stages of life, that is, childhood and they develop  antibodies for this disease, as a result majority of children in many parts of India are already immune to Hepatitis A. This is an example of active immunity.



        Why is HIV infection considered very fatal?

        HIV attacks the immune system and destroys its function. It weakens it to such an extent that the host immune system is unable to fight even  minor infections such as common cold caused by the influenza virus. Small cold can also lead to pneumonia and minor gut infections can result into diarrhea leading to blood loss. Finally, these secondary infections kill  people suffering from HIV infections.


        Fill in the blanks :
        Living organisms carrying the infecting agents from one person to another are called_____.

        Living organisms carrying the infecting agents from one person to another are called Vectors.
        Example, Anopheles mosquito is the vector for Malarial parasite, Plasmodium.


        Give two example of the following:
        Non-infectious diseases

        Diabetes and  Goitre are examples of two non infectious diseases.


        Give two example of the following:
        Infectious diseases

         Chicken pox and Cholera are examples of infectious diseases.


        Give two example of the following:
        Acute diseases

        Examples of two acute diseases are chicken pox and common cold.


        Observe this figure and answer the questions given below:
        The person infected by this virus is attacked by various diseases. Explain.
        1804245_c9e3b3443a194823a53f2b1b2a42c36a.png

        The above virus is the HIV virus that causes the syndrome of AIDS. This virus does not show the symptoms instantly but reduces the immunity of the body gradually by various diseases and helps other infections to infect the body and cause symptoms like fever, cough, etc. Therefore, the person infected by this virus is attacked by various diseases.


        How can we prevent the following disease?
        Hepatitis A

        Hepatitis A occurs due to a virus known as Hepatitis A virus. The symptoms of this disease are often recognizable after two weeks. To prevent this disease infants should be given vaccination. Apart from this, through proper hygiene this disease can be prevented. 


        Fill in the blanks :
        Many skin diseases are caused by_______.

        Many skin diseases are caused by Fungi.
        Some examples include, rashes, athlete's foot, ring worm etc


        Name the target organ for the following disease:
        Hepatitis targets ______.

        Hepatitis targets the Liver
        The virus causes inflammation of the liver and yellowing of the skin and sclera of the eye.


        Give two example of the following:
        Chronic diseases

        Elephantiasis and Tuberculosis(TB) are two examples of chronic diseases.


        Give the preventive measures of following disease.
        Cancer

        Preventive measures for cancer:
        1. Have a healthy diet
        2. Exercise regularly
        3. Avoid smoking and alcohol
        4. Go for regular health checkups 


        Classify the following diseases as infectious or non-infectious:
        (a) Aids
        (b) Tuberculosis
        (c) Cholera
        (d) High blood pressure
        (e) Heart disease
        (f) Pneumonia
        (g) Cancer

        • Infectious diseases include AIDS, tuberculosis, cholera, and pneumonia.
        • Non-infectious diseases include high blood pressure, heart disease, and cancer.


        Write the information on modern diagnostics and treatments of cancer.

        Cancer: Cancer is a non-infectious, deadly disease that results in the uncontrolled growth of the tumor cells or cancer cells. About 20% of the world's total population suffers from cancer. 
        As technology develops, there are modern ways to diagnose and treat cancer in an efficient way. 
        Treatments: 
        Radiation therapy uses high-intensity radiations to kill cancer cells.
        Chemotherapy uses chemical drugs.
        Immunotherapy activates the body's immune system to fight against cancer cells.
        Stem cell treatment. 

        Diagnostics:
        Biopsy where a small tissue is taken and tested.
        Endoscopy where a thin camera is inserted into the body organs.
        Blood tests.
        Sputum and bronchial washing analysis use the sputum or bronchial sections to be analyzed.


        Name the target organs for the following disease:
        Fungal disease targets________.

        Fungal disease targets the skin.
        Example, Rashes, athlete's foot, ring worm etc


        Fill in the blanks:
        ________diease continuous for a few days and causes no longer term effect on body.

        Acute disease continuous for a few days and causes on long term effect on the body.
        Example, Common cold, jaundice etc


        Give examples of the following:
        A. Viral diseases
        B. Bacterial diseases
        C. Diseases spread through insects
        D. Hereditary diseases

        Viral   -   Swine flu, measles, mumps, chickenpox
        Bacterial   -   Tuberculosis, diphtheria, tetanus, cholera, typhoid
        Insects   -   Dengue, malaria, plague
        Hereditary   -   Diabetes, hypertension


        Choose the odd one out: Plague, AIDS, Cholera, Tuberculosis.

        AIDS is the odd one out because it is a viral disease while rest of them are bacterial diseases.


        Fill in the blank:
        Common cold lasts for a short duration of time. It is a type of _____  disease.

        Common cold is an acute disease. It is an acute disease as it lasts for about a week. It is caused by Rhinovirus.
        So, the correct answer is 'acute'.



        What do you mean by disease symptoms ? Explain giving two examples ?

        When the functioning or the appearance of one or more systems of the body will change for the worse, it gives certain abnormal signs of the disease. These visual changes in human beings are called symptoms. Symptoms give indication of the presence of a particular disease. 
        Example (i) Lesions on the skin are the symptoms of chickenpox. 
        Example (ill Cough is the symptom of lung infection. 


        Identify me.
        I live in your small intestine. Pseudocoelom is present in my thread like body. In which phylum will you include me? 

        You belong to the phylum Aschelminthes and your name is Ascaris. 


        What are the harms of tobacco? 

        Following are the harms of tobacco: 
        Staining of teeth and tooth decay 
        Foul smell from the mouth 
        Oral cancer 
        Emphysema of the lungs 
        Lung cancer


        Short Answer.
        Mention the structure of HIV.

        HIV is a retrovirus with a diameter of about 100 nm. It consists of a central core of capsid proteins enclosing two ssRNA and enzyme reverse transcriptase. The core is surrounded by an envelope with glycoprotein recognition sites.
        1778881_1832476_ans_39f4dc65ec0b46f3ad2c5eb4c39e4b46.jpg


        Short Answers:
        How many types of diseases are found?

        Disease means a condition of disturbed functioning of the body or its part. 
        Type of disease are:
        • On the basis of duration : Acute and chronic -Example, Common cold is an acute disease. Tuberculosis is a congenital disease.
        • On the basis of the time of occurrence : Congenital and Acquired - Haemophelia, Phenylketonuria are congenital diseases while Cancer, Diabetes etc are acquired diseases.
        • On the basis of causal agent - infectious and non - infectious. For example Influenza, tuberculosis, pneumonia are infectious diseases. Diabetes and cancer are non-infectious diseases.


        Short answer question
        Define the term: Disease.

        Any condition which impairs health, or interferes with the normal functioning of the body is called disease.


        Draw the diagram of HIV.

        Labelled diagram of HIV
        1733864_1830367_ans_543dd07e55c14585976e4a06472f395b.PNG


        Very Short Answer
        Define good health

        Being free from physical, mental and social disorders is good health.


        Describe in detail the concept of vaccine. Name four diseases for which vaccines are available in the market.

        (i) Vaccines is a product in the form of weakened or inactivated pathogens or proteins which are used to provide protection against a disease which may infect in future and can be fatal. It stimulates the production of antibodies by the body against that particular disease.
        The diseases for which vaccines are available in the market are:
        (ii) (a) Polio, (b) Hepatitis, (c) Measles, (d) Small-pox, (e) Diphtheria, (J) Tetanus, (g) Whooping cough, etc. 


        Differentiate between a benign tumor and malignant tumor.

        Benign tumorMalignant tumor
        (i) Usually, they remain confined to their original location and do not spread to other parts of the body. (i) They spread to other parts of the body as well.
        (ii) They cause little damage.(ii) They cause severe damage.
        (iii) They cannot start a new tumor at a new place.(iii) They may start a new tumor when they reach a new place.


        What is active immunity? 

        When body proactively prepares an antibody against a specific antigen, it is called active immunity. 


        Name the pathological condition when uncontrolled cell division occurs. 

        Tumor is the pathological condition when uncontrolled cell divisions occur. A malignant tumor causes a disease called cancer.


        Differentiate between active immunity and passive immunity.

        Active ImmunityPassive Immunity
        (i) Body prepares antibodies in response to a pathogen or foreign material.(i) Antibodies are deliberately put into the body by artificial means.
        (ii) It is slow and takes time to show a response.(ii) It is fast and responds quickly


        Mention three symptoms of the disease Hepatitis.

        The three symptoms of Hepatitis disease are as follows:
        • Body ache.
        • Eyes turn yellowish, due to the bile pigments - urine turns to deep yellow.
        • Enlargement of liver.


        The following table shows certain diseases, their causative organisms, and symptoms. Fill the gaps.
        Name of the diseaseCausative organismSymptoms
        (i) AscariasisAscaris-
        (ii) -TrichophytonAppearance of dry, scaly lesions on various parts of the body.
        (iii) Typhoid-High fever, weakness, headache, stomach pain, constipation.
        (iv) PneumoniaStreptococcus-
        (v)-Rhino virusesNasal congestion and discharge, sore throat, cough, headache.
        (vi) Filariasis-Inflammation in lower limbs

        (i) Internal bleeding, muscular pain, anemia, fever, blockage of intestinal passage.
        (ii) Ringworm
        (iii) Salmonella typhi
        (vi) Fluid in lungs, fever, difficulty in breathing
        (v) Common cold
        (vi) Wuchereria


        Name any four non-infectious diseases and their causes.

        Four infectious diseases and their causes are as follows:
        Name of the disease     Cause
        Diabetes mellitus     Hyposecretion of insulin
        Arthritis     Degenerative disease due to old age
        Hay fever      Allergic response to pollen, dust mites, tiny flecks of skin and saliva from pets
        Beri-beri     Nutritional deficiency of vitamin B-1 or thiamine.


        What is cancer? How is a cancer cell different from the normal cell? How do normal cells attain cancerous nature?

        Uncontrolled cell division which leads to the formation of a tumor is called cancer. The normal cell loses its ability to divide after certain rounds of cell division. But a cancer cell continues to divide even after endless rounds of cell division. A normal cell has the ability to contact inhibition which inhibits its division after contact with other cells. When this ability is lost in a cell, it becomes cancerous.


        From which plant cannabinoids are obtained? Name any two cannabinoids. Which part of the body is affected by consuming these substances?

        Cannabinoids are obtained from $$Cannabis\,sativa$$. Marijuana and hashish are examples of cannabinoids. They affect the cardiovascular system.


        The outline structure of a drug is given below.
        (a) Which group of drugs does this represent?
        (b) What are the modes of consumption of these drugs?
        (c) Name the organ of the body which is affected by the consumption of these drugs.
        1853254_a15c6d71cd4041cab680d4cd84f1f725.png

        (a) Cannabinoids
        (b) Inhalation and oral ingestion
        (c) Cardiovascular system


        What are lifestyle diseases? How are they caused? Name any two such diseases.

        Diseases which happen because of faulty lifestyle are called lifestyle diseases. These diseases are caused because of overeating and a sedentary lifestyle. Diabetes and hypercholesterolemia are examples of lifestyle diseases.


        Find the odd one out:

        (a) Typhoid, cholera, jaundice, tuberculosis, tetanus.
        (b)         Cold, AIDS, plague, malaria, measles.
        (c)         Scurvy, rickets, haemophilia, pellagra, night blindness.
        (d)         Proteins, carbohydrates, fats, minerals, cancer.

        (a) Jaundice - is a condition caused by a liver disorder, but typhoid, cholera, tuberculosis, and tetanus are diseases caused by bacteria.
        (b) Malaria - is a condition caused by a Protozoa Plasmodium genera. But, cold, AIDS, measles are caused by viruses.
        (c) Haemophilia - is a genetic disorder. But, scurvy, rickets, pellagra, night blindness are nutritional deficiency disorders.
        (d) Cancer - is a disorder, but proteins, carbohydrates, fats, and minerals are nutrition.


        Write very briefly about the following:

        (a) BCG.
        (b) Incubation period.
        (c) Chicken pox.
        (d) Hepatitis A.

        (a) BCG - BCG (Bacillus Calmette Guerin) is a vaccine that is used to treat Tuberculosis (TB) which is a bacterial disease as it develops immunity to TB.
        (b) Incubation period - It is the period between the entrance of the germs and the appearance of the first symptoms of the disease. Incubation period of Tetanus of 4-20 days.
        (c) Chicken pox - It is caused by the Herpes Varicella zoster virus and is a viral disease. It rapidly spreads through close contact with the person infected.
        (d) Hepatitis A - It is caused by the Hepatitis A virus and is a viral disease that results in liver inflammation. It is transferred primarily through contaminated water and food.


        In which diseases, the value of ESR increases. 

        During Rheumatoid Arthritis, Multiple Myeloma, TB etc. the value of ESR increases.


        Match the causative organisms with their diseases.

        • Plasmodium falciparum is a unicellular protozoan parasite of humans and the deadliest species of Plasmodium that cause malaria in humans.
        • The causal agent of elephantiasis is parasitic nematodes, Wuchereria bancrofti that inhabit the lymphatics and subcutaneous tissues. 
        • Pneumonia is a lung disease by inflammation of the airspaces in the lungs, most commonly due to an infection caused by Haemophilus influenza.
        • Typhoid is a bacterial infection, caused by the bacteria Salmonella typhi that leads to high fever, diarrhoea, and vomiting.
        • Amoebiasis is a disease caused by infection with a parasitic amoeba that, when symptomatic, can cause dysentery and invasive extraintestinal problems. The cause of amebiasis is mainly the protozoan parasite Entamoeba histolytica.  
        So, the correct answer is 'C-1, D-2, A-3, E-4, B-5'.


        Give major differences between infectious and non infectious diseases. (any two).

         Infectious disease
        		 Non-infectious disease
         

        These are caused by the attack of pathogens (viruses, bacteria, fungi, protozoans, worms).

        		 

        These are caused by factors other than living pathogens.

         

        These can spread from infected person to healthy person(s).

        		 

        These cannot spread from infected person to healthy person(s).



        What are pathogens ? Give examples.

        Disease causing microorganisms are called pathogens. These include viruses, bacteria, fungi, protozoans and worms.


        During an injury nasal septum gets damaged and for its recovery, cartilage is preferred. Why cartilage is preferred?

        Cartilage is firm but slightly elastic with clear matrix. It is present in larynx, trachea, bronchi. nose etc.


        Name the deficiency diseases caused due to deficiency of:
        (i) Iodine (ii) Vitamin $$B_2$$ (iii) Vitamin D (iv) Fluorine (v) Vitamin C (vi) Vitamin A (vii) Vitamin $$B_{12}$$ (viii) Iron.

        (i) Goitre (ii) Cheilosis (iii) Rickets in children and osteomalacia in adults  (iv) Dental caries (v) Scurvy (vi) Xerophthalmia and night blindness (vii) Pernicious anaemia (viii) Microcytic anaemia.


        Name the vectors of following diseases.
        (i) Kala azar
        (ii) Sleeping sickness
        (iii) Typhus
        (iv) Bubonic plague
        (v) Malaria
        (vi) Dengue

        (i) Sand fly (ii) Tsetse fly (iii) Louse (iv) Rat flea (v)Anopheles (vi) Aedes


        "Heavy supplements are not good during physical exercise in adolescence."
        Do you agree. Give reason in support of your answer.

        $$\textbf{Solution:}$$
        $$\bullet$$ Supplementation during physical activity produces aberrant muscular growth, stiffness, and maturity before reaching adulthood.
        $$\bullet$$ Adolescence is the period of physical development (by cell division or dividing of cells ).
        $$\bullet$$ When a person carries a lot of supplements, the force acts in the opposite direction of the body's growth, disrupting the growth process. 
        $$\bullet$$ As a result, for example basketball players remain shorts while they need to  have a very lengthy height since they apply force in the direction of their body's growth in this sport.





        Name any two organisms that are responsible for ringworms in humans. Mention two diagnostic symptoms. Name the specific parts of the human body where these organisms thrive and explain why.

        The organism causing ringworms in humans are Microsporum/ Trichophyton and Epidermophyton.
        Symptoms: Dry, scaly lesion on skin or nails or scalp and intense itching. These thrive in the body groin or between toes. This is so because they thrive better in heat, moisture or perspired areas. 


        What are enveloped viruses?

        The virus enclosed within a lipid bilayer is called enveloped viruses. They are made up of phospholipid bilayer containing one or more than one glycoproteins (transmembrane envelope) the major function in the attachment of the virus to the host cells and also to penetrate the host cells. Some examples of enveloped viruses are the dengue virus, influenza virus, and measles virus.



        A team of students are preparing to participate in the interschool sports meet. During a practice session you find some vials with labels of certain cannabinoids.
        (a) Will you report to the authorities? Why?
        (b) Name of a plant from which such chemicals are obtained.
        (c) Write the effect of these chemicals on human body.

        a) Yes, because cannabinoids are the type of drugs and its abuse is an illegal practice.
        b) Cannabinoids are obtained from Cannabis sativa.
        c) These chemicals can affects the nervous system and cardiovascular system.


        A student on a picnic to a park on a windy day stared sneezing and having difficulty in breathing on reaching the park. The teacher enquired whether the student was allergic to something.
        (a) What is an allergy?
        (b) Write the two unique characteristics of the system involved in the response observed in the student?

        a) The exaggerated response of the immune system to certain antigens present in the environment is called allergy.
        (b) The system involved is immune system. The unique characteristics are:
        (i) It recognizes foreign antigens & responds to them.
        (ii) It has memory and so it remember antigens.


        Name the disease for which the following of vaccines are given.
        (1) Salk's Vaccine
        (2) B.C.G

        Poliomyelitis vaccine was first developed bu Jonas Salk and hence, is called as Salk's vaccine. BCG stands for Bacillus Calmette Guerin, a vaccine given for protection against tuberculosis.


        What is AIDS? Describe along with symptoms and measures of control.

        AIDS (Acquired Immune Deficiency Syndrome) is discovered for the first time in America in the year 1981.
        Causes of disease: This disease is caused by the infection of a virus known as HIV (Human Immuno Deficiency Virus).
        Transmission: It is transmitted through sexual contact, homosexuality, contaminated needles, blood transfusion, drugs, artificial insemination and organ transplantation etc.
        Symptoms of disease: It is characterised by showing swollen lymph nodes, fever, loss of weight. The person loses the immunity against the infection. In this disease, the number of helper T-cells is reduced.
        Treatment: No suitable drugs available so far against this disease. Only antiviral cells may be increased in the number by immune stimulation method.
        Control: The following measures are advised to prevent the spreading of disease:
        (1) Providing health education and explain the hazardous effects of AIDS.
        (2) Do not reutilize the used syringe.
        (3) The blood of donor person and organs of transplantation like kidney, liver, cornea of eyes, growth hormones should be carefully examined before use.


        Short / Long answer type questions.
        Which scientist is known as father of microbiology ? Who discovered mosaic disease of tobacco?

        Mr. Antoni van Leeuwenhoek is commonly called as father of microbiology. Wendell Meredith Stanley discovered mosaic disease of tobacco.


        SHORT ANSWER TYPE
        Name any four non-infectious diseases and their causes

        1. Diabetes is a disease which occurs due to the loss of insulin production from the pancreas
        2. Sickle-cell anemia is a genetic disease which occurs due to a mutation in the gene carrying hemoglobin
        3. Hypothyroidism is caused due to loss of thyroid hormone production from the thyroid gland
        4. Atherosclerosis is a cardiovascular disease caused due to fat deposition in arteries


        Match the terms to these definitions
        Health,  mental illness,  epilepsy, addiction,  drug,  mental deficiency,  hypnotics, narcotics, hallucinogens,  sedatives, tranquillisers,  alcoholism
        .......... A state of complete physical, mental and social well-being, not merely an absence of disease or infirmity.

        Health


        (i) List any two situations, when a medical doctor would recommend an injection of preformed antibodies into the body of a patient. Name this kind of immunization and mention its advantages.
        (ii) Name the kind of immunity attained when instead of antibodies, weakened antigens are introduced into the body.

        (i)A doctor would recommend preformed antibodies in an injured person in an accident on snake bites and tetanus.  The type of immunization is passive immunization.
        Its advantages are:
        (a)Provides immediate relief.
        (b)Used either prophylactically or therapeutically.
        (ii)This type of immunity is called active immunity. In this, the preparation of antigenic proteins of pathogen or inactivated/weakened pathogens (vaccine) are introduced into the body. It is a slow process as takes time to develop antibodies against the antigen


        Differentiate between.
        Active acquired immunity and passive acquired immunity

        The type of immunity which an organism obtains during the course of its life time, is known as acquired immunity. Active acquired immunity is achieved by injecting small amounts of antigen into the body of an individual, whereas passive acquired immunity develops through injection of immune serum present in  already immunized organisms. 


        Study the diagram showing replication of HIV in humans and answer the following questions accordingly:
        Name the enzyme $$'B'$$ acting on $$'X'$$ to produce molecule $$'C'$$. Name $$'C'$$.
        993243_297c2d76ea3f4fceb01e9ff2bca28a3d.jpg

        The enzyme "B" is reverse transcriptase acting on "X" to produce molecule "C" named as viral DNA .


        Study the diagram showing replication of HIV in humans and answer the following questions accordingly:
        Mention the name of the host cell $$'D'$$ the HIV attacks first when it enters into the human body.
        993245_b6bb2b084c09412abb1d28f4dd6e9bce.jpg

        After getting into the human body virus enters into host cell "D" named as macrophages. Macrophages act as a HIV factory.


        Distinguish between infectious and non-infectious diseases.

        Answer:
         
        Infectious Diseases


        Non-Infectious Diseases
        They are caused by infectious microorganisms like viruses, bacteria, helminths etc.They are caused by pathogens as well has due to old age, nutritional deficiency, smoking, drinking, lifestyle etc.
        The mode of transmission can be fecal-oral, droplets, sexual transmission, direct contact or transmission by vector.These do not transmit from one person to another, but some of them may be genetically inherited. 
         Example: AIDS, Herpes, Cholera,  Tuberculosis, Chicken Pox. Example: Cancer, Diabetes.



        What is immunity? Explain the innate immunity with four types of barriers to defend the body from development of disease.

        Immunity can be defined as the ability of an organism to resiste the pathogenic harm caused by another living organism, or to resist the allergic reactions mediated by the components of living organisms.

        Innate immunity is the inborn and inherent mechanism that an organism is born with. These are present since birth of an individual and are responsible for providing the first line of defense to the body. It is also known as non-specific immunity. The components of the innate immunity are as follows:

        1. The anatomical or chemical barriers- these include the skin, mucous membrane, gastro-intestinal tract, urino-genital tract and respiratory tract that are responsible of preventing the entry of pathogen or to trap the pathogen during its entry in the body.

        2. The phagocytic barriers- these include the leukocytes present in blood that are capable of performing phagocytosis and killing the pathogen, for example, macrophages, neutrophils, natural killer cells.

        3. Plasma proteins- plasma of the blood is rich in proteins that perform immnulogical functions, such as the complement proteins that inform phagocytic cells about a pathogen and also trigger production of antibodies.

        4. Cytokines- these are the proteins produced by the epithelial cells (dendritic cells), neutrophils, macrophages that control the growth and spread of infection.



        On the basis of characteristics given below name the phyIum or class for each:
        Animals with soft cylindrical, unsegmented body with a false body cavity _____.

        Phylum - Aschelminthes
        The general characters of Phylum aschelminthes are 
        • May be free living , aquatic , terrestrial, parasite
        • Dioecious
        • Females are longer than the males
        • Fertilisation internal



        Name 2 bacterial diseases that spread through the medium of 
        a) Air 
        b) Contaminated food

        $$\textbf{Solution:}$$

        $$\bullet$$ Bacterial diseases can be transferred from an infected person to a healthy person through air or contaminated food.

        $$\bullet$$ Bacterial diseases which spread out through the medium of air are Whooping cough (caused by $$Bordetella$$ $$pertussis$$) and Tuberculosis (caused by $$Mycobacterium$$ $$tuberculosis$$).

        $$\bullet$$ Contaminated food or water can also act as the medium of bacterial diseases like typhoid and botulism.

        $$\bullet$$ Typhoid is caused by rod-shaped gram-negative bacteria $$Salmonella$$ $$typhi$$ and botulism or food poisoning is caused by rod-shaped gram-positive bacteria $$Clostridium$$ $$botulinum$$.



        Victim of snake bite is administered with antivenom because, it provides.

        Antivenom is immunoglobulins prepared by immunizing horses with the venom of poisonous snakes and later extracting and purifying the horse's serum. They may be species-specific (monovalent/monospecific) or may be effective against several species (polyvalent/polyspecific).


        What is immunisation?

        Explanation:

        • Immunization is the process whereby a person is made immune or resistant to an infectious disease, typically by the administration of a vaccine.
        • Vaccines stimulate the body's own immune system to protect the person against subsequent infection or disease.


        Give two examples of each of the following 
        Acute disease
        Chronic disease

        Chronic disease
        1)Diabetes
        2) HIV/AIDS
        Acute disease
        1)Appendicitis
        2) Common cold


        'Myasthenia gravis' occurs due to ?

        Myasthemia gravis is the neuromuscular disease and is chronic. Its main symptom is the weakening of the muscles resulting in the weakness of arms, legs etc. It happens when the body immune system produces antibodies that destroy its own healthy tissues. It reduces the formation of the neurotransmitter acetylcholine (chemicals responsible for the formation of nerve impulses), this leads to communication loss between muscles and neurons. Due to a decrease in acetylcholine, there is loss in the strength of muscles, hence muscles weaken.


        Give the names of five non-infectious diseases. 

        Names of non-infectious diseases are :
        • Alzheimer's.
        • Asthma.
        • Cataracts.
        • Diabetes.
        • Heart Disease.


        Riya went to the garden to play with her father. After a few minutes, she started sneezing badly and had difficulty breathing. What do you think could be the possible reason?

        Allergy. The pollen of flowers present in the garden acted as allergens inside Riyas body. The allergens elicited a hypersensitive response and caused the production of IgE which activated the release of histamines. These histamines induced allergic symptoms like sneezing and difficulty breathing.


        Based on the duration of disease what are the different categories of diseases? Differentiate between them with one example each.

         Acute diseases   Chronic diseases
         Acute diseases are diseases that last for a short span of time.  Chronic diseases are those that last for a long period of time. 
         Acute disease does not cause a major effect on general health. 
        Example: cough, dysentery, etc.         		Chronic diseases cause a major effect on general health.
        Example: elephantiasis, tuberculosis, etc. 



        Class 12 Medical Biology Extra Questions