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Human Health And Diseases

Class 12th Biology NCERT Exemplar Solution
Multiple Choice Questions
  1. The term 'Health' is defined in many ways. The most accurate definition of the health…
  2. The organisms which cause diseases in plants and animals are called:…
  3. The clinical test that is used for diagnosis of typhoid is:
  4. Diseases are broadly grouped into infectious and non-infectious diseases. In the list…
  5. The sporozoites that cause infection when a female Anopheles mosquito bites a person are…
  6. The disease chikunguniya is transmitted by:
  7. Many diseases can be diagnosed by observing the symptoms in the patient. Which group of…
  8. Cancer causing genes are called:
  9. In malignant tumors, the cells proliferate, grow rapidly and move to other parts of the…
  10. When an apparently healthy person is diagnosed as unhealthy by a psychiatrist, the reason…
  11. Which of the following are the reason(s) for Rheumatoid arthritis? Choose the correct…
  12. AIDS is caused by HIV. Among the following, which one is not a mode of transmission of…
  13. 'Smack' is a drug obtained from the:
  14. The substance produced by a cell in viral infection that can protect other cells from…
  15. Transplantation of tissues/organs to save certain patients often fails due to rejection of…
  16. Antibodies present in colostrum which protect the new born from certain diseases is of…
  17. Tobacco consumption is known to stimulate secretion of adrenaline and nor-adrenaline. The…
  18. Antivenom against snake poison contains:
  19. Which of the following is not a lymphoid tissue?
  20. Which of the following glands is large sized at birth but reduces in size with ageing?…
  21. Haemozoin is a:
  22. Which of the following is not the causal organism for ringworm?
  23. A person with sickle cell anaemia is
Very Short Answer Type
  1. Certain pathogens are tissue/organ specific. Justify the statement with suitable examples.…
  2. The immune system of a person is suppressed. In the ELISA test, he was found positive to a…
  3. Where are B-cells and T-cells formed? How do they differ from each other?…
  4. Given below are the pairs of pathogens and the diseases caused by them. Which out of these…
  5. What would happen to immune system, if thymus gland is removed from the body of a person?…
  6. Many microbial pathogens enter the gut of humans along with food. What are the preventive…
  7. Why is mother's milk considered the most appropriate food for a new born infant?…
  8. What are interferons? How do interferons check infection of new cells?…
  9. In the figure, structure of an antibody molecule is shown. Name the parts A, B and C.Show…
  10. If a regular dose of drug or alcohol is not provided to an addicted person, he shows some…
  11. Why is it that during changing weather, one is advised to avoid closed, crowded and…
  12. The harmful allele of sickle cell anaemia has not been eliminated from human population.…
  13. Lymph nodes are secondary lymphoid organs. Explain the role of lymph nodes in our immune…
  14. Why is an antibody molecule represented as H2L2?
  15. What does the term `memory' of the Immune system mean?
  16. If a patient is advised Anti Retroviral Therapy, which infection is he suffering from?…
Short Answer Type
  1. Differentiate between active immunity and passive immunity.
  2. Differentiate between benign tumor and malignant tumor.
  3. Do you consider passive smoking is more dangerous than active smoking? Why?…
  4. “Prevention is better than cure”. Comment.
  5. Explain any three preventive measures to control microbial infections.…
  6. In the given flow diagram, the replication of retrovirus in a host is shown. Observe and…
  7. “Maintenance of personal and public hygiene is necessary for prevention and control of…
  8. The following table shows certain diseases, their causative organisms and symptoms. Fill…
  9. The outline structure of a drug is given below.a. Which group of drugs does this…
  10. Give the full form of CT and MRI. How are they different from each other? Where are they…
  11. Many secondary metabolites of plants have medicinal properties. It is their misuse that…
  12. Why cannabinoids are banned in sports and games?
  13. What is secondary metabolism?
  14. Drugs and alcohol give short-term 'high' and long-term ‘damages’, Discuss.…
  15. Diseases like dysentery, cholera, typhoid etc., are more common in overcrowded human…
  16. From which plant cannabiniods are obtained? Name any two cannabinoids. Which part of the…
  17. In the metropolitan cities of India, many children are suffering from allergy/asthma. What…
  18. What is the basic principle of vaccination? How do vaccines prevent microbial infections?…
  19. What is cancer? How is a cancer cell different from the normal cell? How do normal cells…
  20. A person shows strong unusual hypersensitive reactions when exposed to certain substances…
  21. For an organ transplant, it is an advantage to have an identical twin. Why?…
  22. What are lifestyle diseases? How are they caused? Name any two such diseases.…
  23. If there are two pathogenic viruses, one with DNA and other with RNA, which would mutate…
Long Answer Type
  1. Represent schematically the life cycle of a malarial parasite.
  2. Compare the life style of people living in the urban areas with those of rural areas and…
  3. Why do some adolescents start taking drugs. How can this be avoided?…
  4. In your locality, if a person is addicted to alcohol, what kind of behavioural changes do…
  5. What are the methods of cancer detection? Describe the common approaches for treatment of…
  6. Drugs like LSD, barbiturates, amphetamines, etc., are used as medicines to help patients…
  7. What is Pulse Polio Programme of Government of India? What is OPV? Why is it that India is…
  8. What are recombinant DNA vaccines? Give two examples of such vaccines. Discuss their…

Multiple Choice Questions
Question 1.

The term 'Health' is defined in many ways. The most accurate definition of the health would be:
A. Health is the state of body and mind in a balanced condition

B. Health is the reflection of a smiling face

C. Health is a state of complete physical, mental and social well-being

D. Health is the symbol of economic prosperity.


Answer:

The most accurate definition of the health would be ‘Health is a state of complete physical, mental and social well-being ‘, i.e. health isn’t just about being physically well but also being mentally and socially healthy.


Question 2.

The organisms which cause diseases in plants and animals are called:
A. Pathogens

B. Vectors

C. Insects

D. Worms


Answer:

The organisms which cause diseases in plants and animals are called pathogens . Various types of pathogens are:


1.Viruses: These are segments of either DNA or RNA and are not cells. They cause viral infection. Example: Retro virus, Human Immuno Deficiency Virus etc.


2.Bacteria: These are uni-cellular microorganisms which cause bacterial infections. For example: Streptococcus pneumoniae


3.Fungi: These are eukaryotic organisms like molds and yeast. They cause fungal infections. For example Tricophyton, Asperigillus


4.Protozoa: These are unicellular organisms like algae, amoeba & Euglena etc. These are from the family of protists.


5.Worms: Also known as Helminths. They are of many types like hookworm, thread worm, pin worm, flatworm & Roundworm etc.


Question 3.

The clinical test that is used for diagnosis of typhoid is:
A. ELISA

B. ESR

C. PCR

D. Widal


Answer:


Question 4.

Diseases are broadly grouped into infectious and non-infectious diseases. In the list given below, identify the infectious diseases.

i. Cancer

ii. Influenza

iii. Allergy

iv. Small pox

A. i and ii

B. ii and iii

C. iii and iv

D. ii and iv


Answer:

Influenza is an infectious disease caused by Influenza Virus. It may cause Viral, bacterial Pneumoniae and Sinus infections and can be transferred through air from cough and sneezes of infected person.


Small Pox is an infectious disease caused by two viruses Variola Major and Variola Minor. It causes sores in mouth and skin rashes. It can be transferred through contaminated objects & people.


Question 5.

The sporozoites that cause infection when a female Anopheles mosquito bites a person are formed in:
A. liver of the person

B. RBCs of mosquito

C. salivary glands of mosquito

D. gut of mosquito


Answer:

1. When a female Anopheles mosquito bites an infected person, the sporozites, containing the malarial plasmodium cells enter into the gut of the mosquito.


2. Here it multiplies and then they are stored in the salivary glands of the mosquito.


3. When the mosquito bites an uninfected individual these sporozites enter into the liver where they multiply and attack the RBC’s causing them to rupture and release a toxin called Haemozoin which causes fever, chills and shivering.


Question 6.

The disease chikunguniya is transmitted by:
A. house fly

B. Aedes mosquito

C. cockroach

D. female Anopheles


Answer:

The mosquito of Aedes species which are Aedes aegypti and Aedes albopictus transmit chikunguniya by biting people.


Question 7.

Many diseases can be diagnosed by observing the symptoms in the patient. Which group of symptoms are indicative of pneumonia?
A. Difficulty in respiration, fever, chills, cough, headache

B. Constipation, abdominal pain, cramps, blood clots

C. Nasal congestion and discharge, cough, constipation, headache

D. High fever, weakness, stomach pain, loss of appetite and constipation


Answer:


Question 8.

Cancer causing genes are called:
A. structural genes

B. expressor genes

C. oncogenes

D. regulatory genes


Answer:

Oncogenes are the cells which transform a normal cell into a cancerous tumour cell.


Structural genes: These are the genes that code for RNA and other proteins except regulatory proteins.


Regulatory Genes: These are the genes involved in controlling the expressions of various genes.


Question 9.

In malignant tumors, the cells proliferate, grow rapidly and move to other parts of the body to form new tumors. This stage of disease is called:
A. metagenesis

B. metastasis

C. teratogenesis

D. mitosis


Answer:


Question 10.

When an apparently healthy person is diagnosed as unhealthy by a psychiatrist, the reason could be that:
A. the patient was not efficient at his work

B. the patient was not economically prosperous

C. the patient shows behavioural and social maladjustment

D. he does not take interest in sports


Answer:

When an apparently healthy person is diagnosed as unhealthy by a psychiatrist, the reason could be that the patient shows behavioural and social maladjustment.


Question 11.

Which of the following are the reason(s) for Rheumatoid arthritis? Choose the correct option.

i. The ability to differentiate pathogens or foreign molecules from self cells increases.

ii. Body attacks self cells

iii. More antibodies are produced in the body

iv. The ability to differentiate pathogens or foreign molecules from self cells is lost

A. i and ii

B. ii and iv

C. iii and iv

D. i and iii


Answer:

As Rheumatoid arthritis is an auto immune disorder which means the body starts attacking its own cells by producing antibodies against it also the body’s ability to differentiate pathogens or foreign molecules from self cells is lost.


Question 12.

AIDS is caused by HIV. Among the following, which one is not a mode of transmission of HIV?
A. Transfusion of contaminated blood

B. Sharing the infected needles

C. Shaking hands with infected persons

D. Sexual contact with infected persons


Answer:

AIDS is caused by HIV which is a virus that can be transferred the transfer of HIV by:


1.Transfusion of contaminated blood.


2.Sharing the infected needles.


3.Sexual contact with infected persons


Question 13.

'Smack' is a drug obtained from the:
A. latex of Papaver somniferum

B. leaves of Cannabis sativa

C. flowers of Dhatura

D. fruits of Erythroxyl coca


Answer:


Question 14.

The substance produced by a cell in viral infection that can protect other cells from further infection is:
A. serotonin

B. colostrum

C. interferon

D. histamine


Answer:

The substance produced by a cell in viral infection that can protect other cells from further infection is interferon. Interferon is a group of proteins released by the host cell in the presence of virus. In classic cases the viral infected cell releases interferon which heightens the antiviral response of the nearby cells.


Serotonin: It is a Monoamine Neurotransmitter which is involved in the state of being happy.


Colostrum: It is the first milk produced by the mammary glands after childbirth. It consists of antibodies that help in boosting the immune system of the newborn.


Histamine: It is a nitrogenous compound involved in immune responses. Mainly there are H1 and H2 forms of histamine.


Question 15.

Transplantation of tissues/organs to save certain patients often fails due to rejection of such tissues/organs by the patient. Which type of immune response is responsible for such rejections?
A. auto-immune response

B. humoral immune response

C. physiological immune response

D. cell-mediated immune response


Answer:

Transplantation is the procedure of replacing the unhealthy organ with a healthy one in an individual. Sometimes these replaced organs get rejected by the body’s immune system as they are considered as a foreign object by the body. In response to this, cell mediated immune response takes place by T-Lymphocytes. These lymphocytes try to differentiate between self cells and foreign cells because of which sometimes the graft gets rejected.


Question 16.

Antibodies present in colostrum which protect the new born from certain diseases is of
A. Ig G type

B. Ig A type

C. Ig D type

D. Ig E type


Answer:

It is the first milk produced by the mammary glands after childbirth. It consists of antibodies that help in boosting the immune system of the newborn. It consists of Ig G type antibodies in abundance.


Question 17.

Tobacco consumption is known to stimulate secretion of adrenaline and nor-adrenaline. The component causing this could be:
A. Nicotine

B. Tannic acid

C. Curamin

D. Catechin


Answer:

Tobacco consumption is known to stimulate secretion of adrenaline and nor-adrenaline. The component causing this could be Nicotine which is an alkaloid.


Question 18.

Antivenom against snake poison contains:
A. Antigens

B. Antigen-antibody complexes

C. Antibodies

D. Enzymes


Answer:

Snake venom is a poison produced by the snake biologically, in its defence against the predators. To neutralise its effect snake anti venom is used which consists of venom neutralising antibodies derived from animals like horse, sheep etc.


Question 19.

Which of the following is not a lymphoid tissue?
A. Spleen

B. Tonsils

C. Pancreas

D. Thymus


Answer:

All of the above organs are lymphoid tissue except pancreas, which is a mixed gland as it has both endocrine and exocrine glands in it.


Question 20.

Which of the following glands is large sized at birth but reduces in size with ageing?
A. Pineal

B. Pituitary

C. Thymus

D. Thyroid


Answer:

Thymus gland is present in front of the sternum between the lungs. This gland is large sized at birth and helps in the production of T-lymphocytes. After puberty is reached, it decreases in size and is than replaced by fat.


Question 21.

Haemozoin is a:
A. precursor of hemoglobin

B. toxin released from Streptococcus infected cells

C. toxin released from Plasmodium infected cells

D. toxin released from Haemophilus infected cells


Answer:

It is a toxin produced by the ruptured RBC’s when infected by the Plasmodium. This toxin release, leads to shivering, high fever & chills like symptom in the plasmodium infected individual.


Question 22.

Which of the following is not the causal organism for ringworm?
A. Microsporum

B. Trichophyton

C. Epidermophyton

D. Macrosporum


Answer:

Trichophyton, Epidermophyton and Microsporum are all usual organisms for ringworm. Macrosporum is fungus causing disease.


Question 23.

A person with sickle cell anaemia is
A. more prone to malaria

B. more prone to typhoid

C. less prone to malaria

D. less prone to typhoid


Answer:

Sickle cell anaemia is a genetic disorder in which Valine is substituted instead of Glutamic Acid in the beta Haemoglobin chain. This mutation leads to the change of RBC’S shape from disc shape to sickle like shape leading to decreased oxygen in the body and the sickle cell trait developed, also makes people less prone to Malaria.



Very Short Answer Type
Question 1.

Certain pathogens are tissue/organ specific. Justify the statement with suitable examples.


Answer:

Pathogens are disease causing agents. Certain pathogens are tissue/organ specific as they only attack a certain tissue as seen in the case of:

A. Typhoid: Salmonella typhi only infects the small intestine.


B. Intestinal Endoparasite only infects large intestine, causing Amoebic dysentery.



Question 2.

The immune system of a person is suppressed. In the ELISA test, he was found positive to a pathogen.

a. Name the disease the patient is suffering from.

b. What is the causative organism?

c. Which cells of body are affected by the pathogen?


Answer:

a. The patient is suffering from Acquired Immuno Deficiency syndrome (AIDS). In this disease body’s immune system is compromised by the HIV.


b. The causative organism is the Human Immuno Deficiency Virus (HIV). This virus interferes with the body’s ability to fight a disease hence making body more susceptible to various diseases.


C. T4 lymphocytes or helper cells are affected in this disease.



Question 3.

Where are B-cells and T-cells formed? How do they differ from each other?


Answer:

B-cells are produced in the bone marrow. They also goes through maturation in the bone marrow.


T-cells are produced in the bone marrow but they mature in thymus.




Question 4.

Given below are the pairs of pathogens and the diseases caused by them. Which out of these is not a matching pair and why?



Answer:

In the above question option ‘c’ is incorrectly matched. As Microsporum is a fungi which causes Ringworms, the disease’s name is a misnomer as it is caused by fungi and not by worms.The disease filariasis is caused by an infection caused by roundworms of Filarioidea genus.



Question 5.

What would happen to immune system, if thymus gland is removed from the body of a person?


Answer:

Thymus gland is present in front of the sternum between the lungs. This gland is large in size at the time of birth and helps in the maturation of T-lymphocytes. If thymus gland is removed from the body of a person T-lymphocytes would not be able to mature. This would compromise the immune system and the individual would be more susceptible to various diseases.



Question 6.

Many microbial pathogens enter the gut of humans along with food. What are the preventive barriers to protect the body from such pathogens? What type of immunity do you observe in this case?


Answer:

When we eat food, some microbes also enter our gut along with the food and may cause several diseases. To prevent these microbial pathogens from entering the gut, our body has preventive barriers which are as follows:

1. Lysozome present in saliva


2. Mucous coating on the epithelium lining of the gut.


3. Hydrochloric acid secreted by the parietal cells in the stomach.


This type of immunity is known as Innate Immunity. This immunity provides the body with a defence mechanism in response to the antigens produced in the body when any pathogen enters the body. It includes physical barriers like skin, chemical barriers like HCl, lysozome and immunity cells like T & B lymphocytes. It is present in a person since birth.



Question 7.

Why is mother's milk considered the most appropriate food for a new born infant?


Answer:

Mother's milk is considered the most appropriate food for a new born infant because in the initial days the thick yellowish fluid called colostrum is produced. Colostrum has abundant antibodies in it like IgA,IgM & IgG etc, which boosts the immune system of an infant.



Question 8.

What are interferons? How do interferons check infection of new cells?


Answer:

Interferons are a group of natural proteins released by the host cell in the presence of any virus, tumour cells and parasites etc. In classic cases the viral infected cell releases interferon which heightens the antiviral response of the nearby cells.

Interferons check infection of new cells as:


1. Interferons inhibit viral replication within the host cells.


2. Which in turn activates the natural killer cells and macrophages .


3. This increases the presentation of antigens to lymphocytes.


4. Now, these antigens multiply and remove the pathogen.



Question 9.

In the figure, structure of an antibody molecule is shown. Name the parts A, B and C.

Show A, B and C in the diagram.




Answer:

Site A is the constant region for heavy chain.


Site B is the constant region for light chain.


Site C is the variable region of light and heavy chain.



Question 10.

If a regular dose of drug or alcohol is not provided to an addicted person, he shows some withdrawal symptoms. List any four such withdrawal symptoms.


Answer:

If a regular dose of drug or alcohol is not provided to an addicted person, he shows some withdrawal symptoms which are as follows:

1. It leads to anxiety.


2. Trouble concentrating on things and thinking clearly.


3. Headache and nausea.


4. Mood swings are also seen.



Question 11.

Why is it that during changing weather, one is advised to avoid closed, crowded and airconditioned places like cinema halls etc.?


Answer:

During changing weather, one is advised to avoid closed, crowded and air conditioned places like cinema halls etc. because at this time the microbes are active and prevalent. This makes an individual more susceptible to viral infections.



Question 12.

The harmful allele of sickle cell anaemia has not been eliminated from human population. Such afflicted people derive some other benefit. Discuss.


Answer:

Sickle cell anaemia is a genetic disorder in which Valine is substituted instead of Glutamic Acid in the beta Haemoglobin chain. This mutation leads to the change of RBC’S shape from disc shape to sickle like shape leading to decreased oxygen in the body and the sickle cell trait developed, also makes people less prone to Malaria.



Question 13.

Lymph nodes are secondary lymphoid organs. Explain the role of lymph nodes in our immune response.


Answer:

Sites where lymphocytes interact with the antigens and then proliferate to become effector cells are called as secondary lymphoid organs.

Functions of lymph nodes:


1. Main function of lymph node is to clear the lymph (it is a clear liquid which comes from plasma) which carries pathogens and other foreign substances (like cancer cells) that are brought by the lymph, through lymphatic cells.


2. It is also responsible for providing immunity as it is the place were B and T lymphocytes interact.



Question 14.

Why is an antibody molecule represented as H2L2?


Answer:

Antibody is also known as Immunoglobulin. It is a large Y-shaped protein, produced by the plasma. It has two light chains (L2) and two heavy chains(H2) hence the representation H2L2 .Antibodies are produced in response to various antigens (bacteria, virus, fungi etc.) as an immune response.



Question 15.

What does the term `memory' of the Immune system mean?


Answer:

Memory of the immune system means the body remembers the antigen, recognise it from previous encounter and initiate the immune response against it.

During this response the body produces B & T memory cells which are clones of the B and T lymphocyte cells already present in the body.



Question 16.

If a patient is advised Anti Retroviral Therapy, which infection is he suffering from? Name the causative organism.


Answer:

If a patient is advised Anti Retroviral Therapy the patient is suffering from Acquired Immune Deficiency Syndrome (AIDS).The causative organism is a virus called HIV or Human Immuno Deficiency Virus .This virus spreads through contaminated blood, reuse of HIV infected needles etc.




Short Answer Type
Question 1.

Differentiate between active immunity and passive immunity.


Answer:




Question 2.

Differentiate between benign tumor and malignant tumor.


Answer:




Question 3.

Do you consider passive smoking is more dangerous than active smoking? Why?


Answer:

The term Passive smoking means indirectly inhaling the smoke produced by someone else, also known as second-hand smoke. It is equally dangerous as active smoking because an individual inhales nicotine and other harmful substances which may lead to emphysema, lung cancer, coronary heart disease and many more.



Question 4.

“Prevention is better than cure”. Comment.


Answer:

“Prevention is better than cure” the saying is true. It is because if any disease enters the body it may cause irreparable damage and discomfort to the affected person. Hence, prevention is a better option.



Question 5.

Explain any three preventive measures to control microbial infections.


Answer:

Three preventive measures to control microbial infections are:

1. Overcrowded places should be avoided. So as to avoid exposure to already infected people and other microbes in the air.


2. Preventive vaccination could be done.


3. Personal as well as community hygiene should be maintained so as to avoid the growth of microbes.



Question 6.

In the given flow diagram, the replication of retrovirus in a host is shown. Observe and answer the following questions.

a. Fill in (1) and (2)

b. Why is the virus called retrovirus?

c. Can the infected cell survive while viruses are being replicated and released?




Answer:

1) A. Block 1: Viral DNA is produced by reverse transcriptase.


B. Block 2: New viral RNA is produced by the infected cell.


2) RNA is the genetic material of this virus.So it produces DNA by reverse transcription. Hence, it does not follow central dogma hence,is known as retrovirus.


3) Yes, the infected cell survives while viruses are being replicated and released.



Question 7.

“Maintenance of personal and public hygiene is necessary for prevention and control of many infectious diseases”. Justify the statement giving suitable examples.


Answer:

Maintenance of personal and public hygiene is necessary for prevention and control of many infectious diseases because if the hygiene is not maintained microbes would grow and would easily get transmitted.

It can be maintained by taking the following measures:


1. Education: People should be well informed about hygiene, communicable disease and their prevention.


2. Sanitation: Proper sanitation should be provided so that air and water would not get contaminated.


3. Isolation: Infected person should be kept isolated from the rest to minimise the spread of infection.


4. Vaccination: Proper vaccination should be done to control the spread of infection.


5. Sterilisation: It should be done to avoid spreading of infection.



Question 8.

The following table shows certain diseases, their causative organisms and symptoms. Fill the gaps.




Answer:




Question 9.

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 consumption of these drugs.




Answer:

a. It belongs to Cannabinoids group of drugs.


b. This drug can be consumed either orally or Inhalation.


c. The cardiovascular system of the body is most affected.



Question 10.

Give the full form of CT and MRI. How are they different from each other? Where are they used?


Answer:

CT: Computed Tomography


MRI: Magnetic Resonance Imaging




Question 11.

Many secondary metabolites of plants have medicinal properties. It is their misuse that creates problems. Justify the statement with an example.


Answer:

Many secondary metabolites of plants have medicinal properties but their misuse creates problems because tehy could be drugs like opium, heroin, LSD etc which are the chemical compounds that act on receptor of the brain They make a person relax, improves their strength, free from pain, nausea and anxiety.



Question 12.

Why cannabinoids are banned in sports and games?


Answer:

Cannabinoids are the chemical compounds that act on the Cannabinoid receptor of the brain irrespective of their origin. They make a person relax, improves their strength, free from pain, nausea and anxiety. Example: CBGA, THCA etc.

These drugs are banned in sports as they are known to enhance performance and have an adverse affect on the player’s health in a long run.



Question 13.

What is secondary metabolism?


Answer:

These are small pathways or products that are not necessarily important for the growth or survival of an organisms hence are termed as secondary metabolites like antibiotics and pigments produced in bacteria, fungi etc.



Question 14.

Drugs and alcohol give short-term 'high' and long-term ‘damages’, Discuss.


Answer:

Drugs and alcohol give short-term 'high' and long-term ‘damages’ this statement holds true because:

1. Alcohol and drugs may irritate the lining of the stomach and can trigger nausea, vomiting and other gastric troubles.


2. As alcohol is a CNS (Central Nervous System) depressant it may slow down various bodily functions like breathing, heart rate etc.


3. The dependency on alcohol makes a person depressed.


4. The person may suffer from constant fatigue, sleepiness or sleeplessness.



Question 15.

Diseases like dysentery, cholera, typhoid etc., are more common in overcrowded human settlements. Why?


Answer:

Diseases like dysentery, cholera, typhoid etc.are mainly contaminated water based diseases and are more common in overcrowded human settlements because in case of open excretion, the water gets mixed with the infected excreta and the contaminated water spreads the disease further.



Question 16.

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


Answer:

Cannabinoids are the chemical substances that mainly act on the cannabinoid receptor in the brain.


Obtained from: Inflorescence of Cannabis Sativa.


Example of Cannabinoids: Marijuana, Ganja and Charas etc.


Body part affected: Cardiovascular System is he most affected.



Question 17.

In the metropolitan cities of India, many children are suffering from allergy/asthma. What are the main causes of this problem. Give some symptoms of allergic reactions.


Answer:

In the metropolitan cities of India, many children are suffering from allergy/asthma because:

1. All these cities are highly polluted due to the increased use of vehicles, factories and construction which releases pollutants and allergens like dust, smoke in the air.


2. This increased pollution lowers immunity in children and make them more sensitive towards the allergens.


Symptoms:


The general symptoms include:


1. Breathing Difficulty.


2. Sneezing


3. Runny Nose


4. Burning and watery eyes.



Question 18.

What is the basic principle of vaccination? How do vaccines prevent microbial infections? Name the organism from which hepatitis B Vaccine is produced.


Answer:

1. Vaccination is the process of injecting weak or inactive pathogen of a specific disease in the body of an individual.


2. This makes the body generate an immune response by releasing antibodies with memory B and T cells.


3. So, when a vaccinated person is attacked by the same pathogen again, naturally the body remembers and recognise the antigen and release the same antibodies and lymphocytes against it.



Question 19.

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


Answer:

Mutation in the genes may lead to uncontrollable and rapid division of the cells forming a mass or tumour. This mass is known as cancer. A cancer cell is different than the normal cell because they metastise that is move from one place to another through lymphatic system and the bloodstream and are highly invasive.

Normal cells attain cancerous nature when the normal genes goes through mutation which is the alteration in the nucleotide sequence.These mutation occurs due to exposure to UV rays, genetic make up or other radiations.



Question 20.

A person shows strong unusual hypersensitive reactions when exposed to certain substances present in the air. Identify the condition. Name the cells responsible for such reactions. What precaution should be taken to avoid such reactions?


Answer:

This unusual hypersensitive reaction is allergy, caused due to exposure towards allergens. Mast cells are responsible for such reactions. When an allergen binds to the IgE receptors on the mast cell a response is seen.

Precautions:


1. Avoid exposure to such allergens.


2. Take medicines as prescribed.



Question 21.

For an organ transplant, it is an advantage to have an identical twin. Why?


Answer:

Transplantation is the procedure of replacing the unhealthy organ with a healthy one in an individual. Sometimes these replaced organs get rejected by the body’s immune system as they are considered as a foreign object by the body. In response to this, cell mediated immune response takes place by T-Lymphocytes. These lymphocytes try to differentiate between self cells and foreign cells because of which sometimes the graft gets rejected. To avoid this, blood groups and tissue matching is done. In the case of identical twins the chances of graft rejection is less because blood group and tissue match is easy.



Question 22.

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


Answer:

Lifestyle diseases are the diseases caused because of the way a person lives his life or his daily habits and routine. These diseases occurs because of:

1. Unhealthy eating.


2. Intake of substances like alcohol, drugs and cigarettes etc.


3. Lack of physical activity and exercise.


Lifestyle disorders are:


1. Type II Diabetes:High or low blood sugar level is caused due to unhealthy eating, excessive stress and lack of exercise etc.


2. Hypertension:Increased blood pressure due to extreme stress and lack of exercise .



Question 23.

If there are two pathogenic viruses, one with DNA and other with RNA, which would mutate faster? And Why?


Answer:

If there are two pathogenic viruses, one with DNA and other with RNA than the one having RNA would mutate faster because RNA being a single stranded structure is quiet unstable and is able to mutate at a faster rate. Hence, the organism would have a shorter life span and would evolve rapidly.




Long Answer Type
Question 1.

Represent schematically the life cycle of a malarial parasite.


Answer:

Malaria is a mosquito born disease caused by female anopheles mosquito.


Symptoms of Malaria:


1. Headache


2. Fever, chills, and sweating.


3. Muscular Fatigue and pain.


4. Spleen Enlargement


5. Nausea and Vomiting.


Life cycle of Malarial Parasite:



1. The female anopheles mosquito transmits the motile infective form called sporozite to a vertebrate host such as humans.


2. These Sporozites infect the liver where they asexually multiply and mature to form Schizonts.


3. These Schizonts rupture and release Merozoites.


4. Now, Merozoites enter RBC’s where they multiply asexually and infect the RBC leading to cycles of fever.


5. He ring stage trophozites mature into schizonts which release merozites or parsites.


6. Some parasites form gametophytes.


7. The gametophytes produced are ingested by the female anopheles mosquito when it bites the infected person.


8. The parasites then multiply in the gut of the mosquito known as sporogonic cycle.


9. Now, these microgametes enter macrogametes and form zygotes.


10. These zygotes now become motile and elongated called as sporozite.



Question 2.

Compare the life style of people living in the urban areas with those of rural areas and briefly describe how the life style affects their health.


Answer:


The following factors lead to poor health conditions in villages because of lack of proper hygiene, sanitation and basic health facilities.



Question 3.

Why do some adolescents start taking drugs. How can this be avoided?


Answer:

Drugs are chemical substances that have a psychological and physiological affect on your system. Some drugs are illegal such as Cocaine, Morphine,Heroin, LSD etc.

Some adolescents start taking drugs :


1. Peer pressure:


Sometimes peers pressurise a person into taking drugs,so a person starts taking drugs to make themselves accepted in the social circle.


2. Feeling of Betterment:


People start taking drugs to feel better or get a feeling of euphoria.This feeling arises when the drugs interact with the neurological receptors in the brain.


3. Experimentation:


Some people do drugs to experiment, to feel the thrill and excitement behind it.


4. Depression:


Some people take drugs to combat depression. Drugs make a person feel happy and relaxed.


These can be avoided:


1. The person try to deal with the pressure by talking to friends, family or any professional help can also be taken.


2. Strictly say ‘NO’ to any person forcing drugs on you.


3. A person should not give into peer pressure.


4. Stay healthy, eat healthy and do lot of exercises and physical activity.



Question 4.

In your locality, if a person is addicted to alcohol, what kind of behavioural changes do you observe in that person? Suggest measures to overcome the problem.


Answer:

If a person is addicted to alcohol some behavioural changes are seen such as:

1. If a person is addicted, an individual would develop selfish attitude and may deprive his family for the needs to fulfil their own.


2. Significant time is required to get over the influence of alcohol.


3. Reduced attention to personal and professional life.


4. Withdrawal symptoms are seen when alcohol intake stops.


5. Repeated unsuccessful attempts to stop alcohol intake.


Measures to overcome Alcoholism:


1. Seek professional help if required.


2. Talk to family and friends about the issue.


3. Set a drinking limit to drink below the recommended guidelines.


4. Try getting busy with personal and professional life.


5. Watch out for peer pressure. Do not give in to social pressure.



Question 5.

What are the methods of cancer detection? Describe the common approaches for treatment of cancer.


Answer:

Mutation in the genes may lead to uncontrollable and rapid division of the cells forming a mass or tumour. This mass is known as cancer. A cancer cell is different from a normal cell as cancer cells are able to metastasize, that is move from one place to another through lymphatic system and the bloodstream, and are highly invasive.


Methods of cancer detection are:


1. Bone marrow biopsy:


Removal of a small piece of bone within the bone marrow is done to detect the cancer cells.


2. Endoscopic Assessment:


A long, thin lighted tube having X-ray is inserted inside the organ which is to be detected.


3. CT Scan:


CT scan or computed tomography is done which uses X-rays to detect any abnormalities like lumps, tumour within the internal body structures.


4. Monoclonal Antibodies:


These are used in detecting the antigens of the small molecules produced by the cancerous cells.


5. MRI: Magnetic Resonance Imagining is done using magnetic radiations and radio frequencies to detect any abnormality in the soft tissues.


6. Ultrasound:


In this test sound waves are used to produce images of the internal body organs and checking for any abnormality in them.



Question 6.

Drugs like LSD, barbiturates, amphetamines, etc., are used as medicines to help patients with mental illness. However, excessive doses and abusive usage are harmful. Enumerate the major adverse effects of such drugs in humans.


Answer:

Drugs are chemical substances that have a psychological and physiological affect on your system but overdose may lead to the following adverse affects:

1. Anxiety and shakiness is seen in cases of overdose.


2. Nausea and vomiting.


3. Lack of interest in personal and professional life.


4. Social adjustment problems are seen.


5. Withdrawal symptoms are seen.


6. Reckless behaviour, violence and vandalism.


7. Fatigue, restlessness and aggressive behaviour are seen.


8. General lack of interest is seen.


Coping with the issue:


1. The person try to deal with the pressure by talking to friends, family or any professional help can also be taken.


2. Strictly say ‘NO’ to any person forcing drugs on you.


3. A person should not give into peer pressure.


4. Stay healthy, eat healthy and do lot of exercises and physical activity.



Question 7.

What is Pulse Polio Programme of Government of India? What is OPV? Why is it that India is yet to eradicate Polio?


Answer:

1. Polio also known as Poliomyelitis is an infectious disease caused by polio virus which leads to muscle weakness and further inability to move.


2. Pulse Polio Programme is the Government of India initiative to abolish Polio from India since 1995.


3. In this programme all children below the age of five are immunised orally against the polio virus.


4. It included 100% coverage within all the states and Union territories.


5. The programme aimed to eradicate polio from India.


OPV:


1. OPV is Oral Polio Vaccine. This vaccine is used to eradicate polio.


2. In OPV a weakened polio virus is given orally through mouth.


3. OPV consists of a mixture of live attenuated polio virus strains which are injected inside the body to initiate an immune response.


4. The body remembers this response when an actual polio virus enters the body and protects it.


5. One dose of OPV produce long lasting immunity towards all three types of strains of the polio virus.


India is yet to eradicate Polio because even after so many initiatives by the government of India some cases are being reported. This could be because of lack of education, lack of information and inaccessibility in certain areas.



Question 8.

What are recombinant DNA vaccines? Give two examples of such vaccines. Discuss their advantages.


Answer:

1. These are third generation vaccines.


2. They are made up small piece of circular DNA called Plasmids.


3. These plasmids are genetically engineered to produce specific proteins of a pathogen.


4. When these are injected into the body, the body reads the DNA and the host cell start synthesising pathogen proteins.


5. As these proteins are considered as foreign substance. The body starts an immune response.


6. Now, the body recognises the pathogen whenever it enters and initiates the response.


Example:


1. Bird Flu virus vaccine for humans.


2. West Nile virus vaccine for horses.


Advantage:


1. Their is no risk of infection.


2. They initiate both cell mediated and humoral immune response.


3. Initiate a long term immune response.