You can Download Chapter 8 Human Health and Disease Questions and Answers, 2nd PUC Biology Question Bank with Answers, Karnataka State Board Solutions help you to revise complete Syllabus and score more marks in your examinations.

2nd PUC Biology Question Bank Chapter 8 Human Health and Disease

2nd PUC Biology Human Health and Disease NCERT Text Book Questions and Answers

Question 1.
What are the various public health measures, which you would suggest as safeguard against infectious diseases?
Answer:
Public Health Measures:-

  • Garbage – regularly disposed at proper locations. Containers to be properly cleaned should be reused or recycled when applicable.
  • Drainage – To be covered to prevent flies and mosquito. Stag nation of water near household to be removed. Slums to be cleaned.
  • Water reservoirs- To be covered and periodically cleaned and disinfected.
  • Sewage disposal – Properly treated before find disposal.
  • Public places – To be kept clean and fogging to be done periodically.
  • Pollution – Antipollution laws to be enforced strictly.
  • Vaccination and medical care Periodic medical examination and vaccination to be taken properly.
  • Drinking water- To be free from contamination.
  • Facilities- Public toilets and bathrooms to be provided.

Question 2.
In which way has the study of biology helped us to control infectious diseases?
Answer:

  • Helps to properly diagnose the problem and treat them
  • Life cycle, host, reservoir, vectors, agents all can be studied and identified
  • Mechanism of transmission of pathogens to humans are known
  • Protective measures against catching the diseases are suggested.
  • Vaccines and medicines against pathogen are worked out.

Question 3.
How does the transmission of each of the following diseases take place?
(a) Amoebiasis
(b) Malaria
(c) Ascariasis
(d) Pneumonia
Answer:
(a) Amoebiases – Family disposal of faecal matter causing contamination of drinking water and food. Houseflies and air current transport cysts Pet animals.
(b) Malaria – Female Anopheles inject sporozoites along with saliva
(c) Ascariasis – Food particles, dirty hands, taps, soaps etc., by faecal
(d) Pneumonia – Droplets and aerosols of infected person.

Question 4.
What measure would you take to prevent water-borne diseases?
Answer:

  • All water resources, pools, tanks to be cleaned regularly and prevent this contamination. Only properly treated water should be added to it.
  • Use only purified and disinfected water for drinking.
  • Prevent passage of sewage and garbage into water bodies

Question 5.
Discuss with your teacher what does ‘a suitable gene’ means, in the context of DNA vaccines.
Answer:
In DNA vaccines suitable gene means gene controlling formation of immunogenic protein. Gene integrated with vectors immunize a person.

KSEEB Solutions

Question 6.
Name the primary and secondary lymphoid organs.
Answer:

  • Primary lymphoid organs – Organs where B & T – lymphocytes are formed,mature and require antigen specific receptors – Bone marrow and thymus.
  • Secondary lymphoid organs – place or residence of nature lymphocytes – lymph nodes, spleen, tonsils, Peyer’s patches and mucosal surfaces.

Question 7.
The following are some well-known abbreviations, which have been used in this chapter. Expand each one to its full form:
(a) MALT
(b) CMI
(c) AIDS
(d) NACO
(e) HIV
Answer:
(a) MALT – Mucosal associated lymphoid tissue.
(b) CMI – Cell Mediated Immunity
(c) AIDS – Acquired Immuno Deficiency Syndrome
(d) NACO – National AIDS Control Organisation
(e) HIV – Human immunodeficiency virus.

Question 8.
Differentiate the following and give examples of each:
(a) Innate and acquired immunity
(b) Active and passive immunity
Answer:
(a) Innate and acquired immunity

Innate Innate
Present from birth Develops during life time
 Remains throughout life Short or long life
Contact with antigen not necessary Contact with antigen necessary
Is inheritable Can be inherited for brief period to neonates
Prevents from disease contraction Protects from pathogen and other members of some species.

(b) Active and passive immunity

Active Passive
Due to contact with antigen Obtain antibodies from outside
Not immediate Develops immediately
Lasts for sufficiently long time Lasts for few days
Antibodies are produced by body
Side effects are few
Antibodies obtained from outside.

Question 9.
Draw a well-labelled diagram of an antibody molecule.
Answer:
2nd PUC Biology Question Bank Chapter 8 Human Health and Disease 1

Question 10.
What are the various routes by which transmission of human immunodeficiency virus takes place?
Answer:

  • Sexual contact with infected person.
  • Through blood transfusion.
  • By sharing infected needles in case of intra venous drug abusers.
  • From mother to child through placenta.

Question 11.
What is the mechanism by which the AIDS virus causes deficiency of immune system of the infected person?
Answer:
Macrophages helper T-cells and some nerve cells possess T-4, OV CD-4 antigen receptor sites over their surface. HIV gets attached to these site and passes into cells. It multiplies in cells. Virus particles bud out of the cells which die afterward.

The newly released – virus particles attack new cells especially the helper T-cells. Soon the number of helper T- cells decreases. Since helper T-cells are essential for functioning of immune system their reduced number results in deficient functioning of immune system of the infected person.

Question 12.
How is a cancerous cell different from a normal cell?
Answer:
Normal cells remain adhered to one another. They have a definite life span. As some old cells die, they are replaced by new cells which arise by cell division and differentiation. Cancerous cells:- Whenever there is break down of any regulatory mechanism, a cell develops the ability to undergo uncontrolled repeated division forms a clone at cells.

There is no adherence. The cells slip past one another forming a mass of undifferentiated cells called neoplasm or tumour. Tumour results in pressing of surrounding normal cells and tissues causing discomfort and disruption of their functioning.

Question 13.
Explain what is meant by metastasis.
Answer:
The rapid growth of cancerous tumour causes overcrowding and disruption of normal cells. It extends to neighbouring tissues. In the last stage, bits of tumour tissue breakoff and are carried by the circulating blood or lymphs to other parts of the body, where they invade new tissues and start new tumors called secondary tumors. This property is called metastasis. It is fated due to increasing interference with the body’s life processes.

Question 14.
List the harmful effects caused by alcohol/ drug abuse.
Answer:

  • Addicts show reckless behaviour vandalism and violence. Self-confidence lost
  • Neural and neuromuscular junctions are effected.
  • Addiction disturbs peristalsis and secretion of digestive enzymes.
  • Disturbs digestive and nervous systems leads to frequent nausea and vomiting.
  • Effects on cardiovascular system.
  • Damage to liver causes cirrhosis.
  • Insufficiency develops in reproductive system.

KSEEB Solutions

Question 15.
Do you think that friends can influence one to take alcohol/drugs? If yes, how may one protect himself/herself from such an influence?
Answer:
Yes. This can be avoided by

  • Choosing good peer group.
  • Discussing ways and means to counteract the presence if any with family elders and teacher/counsellors
  • Telling the programme of outing to family.
  • Keeping contact with family while outside the home.

Question 16.
Why is that once a person starts taking alcohol or drugs, it is difficult to get rid of this habit? Discuss it with your teacher.
Answer:
A discusses to be done.

Question 17.
In your view what motivates youngsters to take to alcohol or drugs and how can this be avoided?
Answer:

  • Choosing good peer group.
  • Discussing ways and means to counteract the presence if any with family elders and teacher/counsellors
  • Telling the programme of outing to family.
  • Keeping contact with family while outside the home.

2nd PUC Biology Human Health and Disease Additional Questions and Answers

2nd PUC Biology Human Health and Disease One Mark Questions

Question 1.
What do you mean by “Health’?
Answer:
Health is the state of complete physical, mental and social well being.

Question 2.
Name 2 non infectious diseases which are the major cause of mortality?
Answer:
Hepatitis-B, AIDS.

Question 3.
What are pathogens?
Answer:
The organisms which cause diseases in man are called pathogens.

Question 4.
Define diseases.
Ans :
Disease is the condition when the functions of one or more organs/systems of the body are adversely affected by various symptoms.

Question 5.
“All pathogens are parasites” Why?
Answer:
Because they cause damage to the host body by living inside the body of host.

Question 6.
Name 2 protozoan disease.
Answer:
Amoebiasis, malaria, Kalaazar

Question 7.
Name the vectors of malaria and dengue fever?
Answer:

  • Malaria fever – Female Anopheles mosquito
  • Dengue fever- Female aedes mosquito

Question 8.
Give the scientific name of malarial parasite.
Answer:
Malarial parasite – Protozoan – Plasmodium falciparum

Question 9.
Patients suffering from filariasis suffer, swelling in the lower limbs. Why?
Answer:
The filarial worm live in the lymphatic vessels of the lower limbs, where they cause inflammation, that causes swelling of lower, limbs.

KSEEB Solutions

Question 10.
Expand PMNL.
Answer:
Polymorpho- nuclear leucocytes.

Question 11.
Name the common fungal diseases infects on man.
Answer:
Ring worms.

Question 12.
Name the vector responsible for chikungunya. (Delhi 2008)
Answer:
Aedes mosquito.

Question 13.
Write the role of macrophages in providing immunity to humans. (Delhi 2008)
Answer:
Macrophages are phagocytes and through phagocytes they destroy the microbes.

Question 14.
Write the full form of LSD. (CBSE 1994)
Answer:
D-Lysergic acid diethyl amide

Question 15.
What are Psychotropic drugs. (CBSE 1995)
Answer:
These are mood altering drugs which selectively affect behaviour perception and mental activity of a person using them.

Question 16.
Write the full name of pathogen that causes AIDS? (CBSE 1996)
Answer:
Human immunodeficiency virus – HIV

Question 17.
Define the term vaccine.
Answer:
Vaccine is a suspension of killed or alternated pathogenic macro organism or antigenic preparations made out of it which on administration provides immunity towards the pathogen.

Question 18.
What is AIDS (HS&B 98)
Answer:
Acquired Immuno Deficiency Syndrome.

Question 19.
Define Addiction. (HS&B 2001)
Answer:
Addiction is the state of giving up to a drug, alcohol or tobacco due to becoming physically, physiologically and psychologically attached to its certain effects like euphoria and temporary feeling of well being.

Question 20.
What is immunity. (HS&B 2003)
Answer:
Immunity is a natural or acquired ‘resistance of an individual to the development of pathological condition even after having received infective dose of virulent pathogen its taxis or an allergies.

Question 21.
Name 2 major group an of cells required in attaining specific immunity. (CBSE 2005)
Answer:
B-lymphocytes, T-lymphocytes.

Question 22.
Name the disease in humans where the myelin sheath of nerve cells is attacked by antibodies of itself. (CBSE 2005)
Answer:
Multiple sclerosis.

Question 23.
What are interferon?
Answer:
Interferon are the proteins produced by virus infected cells in our body.

Question 24.
Why is antibody-mediated immunity called humoral immunity?
Answer:
Antibodies are the glycol proteins that circulate in the body fluids (humors) hence it is called humoral immunity.

Question25.
Give 2 examples of passive immunity.
Answer:

  • The antibodies IgA in colostrum
  • Antibodies received by foetus through placenta.

Question 26.
How does colostrum provide initial protection against diseases to newborn infants? Give reason.
Answer:
Colostrum contains antibodies like IgA, which provide initial protection against diseases.

Question 27.
While 2 features of acquired immunity.
Answer:

  • It is pathogen specific
  • It is characterised by memory.

KSEEB Solutions

Question 28.
Name 2 types of cells in which the HIV multiplies after gaining entry into the human body.
Answer:
Macrophages and Helps T cells.

Question 29.
Why is the bone marrow considered as the main lymphoid tissue of our body.
Answer:
Because in bone marrow along with blood cells lymphocytes are produced.

Question 30.
What is MALT?
Answer:
MALT refers to the lymphoid tissue located with in the lining of the major tracts (respiratory, digestive, urogenital tract)

Question 31.
Expand ELISA.
Answer:
Enzyme linked Immuno-sorbent assay.

Question 32.
Why does an AIDS patient suffer from many other infectious disease?
Answer:
Due to the reduction in number of helper T-cells, the immune system becomes weak. Consequently, the patient suffers from infectious disease.

Question 33.
When is a tumour is referred to as Malignant?
Answer:
Malignant tumor is a mass of proliferating neoplastic cells, which spread to distant sites through body fluids to develop secondary tumors.

Question 34.
What are oncogenic virus?
Answer:
The viruses which cause cancer are called oncogenic virus.

Question 35.
How does tobacco smoking cause oxygen deficiency in the body.
Answer:
Smoking increases the carbon monoxide content of the blood that refuses.

Question 36.
What type of cells provide Innate immunity?
Answer:
Neutrophils.

Question 37.
What is drug abuse.
Answer:
When drugs are taken for a purpose other than their normal clinical use and in amounts concentrations or frequency that impairs one’s physical, physiological and psychological functions, it constitute drug abuse.

Question 38.
Write any 2 uses of morphine.
Answer:

  • Used as selective
  • Used as painkiller especially in patients who have undergone surgery.

Question 39.
Name the phylum and disease caused by Wucheria Bancroft (CBSE 2005)
Answer:

  • Phylum – Nemathelminthes
  • disease:- Elephantiasis (filaria)

2nd PUC Biology Human Health and Disease Short Answer Type Questions

Question 1.
Mention any 2 measures for prevention and control of alcohol and drug abuse among adolescents.
Answer:

  • Communication: An adolescent should be able to disuses problems in studies, games, friends etc. with parents who should also know all the friends of the child.
  • Avoid undue pressure: The child should not be asked to perform beyond thresholdjimits whether in studies, sports or extra curricular activities.

Question 2.
In which parts of the body of the hosts do the following events in the life cycle of plasmodiurfi take place? Name both the body parts and the host.
(a) Fertilization
(b) Development of gametocytes
(c) Release of Sporozoites
(d) Asexual reproductions.
Answer:
(a) Fertilization: Inside stomach/intestine of mosquito host.
(b) Development of Gamete cites:- In blood of human host.
(c) Release of sporozoites – In to the blood of human host
(d) Asexual Reproductions – Inside liver cells and-RBC’s of human host.

Question 3.
Write the specific symptoms of typhoid.
Name its causative agent. (AI – 2009)
Answer:
Symptoms of typhoid:

  • Sustained high fever
  • Loss of appetite
  • Stomach pain
  • Headache and weakness
  • Intestinal perforations severe cases may cause death causative agent of typhoid is Salmonella typhi.

Question 4.
Write the scientific names of two helminthiasis that are pathogene to man. Name the disease caused by them.
Answer:

  • Ascaris lubricoides causes Ascariasis
  • Wuchereria bancroffi causes filariasis or elephantiasis.

Question 5.
Write the symptoms of pneumonia.
Answer:

  • Fluid-filled alveoli
  • Cough and head ache
  • Fever
  • The nails turns gray to bluish in severe cause.

Question 6.
Name and explain the type of barrier of innate immunity where some cells release inteifetofts when infected.
Answer:
Cytokinin barriers

  • Cells infected by virus release interferons
  • Interferons provide protection to non infected cells from infection.

Question 7.
How do saliva and tear help to prevent bacterial infection?
Answer:
Saliva and tear consists of lysozymes Lysosomes are enzyme which can digest the bacterial cell wall which helps to kill bacteria.

Question 8.
Name and explain the type of barrier of innate immune system, which involves.
Answer:
Cellular barrier
This barrier involves certain types of

  • Polymorphs nuclear leucocytes
  • Monocytes
  • Natural killed cells
  • Macrophages.

KSEEB Solutions

Question 9.
Differentiate between Primary response and secondary response.
Answer:

Primary response Secondary response
The immune response that occurs at the first encounter of the body with antigen is called -primary immune response The immune response that occurs at the second and subsequent, encounters of the body with the antigen is called secondary immune response
It declines rapidly It is severe and lasts for long time

Question 10.
Differentiate between T lymphocyte and B- lymphocyte.
Answer:

T lymphocyte B- lymphocyte.
These are lymphocyte which undergo maturation in thymus Maturation undergo in bone marrow
They constitute cell mediated immune and don’t produce antibodies They constitute the humoral immune response and produce antibodies
They react to organ transplants Don’t respond to organ transplants.

Question 11.
How do B-lymphocyte cells direct humoral immunity?
Answer:
The B-lymphocyte cells multiply in number in response to the attack by antigen. They start producing characteristics proteins called antibodies. These antibodies circulate in the body fluids and act against the pathogen/ antigens.

Question 12.
Describe the cell mediate immunity.
Answer:
Cell mediate immune response is effected by T-lymphocyte. These are two types of T- lymphocytes.

  • Cytotoxic or killer T- cells, which kill the antigens in a variety of mechanisms.
  • Helper T-cells slimulate the B-lymphocyte to produce antibodies. This immunity is responsible for rejection of transplants.

Question 13.
Elst specific symptoms of amoebiases write its causative agent. (CBSE 2009)
Answer:
Symptoms of amoebiasis

  • The patient passes out blood and mucus with the stool.
  • Severe griping pain in the abdominal, fever nausea, exhaustion and nervousness.
    In chronic case, intestinal wall punctures. The causative agent is Entamoeba histolytica.

Question 14.
Explain metastasis. Why is it fatal?
Answer:
The rapid growth of cancerous tumour causes overcrowding and disruption of normal cells. It extends to neighbouring tissues. In the last stage, bits of tumour tissue breakoff and are carried by the circulating blood or lymphs to other parts of the body, where they invade new tissues and start new tumors called secondary tumors. This property is called metastasis. It is fated due to increasing interference with the body’s life processes.

Question 15.
What is vaccination? How does it help in producing immunity?
Answer:
The process of introducing a preparation of antigenic proteins of the pathogens or weakened or killed pathogen into the body.

  • The vaccines induce quick multiplication of B and T lymphocytes, some of them are stored as memory cells.
  • The B-lymphocytes quickly produce antibodies which neutralise the antigen during infection.

Question 16.
What are lymph nodes? What is their function in our immune system?
Answer:
Lymph nodes are small solid structures located at different points along the lymphatic system. They serve to tray the microbes and other antigens. These antigens trapped in the lymph nodes are responsible for the activation of lymphocytes to cause the immune system.

Question 17
(a) Explain the property that prevents normal cells from becoming cancerous
(b) All normal cells have inherent characteristics of becoming cancerous. Explain. (CBSE2009)
Answer:
(a) Contact inhibition
(b) All normal cells have several genes called cellular oncogenes or proto oncogenes.
These genes are activated under certain conditions can lead to oncogenic transformation of cells, i.e. cancer can result.

Question 18.
Write the importance of molecular biology in preventing cancer.
Answer:
Techniques of molecular biology can be applied to detect genes in individuals with inherited susceptibility to certain cancers. Identification of such genes, which predispose individuals to certain cancers may be helpful in prevention of cancer, such individuals are advised to avoid exposure to particular carcinogens to which they may be susceptible.

Question 19.
Why do sports persons always caught by authorities for cocaine addiction? (CBSE2008)
Answer:
Sports persons become addicted to cocaine because.

  • Cocaine has a potent stimulating action on central nervous system.
  • It produces a sense of euphoria and increased energy for performance.

Question 20.
Name one plant and the additive drug extracted from its latex. How does this drug affect the human body? (CBSE 2009)
Answer:
Morphine is obtained from the plant Papaver somniferum (poppy plant).
It is an opioid that binds to specific receptors in the central nervous system and gastro intestinal tract and slows down the body function.

Question 21.
Give four reason to justify the intake of cannabinoids by sports person (A.I. 2008)
Answer:

  • Cannabinoids affect the cardio vascular system.
  • They cause addiction and when the regular dose is not taken, there are unpleasant one term with drawl symptom, which may be life threatening.
  • The person shows reckless behaviour vandatism and violence
  • Excess does can lead to coma and death due to heart failure cerebral hemorrhage etc.

2nd PUC Biology Human Health and Disease Short Answer Type Questions

Question 1.
Mention 3 major categories of factors that affect the health of a person.
Answer:
Health is affected by
(i) genetic disorders:- the defects, deficiencies that are inherited from parents due to defective genes.
(ii) Infections caused by pathogens.
(iii) Life styles which includes

  • Food and water (eating habits)
  • Rest and exercise to the body
  • Habits like drugs, alcohol etc.

Question 2.
How do normal cells get transformed into cancerous neoplastic cells? Mention the difference between viral oncogenes and cellular oncogenes (Foreign 2008)
Answer:
The transformation of normal cells into cancerous neoplastie cells is induced by physical clinical and biological agents collectively called careinogenes, they lose the property of contact inhibition.
Differences between viral oncogenes and cellular oncogenes are

  • Viral oncogenes are the genes present in I the oncogenic virus which affect oncogenic transformation of the cells they infect.
  • Cellular oncogenes are the genes presents in normal cells and code for growth factors, when activated under certain condition can cause oncogenic transformation of the cell.

KSEEB Solutions

Question 3.
What are the side effects of the use of anabolic steroids by females?
Answer:
The side effects in females includes

  • Increased aggressiveness
  • Abnormal menstrual cycle
  • Excessive hair growth on the face and body
  • Enlargement of elitoris
  • Deepening of voice
  • Mood swings and depression.

Question 4.
Give the side effects of the use of anabatic steroids in males.
Answer:
The side effects in males includes

  • Reduction in the size of testicles
  • Decreased sperm productions
  • Breast enlargement
  • Premature baldness
  • Enlargement of prostrate gland
  • Development of acne.

Question 5
(a) List any two situations when a medical doctor would recommend injection of performed antibodies into the body of a patient. Name this kind of immunisation
(b) Name the kind of immunity attained when instead of antibody weakend antigens are introduced into the body. (Delhi 2008)
Answer:
(a) The two conditions include the following

  • When a person is infected by a deadly microbe, for which an immediate immune response is required.
  • Snakebite
    This kind of immunisation is called passive imminisation

(b) Active immunity.

Question 6.
Name the stage of plasmodium that a female Anopheles mosquito injects into a healthy person during its bite. Represent schematically the stages of the pathogen developed in the human body, till it is picked up by a mosquito.
Answer:
2nd PUC Biology Question Bank Chapter 8 Human Health and Disease 2

Question 7.
(a) How are primary lymphoid organs different from secondary lymphoid organs. Give an example of each.
(b) Name any 4 types of cells involved in the cellular barriers of innate immunity.
Answer:
(a)

  • Primary lymphoid organs: These are the lymphoid organs where immature lymphocytes differentiate into antigen sensitive lymphocytes.
    E.g. Bonemarrow, thymus.
  • Secondary lymphoid organs: These are the lymphoid organs where the interaction occurs between lymphocytes and antigen and proliferation occurs.
    E.g. Spleen, tonsil.

(b) The cell types are

  • Poly morpho nuclear leucocytes (PMNL)
  • Monocyte
  • Natural killer cells
  • Macrophages

2nd PUC Biology Human Health and Disease Five Marks Questions

Question 1.
Justify the following statements
(i) Smoking leads to deficiency of oxygen in the body tissue.
(ii) Cancer patients are administered – interferon
(iii) Chewing of tobacco causes an increases in blood pressure.
Answer:
(i) Smoking increases the carbon monoxide (CO) content in blood and reduces the concentration of haem-bound oxygen hence there is deficiency of oxygen in the body tissues.

(ii) Tumor cells avoid detection and destruction by our immune system. Interferon like biological modifiers activate the immune system and help in destroying the tumor cells.

(iii) By chewing tobacco the nicotine reaches the blood and stimulates the adrenal glands to release adrenaline and noradrenaline, both these hormones increases the blood pressure.

Question 2.
(i) Draw a labelled schematic diagram of an antibody molecules
(ii) Mention any 4 warning signals of drug abuse in adolescents.
Answer:
(i)
2nd PUC Biology Question Bank Chapter 8 Human Health and Disease 3
(ii) Warning signals of drug abuse:
Aggressive and rebellious behaviour Loss of appetite
Lack of interest in personal hygiene Drop in academic performance Change in sleeping and eating habits .
(i) Define innate immunity Mention any 2 ways in which it is accomplished in our body.
(ii) How does spleen functions as an organ of our immune system.
Ans:
(i) Innate immunity is defined as the non¬specific type of defence with which an individual is bom and in always available to protect the body. It is accomplished by providing different types of barriers to the entry of antigens / pathogens
(a) Physical barriers: Skin of the body is the greater barrier which prevents the entry of microbes. Mucus coating on the epithelium of major tracts help in trapping the microbes that have entered the body.
(b) Physiological barrier:

  • Saliva in the mouth and tear contain an anti bacterial substance.
  • HC1 scented by the stomach (C) Cytokine barriers:
    Interferon are the proteins which are produced by the body cells in response to viral infection and they protect the non-infected cell from viral infection.
  • Spleen acts as filter of blood by trapping the blood borne microbes. It contain phagocytes which destroy the microbes through phagocytosis.

Question 4.
(a) Differentiate between active immunity and passive immunity.
(b) Describe the different methods of treatment of cancer.
Answer:

Active immunity Passive immunity
When antibodies are produced by our β lymphocytes in response to the antigen, it is called active immunity. When ready made antibodies are injected into the body for defence, the immunity produced is called passive immunity.
It lasts for longer periods It lasts for shorter period.

(b) Different methods for the treatment of cancer are

  • Surgery: The tumour cells are surgically removed to reduce the growth of cancerous cells.
  • Radiation therapy: The tumour cells are radiated lethally taking care of the surrounding normal cells.
  • Chemotherapy: Certain drugs are specific for particular tumors, but have side effects like anaemia, hair loss etc.

Question 5.
(a) Represent schematically the life cycle of HIV or Replication of Retro virus.
(b) What are the various routes by which transmission of human immuno deficiency virus takes place?
Answer:
(a)
2nd PUC Biology Question Bank Chapter 8 Human Health and Disease 4
(b) The various ways of the transmission of ratio virus includes

  • Sexual contact with infected persons
  • By the transfusion of blood
  • By the use of infected needles and syringes
  • From infected mother to child through placenta.

Question 6.
Explain the different methods of detecting cancer.
Answer:
Cancer can be detected by

  • Biopsy and histopathological studies of the tissue
  • Using antibodies against cancer-specific antigens
  • Blood and bone marrow test to check the count of WBC and RBC
  • Use of C T scans (Computerised tomography) MRI (magnetic resonance imaging) and X-rays to detect the cancer of internal parts.
  • Applying principles of molecular biology to detect the genes in individuals with inherited susceptibility to cancer.