CBSE Class 12 Biology Human Health and Diseases VBQs

Question. Full form of PMNL is
(a) Poly Morpho-Nuclear Leucocytes
(b) Para Morpho-Nuclear Lymphocytes
(c) Penta Morpho-Nuclear Leucocytes
(d) Poly Morpho-Nuclear Lymphocytes

Answer : A

Question. Note the following words.
I. Skin II. Phagocytes
III. B-cells IV. Neutrophils
V. Antibodies VI. T-cells
VII. Macrophages VIII. NK-cells
Identify the factors involved in second line of defence.
(a) II, IV, VII and VIII
(b) II, III, V and VI
(c) IV, VI, VIII and VIII
(d) III, V, VII and VIII

Answer : A

Question. The process of removal and replacement of the damaged tissues or organs like heart, eye, liver, kidney with healthy ones from a donor is called as
(a) transplantation
(b) repair and replacement
(c) replacement theraphy
(d) transformation

Answer : A

Question. Which of the following are considered as cellular barrier of the body?
(a) Lymphocytes
(b) Neutrophils
(c) Macrophages
(d) All of these

Answer : D

Question. Antibodies are
(a) proteins produced in response to pathogens in our body
(b) secreted by the action of both T-lymphocytes and B-lymphocytes
(c) molecules that specifically interacts with an antigen
(d) Both (a) and (b)

Answer : D

Question. Which of the following immune responses is responsible for rejection of kidney graft?
(a) Humoral immune response
(b) Inflammatory immune response
(c) Cell-mediated immune response
(d) Auto-immune response

Answer : C

Question. The principle of vaccination or immunisation depends on the property of ..... of the immune system. The most appropriate word to fill the blank is
(a) memory
(b) antigen
(c) pathogen
(d) plasma cells

Answer : A

Question. Humans have acquired immune system that produces antibodies to neutralise pathogens. Still innate immune system is present at the time of birth because it 
(a) is very specific and uses different macrophages
(b) produces memory cells for mounting fast secondary response
(c) has natural killer cells which can phagocytose and destroy microbes
(d) provides passive immunity

Answer : C

Question. Which of the following drugs can be used to quickly reduce the symptoms of allergic reaction?
I. Anti-histamine
II. Adrenaline
III. Steroids
(a) I and II
(b) I and III
(c) II and III
(d) I, II and III

Answer : D

Question. Each antibody has ...A... polypeptide chains, ..B..small chains called ...C... chains and ....D... longer chains called ...E... chains. The antibody, therefore, is represented as ... F.. Here A to F refers to
(a) A–four, B–two, C–light, D–two, E–heavy, F–H 2L2
(b) A–six, B–three, C–light, D–three, E–heavy, F–H 3L2
(c) A–two, B–one, C–light, D–one, E–heavy, F–H1L1
(d) A–five, B–two, C–light, D–three, E–heavy, F–H 2L2

Answer : A

Question. Innate immunity is also called
(a) familiar immunity
(b) inborn immunity
(c) genetic immunity
(d) All of these

Answer : D

Question. Asthma may be attributed to
(a) allergic reaction of the mast cells in the lungs
(b) inflammation of the trachea
(c) accumulation of fluid in the lungs
(d) bacterial infection of the lungs

Answer : A

Question. The most abundant class of Immunoglobulins (Igs) in the human body is
(a) IgA
(b) IgM
(c) IgG
(d) IgE

Answer : C

Question. Which of the following mediates allergic reaction?
(a) IgA
(b) IgG
(c) IgE
(d) IgD

Answer : C

Question. Non-specific host defence that exists prior to the exposure to an antigen is called
(a) acquired immunity
(b) passive immunity
(c) innate immunity
(d) active immunity

Answer : C

Question. The cell-mediated immunity inside the human body is carried out by
(a) T-lymphocytes
(b) B-lymphocytes
(c) thrombocytes
(d) erythrocytes

Answer : A

Question. Which of the following is a suitable example of cytokine barrier?
(a) Interferons
(b) T-lymphocytes
(c) B-lymphocytes
(d) TH cells

Answer : A

Question. In higher vertebrates, the immune system can distinguish self and non-self cells. If this property is lost due to the genetic abnormality and it attacks self-cells, then it leads to 
(a) graft rejection
(b) autoimmune disease
(c) active immunity
(d) allergic response

Answer : B

Question. The figure given below shows an antibody molecule.
Name the parts A, B and C.
Q.67 p.208
(a) A–Antigen binding site, B–Heavy chain, C–Light chain, D–Disulphide bond
(b) A–Antibody binding site, B–Light chain, C–Heavy chain, D–Phosphoester bond
(c) A–Antigen binding site, B–Short chain, C–Long chain, D–Sulphur bond
(d) A–Antibody binding site, B–Long chain, C–Short chain, D–Disulphide bond

Answer : A

Question. The interferons can be used as
(a) antibacterial drugs
(b) antiviral drugs
(c) antibiotic drugs
(d) immunosuppressive

Answer : B

Question. Humoral immunity is also called as
(a) antibody mediated immunity
(b) non-specific immune response
(c) antigen mediated immunity
(d) None of the above

Answer : A

Question. The major phagocytic cells are
(a) antibody
(b) antigen
(c) lymphocytes
(d) macrophages

Answer : D

Question. A substance that causes an allergic reaction is called
(a) allergen
(b) pollen
(c) foreign substance
(d) dander

Answer : A

Question. Interferon is a type of protein, which can be used to counter
(a) homeostatic disorder
(b) hepatitis caused by virus
(c) common cold caused by virus
(d) Both (b) and (c)

Answer : D

Question. If a quick immune response is needed as in tetanus infection, preformed antibodies or antitoxin is injected into the patient body. This type of immunisation is called ……… .
(a) active immunisation
(b) passive immunisation
(c) innate immunity
(d) humoral immunity

Answer : B

Question. Active immunity is an immunity gained after
(a) natural infection
(b) exposure to live pathogen
(c) immunisation
(d) Both (a) and (b)

Answer : D

Question. Which of the following is involved in passive immunity? 
(a) IgA
(b) IgE
(c) IgM
(d) IgD

Answer : A

Question. Choose the correct option regarding antibodies.
(a) IgA - Helps in allergic reaction
(b) IgG - Cross placenta
(c) IgE - Found in secretions
(d) IgM - Exist as dimer

Answer : B

Question. Which type of barriers do saliva in the mouth, tears form eyes and acid in the stomach belong?
(a) Cytokinin barriers
(b) Cellular barriers
(c) Physiological barriers
(d) Physical barriers

Answer : C

Question. Active immunity development is related to
(a) natural killer cells
(b) memory cells
(c) helper T-cells
(d) suppressor T-cells

Answer : B

Question. Common examples of allergens are
(a) dust
(b) pollen grains
(c) animal dander
(d) All of these

Answer : D

Question. Antivenom injection contains preformed antibodies while polio drops that are administered into the body contain
(a) harvested antibodies
(b) gamma globulin
(c) attenuated pathogens
(d) activated pathogens

Answer : C

Question. Humoral immunity is mediated by
(a) B-cells
(b) T-cells
(c) macrophages
(d) monocytes

Answer : A

Question. A person has developed interferons in his body. He seems to carry an infection of
(a) typhoid
(b) filariasis
(c) malaria
(d) measles

Answer : D

Question. Colostrum, the yellowish fluid, secreted by mother during the initial days of lactation is very essential to impart immunity to the new born infants because it contains 
(a) monocytes
(b) macrophages
(c) immunoglobulin-A
(d) natural killer cells

Answer : C

Question. Hepatitis-B vaccine is produced from
(a) yeast
(b) bacteriophage
(c) bacteria
(d) All of these

Answer : A

Question. Antigen binding site of immunoglobulin (antibody) is
(a) variable region of heavy chain
(b) variable region of light chain
(c) constant region of light chain
(d) variable region of both heavy and light chain

Answer : D

Question. Which form of pathogen is used in vaccination?
(a) Activated and strong pathogens
(b) Preformed antigens and antibody
(c) Inactivated and weakened pathogenic agents
(d) None of the above

Answer : C

Question. What is injected into the patient’s body for determining the cause of allergy?
(a) Allergen to which the patient is allergic
(b) IgG
(c) IgE
(d) Steroids

Answer : A

Question. Humoral immune system defends against viruses and bacteria is present in
(a) blood
(b) lymph
(c) Both (a) and (b)
(d) None of these

Answer : C

Question. Except skin, other physical barriers which also help to prevent the entry of the microorganisms are mucus coating of the epithelium lining of
I. the respiratory tract.
II. the gastrointestinal tract.
III. the urogenital tract.
Choose the correct option.
(a) I and II
(b) I and III
(c) II and III
(d) I, II and III

Answer : D

Question. Passive immunisation includes
(a) transfer of lymphocyte directly
(b) transfer of maternal antibodies across placenta to the foetus
(c) introduction of antibodies directly in the body
(d) Both (b) and (c)

Answer : D

Question. An allergic response appears at the site of infection causes sneezing, watery eyes, running nose, pain and heat due to the certain chemicals (allergens), they are
(a) histamine and serotonin
(b) histamine and cerumen
(c) cerumen and serotonin
(d) mucus and cerumen

Answer : A

Very Short Answer Type Questions

Question. Lymph nodes are secondary lymphoid organs Explain the role of lymph nodes in our immune response.
Answer : Lymphoid Organs immune system of human beings consists of lymphoid organs The organs whereas callid the maturation and proliferation of lymphocytes occurs are called lymphoid organs Lymphoid organs are of two types. These are (Image 149) Lymph nodes are small solid structures present at different points along the lymphatic system. They trap the microorganisms or other antigens that enter the lymph and tissue fluid. Antigens trapped in the lymph nodes activate the lymphocytes and produce an immune response.

Question. Why is an antibody molecule represented as H2L2?
Answer : Each antibody molecule has four peptide chains, two small called light chains (represented by L) and two longer called heavy chains (represented by H). Hence, an antibody is represented as H L 2 2.

Question.  What does the term ‘memory’ of the immune system mean?
Answer : When the body encounters a pathogen for the first time, it mounts an immune response by generating antibodies. This response is of low intensity. Subsequent encounter with the same pathogen elicits a highly intensified secondary response. This is ascribed to the fact that our body appears to have memory of the first encounter. This type of secondary immune response is elicited by memory T-cells, B-cell which keep ready to mount a rapid and vigorous attack as soon as the same pathagen infects the body again.

Question. If a patient is advised anti restroviral therapy, which infection is he suffering from? Name the causative organism.
Answer : The patient is suffering from AIDS. The causative agent is HIV virus, a member of ‘retrovirus group’.

Short Answer Type Questions

Question. In the given flow diagram, the replication of retro virus in a host is shown. Observe and answer the following questions.
(a) Fill in (A) and (B) (b) Why is the virus called retrovirus? (c) Can the infected cell survive, while viruses are being replicated and released?
Answer : (a) 

(b) The virus is called retro virus because it does not follow the central dogma of biology (DNA® RNA® Proteins). Its genetic material is RNA that is transcribed to DNA using enzyme reverse transcriptase. (c) Yes, the infected cell can survive, while viruses are being replicated and released.

Question. ‘Maintenance of personal and public hygiene is necessary for prevention and control of many infectious diseaes. Justify the statement giving suitable examples.
Answer : Diseases which are easily transmitted from one person to another, are called infectious diseases. For prevention and control of such diseases, maintenance of personal and public hygiene is necessary, for this purpose, some common preventive measurer should be taken as follows
(i) Education People should be educated about communicable disease to protect themselves from such diseases.
(ii) Isolation The infected person should be kept isolated to minimise the spread of infection.
(iii) Vaccination People should get vaccination on time to avoid infection. (iv) Sanitation The sanitation should be improved to avoid infection from polluted water, contaminated food, etc.
(v) Eradication of Vectors The breeding places of vectors must be destroyed and adult vectors should be killed by suitable methods.
(vi) Sterilisation The patient’s surroundings and articles of use should be completely sterilised to reduce the chances of infection.

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

Question. 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 represents cannabinoids group of drugs.
(b) Mode of consumption−nasal inhalation or oral in take.
(c) Organs affected−heart and cardiovascular system.

Question. Give the full form of CT and MRI. How are they different from each other? Where are they used?
Answer : CT-Computed Tomography. It uses X-rays to generate 3-D images of internal organs MRI−Magnetic Resonance Imaging. It uses strong magnetic fields and non-ionising radiations to detect pathological and physiological changes in the living tissue accuratily. Both are used in cancer detection.

Question. Many secondary metabolites of plants have medicinal properties. It is their misuse that creates problems. Justify the statement with an example.
Answer : Drugs like barbiturates, amphetamines, benzodiazepines, lysergic acid diethylamides (LSD) and other similar drugs, that are normally used as medicines to help patients coping with mental illnesses like depression and insomnia. Morphine is a very effective sedative and painkiller and is very useful in patients who have undergone surgery. Misuse of plant metabolites fruits and seeds in amounts/frequency more than prescribed for medicinal purposes can impair one’s physical, physiological or functional behaviour creating problem for the society and slowly moves towards the eaternal truth (death).

Question. Name any two secondary lymphoid organs in a human body and state the function of any of them.
Answer : Spleen, lymph nodes, tonsils, Peyer’s patches of small intestine, vermiform appendix.
Spleen : They act as sites for interaction of lymphocytes with the antigen and cause immune response.
Function :
Spleen : Trap blood-borne micro-organisms and worn out RBCs, thus filters blood.
Lymph nodes : Trap the micro-organisms / antigens (which happen to get into the lymph and tissue fluid). The trapped antigens activate lymphocytes and cause immune response. 

Question. Mention one application for each of the following :
(a) Passive immunization
(b) Anti-histamine
(c) Colostrum
(d) Cytokine-barriers
Answer : (a) Provide preformed antibodies / anti-toxins for quick response in case of infection by deadly microbes (tetanus) or snake bite.
(b) Reduces symptoms of allergy.
(c) Provides passive immunity / antibodies / Ig A from mother to a new born.
(d) Protection of non-infected cells from further viral infection. 

Question. Name the type of immunity that the colostrum provides to a newborn baby. Write by giving an example where this type of immunity should be provided to a person.
Answer : Passive Immunity.
In case of infection by deadly microbes(tetanus) / snake bite where quick immune response is required.

Question. What happens to an individual when a regular dose of drugs/alcohol is abruptly discontinued? What characteristics manifest in the individual under such a situation ?
                    OR
What is “withdrawal syndrome” ? List any two symptoms, it is characterized by.
Answer : Withdrawal syndrome.
Manifestation of unpleasant characteristics and feelings. 
Anxiety, shakiness, nausea and sweating.

Question. Name the cells, HIV (Human Immunodeficiency Virus) gains entry into after infecting the human body. Explain the events that occur in these cells.
Answer : HIV (Human immune deficiency virus) enters into macrophages after getting into the human body. HIV multiplies first in macrophages and then in helper T-cells or lymphocytes.
Events that occur in the human host after the entry of HIV :
(i) After entering the human body, the HIV virus attacks and enters the macrophages.
(ii) Inside the macrophages, the RNA of the virus replicates with the help of enzyme reverse transcriptase and give rise to viral DNA.
(iii) Then, this viral DNA incorporates into the host cell DNA, uses raw materials and infected cell machinery and directs the synthesis of virus particles.
(iv) At the same time, HIV enters the helper T-lymphocytes, replicates and produce progenies.
(v) As a result, T-lymphocytes start decreasing in number and immune response of the person becomes weak. 

Question. Name one airborne and a waterborne disease in humans. List one specific symptom of each one of them. 
Answer : Air-borne diseases : Tuberculosis (TB), Influenza
Symptoms : Pain and difficulty in breathing/ Coughing.
Water-borne diseases : Diarrhoea, Typhoid.
Symptoms : Loose motions/ Watery stool.

Question. How are oncogenic viruses different from proto-oncogenes?
Answer : Oncogenic viruses are cancer causing viruses / external cancer causing factor.
Proto-oncogenes : Identified in normal cells which when activated (under certain conditions) could lead to oncogenic transformation of cells / internal cancer causing factor. 

Question. Name two drugs obtained from poppy plant. “These drugs are medically useful but are often abused“. Taking the mentioned examples justify by giving reasons.
Answer : Heroin / smack, morphine; morphine obtained from latex of unripe capsules of poppy plant (Papaver somniferum) is an effective pain killer and
sedative. Heroin (a derivative of morphine) is used as drug. If these drugs are taken for the purpose other than medicinal or taken in larger doses, that may impair the physical and mental state of a person, then it is said to be abused.

Question. Why cannabinoids are banned in sports and games?
Answer : Cannabinoids are banned in sports, as athletes misuse these drugs to enhance their performance. But drugs obtained from cannabinoids can cannatnads have, a serious negative effect on their general health and in long term can hamper the normal functioning of organ system.

Question. What is secondary metabolism?
Answer : Secondary metabolism (also called specialised metabolism) is a term for pathways and metabolites are small molecule produced by metabolism that are not absolutely required for the survival of the organism. In case of plant, metabolites aid in the growth and development of plants. It also facilitates the primary metabolism.

Question. Drugs and alcohol give short-term ‘high’ and long-term ‘damages’.
Answer : Curiosity, need for adventure and excitement and experimentation, constitute common causes, which motivate youngsters towards drug and alcohol use. The frequent use of drugs/alcohols drive people to take them even when these are not needed, or even their use becomes self-destructive. Short-term effects of drugs/alcohols l A relaxing effect l Reduced tension l Lowered inhibitions l Poor concentration l Slow reflexes l Slow reaction time l Reduced coordination l Slower brain activity l Sensations and perceptions that are less clear Long-term effects of drugs/alcohols l Disrupts normal brain development l Liver damage and cirrhosis of the liver l Brain cells die, decreasing brain mass l Stomach and intestinal ulcers and destroyed organs l Blood pressure increases, causing heart disease, heart attack or stroke l Male sperm production decreases l Lower levels of iron and vitamin-B, causing anaemia l Alcoholism l Death and l Fetal alcohol syndrome in unborn children.

Long Answer Type Questions

Question. Represent schematically the life-cycle of a malarial parasite.
Answer : The life-cycle of a malarial parasite 

Question. 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 : People think that the city life is better than village life. However, there are so many advantages as well as disadvantages of urban life and rural life Advantages of Urban (city) Life The city life is more comfortable as there are lot of facilities in the city. There are more opportunities for people to progress their lives and they have more opportunities for making money. Children living in the city can get a good education, in the town than in the village. When a person falls ill, there are good government and private hospital in the city to get treatment. There are large shopping complexes, banks, offices, cinemas, clubs, hospitals, etc., in and around the city for recreations. People in the city have better transport facilities than the village. There is electricity, highway, communication, telecommunication, plumb facilities in the city. So, people can lead a comfortable and enjoyable life in the city. Disadvantages of Urban (city) Life Although living in the city has many advantages there are some disadvantages too. The cost of living is very high in the city. Goods are expensive, no fresh air and pure water is present. The environment is polluted with dust, smoke, garbage and gases from factories. Most of the people who live in the city are corrupted, so there are lots of crimes in the city. Many thefts and murders often take place in the city. The city is always busy and noisy. There are a lot of vehicles and people in the road. The streets are dusty and unclean. So, it is hard to lead a healthy life in the city. Advantages of Rural (village) Life The people of the village live in unity and peace. The villagers earn money enough for live. very hardly. So, they live in less competition with each other. They have more friends in the community. The village people always try to protect their traditional habits and culture. The village has clean air and the environment is very beautiful. The village has less noise and rush. So, the pollution is less. The village do not have lot of vehicles. So, roads are less dangerous for driving or cycling. They can get fresh vegetables and fresh fruits. The environment of the village is pleasant and silent and it has scenic beauty. Disadvantages of Rural (village) Life People living in rural area have to face many problems like lack of good education, proper medical facilities, transportation, electricity, telecommunication, etc. Life style affects human health and cause many diseases due to specific food habits, work related posture or exposure to harmful radiation or substances, lack of physical exercise, mental stress, etc. Some life style diseases are cancer, alcoholism, heart diseases, etc.

Question. Why do some adolescents start taking drugs. How can this be avoided?
Answer : The reasons why adolescents and youngsters starts consumption of drugs are
(i) Curiosity of child motivates him/her to do experiment.
(ii) For adventure and excitement.
(iii) Peer group pressure.
(iv) Desire to do more physical and mental work.
(v) To overcome frustration and depression, due to failure in examinations or in other activities.
(vi) Unstable or unsupportive family structures. The following measures can be taken to avoid drug abuses
(i) Avoid undue pressure on child to perform beyond his/her capability in studies, sports or any other activities.
(ii) Education and counselling are very important to face problem of stress and failure in life.
(iii) Seeking help from parents, elders and peers. This would help the young to share their feelings and concern.
(iv) Looking for danger signs and taking appropriate measures to treat them.
(v) Seeking professional and medical help for de-addiction and rehabilation.

Question. In your locality, if a person is addicted to alcohol, what kind of behavioural changes do you observe in that person? Suggest measures to over come the problem.
Answer : If a person is addicted to alcohol, it will give rise to some behavioural changes in that person. Alcoholic drinks are costly and most drinkers, because of their selfish habits, deprive their children and other members of the family of the basic needs. The drinking of alcohol is invariably associated with social crimes and dissolution of moral and cultural inhibitions. Violence and other corrupt practices in the community are often directly or indirectly due to the consumption of alcohol. Measures that should be taken to overcome the above mentioned problem are (i) Avoid Undue Peer Pressure Every person has his/her own choice and personality, which should be kept in mind. So he/she should not be pressed unduly to do beyond his/her capacities, in work condition and other in social get together or activities.
(ii) Education and Counselling Helps to overcome the problems, like stresses, disappointments and failure in life. One should utilise a himself/herself energy in some beneficial activities like sports, music, reading, yoga and other extra curricular activities. (iii) Seeking Help from Parents and Peers In case of minors, whenever, there is any problem, one should seek help and a guidance from parents and peers. Help should be taken from close and trusted friends. This would help young to share their feelings of anxiety and wrong doings.
(iv) Looking for Danger Sings If friends find someone using drugs or alcohol, they should bring this to the notice of parents or teacher so that appropriate measures can be taken to diagnose the illness and the causes. This would help in taking proper remedial steps or treatment.
(v) Seeking Professional and Medical Helps Highly qualified psychologists, psychiatrists and de-addiction and rehabilitation programmes can help individuals who are suffering from drug/alcohol abuse. If such help is provided to the affected persons, with sufficient efforts and will power, the patient could be completely cured and lead normal and healthy life.