CBSE Class 12 Biology Human Health and Disease MCQs Set I

Question: Which part of poppy plant is used to obtain the drug “smack”?
a) Flowers
b) Latex
c) Roots
d) Leaves
Answer: b

Question: Internal bleeding, muscular pain, blockage of the intestinal passage and anaemia are some of the symptoms caused due to infection by
a) Ascaris
b) Wuchereria
c) Plasmodium
d) Trichophyton
Answer: a

Question: Transplantation of tissues/organs fails often due to non-acceptance by the patient’s body. Which type of immune response is responsible for such rejections?
a) Cell-mediated immune response
b) Hormonal immune response
c) Physiological immune response
d) Autoimmune response
Answer: a

Question: Identify the correct pair representing the causative agent of typhoid fever and the confirmatory test for typhoid.
a) Salmonella typhi / Widal test
b) Plasmodium vivax / UTI test
c) Streptococcus pneumoniae / Widal test
d) Salmonella typhi / Anthrone test
Answer: a

Question: Which one of the following is incorrect about cancer cells?
a) They exhibit mass proliferation.
b) They exhibit the property of contact inhibition.
c) They are produced when cellular oncogenes of normal cells are activated.
d) They are metastatic.
Answer: b

Question: Infection of Ascaris usually occurs by
a) Tse-tse fly
b) mosquito bite
c) drinking water containing eggs of Ascaris
d) eating imperfectly cooked pork
Answer: c

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

Question: Some of the events occur during life cycle of Plasmodium are given below. Identify the correct statement.
a) Female mosquito take up sporozoites with blood meal.
b) The sporozoites reproduce sexually in liver cells.
c) When mosquito bites a man, gametocytes are injected.
d) The gametocytes develop in RBCs.
Answer: d

Question: Which of the following sets of diseases is caused by bacteria?
a) Cholera and tetanus
b) Typhoid and smallpox
c) Tetanus and mumps
d) Herpes and influenza
Answer: a

Question: Short-lived immunity acquired from mother to fetus across the placenta or through mother’s milk to the infant is categorised as
a) active immunity
b) passive immunity
c) CMI
d) autoimmunity
Answer: b

Question: The blood does not clot inside the body because of
a) oxygenation of blood
b) movement of blood
c) presence of heparin in blood
d) absence of fibrinogen in blood
Answer: c

Question: Select the correct statement from the ones given below.
a) Barbiturates when given to criminals make them tell the truth.
b) Morphine is often given to persons who have undergone surgery as a pain killer.
c) Chewing tobacco lowers blood pressure and heart rate.
d) Cocaine is given to patients after surgery as it stimulates recovery.
Answer: b

Question: Which of the following immunoglobulins does constitute the largest percentage in human milk?
a) IgA
b) IgG
c) IgD
d) IgM
Answer: c

Question: Read the statements.
(i) IgE antibodies are produced in an allergic reaction.
(ii) B-lymphocytes mediate cell mediated immunity.
(iii) The yellowish fluid colostrum has abundant IgE antibodies.
(iv) Spleen is a secondary lymphoid organ.
a) (i) and (iv) are correct
b) (i) and (ii) are correct
c) (ii) and (iii) are correct
d) (iii) and (iv) are correct
Answer: a

Question: Which one of the following statements is correct with respect to immunity?
a) Preformed antibodies need to be injected to treat the bite by a viper snake.
b) The antibodies against small pox pathogen are produced by T-lymphocytes.
c) Antibodies are protein molecules, each of which has four light chains.
d) Rejection of a kidney graft is the function of B-lymphocytes.
Answer: a

Question: In the immune system, interferons are a part of
a) physiological barriers
b) cellular barriers
c) physical barriers
d) cytokine barriers
Answer: d

Question: Select the correct statement with respect to diseases and immunisation.
a) If due to some reason B and T lymphocytes are damaged, the body will not produce antibodies against a pathogen.
b) Injection of dead/inactivated pathogens causes passive immunity.
c) Certain protozoans have been used in mass production of hepatitis B vaccine.
d) Injection of snake antivenom against snake bite is an example of active immunisation.
Answer: a

Question: Common cold differs from pneumonia in that
a) pneumonia is a communicable disease whereas the common cold is a nutritional deficiency disease
b) pneumonia can be prevented by a live attenuated bacterial vaccine whereas the common cold has no effective vaccine
c) pneumonia is caused by a virus while the common cold is caused by the bacterium Haemophilus influenzae
d) pneumonia pathogen infects alveoli whereas the common cold affects nose and respiratory passage but not the lungs.
Answer: d

Question: The toxic substance, ‘haemozoin’, related to the high fever and chill, is released during which of the following disease?
a) Dengue
b) Malaria
c) Diphtheria
d) Pneumonia
Answer: b

Question: Which of the following is a communicable disease?
a) Diabetes
b) Kwashiorkar
c) Hypertension
d) Malaria
Answer: d

Question: The pathogens of genera, Microsporum, Trichophyton and Epidermorphyton are responsible for
a) Botulism
b) Conjunctivitis
c) Ringworms
d) Skin allergy
Answer: c

Question: Vector for kala azar is:
a) Bedbug
b) Louse
c) Sandfly
d) Housefly
Answer: c

Question: Immunoglobulins are
a) Antigen
b) Antiseptics
c) Antibiotics
d) Antibodies
Answer: d

Question: Mumps is a viral disease and painful swelling of
a) Thyroid
b) Thymus
c) Parotid glands
d) Sublingual glands
Answer: c

Question: Food poisoning is caused by
a) Entamoeba histolytica
b) Escherichia coli
c) Corynebacterium diphtheriae
d) Clostridium botulinum
Answer: d

Question: In which of the following disease, there is always a time lag between the infection and appearance of the symptoms?
a) Allergy
b) Cancer
c) Alcoholism
d) AIDS
Answer: d

Question: A cell-coded protein that is formed in response to infection with most animal viruses is called
a) Antigen
b) Histone
c) Antibody
d) Interferon
Answer: d

Question: To which type of barriers under innate immunity do saliva in the mouth and tears from the eyes belong?
a) Physical barriers
b) Cytokine barriers
c) Cellular barriers
d) Physiological barriers
Answer: d

Question: Infection of Ascaris usually occurs by
a) Eating imperfectly cooked pork
b) Tse-tse fly
c) Mosquito bite
d) Drinking water containing eggs of Ascaris
Answer: d

Question: The letter T in T-lymphocyte refers to
a) Thyroid
b) Thalamus
c) Tonsil
d) Thymus
Answer: d

Question: Passive immunity is defined as immunity
a) Inherited from the parents
b) Achieved through vaccination
c) Acquired through first exposure to the disease
d) Achieved through the sera of other animals enriched in antibodies
Answer: d

Question: Antigen binding site in an antibody is found between
a) Two light chains
b) Two heavy chains
c) One heavy and one light chain
d) Either between two light chains or between one heavy and one light chain
Answer: c

Question: Resistance in body against diseases is given by
a) Vaccinations
b) Histamine
c) Antigens
d) Immunoglobulins
Answer: d

Question: Which of the following results in fever when released in body during disease?
a) Pyrogens
b) Antibodies
c) Interferons
d) Interleukins
Answer: a

Question: When a quick immune response is required due to infection of a deadly microbe, the patient is injected with
a) Protein of pathogen
b) Inactivated or weakened pathogen
c) Vaccine
d) Preformed antibodies
Answer: d

Question: B-lymphocytes are associated with
a) Humoral immunity
b) Production of heparin
c) Cell mediated immunity
d) Internal cleansing
Answer: a

Question: Which of the following is trapped in the lymph nodes and responsible for activation of lymphocytes present there?
a) Antibody
b) Pathogen
c) Lymph fluid
d) Antigen
Answer: d

Question: Hepatitis B and AIDS are
a) Caused by retroviruses
b) Transmitted through sexual contact
c) Congenital diseases
d) Transmitted through infected blood
Answer: d

Question: Short-lived immunity acquired from mother to foetus across placenta or through mother’s milk to the infant is categorized as
a) Active immunity
b) Passive immunity
c) Cellular immunity
d) Innate non-specific immunity
Answer: b

Case Based MCQs

Case  : Read the following passage and answer questions below:
X and Y are communicable diseases whereas W and Z are non-communicable diseases. X is transmitted through vectors whereas Y is transmitted through droplet infection. W is caused due to a hormone deficiency whereas Z is a degenerative disease.
Based on the above information, answer the following questions.

Question: If X and Y both are usual diseases then which of the following holds true?
(a) X could be dengue caused by flavivirus and Y could be AIDS caused by HIV.
(b) X could be chikungunya whereas Y could be rhinitis.
(c) X could be hepatitis whereas Y could be rabies.
(d) X could be chicken pox caused by Varicella zoster virus whereas Y could be yellow fever caused by flavivirus.
Answer: b

Question: Read the given statements and select the correct option.
Statement A : Communicable diseases could be contagious or non-contagious.
Statement B : Diseases that spread through vectors are non-contagious disease.
(a) Both statements A and B are true.
(b) Statement A is true but statement B is false.
(c) Statement A is false but statement B is true.
(d) Both statements A and B are false.
Answer: a

Very Short Answer Type Questions

Question: When is tumour referred to as malignant?
Answer : Tumour is called malignant when it invades and destroys the tissue in which it originates and has the potential to spread to other sites in the body via the bloodstream and lymphatic system.

Question: How does colostrum provide initial protection against diseases to new born infants?
Answer : Colostrum provides protection against disease to new born babies because it is rich in antibodies, e.g. IgA.

Short Answer Type Questions

Question: (a) List any two situations when a medical doctor could recommend injection of preformed antibodies into the body of a patient. Name this kind of immunization and mention its advantages.
(b) Name the kind of immunity attained when instead of antibodies, weakened antigens are introduced into the body.
Answer : (a) If a person is infected with some deadly microbes to which quick immune response is required as in tetanus, we need to directly inject the preformed antibodies or antitoxin.
Even in the cases of snakes bites the injection which is given to the patients, contain preformed antibodies against the snake venom. This type of immunization is called passive immunization. It provides immediate relief.
(b) In vaccination, a preparation of antigenic proteins of pathogens or inactivated weakened pathogens are introduced into the body. This produces immune response and the type of immunity is called active immunity.

Question: A young boy when brought a pet dog home started to complain of watery eyes and running nose. The symptoms disappeared when the boy was kept away from the pet.
(a) Name the type of antibody and the chemicals responsible for such a response in the boy.
(b) Mention the name of any one drug that could be given to the boy for immediate relief from such a response.
Answer : (a) Such a response in the boy is called allergy which occurs due to production of IgE antibodies and chemicals like histamine and serotonin from the mast cells.
(b) Anti-histamine could be given to the boy for immediate relief from such a response.

Question: How does moderate fever help a person in combating infections? What is to be done to bring down very high body temperature?
Answer : Moderate fever strengthens the defence mechanism by activating the phagocytes and by inhibiting the growth of microbes. A very high temperature may prove dangerous. It must be quickly brought down by giving antipyretics (fever reducing drugs e.g., aspirin) and by applying cold packs.

Question: How does the skin serve as the first line of defence?
Answer : The oil and sweat (chemical barriers) secreted by sebaceous and sudoriferous glands of skin contains fatty acids and lactic acid, which make the skin surface acidic.
These have antibacterial and antifungal activity. Lysozyme present in sweat, also kills many bacteria. Thus it provides first line of defence.

Question: (a) What is meant by addictive disorder?
(b) Name any two opiate narcotics.
(c) How does amphetamines affect human body?
Answer : (a) Addictive disorder is a state in which a person has a strong desire to take the addictive substance (drugs, alcohol, tobacco etc.).
(b) The two opiate narcotics are morphine and heroin.
(c) Amphetamines are called antisleep drugs as they are CNS stimulants. They cause alertness, self-confidence, talkativeness and increased work capacity. They suppress hunger. High doses produce euphoria, depression and insomnia. After effects include nausea and vomiting.

Question: How is the fetus with Rh-positive blood affected if the mother is Rh-negative?
Answer : An Rh-ve person, if exposed to Rh+ve blood, will form specific antibodies against the Rh antigens. This is observed in case of Rh-ve blood of a pregnant mother with Rh+ve blood of the foetus. Rh antigens of the foetus do not get exposed to the Rh-ve blood of the mother in the first pregnancy as the two bloods are well separated by the placenta. However, during the delivery of the first child, there is a possibility of exposure of the maternal blood to small amounts of the Rh+ve blood from the foetus. In such cases, the mother starts preparing antibodies against Rh antigen in her blood. In case of her subsequent pregnancies, the Rh antibodies from the mother (Rh-ve) can leak into the blood of the foetus (Rh+ve) and destroy the foetal RBCs. This could be fatal to the foetus or could cause severe anaemia and jaundice to the baby. This condition is called erythroblastosis foetalis. This can be avoided by administering anti-Rh antibodies to the mother immediately after the delivery of the first child.