Please refer to Chapter 8 Human Health and Diseases MCQ Class 12 Biology with answers below. These multiple-choice questions have been prepared based on the latest NCERT book for Class 12 Biology. Students should refer to MCQ Questions for Class 12 Biology with Answers to score more marks in Grade 12 Biology exams. Students should read the chapter Human Health and Diseases and then attempt the following objective questions.

MCQ Questions Class 12 Biology Chapter 8 Human Health and Diseases

The Human Health and Diseases MCQ Class 12 Biology provided below covers all important topics given in this chapter. These MCQs will help you to properly prepare for exams.

Question. The causal organism for African sleeping sickness is
(a) T. gambiense
(b) T.tangela
(c) T.evansi
(d) Trypanosoma cruzi

Question. Mary Mallon was a cook by profession and also a carrier of a particular disease. Which test is commonly used for diagnosis of this disease.
(a) Monteaux test
(b) Widal test
(c) Western bolt
(d) ELISA

Question. Malignant malaria is caused by
(a) Plasmodium vivex
(b) Plasmodium malaria
(c) Plasmodium falciparum
(d) Plasmodium ovale

Question. Widal test is used the susceptibility of:
(a) Malaria
(b) Cholera
(c) Yellow fever
(d) Typhoid

Question. Which of the following is the infective stage of Plasmodium in the secondary host?
(a) Trophozoite
(b) Sporozoite
(c) Microgametocyte
(d) Merozoite

Question. Match the words in Column I with those in Column II-

Column I	Column II
a. PCR	i. Detects and measures antibodies in the blood.
b. ELISA	ii. Amplifies a single DNA sequence to generate thousands to millions of more copies of that particular DNA segment.
c. Montaux test	iii. Diphtheria
d. Schick test	iv. Tuberculosis

(a) a(ii), b(i), c(iv), d(iii)
(b) a(ii), b(iv), c(iii), d(i)
(c) a(i), b(iv), c(ii), d(iii)
(d) a(ii), b(iii), c(i), d(iv)

Question. Which of the following substances are misused by certain sportsperson to enhance their performance?
(a) Narcotic analgesics
(b) Anabolic steroids
(c) Diuretics and certain hormones
(d) All of the above

Question. Read the following statements and select the right option:
I. The spleen is a large bean-shaped organ, which mainly contains lymphocytes and phagocytic cells.
II. The principle of vaccination is based on the property of memory of the immune system.
III. The graft rejection or failure of organ transplantation is due to cell- mediated immunity.
IV. The yellowish fluid colostrum has an abundant amount of IgA antibody which provide active immunity to newborn babies.
(a) I, II, III are correct
(b) I, III, IV are correct
(c) II and IV are correct
(d) Only II is correct

Question. Which of the following statement is incorrect for ECG of human heart?
(a) It is graphical representation of the electrical activity of the heart during a cardiac cycle.
(b) The ECG of a person is obtained by using a machine called electrocardiogram.
(c) To obtain a standard ECG, a patient is connected to the machine with three electrical leads.
(d) Each peak in the ECG is identified with a letter from P to T that corresponds to a specific electrical activity to the heart.

Question. In a mammalian lung the rate at which oxygen could be obtained from the air would increase if :
(a) tidal volume decreased
(b) the cells lining the alveoli and capillaries were thinner
(c) blood hemoglobin content were lower
(d) you ascended to a higher altitude

Question. If you arrange the following structures in the order in which they would be passed by an oxygen molecule during inspiration, which would be third
(a) Bronchiole
(b) Trachea
(c) Alveolus
(d) Epiglottis

Question. The separation of oxygen from hemoglobin is enhanced near exercising muscle (this is known as the Bohr effect) and is caused by :
(a) oxygen binding to hemoglobin in the lung
(b) carbon monoxide binding to oxygenated hemoglobin
(c) carbonic anhydrase
(d) the interaction of lowered pH with oxygenated hemoglobin

Question. The trachea, bronchi and bronchioles of humans have all of the following functions except :
(a) Increasing the surface area available for gas exchange
(b) Moistening the incoming air
(c) conducting mucous away from the alveoli
(d) warming the incoming air to body temperature

Question. Which of the following produces negative pressure within your thoracic cavity
(a) Exhalation
(b) contraction of diaphragm muscles
(c) Relaxation of the muscles between the ribs
(d) Contraction of the muscles in the walls of stomach

Question. Gas exchange in animals always involves
(a) cellular respiration
(b) breathing movements
(c) neural control of exchange
(d) diffusion across membranes

Question. Respiration in silkworm is accomplished by :
(a) external gills
(b) pulmonary sacs
(c) body wall
(d) spiracles & trachea

Question. In which animals is the volume of the lungs relatively constant during all the stages of breathing?
(a) Insects
(b) Reptiles
(c) Mammals
(d) Birds

Question. A person has difficulty in breathing at higher altitudes because
(a) oxygen is likely to diffuse from lungs to blood.
(b) oxygen is likely to diffuse from blood to lungs
(c) partial pressure of O₂ is lower than partial pressure of CO₂
(d) overall intake of O₂ by the blood becomes low.

Question. The CO₂ in the blood is mostly carried
(a) by haemoglobin in RBCs
(b) in the cytoplasm of WBCs
(c) in the plasma as bicrbonate ions
(d) by plasma proteins

Question. When a man inhales air containing normal concentration of O₂ as well as CO he suffers from suffocation because 
(a) CO reacts with O₂ reducing its percentage in air
(b) haemoglobin combines with CO instead of O₂ and forms carboxyhaemoglobin
(c) CO affects diaphragm and intercostal muscles
(d) CO affects the nerves of the lungs.

Question. Severe Acute Respiratory Syndrome
(a) Is caused by a variant of Pneumococcus pnemoniae
(b) Is caused by a variant of the common cold virus (corona virus)
(c) Is an acute form of asthma
(d) Affects non-vegatarians much faster than vegetarians

Question. Respiration is controlled by
(a) medulla oblongata
(b) cerebellum
(c) hypothalamus
(d) cerebrum

Question. The type of epithelial cells which line the inner surface of Fallopian tubes, bronchioles and bronchi are known as 
(a) squamous epithelium
(b) ciliated epithelium
(c) columnar epithelium
(d) cubical epithelium

Question. Chemosensitive area of respiratory centre in medulla is affected by
(a) less CO₂ and H⁺ ions
(b) less O₂ and H⁺ ions
(c) excess CO₂ and H⁺ ions
(d) excess O₂ and H⁺ ions.

Question. Select the incorrect match:
(a) Disease- Malaria, Causative organism-A Protozoan, insect-Anopheles
(b) Disease- Chikungunya, Causative organism-A Bacteria, insect- Culex
(c) Disease- Filarisis, Causative organism-An annelid, Insect- Culex
(d) Disease- Dengue, Causative organism-A Virus, insect- Aedes

Question. The carrier for amoebiasis is:
(a) Entamoebia histolytica
(b) Mosquito
(c) Musca
(d) Plasmodium vivax

Question. An autoimmune disease is 
(a) myasthenia gravis
(b) haemophilia
(c) AIDS
(d) none of these.

Question. Triple antigen vaccine is not used for         
(a) diptheria
(b) pertussis
(c) typhoid
(d) tetanus.

Question. Vaccination of malaria is not possible because     
(a) they produce antibodies and antitoxins
(b) they do not produce antibodies and antitoxins
(c) antibodies resistant to vaccines are produced
(d) none of the above.

Question. In malaria, which of the following is released in blood to cause severe chill       
(a) hematin
(b) hemozoin
(c) Haemon’-bin
(d) hemolysin

Question. Disease which occurs due to malfunctioning of organs is     
(a) deficiency disease
(b) degenerative disease
(c) allergic disease
(d) hereditary disease.

Question. One of the inflammatory reactions induced by histamines is         
(a) vasoconstriction of blood vessels
(b) vasodilation of peripheral blood vessels
(c) increased vascular permeability
(d) accelerated blood clotting.

Question. Which of the following immunoglobulins(lgs) is present in milk?     
(a) lgA
(b) lgG
(c) lgM
(d) lgE.

Question. Most bacteria ingested with food are killed by ,   
(a) cilia and mucus on the lining of the tract
(b) stomach acids
(c) the intrinsic factor in the stomach
(d) bile in the small intestine.

Question. Which of the following blood groups enables a person to give blood to any person?         
(a) A+
(b) B-
(c) AB+
(d) Cr

Question. The letter T in T-lymphocyte refers to       
(a) thalamus
(b) tonsil
(c) thymus
(d) thyroid

Question. Lymphocytes that cause the formation of holes in plasma membranes are       
(a) B cells
(b) killer (cytotoxic) T cells
(c) suppressor! cells
(d) helper! cells.

Question. Which of the following is a pair of viral diseases?     
(a) common cold, AIDS
(b) dysentery, common cold
(c) typhoid, tuberculosis
(d) ringworm, AIDS

Question. Alcohol is mostly metabolised in         
(a) liver
(b) kidneys
(c) all body cells
(d) connective tissue.

Question. Continued exposure to vinylchloride (VC) may cause cancer to the   
(a) vagina
(b) skin
(c) liver
(d) prostate gland.

Question. Artificial immunity can be acquired from a         
(a) serious illness
(b) vaccination
(c) repeated exposure to the same microbe
(d) treatment with penicillin.

Question. Excessive consumption of alcohol mainly leads to     
(a) state of hallucination
(b) loss of memory
(c) suppression of brain function
(d) cirrhosis of liver.

Question. The term immunity refers to         
(a) the combined actions of all white blood cells
(b) events that occur within the lymphatic system
(c) general defenses against all microorganisms
(d) specific defenses against microbes encountered during an earlier exposure.

Question. Fatty liver syndrome is due to         
(a) cigarette smoke
(b) alcoholic drinks
(c) opiate narcotics
(d) psychedelic drugs.

Question. AIDS disease was first reported in         
(a) Russia
(b) USA
(c) Germany
(d) France.

Question. Find the incorrect pair out       
(a) Culex — malaria
(b) Xenopsylla — plague
(c) Aedes — yellow fever
(d) Phlebotomus — kala-azar.

Question. Sporogony of malarial parasite occurs in .     
(a) stomach wall of mosquito
(b) s vary glands of mosquito
(c) RBC sofman
(d) liver of man.

Question. Which of the following organs is not involved in the generation of immune response?     
(a) brain             
(b) lymph nodes
(c) spleen
(d) thymus.

Question. Which cells of immune system causes pore formation at the surface of the plasma membrane?
(a) helper ! cell
(b) killer T-cell
(c) suppressor T-cell
(d) B-cell.

Question. An organism which has been used as a weapon in biological war causes which of the following disease?
(a) malaria
(b) common cold
(c) influenza
(d) anthrax.

Question. If a person shows production of interferons in his body, the chances are that he has got an infection of
(a) typhoid
(b) influenza
(c) tetanus
(d) malaria.

Question. The major histocompatibility complex is a
(a) series of complement-enhanced reactions to antigens ‘
(b) group of antigens, coded by a family of genes, on the surface of body cells
(c) form of autoimmunity
(d) the major cause of cancer.

Question. An allergic reaction is initiated by antibodies of the
(a) !gGgroup ,
(b) iglvl group
(c) igA group
(d) igE group.

Question. Perspiration, s va and tears contains an enzyme, lysozyme, that kills
(a) virus-infected cells
(b) protozoa
(c) bacteria
(d) viruses.

Question. The tobacco products cause
(a) aneurysm
(b) polyarteritis nodosa
(c) thromboangiitis obliterans
(d) Wernicke’syndrome.

Question. Which one of the following statements is correct?
(a) benign tumours show the property of metastasis
(b) heroin accelerates body functions
(c) m gnant tumours may exhibit metastasis
(d) patients who have undergone surgery are given cannabinoids to relieve pain.

Question. Ganja and LSD are classified in
(a) stimulants
(b) narcotics
(c) depressents
(d) hallucinogens

Question. The regions of an antibody that make it distinct from all other kinds of antibodies are its
(a) variable (V) regions
(b) constant (C) regions
(c) mutated (M) regions
(d) bifurcated (B) regions. ;

Question. Which of the following combinations causes damage to gastric mucosa?
(a) alcohol & v um
(b) alcohol & barbiturate
(c) alcohol & aspirin
(d) alcohol & hashish

Question. Persons with severe combined immunodeficiency has no
(a) interferons
(b) macrophages
(c) ! or B cells
(d) functioning lymph nodes.

Question. The major phagocytic cells are
(a) lymphocytes
(b) mast cells
(c) plasma cells
(d) macrophages

Question. Lysozyme kills by destroying
(a) cell walls.
(b) mitochondria) enzymes
(c) lipid bilayers
(d) the machinery for DMA replication

Question. A person likely to develop tetanus is immunised by administering
(a) preformed antibodies
(b) wide spectrum antibiotics
(c) weakened germs
(d) dead germs

Question. Use of anti-histamines and steroids give a quick relief from
(a) nausea
(b) cough
(c) headache
(d) allergy

Question. Blood vessels near a wound dilate and become more permeable in response to which material released from damaged cells?
(a) pyrogens
(b) antibodies
(c) histamine
(d) interferons.

Question. Allergic condition caused by pollen grains of certain flowers causing inflammation of the nose is called
(a) laryngitis
(b) rhinitis
(c) pharyngitis
(d) bronchitis.

Question. Messenger molecules, released by virus-infected cells, that bind to the surfaces of healthy cells and stimulate them to synthesize proteins that prevent viral reproduction are called
(a) interferons
(b) antibiotics
(c) cytotoxins
(d) lymphokines.

Question. Untreated victims of severe combined immunodeficiency usually die from
(a) infections that in other people are minor
(b) anaphylactic shock
(c) congested lungs
(d) unusually high fever.

Question. Hypotensive tranquillizer drug reserpine is obtained from roots of
(a) Ferule asafoetida
(b) Rawolfia serpentine
(c) Papaversomniferurn
(d) Curcuma longa

Question. Synthetic, drugs structurally related to adren ne are
(a) amphetamines
(b) barbiturates
(c) hallucinogens
(d) analgesics

Question. Which one of the following options gives the correct matching of a disease with its causative organism and mode of infection Desease Causative Organisms Mode of Infection
(a) Elephantiasis Wuchereria bancrofti With infected water and food
(b) Malaria Plasmodium vivax Bite of male Anopheles mosquito
(c) Typhoid Salmonella typhi With inspired air
(d) Pneumonia Streptococcus Pneumoniae Droplet infection

Question. Heroin is –
(a) morphine
(b) diacetylmorphine
(c) stimulant
(d), hallucinogen

Question. Which one of the following is the correct statement regarding the particular psychotropic drug specified?
(a) morphine leads to delusions and disturbed emotions
(b) barbiturates cause relaxation and temporary euphoria
(c) has his alters thought, feelings, perceptions and hallucinations
(d) opium stimulates nervous system and causes hallucinations.

Question. Charas or hashish is obtained from
(a) Leaves of Cannabis
(b) Resinous secretion of flowering tops of female Cannabis
(c) Dried leaves of female Cannabis
(d) Resinous secretion from bark of male plants of Cannabis.

Question. Amphetamines are central nervous-system stimulants. Barbiturates are
(a) CNS stimulants
(b) no effect on CMS
(c) hallucinogenic
(d) CMS, depressant   

Question. Methadone is used for
(a) narcotic
(b) relieving chronic pain
(c) deaddiction of morphine and heroin
(d) all of the above.

Question. Use of Cannabis products results in
(a) alteration in perception, thoughts and feelings
(b) depressed brain activity and feeling of calmness
(c) suppressed brain function and relief in pain
(d) stimulation of nervous system, increased alertness and activity.

ASSERTION / REASONING

In each of the following questions a statement of Assertion (A) is given followed by a corresponding
statement of Reason (R) just below it. Of the statements, mark the correct answer as
(a) If both assertion and resaon are true and reason is the correct explanation of assertion
(b) If both assertion and reason are true but reason is not the correct explanation of assertion
(c) If assertion is true but reason is false
(d) If both assertion and reason are false

Question. Assertion : Most fish when out of water, die of suffocation.
Reason : Atmospheric air contains far less oxygen content than the dissolved oxygen in water.

Question. Assertion : During inspiration, pressure of air falls in the thorax.
Reason : There is a rise in volume of thorax during inspiration.

Question. Assertion : During inspiration, the volume of thorax increases.
Reason : This happens due to the relaxation of diaphragm and inspiratory muscles.

Question. Assertion : Forceful expiration occurs through expiratory muscles.
Reason : Expiratory muscles expires quickly.

Question. Assertion : Vital capacity is higher in athletes than non-athletes.
Reason : Vital capacity is about 3.5-4.5 litres in a normal adult person.

Question. Assertion : Gill – lamellae in aquatic anilmals help in exchange of gases
Reason : Each gill lamella carries many blood capillaries.

Question. Assertion : In mammals, complex respiratory system has developed.
Reason : Mammalian skin is impermeable to gases.

Question. Assertion : Abdominal muscles is related with respiration in animals.
Reason : Relaxation of abdominal muscles draws in air.

Question. Assertion : Inspiration occurs due to muscular relaxation.
Reason : During inspiration the diaphragm and internal intercostal muscle contract simultaneously.

Question. Assertion : If there is no air in trachea, it will collapse.
Reason : Trachea is without cartiagenous ring.

Question. Assertion : Ciliated epithelium is present in the inner lining of trachea and large bronchi.
Reason: Ciliary movement propel the mucus and foreign particle towards the larynx.

Question. Assertion : Emphysema is a chronic disorder in which alveolar walls are damaged.
Reason : Emphysema is closely related to cigarette smoking.

Question. Assertion : In cockroach respiratory gases directly comes in contact with the various organs of the body.
Reason : Cockroaches do not have respiratory pigment.

Question. Assertion: Blood is colourless in the insects.
Reason : Insect blood has no role in O₂ transport.

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