Category: Class 12 Biology Objective Questions

Biology Multiple Choice Questions on “Viral Diseases in Humans-1”.

1. Which virus causes Small Pox disease?
a) Variola virus
b) Varicella zoster
c) Rubeola virus
d) Rhabdo virus
Answer: a
Clarification: Variola virus causes Small Pox disease. Varicella zoster, Rubeola and Rhabdo viruses cause Chicken Pox, Measles and Rabies respectively.

2. Variola virus has ________ as genetic material.
a) Single stranded RNA
b) Double stranded RNA
c) Single stranded DNA
d) Double stranded DNA
Answer: d
Clarification: Variola virus has double stranded DNA as genetic material. Plant viruses generally have Single stranded RNA as a genetic material. Animal viruses have Single stranded or Double stranded RNA or Double stranded DNA as genetic material. Bacteriophages have Double stranded DNA as genetic material.

3. Small Pox vaccine is which kind of vaccine?
a) Attenuated Vaccine
b) Inactivated Vaccine
c) Second Generation Vaccine
d) Third Generation Vaccine
Answer: a
Clarification: Small Pox vaccine is an Attenuated Vaccine. Attenuated Vaccines are made by weakening the virulent properties of the pathogen. These vaccines provide Artificial Active Immunity and vaccination is the best preventive remedy for Small Pox.

4. Who is known as the Father of Immunology?
a) Dmitry Ivanovsky
b) Edward Jenner
c) Erik Acharius
d) Francesco Redi
Answer: b
Clarification: Edward Jenner is the Father of Immunology. He discovered the Small Pox vaccine in 1796. Dmitry Ivanovsky is known as the Father of Virology. Erik Acharius is the Father of Lichenology. Francesco Redi is the Father of Parasitology.

5. When was Small Pox eradicated from the world?
a) 1971
b) 1977
c) 1967
d) 1980
Answer: d
Clarification: The last known case of Small Pox was in 1977. However, the world was declared Small Pox free in 1980 by the World Health Organisation.

6. In Chicken Pox, rashes first appear on the body and then on the face.
a) True
b) False
Answer: a
Clarification: Rashes first appear on the body and then on the face in Chicken Pox disease. The rash comes out in crop and with each fresh crop, there may be slight fever again. Rashes change into Papules-vesicles without fluid and then into pustules and finally into a dark brown scab which falls off leaving no scar.

7. Which of the following is the most common late complication of Chicken Pox?
a) Fever
b) Shingles
c) Small Pox
d) Mumps
Answer: b
Clarification: The most common late complication of Chicken Pox is Shingles which is caused by the reactivation of Varicella zoster virus. Shingles cause the appearance of painful rashes which appear as a stripe of blisters on the trunk or the back.

8. What is the full form of MMR vaccine?
a) Mumps Measles Rabies
b) Malignant Melanoma Rheumatism
c) Measles Mumps Rubella
d) Malignant-Malaria Rheumatoid
Answer: c
Clarification: MMR Vaccine is a combined vaccine given to babies within 12-15 months of their birth for the protection against Measles, Mumps and Rubella viruses.

9. What is the incubation period of Rhabdo virus?
a) 1 day-2 weeks
b) 10-20 days
c) 2-4 weeks
d) 10 days-1 year
Answer: d
Clarification: Rhabdo virus is introduced in the body by the bite of rabid or mad dogs usually. It can also be injected by the bite of cats, wolves etc. The incubation period of this virus is from 10 days to one year.

10. Which is the most important characteristic symptom of Rabies?
a) Fear of Height
b) Fear of Water
c) Fear of Cats
d) Fear of Fire
Answer: b
Clarification: Rabies is commonly called as hydrophobia which means Fear of Water. Therefore, Fear of Water is the most important characteristic symptom of Rabies. Other symptoms include excess salivation, severe headache, alternating phases of excitement and depression.

11. What is the mortality rate of humans if they contract rabies?
a) 50% fatal
b) 100% fatal
c) No effects
d) 33% fatal
Answer: b
Clarification: Rabies is 100% fatal if neurological symptoms have developed like violent movements, uncontrolled excitement, inability to move the parts of the body, confusion and loss of consciousness. Once these symptoms appear, the result is always death.

12. What is the earliest sign of contracting Polio?
a) Paralysis
b) Inflammation of the body
c) Inability to bend the head forward
d) Inability to walk
Answer: c
Clarification: The earliest sign of Polio is the inability to bend the head forward. However, the attack of paralysis begins with high fever, headache, chills, vomiting and pain all over the body. Within 2-3 days the paralysis reaches its maximum.

13. Which of the following options is incorrect regarding the contraction of Polio?
a) It spreads through intestinal discharges
b) It spreads through contaminated food and water
c) It spreads by flies
d) It spreads through mosquito bites
Answer: d
Clarification: Polio disease mainly spreads through intestinal discharges like the faeces. It may also spread through contaminated food or water and by flies or other insects which contaminate food or drink. Poliovirus usually enters the body through the alimentary canal where it multiplies and then reaches the nervous system via bloodstream.

14. What is the full form of OPV?
a) Oral Polio Vaccine
b) Oesophagus Polio Vaccine
c) Oral Plague Vaccine
d) Oesophagus Plague Vaccine
Answer: a
Clarification: The full form of OPV is the Oral Polio Vaccine. The Oral Polio Vaccine was developed by Albert Sabin and came into commercial use in 1961.

Biology Multiple Choice Questions on “Human Health and Disease – Immune System in the Body”.

1. What is the life span of the memory B-cells of the immune system?
a) A few days
b) A few hours
c) A few years
d) A few years to whole life
Answer: d
Clarification: The life span of the memory B-cells of the immune system is a few years to whole life. These memory cells do not produce antibodies but when the same pathogen attacks for the second time, that differentiate into effector cells.

2. Which of the following is introduced during smallpox vaccination?
a) Antibodies
b) Antigens
c) Attenuated virus
d) WBCs
Answer: c
Clarification: Small Pox vaccination is a first-generation vaccine where an attenuated form of the virus is injected into the body of the patient. The first vaccination was developed by Edward Jenner against smallpox.

3. Primary response of the body to an antigen is much stronger and intense that the Secondary response.
a) True
b) False
Answer: b
Clarification: Primary immune response is the first immune response developed during the first encounter with the antigen. It is feeble but relatively longer. The secondary immune response is a quick heightened immune response against a subsequent encounter with the same antigen. It is due to the presence of memory cells against that antigen. Hence, the secondary response is more intense than the primary response.

4. Formation of a large number of effector cells against a particular antigen is called ______
a) Mass replication
b) Clonal selection
c) Mass selection
d) Pure line selection
Answer: b
Clarification: Formation of a large number of effector cells against a particular antigen is called Clonal selection. It involves the formation of a clone of cells by each activated T-lymphocyte and antibody-producing plasma cells by activated B-lymphocyte, each exhibiting the specificity for the same antigen.

5. Which of the following immunoglobulins is also called secretory immunoglobulin?
a) IgG
b) IgA
c) IgM
d) IgE
Answer: b
Clarification: IgA immunoglobulins are also called secretory immunoglobulin because it is present in all the body secretions including colostrum and mother’s milk. It functions as the first line of defence against ingested and inhaled pathogens by activating alternative pathways of the complement system.

6. Which of the following is an immunosuppressant drug?
a) Antihistamine
b) Cyclosporin
c) Neomycin
d) Streptokinase
Answer: b
Clarification: Cyclosporin is an immunosuppressant drug. This drug prevents rejection of kidney, heart and liver transplants. It destroys T-cell mediated immune responses while spares humoral antibody responses.

7. Which one of the following people are given the highest priority in transplanting organs to a donor?
a) Identical twin
b) Sibling
c) Parent
d) Unrelated donor
Answer: a
Clarification: For organ or tissue transplantation, the preference order for the donor is Identical twin > Sibling > Parent > Unrelated Donor. As there are antigens which are likely to be attacked by recipient T-cells and antibodies, the recipients of organ or tissue transplants are always given immunosuppressants.

8. Immunosuppressants are chemicals which enhance the immune system of the body.
a) True
b) False
Answer: b
Clarification: Immunosuppressants are chemicals which suppress the immune reaction of the body so that the antigens of the patient’s body do not attack the transplanted organs or tissues.

9. What is the full form of SCID?
a) Severe Combined Immunodeficiency
b) Sarcolemma Infected Disease
c) Septic Infectious diseases
d) Seven Convoluted Immunity disorder
Answer: a
Clarification: SCID stands for Severe Combined Immunodeficiency where very few T-lymphocytes are formed. B-lymphocytes are also deficient. As a result, the patient dies of even minor infections.

10. Which of the following is not a cause of Immunodeficiency diseases?
a) Gene mutation
b) Infection
c) Accident
d) Shortage of water in the body
Answer: d
Clarification: Immunodeficiency diseases are disorders of the immune system where one or more components of innate or acquired immunity become defective due to gene mutations, Infections, Malnutrition or eve accidents.

11. Lymphoid Organs are not responsible for ___________
a) Proliferation of lymphocytes
b) Differentiation of lymphocytes
c) Destruction of lymphocytes
d) Maturation of lymphocytes
Answer: c
Clarification: Lymphoid organs are not responsible for the destruction of lymphocytes. Lymphoid organs are those organs having lymphatic tissues where maturation, proliferation and differentiation of lymphocytes occur.

12. In which of the following places MALT is not found?
a) Respiratory tract
b) Digestive tract
c) Urogenital tract
d) Eyes
Answer: d
Clarification: MALT is not found in the eyes. MALT is a lymphoid tissue which is located within the mucosal lining of the major tracts like respiratory, digestive and urogenital tracts.

13. MALT constitutes for about _______ percentage of the lymphoid tissue in the human body.
a) 30%
b) 40%
c) 50%
d) 60%
Answer: c
Clarification: MALT stands for Mucosal Associated Lymphoid Tissue. It constitutes about 50% of the lymphoid tissue in the human body.

14. Which of the following organs is also called as “Graveyard of RBCs”?
a) Spleen
b) Heart
c) Bone Marrow
d) Liver
Answer: a
Clarification: Spleen is also called as Graveyard of RBCs. It is a large bean-shaped organ which mainly contains lymphocytes, phagocytes and a large number of erythrocytes. It acts as a filter of blood by trapping blood-borne microorganisms.

15. Which of the following organ is also called as “Throne of Immunity”?
a) Bone Marrow
b) Thymus
c) Brain
d) Heart
Answer: b
Clarification: Thymus is also called as Throne of Immunity or training school of T-lymphocytes. It is a lobed organ located near the heart and beneath the breast bone. It is the site where T-lymphocytes mature.

Biology Multiple Choice Questions on “Animal Breeding”.

1. Which of the following is not an aspect of animal breeding?
a) Improve desirable qualities of breeds
b) Increasing the yield
c) Making diseased organisms
d) Making disease resistance breeds
Answer: c
Clarification: Breeding of animals is an important aspect of animal husbandry. Animal breeding aims at increasing the yield of animals and improving the desirable qualities of their produce and making them disease resistant.

2. What is a breed?
a) Animals related by descent
b) Animals related by an ascent
c) Animals not related at all
d) Clone of animals
Answer: a
Clarification: A group of animals related by descent and similar in most characters like general appearance, features, size, configuration, etc., are said to belong to a breed.

3. Animals are selected for breeding on the basis of all of the following except ______
a) Mammary system and udder
b) ratio of yield to diet
c) Having long ears
d) Disease resistance
Answer: c
Clarification: Animals are selected for breeding on the basis of quality and quantity of yield, the ratio of yield to diet, duration of reproductive period and lactation, mammary system and udder and disease resistance.

4. What is inbreeding?
a) Mating of closely related species
b) Mating of unrelated species
c) Mating of clones
d) Mating of different breeds
Answer: a
Clarification: Inbreeding refers to the mating of more closely related individuals within the same breed for 4-6 generations. The breeding strategy is as follows-superior males and superior females of the same breed are identified and mated in pairs.

5. Crosses between different breeds are called inbreeding.
a) True
b) False
Answer: b
Clarification: When breeding is between animals of the same breed, it is called inbreeding, while crosses between different breeds are called outbreeding. Also, inbreeding is the mating of two related species while outbreeding is the mating of two unrelated species.

6. Which of the following is not associated with inbreeding?
a) Mating between animals of unrelated species
b) Elimination of undesirable characters
c) Increases homozygosity
d) Causes inbreeding depression
Answer: a
Clarification: Inbreeding is the mating between the animals of the same breed having common ancestors up to 4-6 generations. Inbreeding increases homozygosity. It is also responsible for the elimination of undesirable characters and it causes inbreeding depression.

7. Which of the following type of animals breeding is used to develop a pure line in any animal?
a) Outcrossing
b) Crossbreeding
c) Hybridisation
d) Inbreeding
Answer: d
Clarification: Inbreeding increases homozygosity, thus inbreeding is necessary if we want to evolve a pure line in any animal. Inbreeding also exposes harmful recessive genes that are eliminated by selection. It also helps in the accumulation of superior genes and the elimination of less desirable genes.

8. Which breeding is used to overcome inbreeding depression?
a) Out-crossing
b) Cross-breeding
c) Interspecific hybridisation
d) Inbreeding
Answer: a
Clarification: Continued inbreeding, especially close inbreeding, usually reduces fertility and even productivity. This is called inbreeding depression. Whenever this becomes a problem, selected animals of the breeding population should be mated with unrelated animals of the same breed. This is called as outcrossing and it often helps to overcome inbreeding depression.

9. Which of the following is the best breeding method for animals which are below average in productivity?
a) Out-breeding
b) Out-crossing
c) Inbreeding
d) Interspecific hybridisation
Answer: b
Clarification: Out-crossing is the practice of mating of animals within the same breed, but having no common ancestors on either side of their pedigree. The offspring of such a mating is known as an outcross. It is the best breeding method for animals that are below average in productivity in milk production, the growth rate in beef cattle, etc.

10. Which of the following is not included in out-breeding?
a) Out-crossing
b) Cross-breeding
c) Inbreeding
d) Interspecific hybridisation
Answer: c
Clarification: Out-breeding is the breeding of the unrelated animals which may be between individuals of the same breed but having no common ancestors for 4-6 generations (Out-crossing) or between different breeds (Cross-breeding) or different species (Interspecific hybridisation).

Biology Problems for MBBS Entrance Exams on “Plant Diseases caused by Fungi and Nematodes”.

1. Disease-causing fungi are of ____ types.
a) Two
b) Three
c) Four
d) Five
Answer: a
Clarification: Disease-causing fungi are of two types, obligate and non-obligate parasites. Obligate parasites can grow and multiply only in the association of their host plants. Non-obligate parasites become parasitic only when they come in contact with a suitable host.

2. Symptoms of fungal diseases may be localised or systemic.
a) True
b) False
Answer: a
Clarification: Symptoms of fungal diseases may be localised i.e. restricted to an area of infection or maybe systemic i.e. spreading throughout the plant body.

3. Which of the following is not a method of controlling fungal diseases?
a) Antibiotics
b) Fungicides
c) Resistant varieties
d) Use of pathogen-free seeds
Answer: a
Clarification: Fungal diseases can be controlled by roguing or removal of diseased parts, sanitation or destruction of plant debris, resistant varieties, use of pathogen-free seeds, bio pesticides if available and spraying with fungicides like Bordeaux mixture.

4. Witches’ broom is a characteristic symptom of diseases caused by ___________
a) Virus
b) Fungi
c) Bacteria
d) Nematodes
Answer: b
Clarification: Witches broom is a characteristic symptom of diseases caused by fungi. The various symptoms of the fungal disease include necrosis, leaf spots, cankers, scabs, pustules, dieback, damping off, blights, rots, stunting, leaf curls, overgrowths, warts, galls, witches’ broom, wilt, rust, smut and mildew.

5. The following diagram represents the infected leaf of ________

a) Early blight of potato
b) Late blight of potato
c) Black rust of wheat
d) Smut of Wheat
Answer: b
Clarification: The following diagram represents the infected leaf of Late blight of potato. It is caused by the fungus Phytophthora infestans. The disease kills the foliage, reducing the yield of tubers which are often are infected.

6. The following diagram represents the infected black stem of ___________

a) Rice
b) Wheat
c) Barley
d) Cocoa
Answer: b
Clarification: The above diagram represents the infected black stem rust of wheat. Rusts of Wheat are brownish to blackish spore rich pustules which develop on the leaves and stem surface of Wheat. Rusts are generally caused by Puccinia.

7. Which of the following statements is not related to Loose smut of Wheat?
a) Caused by Ustilago
b) Attacks barley
c) Caused by Puccinia
d) A disease common in humid areas
Answer: c
Clarification: Loose smut of wheat is a highly damaging smut disease that is more common in humid areas. The disease is caused by Ustilago. It also attacks Barley and a number of grasses.

8. Which of the following is a Non-characteristic symptom of Nematode disease?
a) Yellowing of Foliage
b) Distortion of leaves
c) Necrotic lesions
d) Blotches
Answer: a
Clarification: Non- characteristic above-ground symptoms of nematode disease include reduced growth, yellowing of foliage, wilting and low-quality yield of the plant.

9. Fungicides can be used to treat diseases caused by Nematodes.
a) True
b) False
Answer: b
Clarification: Measures used to control diseases caused by nematodes include disinfection of soil by steam, rotation of crops, fallowing, biological control agents, uncontaminated seeds, resistant varieties and spraying crops with nematicides.

10. Which of the following statement is not related to Root-Knot of Brinjal and Tomato?
a) Caused by Meloidogyne
b) The male worm is cylindrical
c) The female worm is circular
d) Site of infection produces gall
Answer: c
Clarification: Root-knot of Brinjal and Tomato is caused by nematode Meloidogyne incognita. The male worm is cylindrical and female worm is pear-shaped. Infected cells proliferate near the site of infection produces spherical to elliptical swellings called galls.

To practice Biology Problems for MBBS Entrance Exams,

Biology Exam Questions for Schools on “Tools of Recombinant DNA Technology: Competent Host”.

1. The molecule which dissolves in water is called _______
a) hydrophilic molecule
b) hydrophobic molecule
c) soluble molecule
d) insoluble molecule
Answer: a
Clarification: The molecule which dissolves in water is called hydrophilic molecules. They are polar in nature which helps them in dissolution in water. Being hydrophilic in nature DNA cannot pass through the cell membrane.

2. ______ is a hydrophilic molecule.
a) Lipid
b) DNA
c) Palmitic acid
d) Lipohilic
Answer: b
Clarification: DNA is an example of a hydrophilic molecule. Hydrophilic molecules are water-loving and tend to dissolve in water easily. They carry a positive or negative charge.

3. Which divalent cations are usually used to make competent cells?
a) Carbon
b) Nitrogen
c) Copper
d) Calcium
Answer: d
Clarification: The divalent cations of calcium are used to make cells competent. Calcium is used in the form of a salt of calcium chloride. It increases the efficiency of the bacterial membrane to allow the passage of foreign DNA.

4. The cells which have the ability to incorporate foreign DNA within them are called ______
a) water-loving
b) plasma cells
c) competent cells
d) hydrophobic
Answer: c
Clarification: Some bacterial cells have the ability to incorporate foreign DNA within them. These cells are called competent cells. This leads to the alteration of the genetic material of the cell.

5. Competent cells can be prepared using ________
a) electrophoresis
b) chromatography
c) heat-shock treatment
d) pipetting
Answer: c
Clarification: Heat-shock treatment is a method in which the vial is incubated in ice, then treated at temperature up to 50°C and again transferred on ice. It is usually used in transferring recombinant DNA within the host (bacterial cell).

6. The method by which recombinant DNA is directly injected into the nucleus of an animal cell is called ________
a) heat-shock
b) micro-injection
c) transferring
d) insertional inactivation
Answer: b
Clarification: The method by which recombinant DNA is directly injected into the nucleus of an animal cell is called micro-injection. A glass micropipette is used for injecting the material into cells.

7. Biolistics is also known as ______
a) micro-injection
b) micro-pipetting
c) insertional inactivation
d) gene gun
Answer: d
Clarification: Biolistics is also known as a gene gun. It is a method in which cells are bombarded with high-velocity micro-particles of gold or tungsten coated with DNA. It is mostly used for plant cells.

8. What temperature is suitable for heat-shock treatment?
a) 100°C
b) 0°C
c) 42°C
d) 95°C
Answer: c
Clarification: 42°C-45°C is the ideal temperature for heat-shock treatment. Mostly calcium chloride is used in this. It is suitable for the transformation of bacterial cells such as E.coli.

9. Calcium is a ________ cation.
a) monovalent
b) trivalent
c) divalent
d) tetravalent
Answer: c
Clarification: Calcium is a divalent cation. It has a valency of 2 and is written as Cu²⁺. Some other examples of divalent atoms are Zn²⁺, Mg²⁺, Co²⁺, etc.

10. Which metal microparticles are used in gene gun?
a) Aurum
b) Nitrogen
c) Magnesium
d) Cuprum
Answer: a
Clarification: The microparticles of gold-coated with DNA are used in gene gun technique. Aurum is a Latin word for gold. Other metal used for this technique is tungsten.

11. Which method uses a ‘disarmed pathogen’ vector?
a) Transformation
b) Biolistics
c) Insertional inactivation
d) Sequencing
Answer: b
Clarification: Biolistics or gene gun is the method that uses a ‘disarmed pathogen’ vector. A pathogen from which virulence or disease-causing genes are removed is known as a disarmed pathogen. It is a process in which DNA is transferred into a host without any risk of infection.

To practice Biology Exam Questions for Schools,

Biology Multiple Choice Questions and Answers for Class 12 on “Biotechnology Applications – Ethical Issues – 2”.

1. What is the term used to refer to the use of bio-resources by multinational companies and other organizations without proper authorization from the countries and people concerned without contemporary payment is?
a) Bio-piracy
b) Bioremediation
c) Biodegradation
d) Bioethics
Answer: a
Clarification: the term used to refer to the use of bio-resources by multinational companies and other organizations without proper authorization from the countries and people concerned without contemporary payment is Bio-piracy. It happens when biological resources are taken or exploited without official sanction.

2. The Indian Parliament has recently cleared the ______ amendment of the Indian Patents Bill.
a) eight
b) first
c) third
d) second
Answer: d
Clarification: The Indian Parliament in 2000 cleared the Second amendment of Indian Patents Bill. It was put forward to bridge the conflicts between TRIPS (Trade-Related Aspects of Intellectual Property Rights) and The Patent Act of 1970.

3. The Indian Patents Bill takes issues such as ______ into consideration.
a) biology
b) biodegradation
c) patent terms
d) vaccination
Answer: c
Clarification: The Indian Patent Bill passed in the second amendment considers issues such as patent terms. It grants new rights for patentable inventions and extension of the term protection.

4. The Indian Patent Bill does not consider the issue of research and development initiative.
a) True
b) False
Answer: b
Clarification: The Indian Patent Bill was put forward in the second amendment in 2000. It considers various issues of research and development initiatives. It also grants new rights for patentable inventions.

5. Currently, the manipulation of microbes, plants, and animals has raised serious ethical questions.
a) True
b) False
Answer: a
Clarification: Ethics are the moral principles of people. Any issues or conflicts regarding these moral principles lead to various ethical issues. Nowadays the manipulation (genetic) in organisms has raised serious ethical questions.

To practice Biology Multiple Choice Questions and Answers for Class 12,