Free Introduction to Biology MCQs with Answers

61. The transgenic plants, such as golden rice, are produced primarily with the help of:

• A. Escherichia coli
• B. Proteus mirabilis
• C. Agrobacterium tumerfaciens
• D. Ralstonia solanacearum

Explanation: Transgenic plants such as golden rice are produced primarily with the help of Agrobacterium tumefaciens. Agrobacterium tumefaciens is a bacterium that causes crown gall disease in plants. It is also a natural genetic engineer, as it can transfer its own DNA into plant cells. This ability has been exploited to create transgenic plants, which are plants that have had their DNA modified to include genes from other organisms.

62. Which of the following chemicals is most commonly used to preserve biological specimen?

• A. Formalin
• B. Glutaraldehyde
• C. Ethylene Oxide
• D. Iodine

Explanation: Formalin is a solution of formaldehyde in water. It is the most common preservative used for biological specimens, as it is effective and inexpensive. Formalin preserves specimens by cross-linking proteins, which prevents them from decaying.

63. All of the following paired organs/structures have homology except:

• A. Human hand: Bat's wing
• B. Bat's wing: Wings of butterfly
• C. Horse front leg: Front flappers of Whale
• D. Forelimb of a cat: Forelimb of a whale.

Explanation: The wings of a bat and the wings of a butterfly are analogous structures, but not homologous. Analogous structures are structures that have similar functions but different evolutionary origins. Homologous structures are structures that have similar evolutionary origins but may have different functions. The wings of a bat and the wings of a butterfly are both used for flight, but they have evolved independently from each other. The wings of a bat are modified forelimbs, while the wings of a butterfly are modified outgrowths of the thorax.

64. Identify the correctly matched pair relating to a term and its meaning/ function/ example:

• A. Ecosystem - Organisms of the same species
• B. Habitat - The layer of the Earth's atmosphere
• C. Niche - A large, distinct ecosystem
• D. Biosphere - Where life exists

Explanation: The biosphere is the part of the Earth that supports life, including the atmosphere, hydrosphere (water), and lithosphere (land). It encompasses all ecosystems and living organisms.

65. Which of the following can be effective in preventing viral infection in humans?

• A. Taking antihistamines
• B. Getting vaccinated
• C. Applying antiseptics
• D. Taking antibiotics

Explanation: Vaccination is a highly effective way to prevent viral infections by:1. Introducing a small, harmless piece of the virus (antigen) to the body2. Stimulating the immune system to produce antibodies and immune cells that recognize and fight the virus3. Providing long-term immunity against specific viruses

66. Vaccination is an example of _:

• A. Natural passive immunity
• B. Natural active immunity
• C. Acquired active immunity
• D. Acquired passive immunity

Explanation: Vaccines are antigens injected into the body (artificially) but our body cells are the ones producing antibodies. Hence, this is an example of acquired active immunity.

67. Which of the following is a connective tissue?

• A. Cartilage
• B. Epithelium
• C. Muscle
• D. Nerve

Explanation: Cartilage is a connective tissue that is composed of cells called chondrocytes and an extracellular matrix that contains collagen and elastin fibers. It is tough but flexible tissue that provides support and cushioning to joints and other structures in the body. So, option A is correct.

68. BCG vaccine can be used to treat:

• A. Pulmonary tuberculosis
• B. Typhoid
• C. Cholera
• D. Pneumonia

Explanation: The BCG (Bacillis Calmette-Guerin) vaccine is primarily used to prevent tuberculosis, a bacterial infection that primarily affects the lungs. So, option A is encircled.

69. Which of the following is not an example of disuse of organs?

• A. Snake's legs
• B. Shedding of milk teeth
• C. Muscle atrophy
• D. Movement of ear

Explanation: Shedding of milk teeth is a natural process that occurs as part of normal development, not a result of disuse of organs.

70. Which one of the following branches of biology deals with living organisms in relation to their environment?

• A. Marine Biology
• B. Parasitology
• C. Environmental Biology
• D. Microbiology

Explanation: The correct answer is Environmental Biology because it specifically examines how living organisms interact with their environment, including both living (biotic) and non-living (abiotic) components. Marine Biology is limited to marine environments, Parasitology focuses on parasites, and Microbiology studies microorganisms without emphasizing environmental interactions.