Free Biodiversity and Variety of Life MCQs with Answers

431. Choose the organism which requires a single cellular gene to encode the protein making up the organism:

• A. Viroid
• B. Prions
• C. Virus
• D. Virion

Explanation: Prions are infectious proteins that do not have genetic material and are composed of a misfolded host protein.

432. _ is transmitted through infected blood and hypodermic syringes.

• A. HIV
• B. Influenza virus
• C. Morbilli virus (Measles)
• D. Vibrio Cholerae (Cholera)

Explanation: HIV (Human Immunodeficiency Virus) is primarily transmitted through several key routes. The most common mode of transmission is through unprotected sexual contact with an infected individual, where the virus can enter the body through mucous membranes. Additionally, sharing needles or syringes among intravenous drug users poses a significant risk, as it allows for direct blood-to-blood contact. HIV can also be transmitted from an infected mother to her child during childbirth or breastfeeding, highlighting the importance of preventive measures for pregnant women living with HIV. Lastly, although less common, transmission can occur through blood transfusions or organ transplants from an infected donor, particularly in areas where blood screening is inadequate. Understanding these transmission routes is crucial for implementing effective prevention strategies to reduce the spread of HIV.

433. Which of the following viruses contains single-stranded DNA?

• A. Adenovirus
• B. Herpes virus
• C. Parvovirus
• D. Pox virus

Explanation: Parvoviruses are a group of viruses that carry a single-stranded DNA genome. They are among the smallest DNA viruses and typically infect animals, including humans.

434. Which of the following is used in baking?

• A. Aerobic respiration
• B. External respiration
• C. Internal respiration
• D. Anaerobic respiration

Explanation: During the process of baking, anaerobic respiration is used by yeast to convert sugars in dough into carbon dioxide gas, which causes the dough to rise. So, option D is selected.

435. A virus is what type of agent?

• A. Cellular agent
• B. Infectious agent
• C. Non-infectious agent
• D. Non-protein agent

Explanation: Viruses are regarded as infectious agents because they enter and take over host cells, leading to various diseases. Their ability to replicate only inside living cells is what makes them capable of causing infections.

436. The molecules used to control viruses during infection of animal cells are:

• A. Interferons
• B. Histone
• C. Antigen
• D. Serum

Explanation: Interferons are proteins that play a key role in controlling viral infections. They boost the body's immune defenses and help limit the spread of viruses within the body. The other options listed (antigen, histone, and serum) are not molecules specifically used to control viruses during infection but may have other roles in immune responses or cellular processes.

437. The provirus of HIV is structurally and chemically made up of?

• A. ssRNA
• B. ssDNA
• C. dsRNA
• D. dsDNA

Explanation: The provirus of HIV (Human Immunodeficiency Virus) is structurally and chemically made up of dsDNA (double-stranded DNA)HIV, a retrovirus, initially enters host cells as single-stranded RNA (ssRNA) but undergoes reverse transcription to convert its RNA genome into double-stranded DNA (dsDNA). This dsDNA is integrated into the host cell's genome as the provirus, and it serves as a template for the production of new viral particles. So, the provirus contains dsDNA.

438. Which of the following agents can easily pass through filter paper?

• A. Bacteria
• B. Fungi
• C. Yeast
• D. Virus

Explanation: Viruses can easily pass through filter paper. Viruses are the smallest type of biological agent, with most being smaller than 0.1 micrometers in diameter. Filter paper typically has pores that are several micrometers in diameter, so viruses are small enough to pass through the pores. Viruses can easily pass through filter paper, while bacteria, fungi, and yeast cannot.Bacteria are single-celled organisms that are typically 0.5 to 5 micrometers in size. They are too large to pass through the pores of filter paper, which are typically 0.2 to 0.45 micrometers in diameter.Fungi are eukaryotic organisms that can be unicellular or multicellular. They typically range in size from a few micrometers to several meters. Fungi are too large to pass through the pores of filter paper.Yeast is a type of fungus that is unicellular and typically 5 to 10 micrometers in size. Yeast is too large to pass through the pores of filter paper.

439. How many pieces of ribonucleic acid (RNA) make up the genome of influenza virus?

• A. 4
• B. 6
• C. 8
• D. 10

Explanation: The influenza virus genome is composed of eight pieces of ribonucleic acid (RNA). This virus is classified as a segmented RNA virus, which means its genetic material is divided into multiple RNA segments. Each of the eight segments encodes one or more proteins that are crucial for the virus's ability to replicate and cause infection. The segmentation of the genome allows the virus to undergo reassortment, which is a process that contributes to its genetic diversity and ability to evade the immune system, leading to new strains and potential pandemics. The other options (A, B, and D) are incorrect as they misrepresent the number of RNA segments in the influenza virus genome.

440. The head of some phages are icosahedral, which means that the head possesses:

• A. 6 Sides
• B. 10 Sides
• C. 15 Sides
• D. 20 Sides

Explanation: The head of some phages are icosahedral, which means that the head possesses 20 sides. An icosahedron is a polyhedron defined by having 20 equilateral triangular faces. It is one of the five Platonic solids, recognized for its symmetry and structural efficiency. The icosahedral shape allows for optimal packing of viral proteins and DNA, contributing to the stability and resilience of the virus against environmental stressors. Examples of phages with icosahedral heads include T4 phage, T7 phage, Lambda phage, and MS2 phage. The other options are incorrect because they do not represent the true structural nature of an icosahedron, which is specifically characterized by its 20 triangular faces.