All Free Biology MCQs with Answers

2841. Which of the following is absent from membrane of prokaryotes?

• A. Glycolipid
• B. Cholesterol
• C. Glycoprotein
• D. Phospholipid

Explanation: Cholesterol is a component of eukaryotic cell membranes and is typically absent in prokaryotic cell membranes, such as those of bacteria.

2842. Multicellular, heterotrophic nutrition, cell walls are never present in their cells, which kingdom do these organisms belong to?

• A. Kingdom Protista
• B. Kingdom Fungi
• C. Kingdom Plantae
• D. Kingdom Animalia

Explanation: Organisms with multicellular structures, heterotrophic nutrition, and the absence of cell walls in their cells belong to the Kingdom Animalia.

2843. 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.

2844. _ 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.

2845. 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.

2846. 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.

2847. 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.

2848. 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.

2849. 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.

2850. 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.