Free Biodiversity and Variety of Life MCQs with Answers

2061. A bacterial cell envelope of mollicutes does not include?

• A. Slime
• B. Capsule
• C. Cell wall
• D. Cell membrane

Explanation: Mollicutes is a class of bacteria which does not contain cell wall in its cell envelope.While in most of the bacteria the cell envelope comprises of cell membrane and cell wall, mollicutes lack a peptidoglycan cell wall.

2062. Who coined the term Animalcule for microorganisms like Bacteria and Protozoa?

• A. Robert Koch
• B. Louis Pasteur
• C. Alexander Fleming
• D. Leeuwenhoek

Explanation: Animalcule ('little animal', from Latin animal + the diminutive suffix -culum) is an old term for microscopic organisms that included bacteria, protozoans, and very small animals. The word was invented by 17th-century Dutch scientist Antonie van Leeuwenhoek to refer to the microorganisms he observed in rainwater.

2063. In a bacterial cell, plasma membrane with all things present within it is called:

• A. Cytoplasmic matrix
• B. Cytoplasm
• C. Protoplast
• D. Cell Structure

Explanation: The protoplasm consists of two major divisions in eukaryotes: the cytoplasm, and the nucleoplasm (cell nucleus). The cytoplasm is the eukaryotic cell's jelly-like material. Except for the nucleus it consists of the cytosol, the vesicles, the cytoskeleton, the inclusions and the organelles.

2064. The function of a cell wall in prokaryotes is:

• A. To give cells rigidity
• B. To give specific shape
• C. To protect from osmotic lysis
• D. All of Above

Explanation: All prokaryotic cells have a stiff cell wall located underneath the capsule (if there is one). This structure maintains the 'cell's shape', protects the cell interior, and prevents the cell from bursting when it takes up water. Since the bacterial cell wall is 'thick and rigid', it will maintain the shape of the cell and also 'protect it from osmotic lysis' just like the cell wall of plants. Hence, the correct option is 'D'.

2065. Which of the following is true bacteria?

• A. Archea Bacteria
• B. Cyano Bacteria
• C. Eu-bacteria
• D. Both B and C

Explanation: Eubacteria, on the other hand, encompass a wide range of bacteria that can be found in various habitats, including soil, water, and the bodies of plants and animals. They are more familiar to us and are involved in various ecological roles, including decomposition, nitrogen fixation, and some can cause diseases. So, among the options given, C. Eubacteria is the correct answer because it represents the true bacteria that are commonly encountered in many different environments and play essential roles in various biological processes.

2066. Purple non-sulphur bacteria is an example of which of the following?

• A. Heterotrophic bacteria
• B. Saprotrophic bacteria
• C. Chemosynthetic bacteria
• D. Photosynthetic bacteria

Explanation: Option A: Heterotrophic bacteria is incorrect because heterotrophic bacteria are bacteria that obtain their energy from organic compounds, rather than sunlight.Option B: Saprotrophic bacteria is also incorrect because saprotrophic bacteria are bacteria that obtain their energy by decomposing dead organic matter.Option C: Chemosynthetic bacteria is also incorrect because chemosynthetic bacteria are bacteria that obtain their energy from the oxidation of inorganic compounds, rather than sunlight.OpytionD: Purple bacteria or purple photosynthetic bacteria are gram-negative proteobacteria that are phototrophic which means they are capable of producing their food via photosynthesis. They are pigmented with bacteriochlorophyll a or b, together with various carotenoids, which give them colours ranging between purple, red, brown, and orange.

2067. Which of the following types of bacterial reproduction is most similar to mitosis?

• A. Transduction
• B. Transformation
• C. Binary fission
• D. Conjugation

Explanation: Option A: Transduction is the process by which genetic material is transferred from one bacterium to another by a bacteriophage (a virus that infects bacteria).Option B: Transformation is the process by which bacteria take up DNA from their environment and incorporate it into their genome.Option C: Bacteria reproduce by binary fission. In this process, the bacterium, which is a single cell, divides into two identical daughter cells. The bacterial cell then elongates and splits into two daughter cells each with identical DNA to the parent cell.Option D: Conjugation is the process by which bacteria transfer genetic material between cells by direct cell-to-cell contact.

2068. Which of the following structures provides greater pathogenicity to the bacteria?

• A. Slime
• B. Cell Wall
• C. Cell Membrane
• D. Capsule

Explanation: In the question, you need to identify the structure that provides greater pathogenicity to the bacteria. While each component has some effect on bacterial pathogenicity, the slime, which is a soluble sheath of macromolecules, provides greater pathogenicity to bacteria while also protecting them from phagocytosis. Hence, Option A is the correct answer.

2069. The presence of peptidoglycan in gram-positive bacteria is:

• A. 40% of dry weight
• B. 50% of dry weight
• C. 10% of dry weight
• D. 80% of dry weight

Explanation: Gram-positive bacteria have a thick peptidoglycan layer, which comprises 50% of their dry weight.

2070. Which of the following statements about the systemic effect of bacterial cells is true?

• A. Gram-negative bacteria are more likely to cause systemic effects because they lack an outer membrane, which means they can more quickly infect host cells
• B. Gram-negative bacteria are more likely to cause systemic effects because their outer membrane protects them from antibiotics
• C. Both Options A and B are correct
• D. None of these options are correct

Explanation: gram-negative bacteria have thinner membranes, which allows them to resist many antibacterial medicines.