microbiology chapter 14 test bank

microbiology chapter 14 test bank Related

Review microbiology chapter 14 test bank related questions and content

Some of the viruses have a cubic type of symmetry, which in the shape of

  • A. tetrahedral structure
  • B. hexahedral structure
  • C. dodecahedral structure
  • D. icosahedral structure
Correct Answer: D

Rationale: The correct answer is D: icosahedral structure. Icosahedral symmetry is common in viruses due to its efficient packing of genetic material. It consists of 20 equilateral triangular faces and 12 vertices. This symmetry allows viruses to have a stable structure and optimal capacity for encapsulating their genetic material.

A: Tetrahedral structure is incorrect as it consists of 4 faces and is not commonly found in viruses.
B: Hexahedral structure is incorrect as it consists of 6 faces and is not a common symmetry type in viruses.
C: Dodecahedral structure is incorrect as it consists of 12 faces and is not typically seen in viruses.

In summary, the icosahedral structure is the correct choice due to its stability, efficient packing, and common presence in viral structures compared to the other options.

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Differentiating media are:

  • A. Lowenstein-Jensen and Petraniani
  • B. Apoholate-citrate aga and Brilliant-green phenol-red Lactose Agar
  • C. Endo, Gassner and Levin
  • D. None of the above
Correct Answer: C

Rationale: The correct answer is C because Endo, Gassner, and Levin are all examples of differential media used in microbiology. These media contain specific components that allow for the differentiation of different types of microorganisms based on their metabolic characteristics or biochemical reactions. Lowenstein-Jensen and Petraniani (choice A) are selective media for mycobacteria, not differential. Apoholate-citrate agar and Brilliant-green phenol-red Lactose agar (choice B) are selective media for Salmonella and E. coli, respectively, not differential. Therefore, the correct choice is C as it includes examples of differential media commonly used for microbial identification.

Nonchromosomal DNA molecules found in a bacterial cell are

  • A. endospores.
  • B. transposons.
  • C. plasmids.
  • D. prions.
Correct Answer: C

Rationale: The correct answer is C: plasmids. Plasmids are nonchromosomal DNA molecules commonly found in bacterial cells, providing additional genetic material for bacteria. They are not essential for bacterial survival but can confer advantages such as antibiotic resistance. Endospores (A) are dormant bacterial structures resistant to harsh conditions. Transposons (B) are mobile genetic elements that can move within a genome. Prions (D) are misfolded proteins causing neurodegenerative diseases, not DNA molecules.

Fungi that help the roots of plants to absorb minerals and water from the soil are:

  • A. decomposers
  • B. mycorrhizae
  • C. yeasts
  • D. molds
Correct Answer: B

Rationale: The correct answer is B: mycorrhizae. Mycorrhizae are symbiotic fungi that form a mutualistic relationship with plant roots, aiding in the absorption of minerals and water. They enhance the plant's nutrient uptake capacity, promoting plant growth and health. Decomposers (A) break down dead organic matter, yeasts (C) are single-celled fungi used in fermentation, and molds (D) are fungi that grow in multicellular filaments. These options do not specifically assist plant roots in mineral and water absorption like mycorrhizae do.

Which of the following diseases is generally caused by contaminated food?

  • A. Mumps
  • B. Shigellosis
  • C. Legionellosis
  • D. Tuberculosis
Correct Answer: B

Rationale: The correct answer is B: Shigellosis. Shigellosis is caused by the bacteria Shigella, commonly transmitted through contaminated food and water. The bacteria can spread easily in unsanitary conditions. Mumps (A) is a viral infection spread through respiratory droplets. Legionellosis (C) is caused by the Legionella bacteria found in water sources like cooling towers. Tuberculosis (D) is a bacterial infection transmitted through the air. Therefore, the correct answer is B as it directly relates to contaminated food transmission.

Infections of the reproductive tract resulting from the introduction of microorganisms through a medical procedure are called:

  • A. chronic infections
  • B. endogenous infections
  • C. systemic infections
  • D. iatrogenic infections
Correct Answer: D

Rationale: The correct answer is D: iatrogenic infections. Iatrogenic infections refer to infections caused by medical or surgical treatment, including procedures that introduce microorganisms into the body. In this case, infections of the reproductive tract caused by medical procedures fall under this category.

A: Chronic infections do not specifically refer to infections caused by medical procedures.
B: Endogenous infections arise from organisms already present in or on the body, not introduced through medical procedures.
C: Systemic infections affect the entire body, not specific to infections caused by medical procedures.

Therefore, the term "iatrogenic infections" is the most appropriate choice in this context.

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