Nokea
Bacteria that grow in the absence of oxygen are called:
- A. Obligate aerobes
- B. Facultative anaerobes
- C. Obligate anaerobes
- D. Aerotolerant anaerobes
Correct Answer: C
Rationale: The correct answer is C: Obligate anaerobes. These bacteria cannot survive in the presence of oxygen as they lack the necessary enzymes to detoxify reactive oxygen species. Obligate aerobes (A) require oxygen, facultative anaerobes (B) can grow with or without oxygen, and aerotolerant anaerobes (D) can survive in the presence of oxygen but do not utilize it for growth.
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Which of the following microorganisms are acid-fast?
- A. Streptococcus pyogenes
- B. Mycobacterium tuberculosis
- C. Clostridium perfringens
- D. Bacillus subtilis
Correct Answer: B
Rationale: The correct answer is B: Mycobacterium tuberculosis. Acid-fast bacteria have a unique cell wall component called mycolic acid, making them resistant to decolorization by acid-alcohol during staining. Mycobacterium tuberculosis is acid-fast, as it retains the stain due to its high lipid content. Streptococcus pyogenes (A), Clostridium perfringens (C), and Bacillus subtilis (D) do not possess mycolic acid in their cell walls, so they are not acid-fast.
Which one of the methods is used to identify cytoplasmic inclusions?
- A. Neisser staining
- B. Clett staining
- C. Ziehl-Nielsen staining
- D. Gram staining
Correct Answer: A
Rationale: The correct answer is A: Neisser staining. This method is specifically used to identify cytoplasmic inclusions by staining them with a specific dye that highlights these structures. Neisser staining is designed to selectively target and visualize cytoplasmic inclusions, making it the most appropriate choice for this purpose.
Option B: Clett staining, Option C: Ziehl-Nielsen staining, and Option D: Gram staining are not typically used for identifying cytoplasmic inclusions. Clett staining is not a commonly known staining method for this purpose. Ziehl-Nielsen staining is primarily used to detect acid-fast bacteria like Mycobacterium tuberculosis. Gram staining is used to differentiate bacteria into Gram-positive and Gram-negative based on cell wall characteristics. Therefore, these options are not suitable for identifying cytoplasmic inclusions.
Which of the following eyewash/safety showers should be used for immediate flushing only, until the victim reaches another safety unit?
- A. Emergency shower
- B. Personal eyewash
- C. Handheld drench hose
- D. Combination unit
Correct Answer: B
Rationale: The correct answer is B: Personal eyewash. Personal eyewash is designed for immediate flushing until the victim reaches a more suitable safety unit. It provides a controlled flow of water to safely flush eyes while transporting the victim. The emergency shower (A) is meant for full-body coverage, not just for the eyes. Handheld drench hose (C) may not provide adequate flushing pressure. Combination unit (D) may not be easily portable for immediate use.
Matrix formed outside the plasma membrane is referred to as:
- A. cytoplasm
- B. glycocalyx
- C. exoplasm
- D. cell wall
Correct Answer: B
Rationale: The correct answer is B: glycocalyx. The glycocalyx is a matrix formed outside the plasma membrane that consists of glycoproteins and glycolipids. It plays crucial roles in cell-cell recognition, protection, and immune response. Cytoplasm (A) is the gel-like substance inside the cell, not outside. Exoplasm (C) is not a recognized term in biology. Cell wall (D) is a rigid structure found in plant cells, not outside the plasma membrane in all cells.
The only way to get energy in haematrophic bacteria is:
- A. Heat production
- B. Biological oxidation
- C. In biosynthetic reactions
- D. Cultivation in culture media
Correct Answer: B
Rationale: The correct answer is B: Biological oxidation. Haematrophic bacteria obtain energy through biological oxidation, where they break down organic compounds to generate ATP for cellular processes. This process involves the transfer of electrons from the substrate to an electron transport chain to produce energy. Heat production (A) is a byproduct of metabolism, not the primary way to obtain energy. In biosynthetic reactions (C), energy is utilized rather than generated. Cultivation in culture media (D) is a method of growing bacteria but does not directly provide energy. Therefore, the correct answer is B as it aligns with the metabolic process of haematrophic bacteria.