Which of the following statements about exotoxins is generally false?

• A. Exotoxins are proteins that can be inactivated by heat.
• B. Exotoxins are typically produced by both Gram-positive and Gram-negative bacteria.
• C. Exotoxins can cause specific symptoms depending on their mechanism of action.
• D. Exotoxins are part of the bacterial cell wall and released only upon cell lysis.

Answer: (D)

Verified step by step guidance

1. Step 1: Understand what exotoxins are. Exotoxins are toxic proteins secreted by bacteria into their surrounding environment, not structural components of the bacterial cell wall.
2. Step 2: Review the characteristics of exotoxins: they are proteins, can be heat-inactivated, and are produced by both Gram-positive and Gram-negative bacteria.
3. Step 3: Recognize that exotoxins cause specific symptoms based on their mechanism of action, such as neurotoxins or enterotoxins targeting specific tissues.
4. Step 4: Identify the false statement by comparing it to the known facts: exotoxins are not part of the bacterial cell wall and are not released only upon cell lysis; that description fits endotoxins instead.
5. Step 5: Conclude that the false statement is the one claiming exotoxins are part of the bacterial cell wall and released only upon cell lysis.