What are exotoxins?

Exotoxins are toxic substances that are secreted by bacteria into their environment. These proteins can cause significant harm to the host organism by interfering with various cellular processes, leading to disease. Exotoxins are typically produced by both gram-positive and gram-negative bacteria and can have a wide range of effects, such as disrupting nerve function, damaging tissues, or affecting the immune response.

The other options do not accurately describe exotoxins. Toxins found in the cell wall refer more to structures associated with endotoxins, which are part of the outer membrane of gram-negative bacteria. Endotoxins are not typically secreted in the same way as exotoxins. The statement that exotoxins are only produced by gram-positive bacteria is misleading, as many gram-negative bacteria also produce exotoxins. Finally, molecules used for bacterial growth do not describe exotoxins, which are specifically harmful agents produced by bacteria. Exotoxins are crucial for pathogenicity, making their identification and understanding important in microbiology and medicine.