Common Misconceptions
Part of Human Defense Systems - Non-specific — GCSE Biology
This common misconceptions covers Common Misconceptions within Human Defense Systems - Non-specific for GCSE Biology. Physical and chemical barriers, white blood cell responses, inflammatory response It is section 11 of 16 in this topic. Use this common misconceptions to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 11 of 16
Practice
19 questions
Recall
22 flashcards
Common Misconceptions
Misconception: "Mucus kills bacteria."
Reality: Mucus itself does not kill bacteria — it physically traps them. The killing is done by lysozyme and other antimicrobial chemicals dissolved within the mucus. Mucus is sticky because of glycoproteins, and this stickiness is what captures pathogens. The cilia then sweep the mucus away before pathogens can escape and cause infection.
Misconception: "All white blood cells engulf and destroy pathogens."
Reality: Only phagocytes engulf pathogens by phagocytosis. Other white blood cells work differently — lymphocytes produce antibodies or kill infected cells directly. At GCSE, the key type to know is the phagocyte and its role in phagocytosis.
Misconception: "The stomach acid kills everything you swallow."
Reality: Stomach acid (pH ~2) kills most pathogens but not all. Some bacteria have evolved ways to survive stomach acid. Food should still be handled hygienically even though many pathogens will be killed by stomach acid.