Indicate which statements are true. Correct all false statements by changing the underlined words.
__________ A membrane attack complex drills circular holes in a macrophage.

Verified step by step guidance

1. Step 1: Understand the role of the membrane attack complex (MAC) in the immune system. The MAC is part of the complement system, which helps destroy pathogens by forming pores in their membranes.
2. Step 2: Identify the target cells of the MAC. The MAC typically forms pores in the membranes of certain pathogens, especially Gram-negative bacteria, not in host immune cells like macrophages.
3. Step 3: Analyze the given statement: 'A membrane attack complex drills circular holes in a macrophage.' Since macrophages are host immune cells, this statement is false.
4. Step 4: Correct the statement by replacing 'macrophage' with the appropriate target, such as 'bacterial cell' or 'pathogen.' The corrected statement should read: 'A membrane attack complex drills circular holes in a bacterial cell.'
5. Step 5: Summarize the concept: The MAC forms pores in the membranes of pathogens to lyse them, but it does not attack host immune cells like macrophages.

Key Concepts

Membrane Attack Complex (MAC)

The Membrane Attack Complex is a structure formed by complement proteins that creates pores in the membranes of target cells, typically pathogens, leading to cell lysis. It is part of the innate immune system and primarily targets bacterial cells, not host immune cells like macrophages.

Macrophage Function and Immunity

Macrophages are immune cells that engulf and destroy pathogens through phagocytosis. They are part of the host's defense system and are not typically destroyed by the Membrane Attack Complex, which targets foreign cells rather than the body's own immune cells.

Complement System Specificity

The complement system selectively targets pathogens by recognizing foreign surfaces and assembling the Membrane Attack Complex on them. It avoids damaging host cells like macrophages through regulatory proteins that protect self-cells from complement-mediated lysis.