The Immune System

What is the primary mechanism by which a virus causes illness in a host organism?

• It directly poisons the host's bloodstream.

• It uses the host cell's machinery to create copies of itself, eventually destroying the cell.

• It consumes the host cell's nutrients, leading to starvation.

• It forms a protective shell around host cells, preventing nutrient absorption.

Which of the following is a characteristic of human skin that contributes to its role as a primary defense against infection?

• It actively produces antibodies to neutralize pathogens.

• It has a high pH, creating an alkaline environment hostile to bacteria.

• It forms a physical barrier of dead cells and has a low pH.

• It contains specialized cells that directly engulf invading viruses.

What is the primary function of macrophages during an inflammatory response?

• To produce specific antibodies against invading pathogens.

• To release chemicals that lower the body's temperature.

• To engulf and destroy foreign invaders (antigens) that enter the body.

• To form a new protective layer over the infected area.

How do antibodies contribute to specific immunity against pathogens?

• They directly destroy infected host cells.

• They act as general barriers, preventing any pathogen from entering the body.

• They bind to specific antigens on pathogens, marking them for destruction or hindering their function.

• They increase the body's overall temperature to kill heat-sensitive microbes.

What is the primary function of B lymphocytes in the immune system?

• Directly killing virus-infected cells.

• Producing antibodies to target pathogens in body fluids.

• Activating macrophages to engulf foreign particles.

• Developing in the thymus gland.

Which type of immune response involves T lymphocytes directly targeting and destroying infected body cells?

• Humoral response

• Antibody-mediated response

• Cell-mediated response

• Inflammatory response

What critical role do helper T cells play in coordinating the immune response?

• They directly engulf and destroy antigens.

• They produce memory cells for long-term immunity.

• They activate both B cells and killer T cells.

• They are the primary cells infected by HIV.

What does the "Initial response" phase on an immunity graph represent after a first exposure to a pathogen?

• Rapid production of memory cells, leading to immediate protection.

• A period of lag before significant antibody and effector T cell production, often accompanied by symptoms.

• The body's ability to quickly eliminate the pathogen without any noticeable effects.

• A state of permanent immunity where no further infections can occur.