chemical and physical Barriers year 9

Which is an example of a physical barrier of defense against pathogens?

• Stomach acid

• Lysosomes

• Inflammation

• Skin

Answer explanation

Skin is an example of a physical barrier of defense against pathogens, acting as the first line of defense by preventing pathogens from entering the body.

What is the primary purpose of the inflammatory response?

• To eliminate foreign substances and initiate healing

• To increase antigens

• To maximise the use of antibiotics

• To enhance phagocytes activity

Answer explanation

The primary purpose of the inflammatory response is to eliminate foreign substances and initiate healing, not to increase antigens, maximise the use of antibiotics, or enhance phagocytes activity.

Which of the following is an example of a chemical barrier in the body's defense against pathogens?

• Stomach acid

• Fatty acid on the skin

• Mucous membrane

• All of these

Answer explanation

The correct choice is 'All of these' because stomach acid, fatty acid on the skin, and mucous membrane are all examples of chemical barriers in the body's defense against pathogens.

What is the purpose of physical and chemical barriers of the body's defense against pathogens?

• To prevent entry of pathogens

• To neutralise extracellular pathogens

• To activate the immune response

• To enhance B-cell and T-cell activities

Answer explanation

The purpose of physical and chemical barriers is to prevent entry of pathogens, acting as the first line of defense against infections.

Which of the following is the name for a micro-organism that can cause disease?

• Pathogen

• Antibodies

• B-cells

• Lymphocyte

This sticky fluid traps any pathogens that try and get in our body

• Mucous Lining

• Blood

• Stomach Acid

• Skin

What are two examples of chemical barriers?

• Lysozyme enzyme in our tears

• Skin

• White Blood Cells

• Stomach Acid

Which of the following is a type of white blood cell that will help to destroy pathogens which get past our physical barriers and chemical defences?

• bacterium

• antibody

• antigen

• lymphocyte

Which cells produce antibodies to pathogens?

• Red blood cells

• Bacteria

• lymphocytes

• phagocytes

What is a preparation of dead or weakened pathogens that is introduced into the body to cause an immune response?

• fungi

• vaccine

• antigens