Infection And Response

Question 1

What is an antigen?

Answer 1

Antibody generating molecule recognized as Non-self or foreign

Antigens can stimulate an immune response.

Question 2

What are examples of antigens?

Answer 2

• Proteins
• Polysaccharides
• Glycoproteins
• Glycolipids
• Free molecules (e.g., toxins)

Antigens can be found on microorganisms, viruses, tissue or organ transplants, and as free molecules.

Question 3

Where can antigens be found?

Answer 3

• Cell surface of a microorganism
• Surface of a virus
• Cell surface of a tissue or organ transplant
• As a free molecule (e.g., toxin)

Antigens are typically foreign substances that stimulate an immune response.

Question 4

What characterizes the most effective antigens?

Answer 4

They are large and complex

The complexity and size help in eliciting a stronger immune response.

Question 5

What is antigen variability?

Answer 5

Changes in the shape of an antigen due to mutations in the pathogenic DNA

This can render previous immunity ineffective.

Question 6

How does antigen variability affect immunity?

Answer 6

Previous immunity becomes ineffective if the shape of the antigen changes

Memory cells in the blood will only recognize the old antigen shape.

Question 7

Why is a new flu vaccine created each year?

Answer 7

The influenza virus mutates and changes its antigens quickly

This rapid change necessitates updated vaccines to match the new antigen shapes.

Question 8

True or False: Antigens are always foreign substances.

Answer 8

False

While they are usually foreign, not all antigens are.

Question 9

Fill in the blank: Antigens can be found on the _____ of a virus.

Answer 9

surface

This is one of the locations where antigens are commonly found.

Question 10

What are the two types of defence mechanisms?

Answer 10

Non-specific and Specific

Question 11

Non-specific defense

Answer 11

Response is immediate and the same for all pathogens: it is a physical barrier e.g skin, or phagocytosis

Question 12

Specific defense mechanism

Answer 12

Response is slower and specific to each pathogen. It is a cell mediated response e.g T lymphocytes, or a humoral response e.g B lymphocytes

Question 13

Cytokines

Answer 13

Cell signalling molecules that aid cell-to-cell communication in immune responses and stimulate the movement of cells towards sites of inflammation, infection and trauma

Question 14

What generally triggers inflammation?

Answer 14

Occurs when an infection is relatively localised

Question 15

What type of cells release histamines during inflammation?

Answer 15

Mast cells

Question 16

Where are mast cells typically found?

Answer 16

In connective tissue below the skin and around blood vessels

Question 17

What effect do histamines have on blood vessels?

Answer 17

Cause blood vessels to dilate, leading to local heat and redness

Question 18

What happens to capillary walls during inflammation?

Answer 18

Become more leaky, allowing fluid and white blood cells to exit

Question 19

What type of white blood cells are mainly forced out of capillaries during inflammation?

Answer 19

Neutrophils

Question 20

Fill in the blank: Histamines cause blood vessels in the area, particularly ________, to dilate.

Answer 20

arterioles

Question 21

What are the main components of the fluid that leaks out of capillaries during inflammation?

Answer 21

Plasma, containing WBCs and antibodies

Question 22

True or False: Basophils are responsible for releasing histamines during inflammation.

Answer 22

False

Question 23

What are the common symptoms associated with inflammation?

Answer 23

Swelling and pain

Question 24

What are non-self cells or molecules?

Answer 24

Cells or molecules that the immune system has not had exposure to during maturation or does not normally encounter in the body

Non-self cells trigger an immune response to destroy them.

Question 25

What happens if a non-self cell is detected?

Answer 25

A response will be triggered to destroy the cell

This is a key function of the immune system.

Question 26

What type of entities can the immune system identify?

Answer 26

The immune system can identify:
* Pathogens (e.g., bacteria, fungi, viruses)
* Cells from other organisms of the same species
* Abnormal body cells (e.g., cancer cells)
* Toxins released by pathogens

These identifications are crucial for the immune response.

Question 27

Fill in the blank: The immune system can identify pathogens such as _______.

Answer 27

[bacteria, fungi, viruses]

Examples include HIV as a virus.

Question 28

True or False: The immune system can identify cells from other organisms of the same species.

Answer 28

True

This is particularly relevant in organ transplants.

Question 29

What are some examples of abnormal body cells identified by the immune system?

Answer 29

Abnormal body cells include cancer cells

The immune response can target these cells for destruction.

Question 30

What kind of toxins can the immune system identify?

Answer 30

Toxins released by pathogens

An example is cholera toxin.