the immune system

Question 1

What are antigens?

Answer 1

Molecules (proteins or polysaccharides) found on cell surfaces that trigger an immune response.

Question 2

How does the immune system recognize pathogens?

Answer 2

It detects foreign antigens on the surface of pathogens.

Question 3

What are the two types of immune response?

Answer 3

Non-specific (general defense) and specific (targeted response).

Question 4

What is a phagocyte?

Answer 4

A type of white blood cell that engulfs and digests pathogens.

Question 5

What is phagocytosis?

Answer 5

The process by which phagocytes engulf and digest pathogens.

Question 6

What is a phagosome?

Answer 6

A vesicle that encloses an engulfed pathogen inside a phagocyte.

Question 7

What do lysosomes do in phagocytosis?

Answer 7

They fuse with the phagosome and release digestive enzymes to break down the pathogen.

Question 8

What is an antigen-presenting cell (APC)?

Answer 8

A phagocyte that presents a pathogen’s antigens to activate other immune cells.

Question 9

What are opsonins?

Answer 9

Molecules in the blood that attach to pathogens to aid phagocytosis.

Question 10

What are cytokines?

Answer 10

Messenger proteins that signal immune cells to move to infection sites.

Question 11

What is a T lymphocyte?

Answer 11

A type of white blood cell involved in the specific immune response.

Question 12

How do T lymphocytes recognize pathogens?

Answer 12

Their surface receptors bind to complementary antigens on APCs.

Question 13

What is clonal selection?

Answer 13

The activation of a T lymphocyte when its receptor binds to a specific antigen.

Question 14

What is clonal expansion?

Answer 14

The process where an activated T lymphocyte divides to produce clones of itself.

Question 15

What are the three main types of T lymphocytes?

Answer 15

T helper cells

Question 16

What do T helper cells do?

Answer 16

Release substances to activate B lymphocytes and T killer cells.

Question 17

What do T killer cells do?

Answer 17

Attach to and kill virus-infected cells.

Question 18

What do T regulatory cells do?

Answer 18

Suppress the immune response to prevent attacking the body’s own cells.

Question 19

What happens to some activated T lymphocytes?

Answer 19

They become memory cells.

Question 20

What do B lymphocytes do?

Answer 20

Bind to antigens using their antibodies and activate the immune response.

Question 21

How do B lymphocytes recognize pathogens?

Answer 21

Their antibodies bind to complementary antigens

Question 22

What is clonal selection in B lymphocytes?

Answer 22

Activation of a B lymphocyte when its antibody binds to a specific antigen.

Question 23

What is clonal expansion in B lymphocytes?

Answer 23

The activated B lymphocyte divides by mitosis into plasma cells and memory cells.

Question 24

What is cell signaling?

Answer 24

The process by which cells communicate using substances that bind to receptors on other cells.

Question 25

Why is cell signaling important in the immune response?

Answer 25

It activates different types of white blood cells when a pathogen is detected.

Question 26

What do T helper cells release to activate B lymphocytes?

Answer 26

Interleukins (a type of cytokine).

Question 27

What are plasma cells?

Answer 27

Clones of activated B lymphocytes that produce antibodies.

Question 28

What do plasma cells do?

Answer 28

Secrete large amounts of antibodies into the blood.

Question 29

How do antibodies help in immune response?

Answer 29

They bind to antigens on pathogens

Question 30

What do the variable regions of antibodies do?

Answer 30

Form antigen-binding sites with a complementary shape to specific antigens.

Question 31

Why do antibodies have hinge regions?

Answer 31

To allow flexibility when binding to antigens.

Question 32

What do the constant regions of antibodies do?

Answer 32

Allow binding to immune system cells (e.g.

Question 33

What holds antibody polypeptide chains together?

Answer 33

Disulfide bridges.

Question 34

How do antibodies help clear an infection?

Answer 34

Through agglutination

Question 35

What is agglutination?

Answer 35

Antibodies bind to multiple pathogens at once

Question 36

What type of antibodies act as agglutinins?

Answer 36

Antibodies with two binding sites that can link multiple pathogens together.

Question 37

How do antibodies neutralize toxins?

Answer 37

Anti-toxins bind to toxins

Question 38

How do antibodies prevent pathogens from binding to human cells?

Answer 38

They block pathogen surface receptors needed for host cell attachment.

Question 39

What is the primary immune response?

Answer 39

The body's first response to a pathogen

Question 40

Why is the primary immune response slow?

Answer 40

There aren't many B lymphocytes that can produce the necessary antibodies at first.

Question 41

What happens during the primary immune response?

Answer 41

B and T lymphocytes are activated

Question 42

What are memory cells?

Answer 42

Long-lasting immune cells that remember specific antigens for a faster response upon reinfection.

Question 43

What do memory T lymphocytes do?

Answer 43

Remember specific antigens and recognize them during reinfection.

Question 44

What do memory B lymphocytes do?

Answer 44

Record the specific antibodies needed to bind to the antigen.

Question 45

What does it mean to be immune to a disease?

Answer 45

The immune system can quickly respond to a second infection before symptoms develop.

Question 46

What is the secondary immune response?

Answer 46

A faster immune response to an already recognised disease

Question 47

Why is the secondary immune response faster?

Answer 47

Memory B lymphocytes quickly divide into plasma cells

Question 48

How does clonal selection differ in the secondary response?

Answer 48

It happens much faster because memory cells are already present.

Question 49

Why do people often not show symptoms during a secondary response?

Answer 49

The immune system eliminates the pathogen before symptoms appear.

Question 50

How do the primary and secondary immune responses differ in speed?

Answer 50

The primary response is slow

Question 51

Which cells are activated in the primary vs. secondary response?

Answer 51

The primary response activates B and T lymphocytes; the secondary response activates memory cells.

Question 52

Are symptoms present in the primary and secondary responses?

Answer 52

Symptoms occur in the primary response but usually not in the secondary response.

Question 53

What is a blood smear?

Answer 53

A blood smear is a sample of blood smeared over a microscope slide. Stains are added to make the different cells easy to see. It typically shows red blood cells, white blood cells, and platelets.

Question 54

How can you identify red blood cells on a blood smear?

Answer 54

Red blood cells can be identified by their shape and the absence of a nucleus.

Question 55

What is a neutrophil?

Answer 55

A neutrophil is a type of white blood cell with a multi-lobed nucleus (three interconnected blobs) and a grainy cytoplasm.

Question 56

What is a lymphocyte?

Answer 56

A lymphocyte is a small white blood cell with a nucleus that takes up most of the cell and very little cytoplasm. It’s not grainy, and you cannot distinguish between a T or B lymphocyte under a light microscope.

Question 57

What is a monocyte?

Answer 57

A monocyte is the largest white blood cell and a type of phagocyte. It has a kidney-bean shaped nucleus and a non-grainy cytoplasm.