Chapter 43: The immune system

Question 1

Lysozyme

Answer 1

A protein that acts as an antimicrobial agent

Question 2

Phagocytosis

Answer 2

Cell eats another cell, usually virus or some kind of antigen

Question 3

Hemocyte

Answer 3

Travel in Hemolymph to carry out phagocytosis

Question 4

Antigen

Answer 4

Something which causes a reaction for the body

Question 5

Antigen receptor

Answer 5

A part of the body which detects the antigen

Question 6

Epitope

Answer 6

The part of T or B cell which recognizes the antigen

Question 7

Antibodies

Answer 7

Physically block antigens from moving by filling up all of their epitopes

Question 8

Immunoglobulins

Answer 8

A protein that helps the body fight infection

Question 9

Neutralization

Answer 9

Antibody binding to a cell to prevent it from binding to a host cell

Question 10

Opsonization

Answer 10

The binding of antibodies to a cell signals to macrophages that they should eat the cell

Question 11

Immune rejection

Answer 11

Immune system rejects cells from another organism, thus causing the immune system to destroy it

Question 12

Antigenic variation

Answer 12

A virus changing its epitomes which our immune system is looking for

Question 13

What are the two types of immunity and how do they differ?

Answer 13

Innate: Things which do not change, always looking for the same things
Adaptive: Can change according to what the body is fighting off

Question 14

What is an antimicrobial peptide?

Answer 14

A protein released by the body which interferes with pathogen reproduction, such as Interferon

Question 15

What are the similarities and differences in the innate responses of invertebrates and vertebrates? What additional defenses are unique to vertebrates?

Answer 15

Similarities: Outside barriers and a lined digestive system
Differences: Hemocytes (invert.), Interferons and Natural killer cells (Vert.)

Question 16

What is a barrier defense?

Answer 16

A barrier which physically stops microbes from entering our body

Question 17

What are the major types of phagocytic cells and how do they differ from one another?

Answer 17

Neutrophils: Most common, found in blood
Macrophages: Really large, found in lymph nodes
Eosinophils: Releases enzymes, found in mucus
Dendritic cells: Stimulate adaptive immunity, found in skin

Question 18

What are the two classes of antimicrobial peptides that are unique to vertebrates?

Answer 18

Defensins and Cathelicdins

Question 19

What is the role of mast cells in the inflammatory response?

Answer 19

Release histamines which causes blood vessels to dilate

Question 20

What is the relationship between natural killer cells and class 1 MHC protein?

Answer 20

NK cells are checking body cells for Class 1 MHC proteins, if it does not have it then it is either not a body cell or a malfunctional body cell (such as cancer), in either scenario it will try to kill it

Question 21

What does immunological memory mean?

Answer 21

Your immune system remembers pathogens through memory cells, so it knows what to do if it encounters the same pathogen once again

Question 22

What are cytokines?

Answer 22

A protein which draws in lymphocytes to the site of release and makes them do their job

Question 23

What is a B cell and how is its receptor constructed?

Answer 23

It is a lymphocyte that matured in the bone marrow, it has two epitopes

Question 24

What is a T cell and how is its receptor constructed?

Answer 24

A lymphocyte which matured in the Thymus, only one epitope

Question 25

How do B cells and T cells differ with respect to antigen binding?

Answer 25

B-cells look mostly at what is in your blood (humoral immune response) and T-cells look at other cells to see if they are body (cell-mediated immune response)

Question 26

What is the role of MHC molecules in an infected cell?

Answer 26

It stops being there, causing it to alert NK and T-cells to the fact that it is infected

Question 27

What is the difference between Class I and Class II MHC molecules?

Answer 27

Class 1: Found in all body cells (except blood) Class 2: Found only in antigen presenting cells, acts as a signal to helper T-cells to show that this is an antigen presenting cell

Question 28

What are four important properties of the adaptive immune system

Answer 28

Receptor diversity Lack of reactivity to host cells Cell proliferation Immunological memory

Question 29

How is it possible for each person to produce more than 1 million different B cells and 10 million different T cells when there are only ~20,000 protein-coding genes in the human genome?

Answer 29

It is because of gene reconfiguration, the process where two random genes in a cell are picked as the primary genes, and anything between those are deleted, leading to a ton of possibilities

Question 30

What is meant by the term self-tolerance?

Answer 30

Won't try to kill its own cells

Question 31

What is clonal selection?

Answer 31

T or B-cells encounter a pathogen that it can react to, then rapidly divides into effector cells and memory cells

Question 32

How do effector cells and memory cells differ?

Answer 32

Memory cells: Don't act right away, there to make sure if the antigen appears again the body knows how to react, long life Effector cells: Do the deed right there, then die shortly after

Question 33

How does the secondary immune response differ from the primary immune response?

Answer 33

Much faster and more intense

Question 34

What are the two branches of adaptive immunity?

Answer 34

Humoral immune response: Looks at the blood to check for pathogens Cell-mediated immune response: Checks the body cells for infections

Question 35

What is the role of the helper T cells in the humoral and cell-mediated immune responses?

Answer 35

It calls B and T cells to action

Question 36

Which cells are primarily involved in the humoral immune response?

Answer 36

B-cells

Question 37

Distinguish between active and passive immunity

Answer 37

Active: Your own immune system working to keep you safe Passive: Immediate but for short term protection, given by somebody else

Question 38

How does immunization (vaccination) protect against an infectious disease?

Answer 38

It gives your body a not disease causing version of the pathogen, that your body then fights off with the proper B or T cells, which then causes it to acquire memory cells for that pathogen, if the real thing ever comes around

Question 39

What is the relationship between MHC molecules and the rejection of tissue grafts and transplanted organs?

Answer 39

Tissue grafts and transplanted organs might have different MHC molecules than what your body is looking for, so if it finds those different MHC proteins your cells will attack it

Question 40

What is an autoimmune disease?

Answer 40

A disease which causes your body to attack its own cells

Question 41

What is an immunodeficiency disease?

Answer 41

A disease where your immune system becomes weakened

Question 42

How does HIV affect the immune system? Why is HIV difficult to eradicate?

Answer 42

It interferes with Helper T-cells, this means that neither of the immune responses can function properly