Immune System

Question 1

Pathogens

Answer 1

Any disease-causing organism or particle (e.g., bacteria, viruses, fungi, worms, or protists).

Question 2

Immune system

Answer 2

The body’s defense system that recognizes, attacks, and destroys pathogens and foreign substances.

Question 3

Innate immunity

Answer 3

(Nonspecific Defense)
Present at birth; always active.
First line of defense: barriers (skin, mucous membranes).
Second line: internal defenses (cells, inflammation, fever).

Question 4

Adaptive immunity

Answer 4

Adaptive Immunity (Specific Defense)
Develops after exposure to pathogens.
Uses specialized cells (T and B lymphocytes).
Has memory for faster responses next time.

Question 5

Interferons

Answer 5

Proteins released by virus-infected cells that warn nearby cells and help block viral replication.

Question 6

Toll-like receptors

Answer 6

Proteins on immune cells that recognize molecules common to many pathogens and trigger an immune response.

Question 7

Neutrophils

Answer 7

White blood cells that engulf and destroy pathogens (phagocytosis).

Question 8

Macrophages

Answer 8

“Big eaters”; engulf and digest pathogens, also help activate adaptive immunity.

Question 9

Dendritic Cells

Answer 9

Capture antigens and present them to T cells, linking innate and adaptive immunity

Question 10

Eosinophils

Answer 10

Attack large parasites (like worms) and release enzymes that damage invaders.

Question 11

Natural Killer Cells

Answer 11

Kill virus-infected or cancerous body cells by triggering apoptosis (programmed cell death).

Question 12

Histamine

Answer 12

Chemical released by mast cells during inflammation; increases blood flow and permeability to bring immune cells to the area.

Question 13

Septic Shock

Answer 13

Widespread inflammation in response to infection that causes a dangerous drop in blood pressure.

Question 14

Crohn’s disease

Answer 14

Chronic inflammation of the digestive tract caused by an overactive immune response.

Question 15

Ulcerative colitis

Answer 15

Inflammation of the colon and rectum; another autoimmune inflammatory bowel disease.

Question 16

Complement system

Answer 16

A group of proteins in the blood that help antibodies and immune cells kill pathogens, by forming pores in their membranes or marking them for destruction.

Question 17

Lymphocytes

Answer 17

B Cells – Mature in bone marrow; make antibodies.
T Cells – Mature in the thymus; kill infected cells or help other immune cells.

Question 18

Epitope

Answer 18

the part of an antigen molecule to which an antibody attaches itself.

Question 19

Thymus

Answer 19

Gland where T cells mature (not where both T and B are made—B cells form in bone marrow).

Question 20

Antigens

Answer 20

Foreign molecules (like on bacteria or viruses) that trigger an immune response.

Question 21

Antigen receptors

Answer 21

Proteins on B and T cells that recognize and bind to specific epitopes.

Question 22

Heavy chains/Light chains

Answer 22

The two types of protein chains in antibodies made by B cells.

Question 23

Antibody

Answer 23

A Y-shaped protein released by B cells that binds to antigens to mark or neutralize them.

Question 24

MHC

Answer 24

Molecules on cell surfaces that present antigens to T cells and also determine tissue compatibility between individuals.

Question 25

Antigen presentation

Answer 25

Process where MHC displays antigen fragments on the cell surface for T cells to recognize.

Question 26

4 Characteristics of Adaptive

Answer 26

Specificity – Targets specific pathogens. Diversity – Can recognize millions of antigens. Self-Tolerance – Doesn’t attack the body’s own cells. Memory – Responds faster to previously encountered pathogens.

Question 27

Immunoglobulin

Answer 27

Gene segments that recombine to form unique antibodies.

Question 28

Apoptosis

Answer 28

Programmed cell death (used to destroy infected or defective cells).

Question 28

Recombinase

Answer 28

Enzyme that rearranges DNA segments to create unique antigen receptors.

Question 29

Clonal selection

Answer 29

When a specific B or T cell is activated by an antigen and clones itself to make effector and memory cells.

Question 30

Effector cells

Answer 30

Active, short-lived cells that fight infection immediately (plasma B cells or active T cells).

Question 31

Memory cells

Answer 31

Long-lived cells that “remember” the pathogen for future responses

Question 32

Primary immune response

Answer 32

First exposure, slower and weaker response.

Question 33

Secondary immune response

Answer 33

Faster and stronger response due to memory cells.

Question 34

Humoral

Answer 34

B cells produce antibodies that circulate in blood and lymph to neutralize pathogens.

Question 35

Cell-mediated response

Answer 35

T cells directly attack infected or abnormal cells.

Question 36

Neutralization

Answer 36

Antibodies bind to pathogens/toxins and block them from entering cells.

Question 37

Opsonization

Answer 37

Antibodies coat pathogens, making them easier for phagocytes (like macrophages) to engulf.

Question 38

Cytotoxic T cells

Answer 38

Destroy infected body cells by releasing enzymes that trigger apoptosis.

Question 39

Immunization

Answer 39

Process of exposing the body to antigens (via vaccine) to build adaptive immunity.

Question 40

Misinformation

Answer 40

Bad rep towards immunization

Question 41

Active immunity

Answer 41

Your body makes its own antibodies after infection or vaccination.

Question 42

Passive immunity

Answer 42

Passive Immunity – Antibodies are transferred from another source (e.g., mother’s milk or antibody injection).

Question 43

Monoclonal

Answer 43

Lab-made identical antibodies that target one specific antigen; used in treatments.

Question 44

Allergies

Answer 44

Overreaction of the immune system to harmless substances (allergens).

Question 45

Autoimmune disease

Answer 45

The immune system attacks the body’s own cells (e.g., lupus, rheumatoid arthritis).

Question 46

Inborn immunodefiecny

Answer 46

Genetic or developmental defect that prevents immune system from functioning properly.

Question 47

Acquired immunodefincy

Answer 47

Caused by infection (like HIV) or external factors (malnutrition, drugs, etc.).

Question 48

Latency

Answer 48

When a virus remains dormant in host cells and can reactivate later (e.g., herpes).

Question 49

HIV

Answer 49

HIV (Human Immunodeficiency Virus) – Attacks helper T cells, weakening the immune system.

Question 50

AIDS

Answer 50

(Acquired Immunodeficiency Syndrome) – Advanced stage of HIV infection where the immune system can no longer fight infections effectively.