AP Biology: ch43 Immune

Question 1

Innate immunity

Answer 1

Is present before any exposure to pathogens and is effective from the time of birth
Involves nonspecific responses to pathogens

Question 2

Acquired immunity ( aka adaptive)

Answer 2

after exposure to inducing agents such as microbes, toxins, or other foreign substances
Very specific response to pathogens

Question 3

INNATE IMMUNITY- BROAD DEFENSE

Broken down into:

Answer 3

1. external defenses

2. Internal Defenses: cellular and chemical mechanisms

Question 4

External defense:

Answer 4

1. Intact skin and mucous membranes
   Form physical barriers that bar the entry of microorganisms and viruses
   Secretions:
   Mucus production- viscous and traps particles
   Tears- contain lysosome
   Oil and sweat glands- acidic

Question 5

In the trachea, ciliated epithelial cells

Answer 5

Sweep mucus and any entrapped microbes upward, preventing the microbes from entering the lungs

Question 6

Internal cellular defenses

Answer 6

Depend mainly on phagocytosis

Question 7

Phagocytes, types of white blood cells

Answer 7

Ingest invading microorganisms

Initiate the inflammatory response

Question 8

Phagocytes attach to their prey via surface receptors

Answer 8

And engulf them, forming a vacuole that fuses with a lysosome

Question 9

Macrophages, a specific type of phagocyte

Answer 9

Can be found migrating through the body

Can be found in various organs of the lymphatic system

Question 10

The lymphatic system

Answer 10

Plays an active role in defending the body from pathogens

Question 11

Antimicrobial Proteins- Internal Innate Immunity

Answer 11

Attack microbes directly of impede their reproduction
Complement System: made of 30 different proteins
causes lysis of invading cells and help trigger inflammation
Interferons ( alpha and beta)
Secreted by virus infected cells and cause other cells to inhibit viral reproduction

Question 12

Histamine and other chemicals released from injured cells

Answer 12

Promote changes in blood vessels that allow more fluid, more phagocytes, and antimicrobial proteins to enter the tissues

Question 13

Natural killer (NK) cells

Answer 13

Patrol the body and attack virus-infected body cells and cancer cells
Trigger apoptosis in the cells they attack

Question 14

Many invertebrates defend themselves from infection

Answer 14

Sea stars: ameboid cells do phagocytosis
Insect exoskeleton, mucous membrane- external barrier
Insects hemolymph- contains hemocytes which ingest bacteria

Question 15

lymphocytes provide specific defenses against infection

Answer 15

Triggered after innate immunity is turned on

Cytokines- chemicals released from phagocytes that activate lymphocytes

Question 16

An antigen is any foreign molecule

Answer 16

recognized by lymphocytes and elicits a response from them

Question 17

A lymphocyte actually recognizes

Answer 17

and binds to specific site called epitope

Question 18

The vertebrate body is populated by two main types of lymphocytes

Answer 18

B lymphocytes (B cells) and T lymphocytes (T cells)
Circulate through blood
Concentrated in spleen, lymph nodes, and other lymph tissue
Each cell only one type of antigen

Question 19

B Cell Receptors for Antigens

Answer 19

Two specific binding sites- attach to whole antigens

Are often called membrane antibodies or membrane immunoglobulins

Question 20

T Cell Receptors for Antigens and the Role of the MHC

Answer 20

Consists of two different polypeptide chains

Single antigen binding site for each

Question 21

T cell receptors

Answer 21

T cells bind to small fragments of antigens
That are bound to normal cell-surface proteins called MHC molecules
MHC molecules
Are encoded by a family of genes called the major histocompatibility complex

Question 22

Infected cells produce MHC molecules

Answer 22

Antigen presentation: antigen fragments bound and transported to the cell surface

Question 23

A nearby T cell

Answer 23

Can then detect the antigen fragment displayed on the cell’s surface

Question 24

Class I MHC- nucleated cells that have been infected or turned cancerous

Answer 24

Display peptide antigens to cytotoxic T cells ( kills cells when activated)

Question 25

CLASS II MHC in dendritic, macrophages and B cells

Answer 25

Obtain antigens through phagocytosis | Display antigens to helper T cells

Question 26

MHC importance

Answer 26

Family of genes to encode for MHC ( at least 6) Most polymorphic allele sets per person Most people heterozygous for EACH gene Each person has a MHC fingerprint As many genes as possible to match when doing organ transplants

Question 27

LYMPHOCYTES:

Answer 27

develop in bone marrow

Question 28

Newly formed lymphocytes are all alike

Answer 28

But they later develop into B cells or T cells, depending on where they continue their maturation

Question 29

As B and T cells are maturing in the bone and thymus

Answer 29

Their antigen receptors are tested for possible self-reactivity

Question 30

Lymphocytes bearing receptors for antigens already present in the body

Answer 30

Are destroyed by apoptosis or rendered nonfunctional

Question 31

In a primary immune response

Answer 31

Clonal selection: Binding of antigen to a mature lymphocyte induces lymphocyte proliferation and differentiation Peaks at 10- 17 days

Question 32

Clonal B Cell Selection

Answer 32

Generates a clone of short-lived activated effector cells and a clone of long-lived memory cells

Question 33

SECONDARY IMMUNE RESPONSE

Answer 33

Memory cells facilitate a faster, more efficient response

Question 34

Humoral immune response

Answer 34

activation and clonal selection of B cells, production of secreted antibodies

Question 35

Cell-mediated immune response

Answer 35

activation and clonal selection of cytotoxic T cells

Question 36

Helper T cells produce CD4, a surface protein

Answer 36

``` Helps Helper T to bind to class II MHC molecule–antigen Activation of the helper T cell then occurs ```

Question 37

Cytotoxic T Cells: eliminate infected and cancer cells

Answer 37

Bind to Class I MHC antigen on target cell make CD8 protein that enhances the interaction between a target cell and a cytotoxic T cell Activated cell releases perforin to make holes in cell and proteolytic enzymes (granzymes) to kill cell

Question 38

Activation of B cells

Answer 38

Is aided by cytokines and antigen binding to helper T cells

Question 39

B cell clonal selection

Answer 39

Generates antibody-secreting plasma cells Class II MHC molecules + CD4 displayed ON macrophage after phagocytosis Helper T cell produces clones Helper T activates B cell with help of cytokines from T cell B cell clonal selection to make memory B cells and Plasma cells which secrete antibody

Question 40

The binding of antibodies to antigens

Answer 40

Leads to elimination of microbes by phagocytosis and complement-mediated lysis

Question 41

Active Immunity

Answer 41

Develops naturally in response to an infection Or by immunization, also called vaccination ( uses nonpathogenic form or part of a microbe to create an immune response and create memory cells)

Question 42

Immediate, short-term protection

Answer 42

Is conferred naturally when IgG crosses the placenta from mother to fetus or when IgA passes from mother to infant in breast milk Can be conferred artificially by injecting antibodies into a nonimmune person

Question 43

Certain antigens on red blood cells

Answer 43

Determine whether a person has type A, B, AB, or O blood | Opposite antibody is present in serum

Question 44

Recipient-donor combinations

Answer 44

Can be fatal or safe

Question 45

Another red blood cell antigen, the Rh factor

Answer 45

Creates difficulties when an Rh-negative mother carries successive Rh-positive fetuses Mother can mount a immune reaction against the fetus Later pregnancies of Rh + fetus – mother has memory cells which can destroy baby RBC Preventable- mom can be injected with Anti-Rh IgG antibodies

Question 46

MHC molecules

Answer 46

Are responsible for stimulating the rejection of tissue grafts and organ transplants

Question 47

The chances of successful transplantation are increased

Answer 47

If the donor and recipient MHC tissue types are well matched | If the recipient is given immunosuppressive drugs

Question 48

Allergies are exaggerated (hypersensitive) responses

Answer 48

To certain antigens called allergens Originally a response to parasitic worms? Antibodies are released in response to pollen etc If pollen gets in launches histamine for full inflammatory response

Question 49

An acute allergic response sometimes leads to anaphylactic shock

Answer 49

A whole-body, life-threatening reaction that can occur within seconds of exposure to an allergen

Question 50

ANAPHYLATIC SHOCK

Answer 50

Acute allergic response Mast cells all drop granules causing massive blood vessel dilation Blood pressure drops Death can happen in a few minutes Epi pen- counteracts blood vessel dilation

Question 51

Autoimmune Diseases

Answer 51

The immune system loses tolerance for self and turns against certain molecules of the body Lupus- antibodies ( autoantibodies) against histones and DNA that is being released from broken down cells

Question 52

Rheumatoid arthritis

Answer 52

Leads to damage and painful inflammation of the cartilage and bone of joints

Question 53

Other examples of autoimmune diseases include

Answer 53

Multiple sclerosis Insulin-dependent diabetes Crohns disease

Question 54

Immunodeficiency Diseases

Answer 54

Inability to protect body from pathogens or cancer cells

Question 55

An acquired or secondary immunodeficiency | In severe combined immunodeficiency (SCID)

Answer 55

Called Bubbly Boy syndrome | Both the humoral and cell-mediated branches of acquired immunity fail to function

Question 56

People with AIDS

Answer 56

Are highly susceptible to opportunistic infections and cancers

Question 57

Arises from the loss of helper T cells

Answer 57

Both humoral and cell-mediated immune responses are impaired

Question 58

The loss of helper T cells

Answer 58

Results from infection by the human immunodeficiency virus (HIV)