UNIT 4 6A: Recognising self from non-self

Question 1

Disease

Answer 1

Any condition that affects the normal function of either a part of an organism or the complete organism

Question 2

Non-infectious Disease

Answer 2

A disease that cannot be transmitted from one organism to another

Question 3

Infectious Disease

Answer 3

A disease that can be transmitted from one organism to another

Question 4

Pathogen

Answer 4

A disease-causing agent

Question 5

Epidemic

Answer 5

The rapid spread of an infectious disease to a large number of people within a population

Question 6

Pandemic

Answer 6

An outbreak of infectious disease that occurs over a wide geographical area, affecting a large number of people

Question 7

Host

Answer 7

An organism that has been infected by a pathogen

Question 8

Vector (Immunity)

Answer 8

A living organism that carries and transmits a pathogen from one organism to another

Question 9

Antigen

Answer 9

A unique marker on the surface of cells or viruses that is used in the identification of self from non-self

Question 10

Self Antigen

Answer 10

An antigen on the surface of cells of an organism that is identified by the immune system as belonging to the organism and therefore does not trigger an immune response

Question 11

Non-self antigen

Answer 11

An antigen on the surface of cells of an organism that is identified by the immune system as foreign to the organism and triggers an immune response when detected

Question 12

MHC Marker (Major histocompatibility marker)

Answer 12

a protein that is found on the surface of cells and is used in the identification of pathogens in the immune response

Question 13

Epitope

Answer 13

The specific region of an antigen that is recognised by the immune system

Question 14

MHC Class 1 marker

Answer 14

A type of protein marker on the surface of all nucleated cells that assists in the identification of self from non-self

Question 15

MHC Class 2 marker

Answer 15

A type of protein marker on antigen-presenting white blood cells that is used in the activation of a specific immune response

Question 16

Antigen-presenting cell (APC)

Answer 16

A specific type of white blood cell that uses phagocytosis to engulf a pathogen before displaying peptide fragments (epitopes) on its MHC Class 2 markers for detection by white blood cells

Question 17

Allergen

Answer 17

Any substance that causes an allergic reaction

Question 18

What are the top 2 causes of death worldwide

Answer 18

heart disease
Stroke

Question 19

Examples of contact transmission

Answer 19

Handshaking

Bodily fluid exchange

Infected blood or body fluids from drinking glasses, toothbrushes

Question 20

Examples of medium transmission

Answer 20

Airborne
Waterborne
Foodborne

Question 21

Carrier

Answer 21

Is a living organism that is infected by the pathogen it is carrying, and carries and transmits a pathogen from one organism to another

Question 22

What are 2 common vector-borne diseases

Answer 22

Dengue
Malaria

Question 23

What is the course of disease

Answer 23

1.Incubation
The pathogen may take time to multiply to a number sufficient to cause disease
May take time to reach target tissue which is susceptible to its actions

2. Symptoms of disease
   Symptoms are the result of the body attempting to eliminate the infection
   OR are the effect the pathogen has on the body of the host

3.Recovery
The final stage of the disease
If the pathogen cannot be eliminated, then disability or death is likely

Question 24

Role of MHC markers

Answer 24

Their role is to identify a cell as ‘self’ if healthy, and ‘non self’ if infected by a pathogen, by presenting small peptides to circulating immune cells

Question 25

Why are allergens not considered pathogens

Answer 25

Allergens are not considered to be pathogens because pathogens elicit an immune response in all individuals (with or without symptoms) whereas an allergen only affects individuals who have a specific sensitivity to it

Question 26

What is the cause of the symptoms associated with an allergic response

Answer 26

The symptoms associated with an allergic response are due to a process known as hypersensitivity.