Communicable Diseases (4.1)

Question 1

Pathogen

Answer 1

Organisms that cause disease

Question 2

Active immunity

Answer 2

Resistance in an organism that has developed through the production of specific antibodies in response to a pathogen. It provides long-lasting immunity as memory cells are produced.

Question 3

Antibiotic

Answer 3

A chemical/compound that kills or prevents the growth of bacteria

Question 4

Antibiotic-resistant bacteria

Answer 4

Bacteria that mutate to become resistant to an antibiotic, survive and reproduce very rapidly, passing on their antibiotic resistance.

Question 5

Antibodies

Answer 5

Immunoglobulins produced by B-lymphocytes in response to a specific antigen, triggering an immune response

Question 6

Antigen

Answer 6

A chemical present on the surface of a cell that induces an immune response

Question 7

Antigen-presenting cell

Answer 7

A macrophage that displays foreign antigens by isolating the antigen from a pathogen and placing it on the plasma membrane - to activate other immune system cells

Question 8

Anti-toxins

Answer 8

Chemicals produced by white blood cells that neutralise toxins released by pathogens

Question 9

Artificial passive immunity

Answer 9

The immunity acquired from the administration of specific antibodies from another organism, e.g: by vaccination

Question 10

Agglutinins

Answer 10

Antibodies that cause pathogens to stick together - so phagocytes can phagocytoses a lot of pathogens all at once

Question 11

Autoimmune disease

Answer 11

A condition in which the immune system attacks and destroys healthy body tissue, e.g: arthritis, lupus

Question 12

B effector cells

Answer 12

A type of B lymphocyte that divides to form plasma cells

Question 13

Black sigatoka

Answer 13

A fungal disease in tomatoes caused by Mycosphaerella fijiensis, the hyphae of which penetrate and digest host leaf cells, turning them black.

Question 14

B lymphocytes

Answer 14

Lymphocytes that mature in the bone marrow. There are three main types; plasma cells, B effector cells and B memory cells.

Question 15

B memory cells

Answer 15

B lymphocytes that provide immunological memory - they remain in the blood for a long time which provides long term immunity

Question 16

Callose

Answer 16

A large polysaccharide deposit that blocks old phloem sieve tubes - deposited between the cell walls and cell membranes in cells adjacent to infected cells - defence against pathogens

Question 17

Clonal expansion

Answer 17

Mass production of specific antibody-producing cells (eg mitosis to produce many B cells)

Question 18

Clonal selection

Answer 18

The identification of a antibody-producing cell with complementary receptors to the shape of the antigen (means B or T cells with complementary receptors to antigen are activated)

Question 19

Communicable disease

Answer 19

A disease caused by a pathogen which is directly transmitted between organisms

Question 20

Cytokines

Answer 20

Cell signalling molecules which attract white blood cells to site of damage - used to stimulate immune response

Question 21

Expulsive reflexes

Answer 21

Coughs or sneezes initiated upon irritation of the respiratory tract. They remove microorganism-containing mucus from the gaseous exchange system

Question 22

Fungi

Answer 22

Eukaryotic, often multicellular organisms that may cause disease. They digest and destroy cells, and produce spores that can spread rapidly between organisms.

Question 23

Bacteria

Answer 23

Prokaryotic cells that have cell walls but lack organelles. Some bacteria are pathogenic, producing toxins that damage host cells.

Question 24

Histamine

Answer 24

A chemical released by mast cells in damaged tissue. During an allergic reaction it constricts muscles in the lungs, making it harder to breathe

Question 25

Human Immunodeficiency Virus (HIV)

Answer 25

An infectious virus that destroys T helper cells, weakening the immune system of the body. HIV makes an individual more susceptible to infections and can lead to AIDS (Acquired Immunodeficiency Syndrome).

Question 26

Inflammation

Answer 26

A localised response of vascular tissue to pathogens, damage or irritants

Question 27

Influenza

Answer 27

Viral infection that destroys ciliated epithelial cells in the gaseous exchange system, exposing the airways to secondary infection.

Question 28

Interleukins

Answer 28

Signalling molecules used to communicate between different white blood cells - a group of cytokines produced by T helper cells that stimulate B cells

Question 29

Lymphocytes

Answer 29

White blood cells that contribute to specific immune response (B and T cells)

Question 30

Lysosome

Answer 30

Membrane-bound organelle that contains digestive enzymes

Question 31

Malaria

Answer 31

Disease caused by the protoctista *Plasmodium* that lives within two hosts, (mosquitoes and humans)

Question 32

Mast cells

Answer 32

Specialised cells in connective tissue that are important in the inflammatory response, releasing histamines and cytokines

Question 33

Mucous membranes

Answer 33

The membranes lining body cavities that secrete a sticky mucus

Question 34

Natural active immunity

Answer 34

The production of antibodies by the immune system following infection

Question 35

Natural passive immunity

Answer 35

The immunity acquired by an infant mammal when antibodies are transferred through the placenta or breastfeeding from the mother

Question 36

Non-specific defences

Answer 36

Defenses that are always present and are the same for all organisms, e.g: skin, blood clotting, inflammation, mucous membranes and expulsive reflexes

Question 37

Oposins

Answer 37

Proteins that bind to the antigen on a pathogen and then allow phagocytes to bind

Question 38

Passive immunity

Answer 38

Immunity achieved when antibodies are passed to the individual through breast feeding or injection