Communicable diseases

Active immunity

Resistance in an organism that developed through the production of specific antibodies in response to a pathogen

Draw the structure of an antibody

What is an antibody?

Y-shaped glycoprotein produced by B lymphocytes in response to an antigen

why is active immunity long lasting?

Memory cells are produced

Agglutinins

Chemicals that cause pathogens to clump together, allowing phagocytes to digest multiple pathogens at once

Antibiotic

A chemical or compound produced by a living organism that kills or prevents the growth of bacteria

How does bacterial resistance to antibiotics work?

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

Antibodies

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

Antigen

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

Antigen-presenting cell

A macrophage captures an antigen and presents it to T cells

Artificial active immunity

The production of antibodies by the immune system following the exposure to a weakened or dead pathogen

example of artificial active immunity

Vaccinations so organism produces its own antibodies

example of artificial passive immunity

antibodies from other organisms

Example of natural activity immunity

Normal immune response

Example of passive natural immunity

Mother to baby

State 3 differences between active and passive immunity

1. Active is exposed to antigens, passive is not exposed to antigens

2. Passive only B memory cells active, active both B and T lymphocytes

3. Active protection is long term, passive short term

Artificial passive immunity

The immunity acquired from the administration of specific antibodies from another organism

Autoimmune disease

A condition in which the immune system attacks and destroys healthy body tissue

Example of autoimmune diseases

Arthritis, lupus

Bacteria

Prokaryotic cells that have cell walls but lack organelles

How are pathogenic organisms harmful?

Produce toxins that damage host cells

B effector cells

A type of B lymphocyte that divides to form plasma cells

Black Sigatoka

A fungal disease in tomatoes, turning leaves black

B lymphocytes

Lymphocytes that mature in bone marrow

What are the 3 types of B lymphocytes?

Plasma cells, B effector cells and B memory cells

B memory cells

B lymphocytes that provide immunological memory

Callose

A plant polysaccharide that is deposited between the cell wall and cell membrane in cells adjacent to infected cells, serving as a defence against pathogens

Clonal selection

The identification of an antibody-producing cell with complimentary receptors to the shape of a specific antigen

Communicable disease

A disease that is caused by a pathogen and transmitted directly between organisms

Cytokines

Cell-signalling molecules produced by mast cells in damaged tissue, attracting white blood cells to the site of damage

Direct transmission

The transfer of a pathogen directly from one organism to another

Epidemic

a rapid rise in the incidence of a communicable disease at a local or national level

Expulsive reflexes

Coughs or sneezes initiated upon irritation of the respiratory tract

What is the purpose of expulsive reflexes?

They remove microorganism-containing mucus from the gaseous exchange system

Fungi

Eukaryotic organisms that may cause disease

What do fungi do that can cause diseases?

Digest and destroy cells, and produce spores that can spread rapidly between organisms

Histamine

A chemical produced by mast cells in damaged tissue, making blood vessels dilate and cause their walls to become leakier

Human Immunodeficiency Virus (HIV)

An infectious virus that destroys T helper cells, weakening the immune system of the body

Indirect transmission

The transfer of a pathogen indirectly between organism

How can diseases spread via indirect transmission?

Fomites, vectors or soil contamination

Inflammation

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

Influenza

A common infection caused by viruses that destroy ciliated epithelial cells in the gaseous exchange system, exposing airways to secondary infection

Interleukins

Cytokines produced by T helper cells that stimulate B cells

Lymphocytes

White blood cells that contribute to the specific immune response

Lysosome

A membrane-bound organelle that contains hydrolytic enzymes

Malaria

A disease caused by protoctist Plasmodium that lives within two hosts, mosquitoes and humans

Mast cells

Specialised cells in connective tissue that are important in the inflammatory response

Which chemicals do mast cells release?

Histamines and cytokines

Natural active immunity

The production of antibodies by the immune system following infection

Natural passive immunity

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

Non-specific defences

Defences that are always present and are the same for all organisms

Examples of non-specific defences

Skin, blood clotting, inflammation, mucous membranes and expulsive reflexes

Mucous membranes

The membranes lining body cavities that secrete a sticky mucus

Opsonins

Chemicals that bind to and tag foreign cells, making them easily recognisable to phagocytes

Passive immunity

Resistance in an organism acquired via the transfer of antibodies

Why is passive immunity short-term?

No memory cells are produced

Pathogen

A disease-causing microorganism

What kinds of microorganism can pathogens be?

Bacteria, viruses, fungi or protoctista

Penicillin

The first conventional, effective and safe antibiotic

Personalised medicine

A form of medical care that enables doctors to provide healthcare that is customised to an individuals genotype

Phagocytes

Specialised white blood cells that engulf and destroy pathogens

What are the two types of phagocytes?

Neutrophils and macrophages

Phagocytosis

The process by which phagocytes engulf and destroy pathogens

Phagolysosome

A vesicle within within a phagocyte formed by the fusion of a phagosome and lysosome

Phagosome

A vacuole inside a phagocyte in which a foreign particle is engulfed

Plasma cells

B lymphocytes that produce antibodies specific to a particular antigen

Potato blight

A disease caused by protoctist causing collapse and decay of the leaves, fruit and tubers

Primary immune response

The response of the immune system to a pathogen when it is first encountered

How many antibodies and how quickly are they produced during the primary immune response?

A small number and slowly

Ring rot

A bacterial disease in tomatoes and potatoes that results the leaves, fruit and tubers

Secondary immune response

The response of the immune system to a pathogen when it is encountered for a second or more time

How many and how quickly are antibodies produced during the secondary immune response?

Lots of antibodies, rapid production

Synthetic biology

The design and construct of new biological entities, as well as the reconstruction of pre-existing natural biological systems

T helper cells

T lymphocytes with CD4 receptors on the cell surface membrane, which bind to antigen-presenting cells and secrete interleukins

T killer cells

T lymphocytes that produce perforin, destroying pathogens with a specific antigen

T lymphocytes

Lymphocytes that mature in the thymus gland

What are the 4 types of T lymphocyte?

Helper, killer, regulator and memory

T memory cells

T lymphocytes that provide immunological memory

Tobacco mosaic virus (TMV)

A virus that infects many species of plants, damaging the leaves, flowers, and fruit

T regulator cells

T lymphocytes that regulate the immune response by suppressing other T cells and maintaining tolerance to self-antigens

Tuberculosis (TB)

A bacterial disease that damages lung tissue and weakens the immune system

Vector

A living or non-living agent that transmits a pathogen between organisms

Viruses

Non-living infectious agents that invade host cells and take over cell metabolism, replicating within them

Describe the stages of phagocytosis

1. Phagocyte recognises antigen as foreign

2. cell membrane of phagocyte fuses around pathogen, engulfing into a vesicle

3. A lysosome fuses with the vacuole and empties its digestive enzymes to digest/hydrolyse the microorganism

What extra step of phagocytosis happens in macrophages?

Antigens are presented on the cell surface membrane

Useful products are taken to the cytoplasm and wasted products exocytosed