Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
72 Cards in this Set
- Front
- Back
|
What is a pathogen? |
A microorganism that causes disease |
|
|
What is direct transmission? |
Passing a pathogen from host to new host with no intermediary |
|
|
What is indirect transmission? |
Passing a pathogen from host to new host via a vector |
|
|
What is transmission? |
Passing a pathogen from an infected individual to an uninfected individual |
|
|
What is a vector? |
An organism that carries a pathogen from one host to another |
|
|
What is callose? |
A large polysaccharide that blocks old phloem sieve tubes |
|
|
What is inflammation? |
Swelling and redness of tissue caused by infection |
|
|
What is mucous membrane? |
Specialised epithelial tissue that is covered by mucus |
|
|
What are primary defences? |
Those that prevent pathogens entering the body |
|
|
What is an antigen-presenting cell? |
A cell that isolates the antigen from a pathogen and places it on the plasma membrane so it can be recognised by other cells in the immune system |
|
|
What is clonal selection? |
Selection of B or T cells that is specific to the antigen |
|
|
What are cytokines? |
Hormone-like molecules used in cell signalling to stimulate the immune repsonse |
|
|
What are neutrophils? |
Type of white blood cell that engulfs foreign matter and traps it in a large vacuole which fuses with lysosomes to digest the foreign matter |
|
|
What are opsonins? |
Proteins that bind to the antigen on a pathogen and then allow phagocytes to bind |
|
|
What are antibodies? |
Specific proteins released by plasma cells that can attach to pathogenic antigens |
|
|
What are B memory cells? |
Cells that remain in the blood for a long time providing long-term immunity |
|
|
What is clonal expansion? |
An increase in the number of cells by mitotic cell division |
|
|
What are interleukins? |
Signalling molecules that are used to communicate between different white blood cells |
|
|
What are plasma cells? |
Derived from B lymphocytes, these are cells that manufacture antibodies |
|
|
What are T helper cells? |
Cells that release signalling molecules to stimulate an immune response |
|
|
What are T killer cells? |
Cells that attack and destroy our own body cells that are infected by a pathogen |
|
|
What are T memory cells? |
Cells that remain in the blood for a long time, providing long-term immunity |
|
|
What are T regulator cells? |
Cells that are involved with inhibiting or ending the immune response |
|
|
What are agglutinins? |
Antibodies that cause pathogens to stick together |
|
|
What are anti-toxins? |
Antibodies that render toxins harmless |
|
|
What is the primary immune response? |
The initial response caused by a first infection |
|
|
What is the secondary immune response? |
A more rapid and vigorous response caused by a second or subsequent infection by the same pathogen |
|
|
What is active immunity? |
Where the immune system is activated and manufactures it's own antibodies |
|
|
What is artificial immunity? |
Immunity achieved as a result of medical intervention |
|
|
What is an epidemic? |
A rapid spread of disease through a high proportion of the population |
|
|
What is natural immunity? |
Immunity achieved through normal life processes |
|
|
What is passive immunity? |
Immunity achieved when antibodies are passed to the individual through breast feeding or injection |
|
|
What is vaccination? |
A way of stimulating an immune response so that immunity is achieved |
|
|
What is an antibiotic? |
A chemical which prevents the growth of microorganisms (antibacterial or antifungal) |
|
|
What is personalised medicine? |
The development of designer medicines for individuals |
|
|
What is synthetic biology? |
-The re-engineering of biology -Production of new molecules that mimic natural processes -Use of natural molecules to produce new biological systems that do not exist in nature |
|
|
Describe bacteria |
-Prokaryotic -Reproduce rapidly -Cause disease by damaging cells or releasing waste products that are toxic to the host -In plants live in vascular tissue and cause blackening/death of tissue |
|
|
Describe fungi |
-Lives under skin and forms a mycelium -Sends out hyphae which grow to skin surface to release spores -In plants lives in vascular tissue, releases enzymes which cause decay |
|
|
Describe viruses |
-Invade cells and take over genetic machinery -Cause cell to make more copies of virus -Eventually bursts, releases new viruses to infect healthy cells |
|
|
Describe protoctista |
Organisms enter host cells and feed on contents |
|
|
Name some diseases caused by bacteria |
-Tuberculosis -Bacterial meningitis -Ring rot (in plants) |
|
|
Name some diseases caused by viruses |
-HIV -Influenza -Tobacco mosaic virus (in leaves) |
|
|
Name some diseases caused by fungi |
-Black sigatoka (bananas) -Ringworm -Athletes foot |
|
|
What diseases are caused by protoctista? |
-Blight (potatoes) -Malaria |
|
|
How can diseases be directly transmitted? |
-Direct physical contact -Faecal/oral transmission -Droplet infection -Transmission by spores |
|
|
What factors affect direct transmission? |
-Hygiene -Treatment of waste/drinking water -Washing/careful prep of food -Poor health/diet/ventilation -Overcrowding/homelessness |
|
|
Describe indirect transmission |
A vector is used by a pathogen to gain entry to the primary host |
|
|
How can plant pathogens be transmitted? |
-Some enter through roots -Spores produced by fungi become carried in the wind -Pathogens in leaves fall to soil and where it can grow and infect plants |
|
|
Why are there more diseases in areas with warmer climates? |
Bacteria and fungi can reproduce and grow more rapidly when the conditions are warm and moist |
|
|
What are passive defences? |
Defences present before infection that prevent entry and spread of the pathogen |
|
|
Name physical passive defences |
-Cell wall -Lignin thickening of cell walls -Waxy cuticles -Bark -Stomatal closure -Callose -Tylose |
|
|
What is tylose? |
A balloon-like swelling that fills a xylem vessel to block water flow and spread of pathogens |
|
|
Name passive active defences |
-Cell walls become thickened -Callose impede pathogens at site of infection -Increased production of chemicals -Oxidative bursts produce reactive oxygen molecules that damage cells of invading organisms |
|
|
What is necrosis? |
-Deliberate cell suicide -Kill cells surrounding infection, limits pathogens water/nutrients access -Brought about by intracellular enzymes |
|
|
What is a canker? |
A sunken necrotic lesion in woody tissue, causes death of cambium tissue in bark |
|
|
What are terpenoids? |
Range of essential oils that have antibacterial/antifungal properties |
|
|
What are phenols? |
Have antibacterial/antifungal properties |
|
|
What are alkaloids? |
-Nitrogen-containing compounds -Give bitter taste to inhibit herbivores feeding -Some inhibit protein synthesis |
|
|
What are defensins? |
-Small cysteine-rich proteins -Act in plasma membrane of pathogens, inhibit ion transport |
|
|
What are hydrolytic enzymes? |
-Found in spaces between cells -Chitinase, glucanase, lysozymes |
|
|
How does the skin work as a primary defences? |
-Keratinocytes produced at base of epidermis -Migrate to skin surface, dry out, cytoplasm replaced by keratin -When they reach surface, they are dead, acts as a barrier |
|
|
How does blood clotting work as a primary defence? |
-Clotting factor released from platelets/damaged tissue -Activates an enzyme cascade -Clot forms scab, scab shrinks and draws sides of cut together -Fibrous collagen deposited under scab, stem cells from epidermis differentiate to form new skin |
|
|
Why does inflammation occur after infection? |
-Histamine released -Causes vasodilation to make capillary walls more permeable to white blood cells -Increases tissue fluid production, causes swelling |
|
|
Name three other primary defences |
-Antibodies and enzymes in tears -Wax in ear canals -Mucus plug in cervix, acid in vagina |
|
|
Where are neutrophils made? |
Bone marrow |
|
|
What are antigens? |
Chemical markers on the outer membrane of a pathogen |
|
|
What are macrophages and how do they work? |
-Larger cells made in bone marrow -Travel in blood as monocytes -When they engulf pathogens, antigen is saved and moves it to cell surface in a special protein complex, becomes antigen-presenting cell |
|
|
What is antigen presentation? |
Antigen-presenting cell moves around body where it can come into contact cells to activate full immune repose to increase chance antigen will come in contact with correct T or B cell |
|
|
What is an autoimmune disease? |
-When the immune system attacks a part of the body -Antibodies start to attack our own antigens |
|
|
What are two examples of autoimmune diseases? |
Arthritis and lupus |
|
|
What is the order of the specific immune response? |
-Infection -Presentation of antigens -Clonal selection -Proliferation/clonal expansion -Differentiation -Action |
|
|
Describe the structure of an antibody |
-Y shaped -Four polypeptide chains -Disulfide bridges hold polypeptides |
