Communicable Diseases Flashcards
Characteristics of viruses?
Smaller than bacteria, non-living, invade cells and multiply inside causing them to burst
Characteristics of bacteria?
Larger, prokaryotic, don’t have membrane-bound organelles, produce toxins to make you feel ill
How do you stain bacteria?
Gram-positive looks purple-blue under a microscope and Gram-negative appears red
What is a parasite?
An organism that feeds off a host at their expense
Characteristics of fungi?
Eukaryotic, found on plants, makes plants unable to photosynthesise and digest food, kills the plant
Name all the plant diseases?
Ring rot, Tobacco Mosaic Virus, Potato Blight, Black Sigatoka
Symptoms of ring rot?
Bacterial disease, Gram-positive, Effects the leaves, tubers and fruit, Destroys the crop and has no cure
Tobacco Mosaic Virus symptoms?
Viral infection, damages leaves making them look all discoloured, prevents photosynthesis, no cure, treat by cutting infected leaves, leads to crop loss
Potato blight?
Fungal infection, dark brown patches on leaves around edges going towards middle, remove infected plants, insecticides, prevent by cleaning equipment, spread plants far apart
Explain Black Sigatoka?
Fungal disease, turns leaves black, hyphae digests the cells, reduces crop yield, use fungicides to treat
Tuberculosis?
Bacterial disease, caused by mycobacterium tuberculosis, destroys the lung tissue and suppresses the immune system, take antibiotics to treat, spread by droplet inhalation
Explain bacterial meningitis?
Bacterial infection, effects the meninges of the brain, can spread to the rest of the body and causes blood poisoning, affects 15-19 year olds typically, a symptom is a red/purple rash appears once glass is pressed to skin, treated by antibiotics, can get vaccinated from it
HIV/AIDS?
Viral infection, destroys the immune system and makes people susceptible to other diseases, transmitted by exchange of bodily fluids, sharing needles and unprotected sex, use drugs to slow the process down, no cure or vaccine yet
Influenza?
Viral infection, targets ciliated epithelium cells involved in gas exchange, can be fatal, leaves always open for secondary infection, 3 strands of it (A, B and C) Can be prevented with vaccination, the virus can mutate
Malaria?
Protist, spread by mosquitoes as vectors, infects red blood cells, the liver and the brain, symptoms are like the flu, prevent spread by using mosquito nets
What type of mosquitoes spread malaria?
Anopheles (female mosquitoes)
What is ring worm?
Fungal disease, causes grey-white, crusty, infectious, circular areas on the skin, treated by anti fungal creams, spread by direct contact
Athlete’s foot?
Fungal disease, causes cracking, spread by contact on clothes or towels, treated with anti-fungal creams
What are the three types of direct contact?
Direct contact (kissing, STDs, skin), Inoculation (animal bite, break in skin), Ingestion (contaminated food)
Different types of indirect transmission?
Fomites (inanimate objects), Droplet inhalation and Vectors
Factors effecting transmission?
Overcrowding, Poor nutrition, Compromised immune system, Climate, Hygiene
Non-specific defenses of mammals?
HCL stomach acid, skin acting as a barrier, blood clotting, inflammatory response, mucus membranes, cilia, expulsive reflexes
Explain the inflammatory response?
Histamine (dilates blood, more leaky) and cytokines (attract phagocytes) are released. Red, high temps and swelling occurs
Explain how blood clots?
An enzyme cascade is triggered by thromboplastin making a blood clot. Serotonin is released constricting blood flow to area. Clot dries and toughens
Physical plant defences?
Deposition of callose in the plasmodesmata blocking pores, lignin acting as barrier
Chemical defenses in plants?
Terpenoids, toxins and insect repellents
Describe the process of phagocytosis?
Phagocytes recognize non-human antigens, phagocyte engulfs pathogen becoming a phagosome, this combines with lysosome forming a phagolysosome, enzymes digest and destroy pathogen
What is an opsonin?
Chemicals that bind and ‘tag’ pathogens making more recognizable to phagocytes
What in an antibody?
A Y-shaped glycoprotein called immunoglobins which bind to specific antigens
What is it called when the antibody has bound to an antigen?
Antigen-antibody complex
Structure of an antibody?
2 heavy and 2 light chains, held together by disulfide bridges, variable region for antigen binding sites, constant region too, hinge for flexibility
Ways that antibodies defend the body?
Agglutination, Neutralization, Anti-toxins, Opsonin
What produces antibodies?
Plasma cells
Role of T helper cells?
Bind to APC’s and produce interleukins
What do interleukins do?
Stimulates the activity of B cells for humoral immunity
What do memory cells contribute to?
The immunological memory
Role of T regulator cells?
They suppress the immune system once pathogen eliminated, prevents autoimmune disease
Where are B and T cells matured?
B cells = Bone marrow
T cells = Thymus
Describe the process of cell-mediated immunity?
Macrophage APCs bind with a T helper cell to release interleukins and stimulate mitosis into T memory cells or T killer cells
What is clonal selection?
Selecting the best B cell for the particular antigen
What is clonal expansion?
The activated B cells dividing by mitosis into plasma and memory cells
Difference in primary and secondary immune response?
Primary can take days or weeks, secondary uses memory cells to produce correct antibody quicker, more efficient
What is an autoimmune disease?
When the body stops recognizing ‘self’ cells and attacks healthy body tissue
Examples of autoimmune diseases?
Lupus, arthritis and type 1 diabetes
How are autoimmune diseases treated?
Immunosuppressant drugs
Natural immunity?
Natural Active - The immune response
Natural Passive - Antibodies from mothers milk/ placenta
Artificial immunity?
Artificial Active - Vaccination
Artificial Passive - Antibodies injected
How does a vaccine work?
Dead/ inactive pathogens are injected into the blood, primary response triggered to produce antibodies and memory cells so that secondary response will be quicker
What is an epidemic?
When a communicable disease spreads rapidly to a lot of people at a local level
What is a pandemic?
When a disease spreads rapidly on a global level
Herd immunity?
When a significant number of the population have been vaccinated and have developed immunity, disease dies out
Different sources of medicine?
Willow is used for aspirin (painkiller), foxgloves is used for digoxin (heart disease) and extraction from mold developed penicillin
Pharmacogenomics?
A combination of drugs that work with your genetics and disease - personal medicine
What is synthetic biology?
Genetic engineering of modified bacteria
3 things that drugs need to be tested to find out?
Toxicity, effectiveness and dosage
Examples of antibiotic-resistant bacteria?
MRSA and C. diff
