Module 4.1.1 - Communicable Diseases, Disease Prevention & The Immune System Flashcards
What is a gram positive bacteria?
Looks purple/blue under light microscope
Stained with crystal violet
What is an example of a gram positive bacteria?
MRSA
What is gram negative bacteria?
Looks red under a light microscope
Stained with safranin
What is an example of a gram negative bacteria?
E.coli
What are the 4 different shapes of bacteria?
Cocci (spherical)
Vibrio (curved)
Bacilli (rod-shaped)
Spirilli (spiral)
What are the problems with bacteria reproducing so quickly?
Food spoilage & spread of disease
How do bacteria cause disease?
Release toxins (from antigens on bacteria)
- cause symptoms by cell damage
- damage cell membranes/enzymes or genetic material
What are some examples of bacterial diseases and what bacteria causes them?
Tuberculosis - Mycobacterium Turberculosis
Bacterial meningitis - Streptococcus Pnuemoniae
Ring rot - (gram positive) Clavibacter Michiganesis
What is the structure of a bacteriophage?
Protein coat
Loose genetic material
Tail plate
Injection tube
What are the stages of bacteriophages invading living cells?
1) virus attaches itself to specific host cell
2) the genetic material from the virus is injected into the host cell
3) the viral genes cause the host cell to make new viruses
4) the host cell splits open, releasing the new virus
What are some examples of viral diseases?
HIV/AIDS - Human Immunodeficiency Virus
Influenza - orthomyxoviridae spp.
Tobacco Mosaic virus
What is the structure of a fungi?
Cell wall
Nucleus
Cell membrane
Cytoplasm
Vacuole
Mitochondria
How do fungi reproduce?
Asexually - by budding
What are some examples of fungal diseases?
Cattle ringworm - Trichophyton Verrucosum
Athlete’s foot - Tinia Pedia
Black Sigatoka - Mycosphaerella Fljensis
What is the structure of protoctists?
Unicellular
Nucleus
What are some examples of protozoan diseases?
Blight in potatoes/tomatoes - Protoctist Ommycete
Malaria - Plasmodium
What are the direct ways of transmission between animals?
Direct contact (transmission through bodily fluids)
Inoculation (break in the skin - animal bite/puncture wound/sharing needles)
Ingestion (taking in contaminated food or drink/transferring pathogens from hand to mouth)
What are the indirect ways of transmission between animals
Fomites (inanimate objectes)
Droplet infection (breathing in saliva/mucus from the air that is expelled from someone when sneezing/coughing)
Vectors (e.g. mosquitoes for malaria)
What are the factors that increase the transmission of communicable diseases in animals?
Over population
Poor disposal of waste
Malnutrition
Globalisation
Infrastructure
Climate change
Invasive species
Culture
Access to healthcare
Socioeconomic factors
What are the ways of direct transmission in plants?
Direct contact (Healthy plant touches any part of an infected plant)
What are the ways of indirect transmission in plants?
Soil contamination (infected plants offer pathogens in the soil which can affect the next crop)
Vectors (e.g. wind/water/animals/humans)
What are the factors that increase the transmission of communicable diseases in plants?
Climate change
Overcrowding
Damp & warm conditions
Poor soil/mineral nutrition
Plant varieties susceptible to disease
What are the physical defences of plants against pathogens?
Cellulose cell wall - physical barrier, lignin thickening cell walls (waterproof & ingestible)
Waxy cuticle - prevents water collecting on the surface (pathogens need water)
Guard cells - close stomata
Callose - large polysaccharide deposited into sieve tubes at the end of the growing season (blows flow so pathogens can’t spread)
What are the chemical defences of plants against pathogens?
Terpenoids - antibacterial & antifungal properties (some create a scent)
Alkaloids - nitrogen compounds with a bitter taste (e.g. caffeine/nicotine/cocaine/morphine), stops herbivores feeding on them - less grazing = less exposure
What is active immunity?
Happens when you have a cellular response e.g. T&B cells & antibodies
What is Natural Active immunity?
Happens when a pathogens enters your body - cellular response
What is Artificial Active Immunity?
Vaccines that are injected into you that have a long term effect
What is Passive Immunity?
When antibodies are injected/digested into you - you didn’t make them
What is Natural Passive Immunity?
Happens when babies drink their mothers milk/antibodies passed through the placenta to the foetus
Colostrum - packed with antibodies
What is Artificial Passive Immunity?
Having an injection that is temporary (antibodies don’t last forever)
What is an Autoimmune disease?
When an organs immune system is unable to recognise its own cells & launches an immune response on the organisms own tissues
What are some examples of autoimmune diseases?
Lupus
Arthritis
What is herd immunity?
Where unvaccinated people are protected because the occurence of the disease is reduced by the number of people who are vaccinated
What is a vaccine?
A substance used to stimulate immunity to a particular infectious disease/pathogen
Made from dead/weak forms of the agent
What is immunisation?
The action of making a person/animal resistant to a particular infectious disease/pathogen typically by vaccination
What is an epidemic?
A widespread occurence of an infectious disease in a community at particular time
What is a pandemic?
An epidemic of an infectious disease that as spread across a large region e.g. continents
What is antigenic variability?
The antigens of some pathogens are constantly changing. Each antigen causes its own immune response.
What is the non-specific primary immune defence?
Refers to an immune response which happens regardless of which pathogen it is - general response to a foreign molecule
What is the primary defence?
The body preventing pathogen’s entry
What is the barrier method?
Skin
What is the chemical defences in the body?
Mucus & lysozymes (enzymes that digest pathogens)
What is the third primary defence for the body?
Blood clotting
What is the secondary defence in the body?
The response that happens after the pathogen has entered the body
What are the secondary defences in the body?
Inflammation & phagocytosis
What is inflammation?
The immune response of vascular tissues when they are infected - activates the mast cells to produce 2 chemicals
What 2 chemicals do the mast cells produce?
Histamines - dilate blood vessels (redness), localised heat (prohibits pathogen reduction) & makes the blood vessels more leaky/permeable (increase of white blood cells to the site - swelling & pain)
Cytokines - cell signalling (attract phagocytes - increase of phagocytosis)
When a plant detects infection what happens?
The pathogen releases pathogenic chemicals into the plant cells & digests the cell wall
The nucleus responds by sending a cascade of reactions to counteract the chemicals
Pathogenic chemicals can travel across the plasmodesmata & spread to the rest of the plant (damage) so the plant produces callose which deposits onto plasmodesmata/along the cell wall/onto sift plates in the phloem/signals more lignin production
Plant may release antibacterial/fungal chemicals
Plant can signal to other cells that they’re under attack - chain effect
How can a pathogen get into the body?
Ears
Eyes
Nose (inhaling droplets of contaminated saliva)
Mouth (eating contaminated food)
Genital
Hands (putting hands in mouth after touching contaminated substances)
Skin (cuts/grazes)
What are phagocytes
Specialised white blood cells
What are the 2 types of phagocytes?
Neutrophils & macrophages
What is the structure of a neutrophil & what do they do?
Have a lobed nucleus
Takes approximately 10 mins to engulf & destroy a pathogen (can get through the pores in the capillaries)
What is the structure of a neutrophil and what do they do?
Have a rounded nucleus
When a pathogen is destroyed its antigens combine with glycoproteins in the cytoplasm (major histocompatability complex) which takes the antigen to the cell surface membrane - now an APC (antigen presenting cell) & can stimulate a specific response
What is phagocytosis?
The process of which a phagocyte engulfs & destroys a pathogen
What happens during phagocytosis?
1) the phagocyte recognises antigens on invading bacterium as foreign by chemicals
2) the phagocyte engulfs the pathogen & encloses it in a phagosome - the cell membrane of the phagocyte fuses around the bacterium engulfing it into the phagosome
3) the phagosome combines with a lysosome to form a phagolysosome - empties it’s digestive system to digest the microbe
4) enzymes from the lysosome digest & destroy the pathogen - antigens are presented on the cell surface membrane. Useful products are taken into the cytoplasm (diffusion/AT) & wasted products exocytosed
What are the different components of blood?
Red blood cells (erythrocytes)
White blood cells (leucocytes)
Platelets (thrombocytes)
What makes up white blood cells?
Granulocytes
Agranulocytes
What white blood cells are granulocytes?
Neutrophils
Eosinophils
Basophils
What white blood cells make up agranulocytes?
Lymphocytes
Monocytes
What is a T lymphocyte?
A white blood cell made in the blood marrow but matured in the thymus
What is a B lymphocyte?
A white blood cell made & matured in the bone marrow
What are the 4 different types of T lymphocyte?
T-Helper
T-Killer
T-Regulator
T-Memory
What is a T-Helper lymphocyte?
A white blood cell that detects an APC using CD4 receptors & binds to the AG-MHC complex on the APC to be alerted of the attack & detect MHC - knows it is an APC not a pathogen that needs to be destroyed
What chemicals to T-Helper cells produce and what do they do?
Interleukins (type of cytokine) - stimulates B cells to make antibodies & other T cells to divide
Stimulate macrophages - increase in phagocytosis
What is a T-Killer lymphocyte & what does it do?
A white blood cell that destroys cells by releasing perforin - makes holes on the cell surface membrane
What is a T-Regulator lymphocyte?
A white blood cell that suppresses the immune system using interleukins
What is a T-Memory cell?
A white blood cell that has an immunological memory of antigens to produce a rapid secondary immune response
