Diseases and the Immune system Flashcards
what is a disease
condition that impairs the normal functioning of an organism
what are the types of pathogen
- bacteria
- proctista
- virus
- fungi
what are the types of bacteria
Cocci
- small surface area to volume ratio
- survive in dry conditions
- cause acne
Bacilli
- large surface area and take up nutrients
- causes food poisoning
Vibrio
- large surface are and takes up nutrients
- causes cholera
Spirillum
- corkscrew motion
- stomach ulcers
how do bacteria reproduce
- chromosomes duplicate
- cells grows
- cell divides into two
quick reproduction can cause spoiled food and spread disease
how do bacteria cause disease
- antigen on bacterium
- produce toxins
- damage cell membranes, enzymes, genetic material
what are the bacterial diseases
Tuberculosis
- caused by droplet infection
- dry cough, fever, fatigue, weight loss
Bacterial meningitis
- spread or respiratory and throat secretions
- fever, vomiting
Ring Rot
- discolouration
- leaf curling
what is protoctista
- unicellular
- nucleus
what is plasmodium
- live as a parasite inside a female mosquito
- mosquito secretes saliva into bloodstream that contains sporozoites
- attack liver cells
- merozoites reproduced asexually and attack red blood cells
- maturation and production of parasites
- female mosquito pregnant with parasite
- infects human
what are the protozoan diseases
Blight in potatoes/tomatoes
- fungus like organism that spreads rapidly through potato in warm wet conditions
- leaves collapse, shrivel, turn brown
Malaria
- caused by a parasite
- fever, chills, discomfort, headache, nausea
Bacteriophage
- attaches to a specific host cell
- injects genetic material into the host cell
- viral gene causes the host cell to reproduce new viruses
- host cell splits open to release the new virus and the process repeats
what is retrovirus replication
- virus attaches to the host cell
- virus fuses with cell surface membrane and enters cell by endocytosis
- virus injects RNA
- RNA used as a template to make DNA
- DNA inserted into chromosomes by protein integrase
- viral RNA synthesised by host cell by transcriptase
- leaves nucleus and cell
what are viral diseases
HIV/AIDS
- sexually transmitted
- fever, night sweats, weight loss
Influenza
- droplet inflection
- fever, aching, dry cough, sore throat
Tobacco mosaic virus
- direct contact with plants
- reduce crop yield, yellow spotting, mosaic pattern, malformation
what are fungal diseases
Cattle ringworm
- infection of hair and surface layers of the skin
- itchy skin, cracked skin, hair loss
Athlete’s foot
- fungi living on skin, hair, nails called dermophytes that favour warm humid conditions
- sore flaky patches, blisters, itchy skin
Black sigatoka
- airborne
- streaks or leaf spots
what is indirect transmission
Fomites
- inanimate objects
- bedding, socks
Vectors
what is indirect transmission
Direct Contact
- contact with bodily fluids
- skin to skin
Inoculation
- break in the skin
- puncture wound
Ingestion
Droplet infection
what are factors that increase the transmission of communicable diseases in animals
- overcrowded populations
- poor waste disposal
- compromised immune system
- culture
- climate change
what are primary defences
Blood clotting = thromboplastin causes blood to clot
Skin = produces sebum that inhibits the growth of pathogens
Expulsive reflexes = coughing and sneezing
Nose = hair and mucus trap and destroy microbes
Eye = tears and REM
Ear = ear wax traps pathogens
Cilia = trap microbes and swallowed
Eating = stomach acid kills microbes
types of phagocytes
Neutophils
- lobed nucleus
- engulf and destroy pathogens
Macrophages
- round nucleus
- pathogens antigens combined with glycoproteins to make the antigen and antigen presenting cell
what are non-specific defences
Inflammation
- damaged tissues release histamines to make vessels dilate and leaky
- prevents pathogens from reproducing
what is phagocytosis
- phagocyte recognises antigens of invading bacterium as foreign
- cell membrane of the phagocyte fuses around the bacterium and engulfs it
- lysosome fuses with vacuole and digestive enzymes hydrolyse microorganisms
- antigens presented on cell surface membrane
what is cellular immunity by T Lymphocytes
- surface covered with receptors
- receptors bind to antigens
- receptor on T lymphocyte meets complementary antigen
- activates T-Lymphocyte (clonal selection)
- matures in bone marrow
- clonal expansion (clones of plasma and memory cells)
what is humoral immunity by B lymphocytes
- covered with antibodies
- antibodies bind with antigen to form antigen-antibody complex
- antibody on the surface of a B-lymphocyte meets and complementary antigen binds
- helper t cell release interleukins to activate B lymphocytes
- clonal expansion
what are the types of T-Lymphocytes
T Helper Cells
- secrete interleukins to activate T and B cells
T regulatory cells
- supress immune response from attacking host cells
T memory cells
- remain in lymph nodes to respond rapidly if the same pathogen invades again
Killer T cells
- protein binds to non-self antigen
- perforin released
- foreign cell identified
- lysis
- non-self cell splits and destroyed
what are the types of antibodies
Opsonin’s
- bind to antigen and act as a marker for phagocytes
Agglutin’s
- bind to antigens to cause clumping to prevent them from entering body cells
Anti-Toxins
- bind to toxins to prevent harm
what is the structure of an antibody
- glycoproteins with 4 polypeptide chains
- variable regions from antigen binding sites
- hinge region allows for flexibility when antibody binds to an antigen
- constant region allows binding receptors on immune system cells
what is the primary response
- pathogen enters the body for the first time
- not many B lymphocytes can make the correct antibody quickly
- shown symptoms
- memory cells produced
- T - lymph record antigen on the pathogen
- B - Lymph remember antibodies
what is the secondary response
- same pathogen enters the body
- clonal selection happens faster
- memory B divide into plasma cells to produce correct antibody
- memory T divide and kill pathogen with antigen
- may not show symptoms
what is active immunity
- happens naturally when a pathogen enters the body for the first time
Natural
- antigens on pathogen trigger immune response
Artificial
- vaccine contains weakened pathogen that triggers antibody production
what is passive immunity
- transfer of antibodies from outside of the body
Natural
- babies drink mothers breastmilk
Artificial
- blood transfusions
what is herd immunity
unvaccinated people are protected because the occurrence of the disease is reduced by the number of people who are vaccinated
what are autoimmune diseases
- organisms immune system is unable to recognise self-antigens
- treats self-antigens as foreign and launches an immune response
Lupus
- immune system attacks cells in connective tissues
- damage tissues and causes painful inflammation
- affects skin, joints, organs
Arthritis
- immune system attacks cells in the joints
what are the routine vaccinations
MMR
- at 1 and before school starts
Meningitis C
- 3 months, 1 year, booster as teen
HPV
- lead to cervical cancer
- year 8 girls
how do bacteria develop resistance to antibiotics
- mutation
- bacteria that are resistant survive
- surviving bacteria reproduce passing resistance gene on
- whole population becomes resistant
Antibiotic resistance
Causes
- overuse
- not finishing a course
Problems
- resistant strains are hard to treat (MRSA)
Prevention
- complete full dose
- only take when needed
what are possible sources of medicines
Penicillin - mould, inhibits synthesis of bacterial cell walls
Docetaxel - treat breast cancer as it induces cell death
Aspirin - willow bark, pain killer
Vancomycin - soil fungus, antibiotic
Digoxin - atrial fibrillation and heart failure
what are pharmacogenetics
- test peoples genomes to detect whether or not a drug will work
- replaces ‘one fits all’ approach
- tailored to individual
What is synthetic biology
- develop of molecules that mimic aspects of biology
- enzymes
- pigments - pigment in blueberries has health benefits
- genetic engineering
transmission of disease between plants
Direct contact = healthy plant touches infected plant
Indirect contact = soil contamination, infected plants leave pathogens in the soil
Vectors
factors that increase the transmission of communicable diseases in plants
- overcrowding
- poor mineral nutrition
- damp and warm conditions
- climate change
what are chemical defences of plants
Terpenoids
- antibacterial and antifungal properties
- can create a scent
Alkaloids
- nitrogen containing compounds with a bitter taste
- stops herbivores from feeding
- less grazing = less pathogen exposure
what are physical defences of plants
Cellulose cell wall
- lignin thickens
- waterproof
Waxy cuticle
- prevents water from collecting on the surface
Guard cells
- closes stomata
