Master this deck with 98 terms through effective study methods.
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A condition that impairs the normal functioning of an organism
A microorganism that causes disease
A disease that can be transmitted person to person, animal to person and insect to person
1). Bacterium 2). Animals - typically humans and cattle
1). Bacterium 2). Potato and tomato plants
1). Virus 2). Humans
1). Virus 2). Humans and animals
1). Virus 2). Plants
1). Fungus 2). Banana plants
1). Fungus 2). Humans
1). Protoctista 2). Humans and some animals
1). Protoctista 2). Potatoes and tomatoes
Contact with blood (including placenta to foetus), semen, vaginal discharge, breast milk and sexual intercourse without protection.
human immunodeficiency virus
Antiretrovirals
AIDS is acquired immunodeficiency syndrome: the end stage of the HIV infection. At this point, the virus has attacked and weakened a person's immune system to an irreversible extent.
- AIDS leads to a lack of immune ability. - AIDS doesn't kill a person, however a secondary infection like a common cold without an immune system is usually fatal. - This is known as an opportunistic infection (an infection that is not usually fatal but becomes fatal when someone has AIDS)
Spreading of spores via touch / wind
Droplet infections: coughs / sneezes / snot / saliva
A vector
By female Anopheles mosquitoes (vector).
- living conditions e.g. overcrowding - social factors e.g. access to healthcare / education - climate e.g. the geographical location
If a disease is transmissible by droplet / close contact, overcrowding leads to mass infection VERY quickly.
In places where access to healthcare is bad, disease transmits faster. Eg. HIV is rife in certain African countries where the standard of healthcare is poor, and due to economic restrictions, drug availability is very low and very expensive to supply.
If there is a lack of education around disease transmission, disease will spread faster. For example in rural Nigeria, it is widely believed that a person can rid themselves of AIDS by raping a young girl and the virus will exit the body in the semen. This only spreads the disease to more people, and education is hard when governments censor information from more developed countries.
Geographical location can determine exposure to certain diseases. For example, malaria is most common in tropical countries as this is the habitat for Anopheles mosquitos. Potato late blight can only spread when there is excess rain, hence wetter climates will increase transmission of this disease.
1. The skin 2. Mucous membranes 3. Blood clotting 4. Inflammation 5. Wound repair 6. Expulsive reflexes 7. Stomach acid
- Physical barrier to pathogens - Chemical barrier via antimicrobial production - Skin cells secrete fatty acids that kill bacteria - Skin cells secrete lysozyme which also kills bacteria
- Protect body openings (such as mouth, nostrils, ears, genitals and the anus) - Goblet cells secrete mucus which traps microorganisms that enter body openings. - Ciliated epithelial cells waft mucus back to the opening.
- Platelets when exposed to damaged blood vessels release substances to stimulate a cascade reaction - this forms fibrin mesh networks which trap more platelets and forms a blood clot - blood clots plug wounds to prevent blood loss and pathogen entry
When tissue is damaged / pathogens are detected: - Mast cells release histamine which causes vasodilation hence increased blood flow. - Histamine also causes increased capillary permeability so blood flows into surrounding tissue causing swelling and redness to isolate infected tissue. This also makes the area hot. - Cytokines are released which attract white blood cells to the area. - Interleukins are released which activates the immune response, causes fever and stimulates antibody production.
- The skin can repair itself when cut by rapidly undergoing mitosis. - New cells migrate to the edges of the wound. - Tissue underneath contracts to close the wound - Collagen fibres are produced rapidly which usually results in the formation of scars.
- coughs and sneezes eject pathogen-laden mucus from the gas exchange system - vomiting and diarrhoea expel the contents of the gut along with any infective pathogens
The hydrochloric acid is strong enough to kill any pathogens that make it into the stomach
C. Difficile
- thick, waxy cuticle - cell walls - callose deposition
- Plants produce a polysaccharide called callose - Callose is deposited between cell membranes during infection to prevent movement of pathogen - Callose is deposited in plasmodesmata to prevent pathogens moving between cells as well as
Saponins - destroy cell membranes of pathogens Phytoalexins - inhibit growth of fungi Other toxic chemicals are produced which prevents insects feeding on them, reducing risk of vector infection.
A physiological, SPECIFIC process coordinated by the immune system to eliminate SPECIFIC foreign antigens
Phagocytosis
1). A phagocyte recognises foreign antigens on the surface of a pathogen. 2). The cytoskeleton in phagocytes contracts causing the cell surface membrane to move around the pathogen and engulf it. 3). The cell surface membrane splits off and compartmentalises the pathogen into a phagosome (type of vesicle). 4). Lysosomes travel along microtubules via transport proteins and fuse with the phagosome to produce a phagolysosome. 5). The lysosome contains hydrolytic, digestive enzymes which breaks down the pathogen. 6). The phagocyte absorbs any useful material from pathogens into the cytoplasm, any waste is secreted via exocytosis. 7). The phagocyte then presents the pathogen's antigen on its cell surface membrane to activate other immune cells. The phagocyte is now an antigen-presenting cell (APC).
Neutrophils release a type of cytokine called an interleukin which are a group of chemical messengers that attract T-lymphocytes. 1). T-helper cells have numerous receptors called CD4 receptors, which will bind to antigens presented by APCs after phagocytosis. 2). When the receptor binds to the complementary antigen, it is called clonal selection, and the T-cell is said to be activated. 3). Clonal selection triggers the T-cell to rapidly proliferate by mitosis into different variations of T-cells. This is called clonal expansion. 4) T-cells proliferate into T-helper cells, T-killer cells, T-regulatory cells and T-memory cells.
They secrete interleukins and cytokines to attract more un-activated T-cells to the infection site to continue to undergo clonal selection and expansion.
They secrete hydrogen peroxide which kills infected cells. They make a protein called perforin which penetrates pathogens or infected cells, killing them.
Dampen down the immune response; prevents destruction of self tissue (autoimmunity)
these live for a long time and are part of the immunological memory. if they meet an antigen a second time, they divide rapidly to form a huge number of clones of T killer cells that destroy the pathogen
B-lymphocytes are covered in antibodies. Each B-lymphocyte has different antibodies on its surface. 1).
They are clones of the activated B-lymphocyte. They produce and release loads of antibodies specific to the antigen of a certain pathogen. These antibodies will bind to antigens on the pathogen's surface to form an antigen-antibody complex.
B memory cells provide long-lasting immunological memory of an antigen.
T helper cells release interleukins that bind to receptors on B lymphocytes. This activates the B lymphocytes- the T helper cells are signalling to the B lymphocytes that there's a pathogen in the body.
A multi-lobed nucleus (3 distinct 'blobs'). The cytoplasm of a neutrophil is grainy
Kidney-bean shaped nucleus Cytoplasm is not grainy
- Smaller than phagocytes - Very little cytoplasm - Huge nucleus * NB: it is impossible to distinguish T and B lymphocytes under a light microscope.
- Quaternary protein structure - Two heavy and two light polypeptide chains - Constant region (most of the polypeptide chains) - 2 Variable regions complementary to the epitope (antigen binding site) - Hinge region for flexibility - Bonded together by disulfide bridges (therefore must contain cysteine)
epitope
- Opsonins - Agglutinins - Antitoxins
Each antibody has two binding sites so antibodies bind two pathogens at the same time. Pathogens become 'aGLUED' together to make phagocytosis more efficient by engulfing large clumps at the same time.
They bind to pathogens and act as 'markers' for phagocytes to locate and engulf pathogens.
To neutralise toxins secreted by pathogens like bacteria. Toxin-antibody complexes are phagocytosed.
They can prevent the binding of pathogen antigens to human cells by binding to all available pathogen antigens.
Production of antibodies and memory cells from new B-cells, after antigen enters body for the first time.
Due to the presence of B and T memory cells, the immune system can act faster before you have the chance to get ill if infected a second time.
Because memory B-cells and Memory T-cells can recognise the antigen and produce the correct antibodies quicker.
Memory cells have limited lifespans
As memory cells have limited lifespans
Clonal selection and clonal expansion happen slowly as the antigen is foreign and unrecognised. NEW antibodies must be synthesised
No - the pathogen is eliminated before symptoms start
The immunity you get when your immune system makes its own antibodies after being stimulated by an antigen
When you become immune after catching a disease and recovering. E.g. if you get chickenpox as a child, you normally do not get symptoms again in your lifetime.
When you become immune after being given a disease artificially. E.g. vaccinations
The type of immunity you get when antibodies are made by a different organism, not your own cells.
When someone is immune due to natural transfer of antibodies. E.g. antibodies passed on from a mother to a baby via shared blood at the placenta.
When you become immune after being injected with antibodies from someone else. E.g. if you catch tetanus, you are injected with tetanus antibodies collected from blood donations from others.
When the body cells cannot self-recognise its own antigens hence launches an immune response attacking its own tissues.
Rheumatoid arthritis: immune system attacks joints causing pain and inflammation Lupus: immune system attacks whole organs such as kidney and brain
Contains a dead or inactivated form of the pathogen which stimulates white blood cells to produce complementary antibodies to the pathogen. In the case of a second infection, memory cells can rapidly produce the correct antibodies and prevent illness.
Orally or injection
Vaccine could be broken down by enzymes in the gut or molecules in the vaccine may be too large to enter the bloodstream.
a widespread occurrence of an infectious disease in a community at a particular time.
By producing something called HERD IMMUNITY If enough of a population receives a vaccine, the disease is less likely to spread.
- Vaccination is the administration of antigens (in a vaccine) into the body - Immunisation is the process by which you develop immunity - Vaccination causes immunisation
1). MMR vaccines: protects against measles, mumps and rubella, administered at around 1 years old, and again before starting school. 2). Meningitis C: protects against bacteria. Administered at 3 months old and boosters are given at the ages of 1 and in teenagers. 3). 6-in-1: protects against diphtheria, tetanus, whooping cough, polio, Haemophilus influenza B (Hib), and Hepatitis B. Administered before the age of 1. 4). HPV: protects against papillomavirus and reduces risk of cervical cancer and oral cancer. Administered in teenage years.
- Pathogens can mutate and change their antigens, these are known as 'strains'. - The vaccine will henceforth be ineffective at treating a new strain.
A pathogen which mutates and forms new strains frequently and often.
- The influenza virus - The influenza vaccine changes annually, as strains of influenza are immunologically distinct. - Organisations such as the CDC and the WHO look at global patterns of influenza present in the population. - The strain of influenza circulating during flu season in the Southern Hemisphere is used to predict what strain will circulate in the Northern Hemisphere during their winter, and vice versa. - The most appropriate flu vaccine is then administered in vaccination programmes for that year.
Medicines that help to cure bacterial disease by killing infective bacteria inside the body.
They can target bacterial cells without damaging human body cells
Penicillin by Alexander Fleming in 1928
-anaphylaxis from penicillin -anaphylaxis to cehalosporins -fatal reactions to macrolides or clindamycin are extremely rare -promotion of drug resistant organisms
the ability of a microorganism to withstand the effects of an antibiotic
- There is genetic variation within a population of bacteria - Random genetic mutations make some bacteria naturally resistant to antibiotics by chance - This is an extremely advantageous characteristic and hence is selected for during a course of antibiotics - The resistant bacterium is more likely to survive and reproduce, passing the resistant allele on to future generations, leaving only resistant colonies.
The creation of 'superbugs' which have no cure.
- MRSA: causes serious infections in open wounds, resistant to methicillin - C. difficile: causes severe diarrhoea and cramps, when treated with antibiotics, it takes over stomach.
- developing new antibiotics / modifying existing drugs - reduce widespread usage of antibiotics for minor infections - ensure the complete course of antibiotics are taken - prevent usage of antibiotics in cattle farming
- fungus (penicillin) - soil bacteria (cancer drugs) - daffodils (Alzheimer's drugs)
- only a small proportion of organisms have been investigated as sources of medicine - possible sources of medicines must be protected otherwise cures for medicines could go extinct before we manage to study them
- Personalised medicine are medicines tailored to an individual's DNA. - The theory is that if doctor's have your genetic information, they can use it to predict how you will respond to different drugs, and which will be most effective for you. - This will hopefully make prescriptions more efficient and effective in the future.
abnormal immune response against tissues normally in the body