4.1.1 - Communicable diseases Flashcards
What is a pathogen ?
- Microorganism that causes disease
- Lives in hosts
What are bacteriophages ?
Viruses that can attack bacteria
What are communicable diseases ?
Any disease transmitted from one person or animal; contagious
What are the four groups of microorganisms ?
- Bacteria
- Fungi
- Viruses
- Protoctista
Diseases caused by bacteria
- Tuberculosis
- Bacterial meningitis
- Ring rot in plants
Diseases caused by viruses
- HIV/ AIDS
- Influenza
- Tobacco mosaic virus
Diseases caused by fungi
- Black sigatoka
- Ringworm
- Athletes foot
Diseases caused by protoctista
- Malaria
- Potato/ tomato blight
What are prokaryotic pathogens ?
Bacteria
What are eukaryotic pathogens ?
Fungi
How do bacteria damage hosts ?
- Multiply readily
- Damage cells by releasing waste products and/or toxins
How do fungi damage hosts ?
- Hyphae release extracellular enzymes e.g. celluloses to digest plant tissue
- Causes decay and leaf death —> no photosynthesis
- May produce toxins
How do viruses damage hosts ?
- Invade living cells where genetic material in virus takes over the biochemistry of the host cells
- Makes more copies
- Host cell bursts, releasing viruses
How do protoctista damage hosts ?
Enter host cells and feed on contents before breaking over cells
What are the three shapes of bacteria ?
- Cocci
- Spirillum
- Bacilli
What is the function and shape of cocci ?
- They are spherical prokaryotes that occur singularly, in pairs, in chains and in clusters
- They have the lowest SA:V ratio enabling them to survive in dryer environments
What is the shape and function of spirillum ?
- They are spiral prokaryotes, which range from comma like shapes, to coils to spirochetes.
- They move with a corkscrew motion, and meet less resistance from surrounding water
What is the shape and function of bacilli ?
- Bacilli are rod shaped prokaryotes that are normally solitary
- They have the greatest SA:V ratio enabling them to take up nutrients from dilute solutions more efficiently
What is the bacterial cell wall like in gram positive bacteria ?
- Thick peptidoglycan cell wall traps crystal violet in the cytoplasm
- Alcohol rinse does not remove the crystal violet, which masks the safranin dye
What is the bacterial cell wall like in gram negative bacteria ?
- Thin peptidoglycan cell wall between the plasma and outer membrane.
- Crystal violet is easily rinsed away, revealing the red safranin dye
How do bacteria cause disease ?
- They produce toxin and cause symptoms by cell damage.
- Damage cell membranes, enzymes or genetic material
What are exotoxins ?
- Exotoxins are produced inside mostly gram-positive bacteria as part of their growth and metabolism.
- They are secreted or released following lysis
What are endotoxins ?
Endotoxins are part of the outer portion of the cell wall of gram-negative bacteria. They are liberated when the bacteria die
Are viruses eukaryotic or prokaryotic ?
- Neither
- They are dead
What are bacteriophages ?
They are viruses that can infect and set in motion a genetic takeover of bacteria
Are viruses cells ?
- They are not cells
- They are very small infectious particles consisting of a nucleic acid enclosed in a protein coat
What type of genetic material can they have ?
They can be DNA viruses or RNA viruses, depending on whether their genome is single or double stranded
Describe the lycogenic cycle
- The phage infects the cell
- The phage DNA becomes incorporated into the hosts genome
- The cell divides, and prophage DNA is passed on to the daughter cells
- Under stressful conditions, the prophage DNA is excised from the bacterial chromosomes and enters the lytic cycle
Describe the lytic cycle
- Phage DNA replicates and phage proteins are made
- New phage particles are assembled
- The cell lyses releasing the newly made phages
What can viruses be described as ?
Obligate intracellular parasites
What does Obligate intracellular mean ?
They can replicate only within a host cell
What are fungi ?
- They are heterotrophs.
- Unable to make their own food like plants or to ingest food like animals
How do fungi absorb their nutrients ?
They secrete hydrolytic enzymes that breakdown molecules in their surroundings and absorb the products of that digestion
What are the common fungal bodies ?
- Yeasts
- Multicellular filaments
What is mycois ?
The general term for an infection caused by a fungal parasite
What are protists ?
- They are a group of eukaryotic organisms
- They were all once filled under the kingdom protista but are now recognised as polyphyletic
What are protist diseases in humans caused by ?
They are caused by animal-like protists, protozoa, which make us sick when they become human parasites
What causes malaria ?
- Plasmodium protozoa
- They spread through their hosts via tiny infectious cells called sporozoites
How may protoctista enter the body ?
Through vectors such as mosquitoes
How may protoctista enter through the body directly ?
Polluted water
How can plant diseases affect us ?
- They may starve us, economies may struggle and jobs would be lost
- Plant diseases threaten ecosystems too - entire species can be threatened
What are some pathogens that cause plant diseases ?
- Ring rot
- Tobacco mosaic virus
- Potato/tomato blight
- Black sigatoka
What is ring rot ?
A bacterial disease of potatoes, tomatoes and aubergines caused by the gram positive bacteria Clavibacter michiganensis
What effect does ring rot have on plants ?
- It damages leaves, tubers and fruit
- It can destry up to 80% of the crop and there is no cure
- Once bacterial ring rot infects a field it cannot be used to grow potatoes again for at least two years
What is Tobacco Mosaic Virus ?
TMV is a virus that infects tobacco plants and around 150 other species including tomatoes, peppers, cucumbers, petunias and delphiniums
What effect does TMV have on plants ?
It damages leaves, flowers and fruit, stunting growth and reducing yields, and can lead to an almost total crop loss.
Treatment for TMV
Resistant crop strains are available but there is no cure
What is potato/tomato blight ?
It is caused by the fungus like protoctist oomecyte Phytophthora infestans
What effect does potato/tomato blight have on plants ?
The hyphae penetrate host cells, destroying leaves, tubers and fruit, causing millions of pound of crop damage a year
Treatment for potato/tomato blight
There is no cure but resistant strains, careful management and chemical treatments can reduce infection risk
What is black sigatoka ?
It is a banana disease caused by the fungus Mycospaerella fijiensis, which attacks and destroys the leaves
What effect does black sigatoka have on plants ?
- The hyphae penetrate and digest the cells, turning the leaves black
- If plants are infected it can cause a 50% reduction in yield.
Treatment for black sigatoka
Resistant strains are being developed - good husbandry and fungicide treatment can control the spread of the disease but there is no cure
How can animal diseases affect us ?
They have a profound effect on human health and wellbeing and on national economies
What is Tuberculosis ?
A bacterial disease of humans, cows, pigs, badgers and deer commonly caused by mycobacterium tuberculosis and M.bovis
What does Tuberculosis do ?
It damages and destroys lung tissue and suppresses the immune system, so the body is less able to fight off other diseases
What is the relationship between TB and HIV/AIDS ?
People affected by HIV/AIDS are much more likely to develop TB infections
Treatment for TB
In people TB is both curable by antibiotics and preventable by improving living standards and vaccinations
What is bacterial meningitis ?
It is a bacterial infection of the meninges of the brain which can spread into the rest of the body causing septicaemia and rapid death
What are meninges ?
The protective membranes on the surface of the brain
What is septicaemia ?
Blood poisoning
Who does bacterial meningitis affect ?
It mainly affects very young children and teenagers (15-19)
What are the symptoms of bacterial meningitis ?
A blotchy red/purple rash that does not disappear when a glass is pressed against it is a symptom of septicaemia
Treatment for bacterial meningitis
- Antibiotics will cure the disease if delivered early
- Vaccines can protect against some forms of bacterial meningitis
What is HIV/AIDS ?
It is caused by the human immunodeficiency virus which targets T helper cells in the immune system of the body
What does HIV/AIDS do to the immune system ?
It gradually destroys the immune system so affected people are open to other infections as well as some types of cancer
What is HIV ?
It is a retrovirus with RNA as its genetic material
What enzyme does HIV contain ?
Reverse transcriptase
What is the role of reverse transcriptase ?
Transcribes the RNA to a single strand of DNA to produce a single strand of DNA in the host cell
How is the HIV passed along ?
- The virus is passed from one person to another in bodily fluids.
- Most commonly through unprotected sex, shared needles etc
Treatment for HIV
There is yet no vaccine and no cure, but anti-retroviral drugs slow the progress of the disease to give many years of healthy life
Who is at a particularly high risk of HIV/AIDS ?
Women and girls
What increases the infection rate of HIV/AIDS ?
Traditional practices such as FGM
How does FGM increase the infection rate of HIV/AIDS ?
- If the same equipment is used multiple times then this can spread the infection.
- Women who have undergone FGM are more vulnerable to infection during intercourse
What is influenza ?
A viral infection of the ciliated epithelial cells in the gas exchange system
What does influenza do ?
It kills the ciliated epithelial cells, leaving the airways open to secondary infection
Who does influenza affect ?
- Young children, old people and people with chronic illnesses
- Humans, pigs and birds including chickens
What causes deaths from influenza ?
Severe secondary bacterial infections such as pneumonia
What are the three strains of influenza ?
- A
- B
- C
Which influenza viruses are the most virulent ?
- A viruses
- They are classified further by the proteins on their surfaces
What happens when viruses mutate ?
When there is a major change in the surface antigens, this heralds a flu epidemic as there are no antibodies available
Treatment for influenza
There is no cure
What is zoonosis ?
A disease which people can catch from animals
How can humans be affected by zoonoses ?
The virus mutates and becomes capable of infecting people
How dangerous can zoonoses be ?
Very serious as few people have natural immunity to them
What is malaria ?
Caused by the protoctista plasmodium and spread by the bites of infected mosquitoes
What does malaria invade ?
It invades the red blood cells, liver and even the brain
Describe the plasmodium parasite
- The plasmodium parasite has a complex life cycle with two hosts, mosquitoes and people
- They reproduce inside the female mosquito
- The female needs to take two blood meals to provide her with protein before she lays her eggs - and this is when the plasmodium is passed on to people
Treatment for malaria
There is no vaccine against malaria and limited cures, but preventative measures can be effective
How can mosquitoes be destroyed ?
They can be destroyed by insecticides and by removing the standing water where they breed
How can mosquito bites be prevented ?
Simple measures such as a mosquito nets, window and door screens and long sleeved clothing can prevent them biting people and spreading the disease
What is ringworm ?
- A fungal disease affecting mammals including cattle, dogs, cats and humans.
- Different fungi affect different species
What does ringworm cause ?
- It causes grey-white, crusty, infectious, circular areas of skin
- Looks unsightly and may be itchy
Treatment for ringworm
Antifungal creams
What is athletes foot ?
A human fungal disease caused by Tinia pedia, a form of human ring worm that grows on and digests the warm, moist skin between the toes
What does athletes foot cause ?
It causes cracking and scaling, which is itchy and may become sore.
Treatment for athletes foot
Antifungal creams are an effective cure
What are the two main types of transmission ?
Direct and indirect transmission
What is direct transmission ?
Here the pathogen is transferred directly from one individual to another
What are the forms of direct transmission ?
- Direct contact
- Inoculation
- Ingestion
What is direct contact ?
- Kissing or any contact with the body fluids of another person
- Direct skin to skin contact
- Microorganisms from faeces transmitted on the hands
What is inoculation ?
- Through a break in the skin
- From an animal bite
- Through a puncture wound or through sharing needles
What is ingestion ?
Taking in contaminated food or drink, or transferring pathogens to the mouth from the hands
What is indirect transmission ?
This is where the pathogen travels from one individual to another indirectly
What are the forms of indirect transmission ?
- Fomites
- Vectors
- Inhalation
What are fomites ?
Inanimate objects such as bedding, socks, or cosmetics that can transfer pathogens
What are vectors ?
- A vector transmits communicable pathogens from one host to another
- They are often but not always animals
- Water can also act as a vector of disease
What is inhalation ?
- Minute droplets of saliva and mucus are expelled from your mouth as you talk, cough or sneeze.
- If these droplets contain pathogens, when healthy individuals breathe the droplets in they may become infected
How can you reduce infection rates between animals and humans ?
Minimise close contact with animals and washing hands thoroughly following any such contact
What are the factors affecting the transmission of communicable diseases in animals ?
- Overcrowded living and working conditions
- Poor nutrition
- A compromised immune system
- Poor disposal of waste provides breeding sites for vectors
- Climate change can introduce new vectors and diseases
- Culture and infrastructure can increase transmission
- Socioeconomic factors, e.g. a lack of trained health workers and insufficient public warning when there is an outbreak of disease
How do plants spread diseases ?
- Diseases spread rapidly through plant communities, plant pollen and seed
- They also have a less well developed immune system than humans
Describe direct transmission in plants
- This involves direct contact of a healthy plant with any part of a diseased plant.
- Examples are TMV, tomato and potato blight and black sigatoka
What are the forms of indirect transmission in plants ?
- Soil contamination
- Vectors
Describe soil contamination in plants
- Infected plants often leave pathogens or reproductive spores from protoctista or fungi in the soil, these can infect the next crop
- Some pathogens can survive the composting process so the infection cycle can be completed when contaminated compost is used
How is wind a vector ?
Bacteria, viruses and fungal or oomecyte spores may be carried by the wind
How is water a vector ?
- Spores swim in the surface film of water on leaves
- Raindrop splashes carry pathogens and spores
How are animals vectors ?
- Insects and birds carry pathogens and spores from one plant to another as they feed
- Insects such as aphids inoculate pathogens directly into plant tissues
How are humans vectors ?
Pathogens and spores are transmitted by hands, clothing, fomites, farming practices and by transporting plants and crops around the world
What are the factors affecting the transmission of communicable diseases in plants ?
- Planting varieties of crops that are susceptible to disease
- Over crowding increases the likelihood of contact
- Poor mineral nutrition reduces resistance of plants
- Damp, warm conditions increase the survival and spread of pathogens and spores
- Climate change – increased rainfall and wind promote the spread of diseases; changing conditions allow animal vectors to spread to new areas; drier conditions may reduce the spread of disease
Why are plants targets for microorganisms ?
- They manufacture sugars in photosynthesis and convert this into wide variety of compounds such as proteins and oils
- These proteins and oils are a rich source of nutrients for microorganisms
What is the role of passive defences ?
Prevent entry
What are active defences ?
They are induced when a pathogen is detected
Name the passive defences a plant has
- Cell wall
- Waxy cuticle
- Bark
- Stomatal closure
- Chemicals with anti pathogenic properties
Name the active defences a plant has
- Production of callose
- Strengthen cell walls with additional cellulose and lignin
- Tylose formation
- Wide range of chemicals produced
- Necrosis
Callose as an active defence
Blocks plasmodesmata and sieve plates in the phloem, sealing off the infected part
Tylose as an active defence
- Balloon like swelling that fills the xylem vessel.
- When tylose is fully formed it blocks the vessel
Necrosis as an active defence
- Deliberate cell suicide
- By killing cells surrounding the infections, pathogens access to water and nutrients is limited
Chemicals produced as a part of plants active defences
- Terpenoids
- Phenols
- Alkaloids
- Defensins
- Hydrolysis enzymes
What are terpenoids ?
Essential oils with anti-fungal and antibacterial properties
What are phenols ?
- Have antibiotic and anti-fungal properties
- Tannins bind to salivary proteins and digestive enzymes, deactivating them
What are alkaloids ?
- Nitrogen-containing compounds that have a bitter taste to inhibit herbivores feeding
- Inhibit protein synthesis
- Also inhibit or activate enzyme action
What are defensins ?
- Small cysteine-rich proteins with anti-microbial properties
- Act upon molecules in plasma membrane of pathogens
What are hydrolytic enzymes ?
- Found in spaces between cells
- Include chitinases, glucanases and lysozymes
Describe the process of a plant recognising and dealing with an attack
- Receptors in the cells respond to molecules from the pathogens, or to chemicals produced when the plant cell wall is attacked
- This stimulates the release of signalling molecules that appear to switch on genes in the nucleus
- This in turn triggers cellular responses, which include producing defensive chemicals, sending alarm signals to unaffected cells to trigger their defences, and physically strengthening the cell walls
What do plants produce when attacked by a pathogen ?
Callose
What is callose ?
It is a polysaccharide made up of beta-1,3 link and beta-1,6 linkages between the glucose monomers
How does callose initially take part in the defence mechanism ?
- Within minutes of the initial attack, callose is synthesised and deposited between the cell walls and the cell membrane in cells next to the infected cells.
- This prevents the pathogens entering the plant cells around the site of infection
- Large amounts of callose continue to be deposited in cell walls
What is a specific immune response?
The immune system ‘remembers’ an antigen after an initial response leading to an enhanced response to subsequent encounters
What are antibodies?
Y-shaped glycoproteins made by B cells of the immune system in response to the presence of an antigen
What shape are antibodies ?
Y-shaped
How does the sequence of amino acids affect an antibody?
The sequence of amino acids determines the shape of the variable region (sequence of amino acids) and so which antigen is detected
How many polypeptide chains does an antibody contain?
4
What type of molecule is an antibody?
Protein
What sort of protein are antibodies?
Globular
What is formed when an antibody binds to an antigen?
An antigen-antibody complex
What is the relationship between the two light chains of antibodies?
They are identical
What is the relationship between the two heavy chains of antibodies?
They are identical
How many binding sites are there on an antibody? Where are they?
- 3
- Two antigen binding sites
- One receptor site that allows the body to recognise the antibody as self
How are all antibodies in the body similar?
They share the same common region
What type of bonding occurs between the heavy and light strands in antibodies?
Disulphide
How are the heavy strands attached in antibodies?
Disulphide bonds
How many light strands are in an antibody?
2
How many heavy strands are in an antibody?
2
What is the difference between the light and heavy chains of an antibody?
The light chains are much shorter than the heavy chains
What is the relationship between the variable region and the antigen?
They have complementary shapes
What allows for sulphide bonding?
The amino acid cysteine
Why do antibodies have a hinge?
Allows antibodies to flex slightly and accommodate differently sized antigens
How many amino acids form a binding site?
- 110
How do antibodies defend the body? (4 reasons)
- Act as opsonins so the antigen is ‘tagged’ and easily engulfed
- Act as antitoxins, binding to toxins produced by pathogens to render them harmless
- Cause agglutination (clumping together) of pathogens which have antigen-antibody complexes, preventing them from spreading through the body and makes it easier for phagocytes to engulf several pathogens at once
- Prevents pathogens from effectively invading a host
Where do T-cells mature?
The thymus gland
Where do B-cells mature?
Bone marrow
What is the function of B plasma cells?
To produce antibodies
Name the 4 types of T cells
- Killer T cells
- Helper T cells
- Memory T cells
- Regulator T cells
Name the 3 types of B cells
- B Plasma cells
- B effector cells
- B memory cells
What are T helper cells ?
- They produce interleukins
- The interleukins stimulate the activity of B cells, which increases antibody production, stimulates production of other types of T cells and attracts and stimulates macrophages to ingest pathogens with antigen-antibody complexes
What do T helper cells have on their surface membranes ?
CD4 receptors
What are interleukins ?
They are a type of cytokine (cell-signalling molecules)
What are T killer cells ?
- These destroy the pathogen carrying the antigen.
- They produce perforin
What does perforin do ?
It kills the pathogen by making holes in the cell membrane so it is freely permeable
What are T memory cells ?
They live for a long time and are a part of the immunological memory
What do T memory cells do when they meet an antigen for the second time ?
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
What are T regulator cells ?
They stop the immune response once a pathogen has been eliminated, and make sure the body recognises self antigens and does not set up an autoimmune response
What are plasma cells ?
They produce antibodies to a particular antigen and release them into circulation
What are B effector cells ?
They divide to form the plasma cell clones
What are B memory cells ?
- They live for a long time and provide the immunological memory
- They are programmed to remember a specific antigen and enable the body to make a very rapid response when a pathogen carrying that antigen is encountered
What is cell mediated immunity ?
T lymphocytes respond to the cells of an organism that has been changed in some way
What is cell mediated immunity important against ?
Viruses and early cancers
What happens in cell mediated immunity ?
- Macrophages engulf and digest pathogens in phagocytosis
- They process the antigens from the surface of the pathogen to form an Antigen Processing Cell (APC)
- The receptors on some of the T helper cells fit the antigens
- These T helper cells become activated and produce interleukins, which stimulate more T cells to divide rapidly by mitosis
- They form clones of identical activated T helper cells that all carry the right antigen to bind to a particular pathogen
What can the cloned T cells do ?
- Develop into T memory cells, which give a rapid response if this pathogen invades the body again
- Produce interleukins that stimulate phagocytosis
- Produce interleukins that stimulate B cells to divide
- Stimulate the development of a clone of T killer cells that are specific for the presented antigen and then destroy infected cells
What is humoral immunity ?
- The body responds to antigens found outside the cells and to APCs
- They humoral immune system produces antibodies that are siluble in the blood and tissue fluid and are not attached to cells
What do B lymphocytes have on their surface membrane ?
immunoglobin M (IgM)
What does a B cell do when a pathogen enters the body ?
- A B cell with complementary antibodies to the antigens on the pathogen will bind to those antigens.
- It will the engulf and process the antigens to become an APC
What happens in humoral immunity ?
- Activated T helper cells bind to the B cell APC. This is clonal selection - The point at which the B cell with the correct antibody to overcome a particular antigen is selected for cloning
- Interleukins produced by the activated T helper cells activate the B cells
- The activated B cell divides by mitosis to give clones of plasma cells and B memory cells. This is clonal expansion.
What is the primary immune response ?
Cloned plasma cells produce antibodies that fit the antigens on the surface of the pathigen, bind to the antigens and disable them, or act as opsonins or agglutinins
How long can a primary immune response take ?
- Days or even weeks, this is why we get ill
- The symptoms are the result of the way our body reacts when the pathogens are dividing freely, before the immune response is fully operational
What is the secondary immune response ?
- Some cloned B cells develop into B memory cells.
- If the body is infected by the same pathogen again, the B memory cells divide rapidly to form plasma cell clones
- These produce the right antibody and wipe out the pathogen very quickly, before it can cause the symptoms of disease
What does an autoimmune disease mean ?
Sometimes the immune system stops recognising self cells and starts to attack healthy body tissue
Why does autoimmune disease occur ?
- There appears to be a tendency in some families that sometimes the immune system responds abnormally to a mild pathogen or normal body microorganism
- Even in come cases the T regulator cells do not work effectively
What can be used to treat autoimmune diseases ?
Immunosuppressant drugs, which prevent the immune system working, may be used as treatments
What is a disadvantage of using immunosuppressant drugs ?
They deprive the body of its natural defences against communicable diseases
Define immunity
Being able to kill pathogens if infected before getting symptoms
Define active immunity
Achieved when immune system is activated and manufactures its own antibodies
Define passive immunity
Achieved when antibodies are supplied from another source
Define natural immunity
Achieved through normal life processes
Define artificial immunity
Achieved through medical intervention
Natural active immunity
Achieved as a result of infection
Active artificial immunity
Achieved as a result of vaccination
Passive natural immunity
Antibodies are provided by the placenta or via the breast milk
Passive artificial immunity
Provided by infection of antibodies made by another individual
What are vaccinations ?
Deliberately exposing the body to antigenic material to trigger long-term immunity (through activation of the specific immune response leading to memory cells)
What may vaccines contain ?
- Killed or inactivated bacteria and viruses
- Attenuated strains of live bacteria or viruses
- Toxin molecules that have been altered and detoxified
- Isolated antigens extracted from the pathogen
- Genetically engineered antigens
Explain the main steps of vaccination
- The pathogen is made safe in one of a number of ways so that the antigens are intact but there is no risk of infection
- Small amounts of the safe antigen are injected into the blood
- The primary immune response is triggered by the foreign antigens and your body produces antibodies and memory cells as if you were infected with a live pathogen
- If you come into contact with a live pathogen, the secondary immune response is triggered and you destroy the pathogen rapidly before you suffer symptoms of the disease
How long do vaccines provide artificial active immunity for ?
- May last a year, a few years or a lifetime
- Can get booster vaccine
What is an epidemic ?
When a communicable disease spreads rapidly to a lot of people at a local or national level
What is a pandemic ?
When the same diseases spreads rapidly across a number of countries and continents
What can prevent an epidemic ?
Mass vaccinations at the start of the epidemic
What has to happen to vaccines in order for them to be effective ?
They have to be changing so they can stay effective
What is herd immunity ?
When a significant number of people in the population have been vaccinated, this gives protection to those who do not have immunity
What are some common medicines ?
- Painkillers
- Anti-inflammatories
- Anti-acids
What is penicillin ?
The first widely used, effective, safe antibiotic capable of curing bacterial diseases
Where does penicillin come from ?
Comes from a mould called Penicillium chrysogenum, famously discovered by Fleming in 1928
How was it discovered ?
Fleming saw it growing on his Staphylococcus spp. cultures
Where are most drugs derived from ?
They are derived from or based on bioactive compounds in plants, microorganisms or other forms of life
What is the source of penicillin ?
Commercial extraction originally from mould growing on melons
What is penicillins action ?
- Antibiotic
- The first effective treatment against many common bacterial diseases
What is the source of docetaxel/paclitaxel ?
Derived from yew trees
What is docetaxel/paclitaxel’s action ?
Treatment of breast cancer
What is the source of aspirin ?
Based on compounds from willow bark
What is aspirins action ?
- Painkiller
- Anticoagulant
- Antipyretic
- Anti-inflammatory
What is the source of prialt ?
Derived from the venom of a cone snail from the oceans around australia
What is prints action ?
New pain killing drug 1000 times more effective than morphine
What is the source of vancomycin ?
Derived from a soil fungus
What is vancomycins action ?
One of the most powerful antibiotics
What is the source of digoxin ?
Based on digitoxin, originally extracted from foxgloves
What is digoxins action ?
Powerful heart drug that is used to treat atrial fibrillation and heart failure
How does biodiversity affect medicines ?
We have to maintain biodiversity to make sure that we do not destroy a plant, animal or microorganism which could give us the key to a life saving drug
What is personalised medicine ?
Medicine with a combination of drugs that work with your individual combination of genetics and disease
Define pharmacogenomics
The science of interweaving knowledge of drug actions with personal genetic material
Which gene causes 30 % of breast cancers ?
- HER2
- Caused by a mutation in the gene
What drugs shut down the activity of the HER2 gene ?
- Trastuzumab (herceptin)
- Lapatinib
How much can doctors reduce deaths from breast cancers and how ?
- Can reduce deaths from breast cancer by 50%
- They do this by analysing breast tumours and treating those who have a mutation in the HER2 gene with the relevant drugs
What can we do with genetic engineering and synthetic biology ?
We can develop populations of bacteria to produce much needed drugs that would otherwise be too rare, too expensive or unavailable
What does synthetic biology enable us to do ?
It enables us to use bacteria as biological factories
What is nanotechnology ?
- It is another strand of synthetic biology
- Tiny, non natural particles are used for biological purposes
Give an example of where nanotechnology is used
To deliver drugs to very specific sites within the cells of pathogens or tumours
