CHAPTER 12 - COMMUNICABLE DISEASES Flashcards
1
Q
What are communicable diseases caused by
A
infective organisms called pathogens
1
Q
What are classed under the term pathogens
A
Bacteria, viruses, fungi, protoctista
2
Q
What are vectors
A
A medium that carries a pathogen from one organism to another eg. water or insects
3
Q
What type of organism is a bacteria
A
Prokaryotic - no nucleus or membrane bound organelles
4
Q
Do all bacteria cause disease?
A
no - only a small proportion
5
Q
What are the shapes of bacteria
A
Rod Shaped - bacili
Spherical - cocci
Comma shaped - vibrios
Spiralled - Spirilla
Corkscrew - spirochaetes
Chain of bacteria - Strepto….
Cluster of bacteria - Staphylo..
6
Q
How can bacteria be classified?
A
By their shapes and by their cell walls
7
Q
What are the two types of cell walls
A
Gram positive and gram negative
8
Q
What is the difference between gram positive and gram negative bacteria
A
How the different cell walls react differently
9
Q
What colour do Gram-positive bacteria look after gram staining
A
Purple-blue eg. MRSA
10
Q
What colour do Gram negative bacteria look after gram staining
A
Red eg. E.coli
11
Q
What are viruses
A
Non-living infectious agents
12
Q
What is the basic structure of a virus
A
Genetic material (either DNA or RNA) surrounded by a protein
13
Q
What happens when a virus invades a cell
A
The genetic material of the virus takes over the biochemistry of the host cell to make more viruses
14
Q
What adaptions do viruses have which makes them a successful pathogen
A
Reproduce rapidly
Evolve by developing adaptions to their host
15
Q
What are the viruses that attack bacteria
A
Bacteriophages
16
Q
What are bacteriophages used for
A
To identify and treat some diseases and now very important in scientific research
17
Q
What type of organisms are protoctista (Protista)
A
Eukaryotic
18
Q
What is a example of a disease transmitted by a protist
A
Malaria
19
Q
How do fungi cause disease
A
Most fungi saprophytic, but some are parasitic
Parasitic fungi cause disease, stopping plants from photosynthesising - killing them
Produce millions of spores which travel over large distances
20
Q
How do viruses directly damage host tissue
A
Viruses take over the cell metabolism; Viral genetic material gets into the host cell and is inserted into the host DNA.
Virus uses host cell to make new viruses which then burst out of the cell, destroying it and infecting others (pg 304)
21
Q
How do Protoctista damage host tissue
A
Take over cells and break open as new generation emerge, but dont take over genetic material.
Simply digest and use the cell contents as they reproduce
22
Q
How do Fungi directly damage host tissue
A
Digest living cells and destroy them
Combined with response of body to the damage caused by the fungus gives symptoms of disease
23
Q
How do bacteria indirectly damage host tissues
A
Produce poisons or toxins that that damage host cells by breaking down the cell membranes or damage or inactivate enzymes so cells cannot divide
24
How do fungi indirectly damage host cells
Produce toxins that cause disease
25
Explain what is meant by the term "communicable diseases"
Disease that can be passed from one organism to another
26
Give four ways in which pathogens can attack cells of their host organism and cause disease
Take over cell metabolism, viral genetic material inserted into host DNA
take over cell and
digest contents (e.g., some Protista)
completely digest living cells and destroy them (e.g., fungi)
produce toxins which poison or damage host cells, some toxins break down cell membranes or
inactivate enzymes or prevent cell division (e.g., most bacteria)
27
Explain the difference between the way viruses and protists can cause disease
Viruses insert genetic material into host DNA
and take over cell metabolism to make new viruses before breaking out of cell
protists take over cells and feed on cell contents
and divide before breaking out of the cell
28
Suggest why viruses are described as the ultimate parasite
Viruses only active when inside a host cell
have little structure and take over whole host cell
29
What is the cause of ring rot and what is its effects
Bacterial disease of potatoes tomatoes and aubergines - caused by gram positive bacterium Clavibacter michiganensis
Damages leaves tubers and fruit. Can destroy up to 80% of the crop with no cure, leaving a field unfarmable for 2 years
(pg 305)
30
What is the cause of Tobacco mosaic virus (TMV) and what is its effects
A virus that infects tobacco plants and 150 other species
Damages leaves flowers and fruit, leading to Total crop loss
Some crop strains are resistant but there is no cure
(pg 306)
31
What is the cause of Potato Blight and what is its effects
Caused by a Fungus-like protoctist oomycete (from fungal lineage)
The hyphae penetrate host cells, destroying leaves, tubers and fruit causing millions of £s worth of crop damage per year
No cure but resistant strains and careful management and chemical treatment can mitigate infection risk
32
What is the cause of black Sigatoka and what is its effects
Fungus disease in bananas which destroys the leaves.
The hyphae penetrate and digest cells, turning leaves black, 50% reduction in yield
Resistant strains being developed and fungicide can control spread of disease but there is no cure
(pg 306)
33
What is the cause of Tuberculosis and what is its effects
Bacterial disease of many species
Destroys lung tissue and supresses immune system, so body is less able to fight off other diseases
Rise in HIV/AIDS has caused more TB infections
TB is curable (by antibiotics) and preventable (living standards and vaccinations)
34
What is the cause of bacterial meningitis and what is its effects
Bacterial infection of the meninges in the brain (protective membranes on outer surface). Can spread to rest of body and cause septicaemia (blood poisoning)
Symptom of both is if a blotchy red/purple rash that doesn't disappear when glass is pressed against it
Antibiotics will cure disease if delivered early. Vaccines can protect against some forms of disease
35
What is the cause of HIV and what is its effects
Virus which targets T helper cells in immune system.
Destroys immune system, opening people up to many other infections eg. TB, Pneumonia and some cancers
Also affects non-human primates. HIV is a retrovirus of DNA using RNA as genetic material, containing reverse transcriptase, which transcribes the RNA to a single strand of DNA, interacting with host cell
Virus is passed via bodily fluids eg. unprotected sex, needles, contaminated blood products and pregnancy to an unborn child
No cure or vaccine, but some anti-retroviral drugs slow the progress of the disease down
36
What is the cause of Influenza and what is its effects
Viral infection of the ciliated epithelial cells in gas exchange system. Kills them leaving airways open to secondary infection
Can be fatal, especially to vulnerable individuals. Affects mammals and birds.
3 main strains - A, B and C
A are most virulent and are classified further by proteins on there surface, and mutate regularly
An annual vaccine for vulnerable, no cure
37
What is the cause of Malaria and what is its effects
Caused by protist, spread by bites of infected Anopheles Mosquitos.
Parasite has complex life cycle, reproducing in female mosquito, who needs at least 2 blood meals for protein before eggs are laid
This is when the protist invades the red blood cells, liver and brain
No vaccine or cure, but controlling the vector eg. insecticides and removing standing water in which they breed can prevent spread
38
What is the cause of ring worm and what is its effects
Fungal disease affecting mammals, different fungi cause same disease in various animals
Causes grey-white crusty infectious circular areas of skin. Not damaging but looks unsightly and itchy
Antifungal creams are an effective cure
39
What is the cause of athletes foot and what is its effects
Fungal disease - form of human ring worm
Grows and digests the warm moist skin between the toes
Causes cracking and scaling, which becomes itchy and sore
Antifungal creams are an effective cure
40
Compare and contrast bacterial, viral, protist and fungal diseases of plant and animals
Bacterial:
Ring rot affects potatoes, aubergine, and tomatoes.
TB (affects humans, cows, badgers, deer. Bacterial meningitis affects humans.
Viral:
Tobacco mosaic virus affects tobacco plants and 150 other species.
HIV/aids affects humans and some apes.
Influenza affects mammals including humans, pigs, and birds.
Protist:
Potato blight affects potatoes and tomatoes.
Malaria
Fungal:
Black sigatoka affects bananas and plantains.
Ring worm affects cattle (other spp. Affects most animals including people).
Athlete’s foot affects human feet
41
Suggest 3 ways in which animal diseases and 3 ways in which plant diseases may be spread from one organism to another
Animals:
direct transmission from one animal to another via direct contact,
inoculation,
and ingestion and indirect transmission e.g., droplet infection, fomites vectors etc.
For plants
direct transmission plant to plant
and indirect transmission including soil contamination and
different types of vectors e.g., wind, water, animals, humans
42
How are pathogens directly transmitted between animals
Direct contact -
Kissing or any contact of bodily fluids
Direct skin-to-skin contact
Microorganisms from faeces to hands
Inoculation -
Break in the skin eg. sex
Animal bite
Puncture wound or needle sharing
Ingestion -
Contaminated food or drink
43
How are pathogens indirectly transmitted
Fomites -
Inanimate objects such as bedding, socks or cosmetics
Droplet infection -
Inhaling the droplets of saliva or mucus when an infected person talks, coughs or sneezes
Vectors -
eg. Mosquito or water
44
How can you reduce the impact of catching an animal disease as a person
Minimising close contact with animals, washing hands regularly
45
What factors increase the probability of catching an infectious disease
Overcrowded living and working conditions
Poor nutrition
Compromised immune system - eg. after surgery/immunosuppressants
Poor waste disposal
Climate change - more diseases and vectors
Culture and infrastructure
Socioeconomic factors - no training etc...
46
How are pathogens directly transmitted from plant to plant
Direct contact of healthy plant with any part of a diseased plant
47
How are pathogens indirectly transmitted from plant to plant
Soil contamination -
infected plants leave pathogens /spores in soil, infecting the next crop
Vectors -
Wind - spores carried
Water - spores on surface film of water on leaves or any water surface
Animals - transmitting as they feed from one plant to another, particularly aphids
Humans - hands clothing, fomites, farming, transporting plants, crops
48
What factors affect the transmission of communicable disease in plants
Planting variety of crops that are disease susceptible
Over-crowding increases likelihood of contact
poor mineral nutrition
Damp warm conditions
Climate change - increased rainfall, changing conditions etc...
49
Explain the difference between direct and indirect transmission of communicable pathogens
Direct pathogen is spread directly from one organism to another
Indirect – the pathogen is spread from one organism to another through another medium, e.g. the air, a vector
50
Compare and contrast direct transmissions of animal and plant diseases
Similarities:
being crowded close together increases risk of direct and indirect transmission. Weakened individuals more at risk of infection. Damage to protective outer layers can allow pathogens in
Differences:
Animals actively exchange body fluids (sex, kissing, bites) plants don’t. Animals transfer food and drink into body through mouth which plants don't
51
Compare and contrast indirect transmission of animal and plant diseases
Similarities:
animals, wind and water can act as vectors, fomite, e.g. bedding, sacks, machinery can carry disease from one individual to another, soil contamination is common indirect method of disease spread in plants and can affect animals too.
Differences:
droplet infection from coughs and sneezes doesn’t affect plants BUT droplets and splashes from one leaf to another can do.
52
Suggest different approaches to control the spread of malaria
Treating people to reduce pool of infection using medicines against disease
or using vaccines (no really effective ones developed yet); destroying mosquitoes that spread the disease (insecticide sprays on water and homes)
preventing mosquitoes breeding
draining swamps
removing waste filled with water
preventing mosquitoes reaching people (mosquito nets over beds, screens at doors and windows)
53
As plants dont heal tissue, what do they do instead
Seal off a wound/ diseased tissue and sacrifice it, will regrow using meristems
54
How do plants respond to a pathogen attack
Receptors on cell respond to molecules from the pathogen or to chemicals produced when the plant cell wall is attacked
Stimulates release of signalling molecule that switches on genes in the nucleus
These genes, trigger cell responses, which include producing defensive, chemicals alarm signals and strengthening cell walls
55
What are the physical barriers a plant has to a pathogen
Waxy cuticle of plant leaves, bark on trees, cellulose of cell walls
56
What is the physical defence a plant will use and what is the chain
After minutes of attack, callose is synthesised and deposited between cell wall and membrane next to infected cells, acting as barriers
Callose continues to be deposited, and is lignified to make mechanical barrier thicker and stronger
Callose also blocks sieve plates to phloem sealing off infected part, preventing spread of pathogens
Callose is deposited in the plasmodesmata between infected cells, sealing them all off
57
What are the chemical defences a plant will use against a pathogen
Insect repellant eg. pine resin
Insecticides eg. pyrethrins which act as neurotoxins and caffeine, toxic to insects and fungi
Antibacterial compounds -antibiotics eg. phenols antiseptics eg. gossypol
defensins - protiens that disrupt bacterial and fungal membranes
Lysosomes - break down bacterial cell wall
Antifungal compounds - including chitinases which breakdown fungal cell walls
Anti-oomycetes - including glucanases which beak down glucans in the call walls of oomycetes
General toxins eg. cyanide
58
Describe how the plant response to a pathogen attack is triggered
Receptors respond to molecules from pathogens
or to chemicals produced by the plant cell wall when it is attacked
these attach to receptors, stimulating the release of signalling molecules to switch on genes in the nucleus, triggering cellular responses
59
What are some non-specific defences the body has to keep pathogens out
Skin - covered in healthy microorganisms that outcompete pathogens and sebum, which inhibits growth
Body tracts lined with mucous membranes and lysozymes
Lysozymes in tears and urine, and in acid in stomach
Expulsive reflexes - cough and sneeze etc...
Blood clotting
60
What does blood clotting do and how does it occur
Rapidly seals a wound
Platelets come into contact with collagen in skin or damaged blood vessel, adhering and secreting many substances, including
Thromboplastin - enzyme which triggers a cascade of reactions resulting in the formation of blood clot
Serotonin - making smooth muscle of walls of blood vessel contract, reducing blood supply to the area
Dries out into hard scab, while epidermal cells grow underneath with collagen strengthening it
(pg 316&317)
61
Describe the inflammatory response
Characterised by pain, heat, redness and swelling of tissue
cells release histamines and cytokines
Histamines -
Dilate blood vessels, localising heat and redness, raising temp to pathogens cant reproduce
Makes blood vessels more leaky, so blood plasma is forced out, then called tissue fluid and causing swelling and pain
Cytokines -
Attract white blood cells who dispose of pathogens by phagocytosis
62
How does a body get rid of pathogens when they have entered the system
Fevers
Phagocytosis
63
How does a fever work and why is it a useful adaption
Cytokines stimulate hypothalamus to reset thermostat and temp goes up
Useful because -
Most pathogens reproduce best at or below 37 degrees C, so it inhibits reproduction
Immune system works faster at higher temps
64
Describe the stages of phagocytosis
Pathogens produce chemicals attracting phagocytes
Phagocytes recognise non-self proteins on pathogen
Phagocyte engulfs pathogen and encloses it in phagosome
Phagosomes fuses with lysosome forming phagolysosome
Enzymes in lysosome digets Pathogen
Macrophage combines antigens from Cell surface membrane ad produces glycoprotein called Major histocompatibility complex (MHC), putting antigens on its own surface membrane, becoming an antigen-presenting cell (APC)
Stimulating other cells involved in SPECIFIC immune system to respond
65
What do cytokines do
Act as cell-signalling molecules, informing other phagocytes that the body is under attack, stimulating them to move to the site of infection
Also increases body temperature and stimulates specific immune response
66
What do opsonins do
Chemicals that bind to pathogens and tag them so they can be more easily recognised by phagocytes - which contain receptors on their cell surface membrane that bind to opsonins which then tells them to engulf the pathogen
Strongest opsonins are antibodies such as Immunoglobulin G (IgG) and IgM
67
A woman gets a bad scratch from a bramble. The scratch gets very red hot and the next day it contains pus. Explain what is happening
Localised inflammatory response to pathogens at site of wound, mast cells activated and release histamines and cytokines
histamines cause vasodilation causing localised heat and redness
raised temperature helps prevent pathogens reproducing; histamines make blood vessels leaky forcing tissue fluid out, causing oedema and pain
cytokines attract phagocytes to site which phagocytose pathogens; accumulation of dead phagocytes and pathogens forms visible pus layer
68
Describe the process of phagocytosis (textbook summary q)
Pathogens produce chemicals which attract phagocytes
phagocytes recognise nonhuman proteins in pathogen
this is not a response to a specific type of pathogen, simply to a cell or organism which is ‘not self’
phagocyte engulfs the pathogen and encloses it in a vacuole called a phagosome
phagosome combines with a lysosome to form a phagolysosome
enzymes from lysosome digest and destroy pathogen
69
Explain how cytokines and opsonins make the process of phagocytosis more effective than it would be without them
Cytokines act as cell signalling molecules
that stimulate phagocytes to move to a site of infection or inflammation
Opsonins bind to pathogens
and tag them so they are more easily recognised by phagocytes
because phagocytes have receptors on their membranes which bind to common opsonins, e.g., antibodies
70
What is the job of antigens
to identify an antigen as non-self
71
What are antibodies and what do they do
Y-shaped glycoproteins called immunoglobulins which bind to a specific antigen on the pathogen or toxin that has triggered the immune response,
each antigen is specific to each pathogen
72
What are antibodies comprised of
Polypeptide chains - Heavy chain and light chain, held together by disulfide bridges
2 binding regions
(pg 320)
73
How do antibodies bind to pathogens
Bind to antigens on pathogen using lock and key mechanism
Binding site of 110 amino acids - known as variable region, giving specificity
Rest of molecule remains the same - constant region
74
What is formed when an antigen binds to a antibody
Antigen-antibody complex
75
How do antibodies defend the body
Antibody complex acts as an opsonin so complex is easily engulfed and digested by phagocytes
Most pathogens can no longer invade host cells once part of the antigen-antibody complex
Antibodies act as agglutins, causing clumping, preventing spread
Also acts as anti-toxins to the toxins pathogen produce
76
Where do B lymphocytes mature
Bone marrow
77
Where do T lymphocytes mature
Thymus gland
78
What do T helper cells do
CD4 receptors on their cell-surface membrane, which bind to surface antigens on APC, producing interleukins
Interleukins stimulate activity of B cells, increasing antibody production, T cell production and attracts and stimulates macrophages to ingest pathogen with Antibody-antigen complex
79
What do T killer cells do
Destroy pathogen carrying the antigen.
Produces Perforin, killing pathogen by making holes in the cell membrane so it is freely permeable
80
What do T memory cells do
Live for a long time as part of the immunological memory
If a second invasion of pathogens occurs, they divide rapidly, forming huge number of clones of T killer cells
81
What do T regulator cells do
Suppress immune system, acting as a control to regulate it
Stops immune system attacking own tissue after pathogen has been destroyed
82
What do plasma cells do (a B lymphocyte)
Produce antibodies to a particular antigen and release them in circulation
Only live for a few days but produce 2000 antibodies a second
83
What do B effector cells do
Divide to form plasma cell clones
84
What do B memory cells do
Live for a long time and provide immunological memory,
Programmed to remember a specific pathogen and enable body to make rapid response/production of antibodies
85
Describe the stages of cell mediated immunity and why it is required
Response to cells of an organism that have been changed in some way eg. mutation, viral infection or antigen processing
Non-specific defense system, macrophages engulf pathogen in phagocytosis, process antigens becoming an APC
Receptors on T helper cells bind to antigens, producing interleukins, stimulating division of T helper cells rapidly by mitosis
T cells will either -
Develop into T memory cells
Produce Interleukins and stimulate phagocytosis
Produce interleukins and stimulate B cells to divide
Stimulate development of clone of T killer cells that are specific for the presented antigen
(pg 322)
86
What does Humeral immunity respond to and describe the stages of it
Responds to antigens found outside cells, eg. to pathogen, pathogen toxins or to an APC
Activated T helper cells bind to B cell APC - clonal selection, correct antibody is selected
Interleukins produced by activated T helper cells activate B cells
Activated B cells give clones of plasma cells and B memory cells - clonal Expansion
Cloned plasma cells produce antibodies, or act as opsonins or agglutinins (primary immune response)
Some cloned B cells develop into B memory cells, if the pathogen meets the same pathogen again, it can produce antibodies rapidly (secondary immune response)
(pg 323)
87
What is an autoimmune disease
When the immune system stops recognising self and starts to attack healthy body tissue
88
What do scientists think is the cause of Autoimmune diseases
Genetic tendancy, abnormal response to a mild pathogen or normal microorganisms in the body, or T regulator cells dont work effectively
89
What can be taken to help prevent autoimmune diseases
Immunosuppressant drugs, preventing immune system from working, but deprive body of its natural defences
90
What body part is affected and what is the treatment for type 1 diabetes
Insulin-secreting cells of the pancreas (beta cells)
Insulin injections, pancreas transplants, immunosuppressant drugs
91
What body part is affected and what is the treatment for Rheumatoid arthritis
Joints - especially in hands, wrists, ankles and feet
No cure, anti-inflammatory drugs, steroids, immunosuppressants and pain reliefs are all mitigators
92
What body part is affected and what is the treatment for Lupus
Often affects sin and joints causing fatigue
Can attack any organ including kidneys, liver lungs or brain
No cure, Anti-inflammatory drugs, steroids, immunosuppressants are all mitigators
93
Discuss the problems that could arise from treating an autoimmune disease with immunosuppressant drugs
In autoimmune disease immune system stops recognising ‘self’ and starts attacking healthy cells.
Immunosuppressant drugs reduce activity of immune system
preventing/reducing destruction of
healthy tissue BUT susceptibility to infection increases
as immune system less effective at
recognising pathogens
94
Compare the main types of T and B lymphocytes - what are the similarities and differences
Similarities:
Both T and B cells form clones of active cells
both form memory cells which mean
that when they meet a pathogen a second time there is a rapid response, destroying the pathogen
before it can cause disease
Differences:
T cells stimulate B cells
T cells destroy pathogens directly
B cells produce antibodies which act as opsonins stimulating phagocytes to engulf
pathogens
T cells also regulate immune response so it stops once a pathogen is removed and doesn’t turn against body cells
95
The Humoral immune systems deals well with bacterial and fungal infections but the cell-mediated immune system is more effective at tackling viral infections. Explain the biology behind this statement
Humoral immune system responds to antigens outside of cells
bacterial and fungal cells present
in body have antigens to which humoral system can respond
system makes antibodies to
bacterial and fungal surface antigens, forms antigen-antibody complexes so macrophages readily
engulf pathogen
Cell-mediated system responds to changes in cells
Viruses get into body
cells and take over cell metabolism – not so obvious in blood presenting antigens e.g., bacteria.
However, cell-mediated response detects changes in-virus infected cells and killer T cells attack and
destroy them.
96
What is natural active immunity
When you meet a pathogen naturally for the first time, which your immune system forms antibodies for and destroys the pathogen antigen, producing T and B memory cells to recognise the pathogen next encounter
Active as body as itself acted to produce antibodies and/or memory cells
97
What is natural passive immunity
Antibodies cross the placenta to baby during pregnancy, as well as in mammalian milk which is called colostrum, which is high in antibodies, which pass into bloodstream without being digested
98
How is artificial passive immunity achieved
Antibodies are formed in one individual (often an animal, extracted and then injected into the bloodstream of another individual, giving temporary immunity
No memory cells are produced, multiple injections required
99
How is artificial active immunity achieved
Vaccine, active because body makes own memory cells and antibodies, artificial as it isnt a natural encounter
Pathogen is made safe, so no infection but intact antigens
- Killed or inactivated bacteria
- Weakened (attenuated) strains
- Toxin molecules have been detoxified
- Isolate antigens extracted from pathogen
- Genetically engineered antigens
Small amounts of safe antigen (vaccine) are injected into blood
Primary immune response is triggered, producing antibodies and memory cells
If contact with live pathogen occurs naturally, secondary immune response is triggered rapidly, usually before you feel symptoms of disease
Boosters are sometimes required
100
What is an epidemic
When a communicable disease spreads rapidly to a lot of people at a local or national level
101
What is a pandemic
When the same disease spreads rapidly across a number of countries and continents
102
What are some diseases that cause problems at a global level that cannot yet be prevented by vaccination
Malaria - evasive, spending times inside erythrocytes so it is protected by self antigens
HIV - enters macrophages and T helper cells, disabling immune system
103
What are some common types of medicines
Painkillers, Anti-inflammatories and anti-acid medicines
Cures include chemotherapy, antibiotics and antifungals
104
What are some sources of medicines
Chance and then industrial replication eg. penicillin
3D models on key, computers, libraries etc
Derived from plants or microorganisms
105
Where does penicillin come from and what is its action
Commercial extraction, originally from mould growing on melons
Antibiotic - first effective treatment against many common bacterial diseases
106
Where does docetaxel come from and what is its action
Derived from yew trees
Treatment for breast cancer
107
Where does aspirin come from and what is its action
Willow bark
Painkiller, anti-coagulant, anti-pyretic and anti-inflammatory
108
Where does prialt come from and what is its action
Derived from venom of cone snail
Pain killing drug 1000x more effective than morphine
109
Where does vancomycin come from and what is its action
Derived from a soil fungus
Powerful antibiotic
110
Where does digoxin come from and what is its action
based from digitoxin, extracted from Foxgloves
Powerful heart drug to treat heart failure and atrial fibrillation
111
What is one reason why scientists want to maintain biodiversity
Make sure we dont destroy a plant, animal or microorganism which could give us the key to a life-saving drug
112
Where is the future going with medicines
Personalised medicine - pharmacogenetics
Human genome analysed quickly and cheaply, so a prescription or combination can be given based on persons genetic material (pharmacogenomics)
113
Describe synthetic biology
Using genetic engineering, developing populations of bacteria to produce much needed drugs that would otherwise be too rare, too expensive or not available
Or use of nanotechnology to deliver drugs using non-natural particles to very specific sites within cells of pathogens or tumours
114
What is selective toxicity
Antibiotics interfering with the metabolism of bacteria without it affecting metabolism of humans
115
How have antibiotic resistant bacteria developed
Most of population die but due to Random mutation of a bacterium that causes resistance to drug, renders it ineffective
Bacteria with resistance then survive and rapidly reproduce passing on mutated allele, creating large population
Natural selection
116
What are the anthropogenic causes of bacterial resistance
Over subscription of antibiotics
Not finishing the cycle, which allows any remaining bacteria to survive and reproduce
117
How can antibiotic resistance be reduced in the long term
Minimising use of antibiotics, ensuring every course of antibiotics is completed to reduce risk of resistant individuals surviving and adapting
Good hygiene in hospitals and care homes and in general, reducing the spread
118
How can the bacterial resistance crisis be solved
Development of new antibiotics using computer modelling and other sources in many places,
Funding
119
Suggest why some children still die of communicable diseases in the UK, even in the 21st century
Some diseases so severe that patient killed before body can develop antibodies
some people do not have children vaccinated against diseases
if child immunocompromised, has a comorbidity, or neglected/malnourished will be more vulnerable to infections
bacterial disease may be resistant to current antibiotics
120
Explain how vaccinations may be used to prevent rabies after a person has been bitten by a rabid dog, fox or bat
Most people vaccinated, so if bitten they are given course of injections to deliver antibodies (produced in another animal) directly into blood stream
antibodies form antigen–antibody complex with rabies virus, allowing phagocytes to destroy pathogen (an example of artificial passive immunity)
121
Explain how vaccinations can be used to control epidemics
Epidemic occurs when communicable disease spreads rapidly to a lot of people at either local/ national level
in vaccination, immune system stimulated to make antibodies to a pathogen by exposure to safe form of an antigen injected into blood stream
if an epidemic begins to build, mass vaccination
can protect people in the community by building immunity to infecting pathogen and prevent pathogen spreading disease into the wider population
