Communicable Diseases Flashcards
(135 cards)
1
Q
What is a pathogen
A
A microorganism that causes disease
2
Q
What is the body that the pathogen lives in called
A
- The host
- Pathogen is fed by taking nutrition from the host but also caused damage in the process - can be considerable
3
Q
What are the key features of bacteria
A
- belong to the Kingdom Prokaryotae
- smaller than eukaryotes but reproduce rapidly
- in right conditions can reproduce every 20 minutes
- can cause disease by damaging cells or by releasing waste products and/or toxins that are toxic to the host
- In plants bacteria often live in vascular tissue and caused blackening and death of tissue
4
Q
What are the key features of fungi In humans
A
- Can cause variety of diseases in both plants and animals
- Common fungal infections where the fungus lives in the skin of an animal and where its hyphae which forms a mycelium grows under the skin surface
- The fungus can send out specialised reproductive hyphae which grows to the surface of the skin to release spores
- This causes redness and irritation
5
Q
What are the key features of fungi in plants
A
-Fungus often lives in vascular tissue where it can gain nutrients
-hyphae releases extracellular enzymes such as cellulases to digest the surrounding tissue which causes decay
-Leaves often become mottled in colour curl up and shrivel before dying
-Fruit and storage organs such as tubers (potatoes) will turn black and decay

6
Q
What are the key features of viruses
A
-Causes many diseases in plants and animals
-viruses invade cells and take over the genetic machinery and other organelles of the cell
- they then cause the cell to manufacture more copies of the virus
-The host cell eventually bursts releasing many new viruses which will infect healthy cells

7
Q
What are the key features of Protoctista
A
- Number of diseases caused by animal like protoctists
- organisms usually cause harm by entering host cells and feeding on content as they grow
- malarial parasite plasmadomium Has immature forms that feed on the haemoglobin inside red blood cells
8
Q
Name some diseases caused by bacteria
A
-tuberculosis
A disease that affects many parts of the body killing the cells and tissues the lungs are most often affected
-Ring rot (in plants)
Ring of decay and vascular tissue of the potato tuber or tomato accompanied by leaf wilting
9
Q
Name some diseases caused by a virus
A
-HIV/AIDS
Attack cells in the immune system and compromises the immune response
-tobacco mosaic virus
Causes mottling and discolouration of leaves
10
Q
Name some diseases caused by fungus
A
-ringworm (cattle)
Growth of fungus in skin with spore cases erupting through skin to cause a rash
-Black sigatoka (bananas)
Causes leaf spots on banana plants reducing yield
11
Q
Name some diseases caused by protoctistan
A
-malaria
Parasite in the blood that causes headache and fever may progress to coma and death
-Blight (tomatoes and potatoes)
Affects both leaves and potato tubers
12
Q
What is a pathogens life-cycle
A
- Travel from one host to another (transmission)
- entering the hosts tissues
- reproducing
- leaving for host tissues
13
Q
What is direct transmission
A
Passing a pathogen from host to host with no intermediary
14
Q
What are some examples of direct transmission
A
-Direct physical contact i.e. touching a person who is infected
Wash hands regularly and keep hygienic to avoid
-faceal (oral transmission) by eating or drinking food contaminated by pathogen
Wash all fresh food when cooking
-droplet infection (pathogen carried by water in the air)
Cover your mouth when coughing or sneezing
-transmission by spores (carried by air or side on surfaces or in soil)
Washing skin after contact with soil
15
Q
What are some other factors that affect transmission including social factors
A
- overcrowding -many people living and sleeping together in one house
- Poor ventilation
- Poor health -particularly if a person has HID/AIDS as they are more like to catch other disease 
- Poor diet
- homelessness
- Living or working with people who have migrated from areas for a disease is common
16
Q
What is indirect transmission
A
Passing a pathogen from host to new host via a vector
17
Q
What is a vector
A
An organism that carries a pathogen from one house to another i.e. a mosquito
18
Q
Outline the process of someone getting malaria indirectly
A
1) A person with malaria
2)Gametes of plasmodium in blood
3) female mosquito sucks blood
4)plasmodium Develops and migrate to mosquitoes salivary glands
5) An uninfected person is bitten
6)plamodium migrates to liver
7) Then migrates to blood
19
Q
What are some examples of direct transmission in plants
A
- pathogen is present in the soil will infect plants by entering roots (especially if they have been damaged as a result of re-planting/burrowing animals/ movement caused by a storm)
- airborne transmission - Fungi produce spores as a means of sexual/asexual reproduction these may be carried in the wind
- once pathogen is inside plant it will affect vascular tissue - Pathogens in leaves are distributed when it leaves a shed and carry pathogen back to the soil where it can grow and infect another plant
-Can also enter fruit and seeds and will then be distributed with the seeds so many or all offspring are infected

20
Q
What is an example of indirect transmission in plants 
A
- occurs as a result of insect attack
- Spores/bacteria become attached to burrowing insect (i.e. beetle) which attacks an infected plant
- when beetle attacks another plant the pathogen is transmitted to the uninfected plant
-Beetle acting as a vector i.e. fungus that causes Dutch elm disease is carried by a beetle
21
Q
How does climate affects disease
A
- pathogens can grow and reproduce more rapidly in warm and moist conditions
- tend to be more common in warmer climates than cooler climates
22
Q
Why are different organisms attracted to plants
A
They manufacture sugar in photosynthesis and convert the sugars to a wide variety of compounds i.e. protein/oils
-They represent a rich source of nutrients for many organisms
23
Q
How do plants dedect pathogens
A
- a wide range of structural/chemical/protein based defenses which can detect invading organisms and prevent them from causing extensive damage
- Includes both active and passive defenses
24
Q
What are passive defences
A
Defences present before infection and role is to prevent entry and spread of pathogen
Include physical barriers and chemicals

25
What are the physical defences in plants
- cellulose cell wall
- lignin thickening of cell walls
- Waxy cuticles
- bark
- stomatal closure
- callose
- Tylose formation
26
How does the cellulose cell wall act as a physical defence in plants
Not only acts as a physical barrier but most plant cell walls contain variety of chemical defences that could be activated from packaging is detected
27
How does lignin thickening of cell walls act as a physical defence in plants
lignin is waterproof and almost completely indigestible
28
How do the waxy cuticles acts as a physical defence
- Prevent water collecting on the cell surfaces
| - Since pathogen is collected in water And need water to survive the absence of water is a passive defence
29
How is bark physical defence in plants
Most bark contains a variety of chemical defences that works against pathogenic organisms
30
How does stomatal closure act as a physical defences in plants
- stomata are possible points of entry for pathogens
- stomatal aperture is controlled by the guard cells
- when pathogenic organisms are detected in that part of the plant
31
How is Callose a physical defence in plants
- large polysaccharide that is deposited in sieve tubes at the end of growing season
- Deposited around the sieve plates and blocks the flow in the sieve tubes
- This can prevent a pathogen spreading around the plant
32
How is tylose formation a physical defence in plants
- A tylose is a balloon like swelling/projection that fills the xylem vessel
- When fully formed it blocks the vessel and the vessel can no longer carry water
- Blocking xylem vessels then prevents spread of pathogens through heartwood
- Also contains a high concentration of chemicals such as terpenes that are toxic to pathogens
33
How do chemical defences protect the plant from pathogens
- tissues contain a variety of chemicals that have anti-pathogenic properties including terpenoids/phenols/alkaloids/hydrolytic enzymes
- Some of these chemicals such as terpenes in tyloses and tannins in bark are present before infection
However the production of chemicals requires a lot of energy so many chemicals are not produced until the plant detects an infection
34
What are active defences in plants
- when pathogens attack, specific chemicals in their cell wall can be detected by plant cells
- chemicals include specific proteins and glycolipids
- plabt responds by fortifying the defences already present
- This includes increasing physical defences and producing defensive chemicals
35
What are the active defences in plants 
- cell walls become thickened and strengthened with additional cellulose
- deposition of callose between the plant cell wall and cell membrane near invading pathogen- Callose deposits are polysaccharide polymers that impede Cellular penetration at the site of infection it’s strengthens the cell wall and blocks plasmodesmata
- oxidative burst that produce highly reactive oxygen molecules capable of damaging the cells of invading organisms
- an increase in production of chemicals
- necrosis
- canker
36
What is the action points of terpenoids in plant cells
- Range of essential oils that have antibacterial and antifungal properties
- Also create sent for example the menthols and menthones produced by mint plants
37
What is the action point of Phenols in plant cells
- have antibiotic and antifungal properties
- tannins found in bark Inhibit attack by insects these compounds bind to salivary proteins and digestive enzymes such as trypsin and chymotrypsin deactivating enzymes
- Insects that ingest high amounts of tannins do not grow and will eventually die this helps prevent transmission of pathogens
38
What is the action point of alkaloids in plant cells
- Nitrogen containing compounds such as caffeine/nicotine/cocaine give bitter taste to inhibit herbervores feeding
- also acts on a variety of metabolic reactions via inhibiting for activating enzyme action
- Some alkaloids inhibit protein synthesis -if plants can reduce grazing by large animals then it will suffer less damage that can allow pathogens to enter plant
39
What is the action point of defensive proteins (defensins) in plants cells
- small cytosine rich proteins that have broad antimicrobial activity
- Acts upon molecules in plasma membrane of pathogen possibly inhibiting action of ion transport channels
40
What is the action points of hydrolytic enzymes plant cells
- found in spaces between cells
- these include chitinases (Which breakdown the chitin found in fungal cells walls) glucanases (Which hydrolyses the glycosidic bonds in glucans). And lysosomes (capable of degrading bacterial cell walls)
41
What are the chemicals used in active defences in plants cells
- terpenoids
- phenols
- alkaloids
- defensive proteins (defensins)
- Hydrolytic enzymes
42
What is necrosis
-Deliberate cell suicide
-Few cells are sacrificed to save the rest of the plant
-by killing cells surrounding infection stops pathogens access to water and nutrients and stop spreading further around Plant
-brought about by intracellular enzymes that are activated by injury -Enzymes destroy damaged cells and produce brown spots on leaves/dieback

43
What is a canker
- The parts of the plant where the cells have died after necrosis
- it’s a sunken necrotic lesion in the body tissue such as the main stem/branch
- causes death of the Cambian tissue in the bark 
44
What are primary defences
prevent pathogens entering the body
| Non-specific as will prevent the entry of any pathogen
45
How is the skin a primary defence against disease
- main primary defence
- Outer layer of the skin is called the epidermis and consists of layers of cells
- most of the cells are called keratinocytes
- these are produced by mitosis at the base of the epidermis
- they then migrate out to surface of the skin
- as they migrate they dry out and the cytoplasm is replaced by the protein keratin
- this process is called keratinisation and takes about 30 days
- by the time cells reach the surface they are no longer alive
- keratinised layer of dead cells act as an effective barrier to pathogens
- Eventually dead cells slough off
46
Why is blood clotting and skin repair important
- abrasion/lacerations damage the skin an open body to infection
- When it occurs what do you must prevent excess blood loss by forming a clot making a temporary seal to prevent infection and repair the skin
47
What are the first stages in the Blood clotting and skin repair process
- blood clotting is a complex process as it is important to prevent clots forming in blood vessels where they are not needed
- involves calcium ions and at least 12 factors known as clotting factors
- many of the clotting factors are released from platelets and from the damaged tissue
- These factors activate an enzyme cascade
48
What are the second stages of the blood clotting and skin repair process once the clot has formed
- once clot has formed it begins to dry out and form a scab
- scab shrinks as it dries drawing the sides of the cut together
- this makes a temporary seal under which the skin is repaired
- first stage is the deposition of fibrous collagen under the scab
- Stem cells in the epidermis then divide by mitosis to form new cells which migrate to the edge of the cut and differentiate to form new skin
- New blood vessels great to supply oxygen and nutrients to new tissues
- The tissues contract to help draw the edges of a cut together so that the repair can be completed
- As the new skin is completed the scab will be released
49
Describe the steps in the enzyme cascade
1) Blood vessel is damaged collagen becomes exposed and releases clotting factors platelets bind to collegen and Release clotting factors
2) these cause inactive thrombinkase to be converted to active thrombinkase (an enzyme)
3) this enzyme along with calcium ions then catalyse the conversion of prorthrombin in thr bloood to active thrombin (an enzyme)
4)This enzyme thing catalyses the conversion of soluble fibrogen in plasma to insoluble fibrin
5) these fibres attach to platelet plug and a temporary platelet plug is formed
6) The red blood cells and platelets are trapped and a clot is formed

50
What does an active enzyme become
Phosphorylated
51
Why are mucous membranes needed
- certain substances such as oxygen and nutrients in our food must enter our blood
- Exchange services where this occurs are thinner and less well protected from pathogens
- food and air we breathe in a harbour micro organisms
- Airways lungs and digestive system are at risk of infection
- So protected by mucus membranes
52
How do mucous membranes work (goblet cells)
-epithelial layer contains mucus secreting cells called goblet cells
- There are also extra mucus secreting glands under the epithelium
- In airways the mucus lines the passages and traps any pathogens that may be in the air 
53
How do you mucous membranes work (ciliated cells)
- cilia are tiny hair-like organelles that can move
- They move in a coordinated fashion to waft the layer of mucus along
- they move the mucus up to the top of the trachea where it can enter the oesaphugus
- It is swallowed and passes down the digestive system
- Most packages in digestive system are killed by the acidity of the stomach which can be pH 1-2 debatures pathogens enzymes
54
Where are mucus membranes also found
- gut
- genital areas
- anus
- ears
- nose
55
How is coughing and sneezing a primary defence against disease
- areas prone to attacks are also sensitive
- respond to irritation that may be caused by presence of microorganisms/toxins that they release
- reflexes include coughing/sneezing/vomiting
- In a cough/sneeze the sudden explosion of air will carry with it the micro organism causing the irritation
56
How is inflammation a primary defence against disease
- One of the signs that a tissue is infected is swelling/redness
- presence of micro organism in tissue is detected by specialised cells called mast cells
- cells release a cell signalling substance called histamine
- this has range of effects on surrounding tissue which acts to help combat infection
- main effect is vasodilation and make capillary walls more permeable to white blood cells and some proteins
- blood plasma and phagocytic white blood cells blood and enter tissue fluid
- this leads to increased production of tissue fluid which causes swelling
- excess tissue fluid is drained into the lymphatic system where lymphocytes are stored
- This can lead to pathogen is coming into contact with lymphocytes and initiating specific in the responses
57
What are other primary defences
- The eyes are protected by antibodies and enzymes in tear fluid
- Ear canal is lined with wax which traps pathogens
- Female reproductive system is protected by a mucus plug in the cervix and by maintaining relatively acidic conditions in the vagina
58
When are secondary defences used
-To combat pathogens that have entered the body
59
How do antigens work
- When pathogen invades the body it is recognised as foreign by chemical markers on its outer membrane
- markers are called antigens
- They are protein/Glycoproteins intrinsic to the plasma membrane
- Antigens are specific to the organism
- Our own cells have antigens but these are recognised as our own and do not produce a response
60
How do opsonins work
- Protein molecules that attach to antigens on the surface of a pathogens
- type of antibody 
- some opsonins are not very specific so they can attach to a variety of pathogenic cells
- The role of the opsonin is the enhance the ability of phagocytic cells to bind and engulf the pathogen
61
What do white blood cells differentiate into
- phagocytes (Neutrophils/macrophages)
| - lymphocytes (B cells/T cells)
62
What is the purpose of phagocytes
- first line of secondary defence is phagocytosis
| - Specialised cells in blood and tissue engulf and digest pathogens
63
What cells mature in bone marrow
- neutrophils
| - B cells 
64
Where do you T cells come from
Mature in the thymus gland
65
What is important to note about each antigen 
-A different antibody will be made for each
66
What are the key features of neutrophils
- most common phagocytes
- Multi lobed nucleus
- manufactured in bone marrow
- they travel in blood and often squeeze out of blood into tissue fluid
- neutrophils are short lived but will be released in large numbers as a result of an infection
- contain large number of lysosomes
- engulf and digest pathogens and die after digesting a few
- Dead neutrophils are collected in area of infection and form pus 
67
Outline the process of phagocytosis
1) Neutrophil fines to up soon and attach to the antigen of the pathogen
2) pathogen is engulfed by endocytosis forming a phagosome
3) Lysosomes fuse to phagosone and release lytic enzymes into it
4) After digestion harmless products can be absorbed into the cell
68
What are specialisations of Phagocytes
-Receptors on plasma Membrane that can bind to opsonin or a specific antigen
-Iobed nucleus that allows the cell to squeeze through narrow gaps
-well developed cytoskeleton that helps the cell to change shit to engulf pathogens and move lysosomes and vacuoles around inside the cell
-Many lysosomes containing lysin
-many mitochondria to release energy from glucose
-A lot of ribosomes to synthesise enzymes involved
69
Outline the process of the specific immune response
1) Pathogen enters the cell lined with antigens
2) Antigens on pathogen are then presented on antigen presenting cells
3) Lymphocytes are made in the bone marrow (B cells mature here whilst T cells mature in thymus gland)
4) These then undergo clonal selection with the antigen presenting cell
5) clonal expansion (proliferation) occurs
6) Cells differentiate into specific functions
70
What are the antigen presenting cells
- macrophage
- infected cell
- pathogens in body fluids
71
What are the different types of T cells
-T killer cells - attack infected host cells
-T memory cells-remain in blood providing long-term immunity
-T helper cells -release cytokines that stimulate B cells to divide
-T regulator cells -shut down immune response after pathogen has successfully been removed
Also involved in preventing autoimmunity
72
What is autoimmunity
Attack of own cells 
73
What is clonal selection
- when measuring each receptor has a different shape on plasma membrane
- invading pathogen has specific antigens
- Tries to find the correct cells that are complimentary to antigen on pathogen on the plasma membrane
74
What is clonal expansion (proliferation)
-Once found the correct cells many clorsn ate made with the same one with the same receptors on the outside
75
What is differentiation
These then differentiate into different cells for specific functions
76
What are the different types of B cells
- B memory cells - stay in the blood so you can gain immunological memory/immunity
- Plasma cells that make antibodies
77
What are cytokines
chemicals which are used as cell signalling and communication between cells during the specific immune response
78
What is important to note about cytokines
In order to detect a signal the target cell must have cell-surface receptor complementary shape to the cell signalling molecule
79
How do macrophages use communication by cytokines
- macrophages release monokines
- Some monokines attract neutrophils ( by chemotaxis- The movement of cells towards a particular chemical)
- Others stimulate B cells to differentiate and release antibodies
80
How do T cells/macrophages communicate with cytokines
- T cells and macrophages release interleukins
| - These stimulate clonal expansion and differentiation of B and T cells
81
How do other cells use cytokines as communication
-Many cells release interferon which inhibits virus replication and stimulates the activity of t killer cells
82
How does autoimmune disease occur
- occurs when a immune system attacks self
| - Occurs when lymphocytes develop receptors when the touring that a complimentary to the antigens on our own cells
83
What is normally stops autoimmune disease from occurring
Normally doesn’t happen as B/T cells are destroyed during maturation by apoptosis (programmed cell death)
84
What are some examples of autoimmune disease
- arthritis - Painful inflammation of a joint course is in certain that starts with antibodies attacking the membranes around the joint
- lupus -can affect any part of the body causing swelling and pain -May be associated with antibodies that attack certain proteins in the nucleus in cells and affected tissues
85
What is an antigen
- Molecules that can stimulate and immune response
- any molecule can act as an antigen but are usually proteins/Glyco proteins in the plasma membrane of the pathogen
- A foreign antigen will be detected by immune system and will stimulate the production of antibodies
86
What is important to note about the antibody
- antibodies are specific to the antigen so antibodies are specific to the pathogen
- our own antigens are recognised by our immune system so do not stimulate any response
87
What is the structure of an antibody
- immunoglobulins (complex proteins produced by plasma cells in immune system)- Y shape Has two binding sites and and an end that can stimulate phagocytosis
- region with specific shape that is complementary to particular antigen (variable region)
- Constant region - Same in all antibodies may have a sight for easy binding of phagocytic cells
- 4X polypeptide chains 2x heavy 2x light
- disulphide bridges to hold polypeptides together
- Hinge region to allow flexibility so molecule can grip more than one antigen 
88
What must the immune system do for every antigen detected
- It must manufacture one type of antibody for every antigen that is detected
- it will then attach to the antigen and render it harmless
89
What are the different regions on an antibody called
- variable region which has specific shape to shape of antigen
- Constant region which is the same in all antibodies -May have a site for easy binding of phagocytic cells
90
What is the role of opsonin as an antibody
- Group of antibodies that bind to antigens on pathogen so phagocytes can recognise bacterial cell
- then act as a binding site for phagocytic cells so these can easily find and destroy the pathogen
- Some are not very specific and can bind to other molecules as well as antigens
Neutralisation - Sometimes binds to pathogen before phagocyte comes along so it can’t invade other cells
-Assist in phagocytosis but also prevents pathogen entering a host cell before it can be attacked by phagocytes

91
What is the role of agglutinins as an antibody
-As each antibody molecule has two identical binding sites it is able to cross-link pathogens
-binds to antigen and Pathogen with one binding site to an antigen and another pathogen with other binding site
-When many antibodies before this cross-linking they clump (agglutinate) together pathogens
-this causes the clumped together pathogen from being physically impeded from carrying out functions such as entering host cells
-also can be readily engulfed by phagocytes
- Particularly effective against viruses
92
What is the role of anti-toxins as an antibody
- some antibodies bind to molecules that released by pathogenic cells
- These molecules may be toxic and the action of anti-toxins render them harmless
93
What is the purpose of antigen presenting cells
- weights around the body can come in contact with specific cells that can activate full immune response
- these are T and B cells
- May only be one type of T/B cell with correct recognition sites for antigen
- Antigen presenting cells increase chances that antigen will come into contact with them
94
Where are macrophages manufactured and where do they mature
- manufactured in the bone marrow
- travel in the blood as monocytes before settling in body tissues
- Many found in lymph nodes where they mature into macrophages
- Dendritic cells (type of macrophage) is found in more peripheral tissue
95
What is the role of a macrophage
- When macrophage engulfs pathogen it does not fully digest it
- antigen from the surface of the pathogen is saved and moved to a specific protein complex on the surface of the cell
- macrophage becomes antigen presenting cell
- Exposes antigen on its surface so other cells of the immune system can recognise the antigen
96
How are antigen presenting celld not mistaken as pathogens
Special protein complex ensures antigen presenting cell it’s not mistaken for a foreign cells and attacked by other phagocytes
97
Key difference between neutrophils and Macrophages
Neutrophils- engulf and digest pathogens
| Macrophages -digest pathogens and present antigens 
98
What is the activation of the specific B and T cells called 
Clonal selection
99
What do the different cells look like underneath a microscope
Macrohages - kidney shaped nucleus
Neutrophils - multi lobed nucleus
B+T - smaller and nucleus fills most of its cell
100
What are antibodies
- produced by B cells
| -Specific proteins released by plasma cells that can attach to pathogenic antigens neutralising them
101
What are the different types of antibody
- opsonins
- agglutinins
- Antitoxins
102
What does the graph of a primary and secondary response look like
primary response:
-lower concentration of antibodies produced
-takes a few days before number of antibodies in the blood can rise to a level that can combat infection
Secondary response:
-more rapid
-produces a higher concentration of antibodies 
103
Why is it more rapid in the secondary response
- B memory cells produced in primary response stay in the blood and have the memory to create the right antibodies with complimentary receptors to the antigens
- this means it is much faster there is a greater production of antibodies
104
What happens in the primary response
- clean your selection proliferation and differentiation occurs
- Takes a few days to happen but create memory cells that stay in the blood
105
Why don’t you have any symptoms from the pathogen in the secondary response
-antibody is fast and occurs in high concentrations
106
What is a vaccination
- provides immunity to specific diseases
- created by deliberate exposure to antigenic material that has been rendered harmless
- antigenic material usually injected but some times can be taken orally
107
Why are vaccinations effective 
- immune system treats antigenic material as a real disease
- immune system is therefore activated and manufactures antibodies and memory cells
- Memory cells provide long-term immunity
108
What are the different forms antigenic material can be used in vaccines
- whole life microorganisms - naughties harmful as ones that cause real disease but must have similar antigens so antibodies produced will be effective against real pathogen (smallpox vaccine which uses simalir virus that causes cow pox)
- harmless or attenuated (weakened) version of pathogenic organism (measels and TB)
- Dead pathogen ( typhoid and cholera)
- preparation of antigens from a pathogen ( hepatitis B vaccine)
- toxoid which is harmless version of a toxin (tetanus vaccine) 
109
What is heard vaccination
- using vaccines to provide immunity to all almost all of the population at risk
- Once enough people I mean disease can no longer be spread through the population and you achieve ‘herd immunity’
- In order to be effective it is essential to vaccinate almost all population
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How many people that need to be vaccinated to prevent the spread of measles
95%
111
What is ring vaccination 
- used when a new case of disease is reported
- involves vaccinating all the people in immediate vincinity of new cases
- May mean vaccinating surrounding houses or even whole villages or towns
- Also used in many parts the world to control the spread of livestock disease

112
What is active natural immunity
- immunity provided by antibodies made in the immune system as a result of infection
- person suffers from disease once and then is immune (chickenpox)
113
What is passive natural immunity
- antibodies provided by the placenta or breast milk
- makes the baby immune to diseases to which the mother is immune 
- useful in the first years of the babies life when it’s immune system is developing
114
What is active artificial immunity
- immunity provided by antibodies made in a new system as a result of vaccination
- Person is injected with a weakend dead or similar pathogen with antigens and this activates immune system (TB and influenza)
-Giving antigenic material so you are making antibodies
115
What is passive artificial immunity
- immunity provided by injection of antibodies made by another individual (hepatitis A and B)
- If antibodies are given no memory cells are made = no immunity
- Stimulates a quick fast response
116
What is a genetic mutation
- Changes antigen so B memory cells may not recognise new antigens
- Pathogen may be transmitted and incidence of the disease increases
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What is an epidemic
- Rapid spread of disease through a high proportion of the population
- when certain pathogens (influenza) Are unstable and regularly undergo changes in the antigens
118
What is a pandemic
Worldwide epidemic
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What is a deadly about genetic mutations
- Replaces other versions of the virus
- affect important parts of the virus
- Increases viruses ability to infect cells
120
How do you variants emerge 
- In patient with weakened immune system
| - They are unable to beat the virus and instead the body becomes a breeding ground for forest to mutate
121
Do you vaccine still work against genetic mutations
- Most vaccines train immue system to attack several different parts of the virus so eventhough mutated vaccine should still work
- However ‘vaccine escape’ - When virus changes so dodges full affect of vaccine and can continue to infect more people
122
What is some examples of different variants
Beta Variant S. Africa
| Omnicrom
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What type of Bacteria cause TB
mycobaterium
124
How have bacteria developed resistance
-People don’t take the full course of the antibiotics so the resistant bacteria remains in the bloodstream
-Disc genetically mutated and cause more harm to the house as they can do longer be killed by antibiotics
-Bacterial resistance is due to overuse and miss use of antibiotics
125
What are the reasons why we need to find new sources of medicine
- New diseases are emerging
- many diseases where treatment is ineffective
- Some antibiotic treatments are becoming less effective due to the pathogen gaining resistance
126
What do you use antibiotics against
The growth of fungi or bacteria
127
What are the two examples of bacteria that have become resistant to antibiotics
- C.diff
| - MRSA
128
Why is the secondary response much faster than the primary response
B cells Have produce memory cells that have receptors complimentary to the antigen on the pathogen which remain in the blood after the primary response in the secondary response they can make antibodies quickly and at a greater concentration this means that less time is spent on Clonal selection proliferation and differentiation
129
How has accidental discovery lead to new sources of medicine
- accidental discovery of antibiotic penicillin by Alexander Fleming
- fungus penicillin releases compounds that kill bacteria
- Florey and chain purified penicillin which father demonstrated the potential value of antibiotics
130
How has traditional medicines contributed to sources of new medicines
-many drugs have been used for centuries because people have noted that plants/extracts have a beneficial effect
Poppies - morphine and opium for anaesthetic - reduce nervous action in the central nervous system if the nerves cannot carry impulses then no pain is felt
Willow bark - Relieves pain and fever after discovery of his active ingredient to reduce the side-effect of stomach leading by adding an aceytl group - ibuprofen and aspirin 
131
How is observation of my bike lead to a sources of new medicines
- Monkeys/bears etc rub citrus oils on the case as insecticides and antiseptics important to prevent insect bites/infection
- Bitds line there bests with medicinal leaves in order to protect chicks from mites
132
How has further plant research contributed to sources of new medicine
- Natural drugs have been found in tropical plants due to great diversity they may contain molecules that could form medicine or drugs
- New chemical fingerprinting technology enables scientists to screen natural chemicals more effectively for activity as potential medicines
133
How has research into disease-causing mechanisms contributed to new medicine
- mini micro organs cause disease by receptors on plasma membrane
- Glycoprotein receptor molecules can be isolated in sequence
- once the amino acid sequence is known molecular modelling can be used to determine the shape of the receptor -Next step is to find a drug that mimics the shape of the receptor and can be used to bind to the virus itself which would block the virus from entering the t helper cells
- in a similar way drugs that inhibit the action of certain enzymes can also be developed
134
How his personalised medicine contributed to new medicines being found
- Sequencing technology and molecular modelling has huge potential for future medicines
- possible to screen for genomes of plants/microorganisms to identify potential medicine or compounds from DNA sequences
- hoped that this technology can be taken further once technology is fully developed
- may be possible to sequence change from individuals with particular conditions and develop specific drugs for condition
135
How his synthetic biology contributed to new medicine
- development of new molecules in particular enzymes that mimic biological systems is one form of synthetic biology
- Another way that synthetic biology is used is to design and construct new devices and systems that may be useful in research/healthcare/manufacturing
