4.1.1 Communicable diseases, disease prevention and the immune system Flashcards
1
Q
what are the types of pathogens?
A
-bacteria
-fungi
-viruses
-Protoctista
2
Q
define pathogen
A
a microorganism that causes disease
3
Q
how do pathogens cause disease?
A
-travel from host to host
-get into tissues
-reproduce
-cause damage
4
Q
what are the different ways that pathogens are transmitted?
A
-vector
-physical contact
-droplet infection
-non direct contact
5
Q
what are the different shapes of bacteria?
A
-cocci
-bacilli
-vibrio
-spirilli
6
Q
what is the function of cocci bacteria?
A
have less surface area per volume than bacilli or spirillum, and thus can survive in dryer environments
7
Q
what is the function of spirillum bacteria?
A
spirillum are spiral cells, move with a corkscrew motion, and meet less resistance from surrounding water
8
Q
what is the function of bacilli and vibrio bacteria?
A
bacilli and vibrio have a greater surface area to volume ratio and can take up nutrients from dilute solutions more effectively
9
Q
describe gram positive bacteria
A
-look purple/blue under a light microscope
-stain with crystal violet
-e.g. MRSA
10
Q
describe gram negative bacteria
A
-look red under a light microscope
-stain with safranin
-e.g. E Coli
11
Q
how do bacteria reproduce?
A
they divide into two new bacteria every 20 minutes
12
Q
how do you calculate bacteria reproduction?
A
2^n
where n= the number of divisions
13
Q
how do bacteria cause disease?
A
-produce toxins and cause symptoms by cell damage
-damage cell membranes, enzymes or genetic material
14
Q
what is the structure of viruses?
A
-some genetic material surrounded by a protein shell
-they are non living as they can not replicate by themselves
-a bacteriophage is a virus that infects bacterial cells
15
Q
describe the process of viral reproduction
A
- the virus attaches to a specific host cell
- the genetic material from the virus is injected into the host cell
- the viral genes cause the host cell to make new viruses
- reverse transcriptase enzyme creates DNA from the virus RNA
- virus genetic information now within the host DNA
- viral RNA synthesis by host cell
- the host cell splits open, releasing the new virus
16
Q
describe budding: fungal growth
A
The most common mode of vegetative growth in yeast is asexual reproduction by budding. Here, a small bud or daughter cell is formed on the parent cell. The nucleus of the parent cell splits into a daughter nucleus and migrate into the daughter cell. The bud continues to grow until it separates from the parent cell, forming a new cell. The daughter cell produced during the budding process is generally smaller than the mother cell.
17
Q
describe protoctista
A
-eukaryotic
-a small percentage of pathogens
-protists which cause disease are parasitic
-may need a vector to transfer them to their host e.g. Malaria
-may enter body directly through water e.g. amoebic dysentery
18
Q
label a bacterial cell
A
see paper flashcard
19
Q
draw and label the different bacterial shapes
A
see paper flashcard
20
Q
label and fungal cell
A
see paper flashcard
21
Q
do fungi cause more harm to plants or animals? why?
A
plants- fungi stop plants photsynthesising and so can quickly kill the plant
22
Q
fungi are saprophytes- what does this mean?
A
they feed on dead and decaying matter
23
Q
why can fungi spread so quickly through plants?
A
when fungi reproduce they produce millions of tiny spores which can spread huge distances, this means they can spread rapidly and widely through crop plants
24
Q
describe bacteria
A
cause disease by damaging cells or releasing toxic waste products
25
what are some examples of bacteria?
-tuberculosis
-cholera
-tetanus
26
describe fungi
some live in the skin and send out hyphae to the surface
27
what are some examples of fungi?
-athletes foot
-thrush
-ringworm
28
describe viruses
invade cells and take over the genetic machinery, the cells then replicate the virus until it bursts
29
what are some examples of viruses?
-tobacco mosaic virus
-HIV
-chicken pox
30
describe protoctista
organisms that cause harm by entering the cells and feeding on the contents
31
what are some examples of protoctista?
-malaria
-sleeping sickness
-amoeboid dysentery
32
what is direct transmission?
pathogen directly transported from one individual to another
33
what are the forms of direct transmission?
-direct contact
-inoculation
-ingestion
34
describe the forms of direct contact
(contagious diseases) e.g. kissing or contact with bodily fluid; direct skin-skin contact; contact with faeces
35
describe the forms of inoculation
through a break in the skin (through sex); animal bites; sharing needles
36
describe the forms of ingestion
taking in contaminated food or drink or transferring pathogens from hands to the mouth
37
what is indirect transmission?
pathogen travels from one individual to another indirectly
38
what are the forms of indirect transmission?
-fomites
-droplet infection
-vectors
-water
39
what are fomites?
inanimate objects such as bedding can transfer pathogens
40
what is a droplet infection?
droplets of saliva or mucus are expelled from your mouth as you cough or sneeze and healthy individuals can breathe these in
41
what is a vector?
a living or non-living factor that transmits a pathogen from one organism to another
42
how can water transmit disease?
can also be a vector for disease e.g. diarrhea
43
describe direct transmission of plants
direct contact of a healthy plant with any part of a diseased plant
44
describe the forms of indirect transmission in plants?
vectors and soil contamination
45
what are the different vectors in plants?
-wind= spores carried in the wind
-water=spores swim in the surface of water
-animals=insects and birds carry pathogens
-humans=transmitted by clothes, hands
46
describe how soil contamination transmits disease in plants
infected plants can leave reproductive spores in the soil which can infect the next crop
47
what are the three key factors to reduce the spread of disease in humans?
1. hand washing
2. improvements in living and working conditions- reduce overcrowding and ensure good nutrition
3. disposal of bodily and household waste effectively
48
what are the factors affecting transmission in animals?
-overcrowded living and working conditions
-poor nutrition
-compromised immune system
-climate change can introduce new diseases
-culture and infrastructure, traditional medicine practices can increase transmission
-poor disposal of waste
-socio economic factors
49
what can transmission of disease between animals and humans be reduced by?
-reducing close contact with animals
-washing hands thoroughly
50
why is it important to understand how pathogens are transmitted?
to work out ways to reduce and prevent transmission- strategic planning
51
what are they key factors to reduce the spread of disease in plants?
-leave room between plants
-clear fields as thoroughly as possible after harvesting
-rotate crops, spores and bacteria dip if they do not have access to the host plant
-strict hygiene practices
-control insect vectors
52
what are the factors affecting transmission in plants?
-planting varieties of crops that are susceptible
-overcrowding increases touching
-poor mineral nutrition
-damp and warm conditions
-climate changing= increased rainfall and windspeed
53
what are the primary defenses of plants?
-cellulose cell wall
-waxy cuticle
-bark
54
what happens when plants get infected? why?
plants do not heal wounds/diseased tissue, they seal it off and sacrifice it because they continually grow at the meristems so they can replace damaged parts
55
what do apical meristems cause?
primary growth (lengthening of plant)
56
where do apical meristems occur?
occurs at tips of shoots and roots
57
what do apical meristems produce?
produces new leaves and flowers
58
what do lateral meristems cause?
causes secondary growth (widening of plant)
59
where do lateral meristems occur?
occurs at the cambium
60
what do lateral meristems produce?
produces bark on trees
61
how do plants recognise an attack against their immune system?
1. receptors respond to molecules from pathogens or chemicals released that attack the cell wall
2. the cells will then release signaling molecules
3. these switch on genes in the nucleus
4. this triggers cellular responses such as producing chemicals, sending alarm signals and strengthening the cell wall
62
how do plant cells respond to an immune system attack?
Increased synthesis of callose and lignin:
-callose is deposited between the cell wall and cell membrane in cells next to the infected cells making it harder for the invading pathogen to spread
-lignin makes the mechanical barrier even stronger
-callose blocks sieve plates of the phloem sealing off infection and preventing spread
-callose is deposited in plasmodesmata between infected cells and their healthy neighbours
63
what are some chemical defenses in plants used for?
some are so powerful that we extract and use them or synthesise them to help us to control insect pests- some have strong flavours and are used as herbs and spices
64
define callose
a polysaccharide containing β 1-3 linkages and β 1-6 linkages between the glucose monomers that is important in plant response to infection
65
when is lignin added to plants and what is its purpose?
after the initial infection, making the mechanical barrier to invasion even thicker and stronger
66
what is the purpose of callose in plasmodesmata?
sealing them off from the healthy cells and helping to prevent the pathogen spreading
67
initially callose is synthesised and deposited between the cell wall and cell membrane in cells next to infected cells, what is the purpose of this?
they act as barriers, preventing the pathogens entering the plant cells around the site of infection
68
what is the purpose of callose in phloem vessles?
sealing off the infected part and preventing the spread of pathogens
69
what are the different plant chemical defenses?
-insect repellents
-insecticides
-antibacterial compounds
-antifungal compounds
-anti oomycetes
-general toxins
70
what are some examples of insect repellents?
-pine resin
-citronella
71
what are some examples of insecticides?
-pyrethrin's
-caffeine
72
what effect does pyrethrin have?
act as insect neurotoxins
73
what effect does caffeine have in plants?
toxic to insects and fungi
74
what are some examples of bacterial compounds?
-phenols
-antibacterial gossypol
-defensins
-lysosomes
75
what effect do phenols have?
antiseptics made in many different plants
76
what effect does antibacterial gossypol have?
produced by cotton
77
what effect do defensins have?
plant proteins that disrupt bacterial and fungal cell membranes
78
what effect do lysosomes have?
organelles containing enzymes that break down bacterial cell walls
79
what are some examples of antifungal compounds?
-phenols
-antifungal gossypol
-caffeine
-saponins
-chitanases
80
what affect do saponins have?
chemicals in many plant cell membranes that interfere with fungal cell membranes
81
what effect does chitinases have?
enzymes that break down the chitin in fungal cell walls
82
what is an example of an anti-oomycete?
glucanases
83
what effect does glucanase have?
enzymes made by some plants that break down glucans; polymers found in the cell walls
84
what is an example of general toxins in plants?
some plants make chemicals that can be broken down to form cyanide compounds when the plant cell is attacked
85
what effect does cyanide have?
cyanide is toxic to all living things
86
define pathogen
microorganisms that cause disease
87
define vector
a living or non-living factor that transmits a pathogen from one organism to another
88
define epidemic
when a communicable disease spreads rapidly to a lot of people at a local or national level
89
define pandemic
when a communicable disease spreads rapidly to a lot of people across a number of countries
90
define indirect transmission
when a pathogen travels from one individual to another without physical contact between organisms
91
define direct transmission
when a pathogen is transferred physically from one organism to the next
92
what is a communicable disease?
these are diseases that can be passed from one organism to another, of the same or different species
93
what are some different bacterial diseases?
-tuberculosis
-bacterial meningitis
-ring rot
94
what's the causal agent for TB?
bacteria
95
what are the symptoms of TB?
-appetite loss
-fatigue
-chest pain
-prolonged cough
-night sweats
96
how is TB transmitted?
-droplet infection (needs close contact over a long period of time)
-infected cattle (meat or milk)
97
what are the treatments for TB?
-vaccine
-antibiotics (for 6 months minimum)
98
what is the economic impact of TB?
-it is a public health emergency
-if you have AIDs you are more likely to develop TB
99
what are some medical factors that have led to the decline of TB and its severity?
-vaccinations
-antibiotics
-better medical care
100
what are some social factors that have led to the decline of TB and its severity?
-test cattle regularly for TB
-awareness of personal protective equipment due to COVID
-less overcrowding )better house and better working conditions)
101
why do you think people are against culling badgers, when thousands of cattle infected with TB are slaughtered each year?
-perception of wildlife is different to that of cattle (the killing of badgers would effect the ecosystem)
-people generally have a higher value for wildlife
-there's more human alternatives to slaughtering them
102
what might be the difficulties be in vaccinating a wild population?
-catching the animal causes it stress
-if you put it in food you can't control what badgers eat it of the dosage
-there's no way to know if all the badgers eat the food
103
what is the causal agent for meningitis?
bacteria
104
what are the symptoms of meningitis?
-infection in meninge of the brain
-red rash
-can't put head on their chest
105
how is meningitis transmitted?
droplet infection and direct contact
106
how is meningitis treated?
-vaccine
-antibiotics (if it's caught early enough)
107
what is the economic impact of meningitis?
-25% of people who recover will have permanent damage (often amputation)
-these people will need healthcare for the rest of their lives
108
what is the causal agent for ring rot?
bacteria
109
what are the symptoms of ring rot?
-damages leaves tubers and fruit
110
how is ring rot transmitted?
-infected seeds
-direct contact between any part of the plant
-indirect contact
111
what is the treatment for ring rot?
no cure (if plant gets infected they cannot use the field for 2 years)
112
what is the economic impact of ring rot?
-farmers can't get money from infected fields
-huge quarantine concern as it's not found in the UK
113
what are the different viral diseases?
-HIV/AIDs
-tobacco mosaic virus
-influenza
114
what is the causal agent for HIV/AIDs?
virus
115
what are the symptoms of HIV?
kills T helper cells which destroys immune system so now contract opportunistic diseases e.g. TB
116
what does HIV stand for?
Human Immunodeficiency Virus
117
what is AIDs?
a collection of opportunistic diseases
118
what does AIDs stand for?
Acquired Immunodeficiency Syndrome
119
what are the treatments for HIV/AIDS?
can't cure- difficult to make a vaccine, however antiretroviral drugs slow the progress of the disease to give many years of a healthy life
120
how is HIV/AIDS transmitted?
in bodily fluids, most commonly through unprotected sex, shared needles, contaminated blood products and from mothers to their babies during pregnancy, birth or breast feeding
121
what is the economic impact of HIV/AIDS?
25 million people live with HIV/AIDS in Africa causing massive social and economic consequences as well as the personal impact to the person infected
122
what is unusual about the genetic material in the HIV virus and what name is given to a virus that contains this?
the genetic material is RNA instead of DNA so it's called a retrovirus
123
why does the retrovirus for HIV contain reverse transcriptase and what is reverse transcriptase?
enzyme that uses RNA as a template and produces DNA
124
what is the protease enzyme used for in the retrovirus HIV?
to break down capsid (protein core) so genetic material can be released
125
what are the green spheres on the outside of the retrovirus HIV and what type of molecule are they?
glycoproteins and also antigens
126
why do glycoproteins make it difficult for a vaccine to be developed against HIV?
they constantly mutate and change
127
what is the causal agent for influenza?
virus
128
what are the symptoms of influenza?
-fever
-aches
-chills
-tiredness
129
how does influenza cause symptoms?
infects ciliated epithelium cells and kills them
130
how is influenza transmitted?
droplet infection and fomites
131
what are the treatments for influenza?
no cure but vaccines are available
132
what are the economic impacts of influenza?
-can be fatal
-can progress to pneumonia
-virus that undergoes zoonosis so can spread between species
133
suggest why people under 65 were more affected by a strain of the flu that came from pigs than people over the age of 65
it is likely that the people who are older would have met this flu before so they had built up some immunity whereas younger people wouldn't have
134
what is the causal agent of tobacco mosaic virus?
virus
135
what are the symptoms of tobacco mosaic virus?
-infects tobacco plants
-damages leaves and fruits
-prevents growth
136
how is tobacco mosaic virus transmitted?
direct and indirect contact (everything)
137
what are the treatments for tobacco mosaic virus?
-no cure
-buy resistant crops
138
what are the economic impacts of tobacco mosaic virus?
farmers are impacted as they have total crop loss
139
what are the different protoctista diseases?
-malaria
-potato/tomato late blight
140
what is the causal agent of malaria?
malaria is the protoctist (a parasite of both humans and mosquitos) and female anopheles mosquitos are vectors
141
what are the symptoms of malaria?
initially flu like, includes high temperature, sweats, chills and vomiting- goes in cycles
142
how is malaria transmitted?
through mosquitos, unsterile needles, blood transfusions and across placenta
143
what are the treatments for malaria?
-no vaccines
-no cures
-everything is about prevention (insect repellents, nets, take prevention drugs)
144
what are the economic impacts of malaria?
one of the most severe public health problems worldwide, leading cause of death in women and children and half worlds population live in areas at high risk of malaria
145
how is malaria transmitted through mosquitos?
1.a female Anopheles mosquito feeds on blood for protein (needed to develop eggs)
2.if a person is infected with plasmodium, its gametes are taken up with the blood into the mosquito
3.gametes fuse and develop in mosquito gut to form the infectious stage, it then moves to the salivatory glands
4.the mosquito feeds again, injecting the plasmodium and anticoagulant into the person
5.plasmodium enters the liver where it multiplies asexually, they are released around 10 days later
6.plasmodium enters the RBC, asexually reproducing still, RBCs rupture releasing plasmodium as a toxin into the blood
7.some plasmodium remain in the RBCs to produce gametes
146
what is the causal agent for potato/tomato late blight?
protoctist
147
what are the symptoms of potato/tomato late blight?
produces hyphae which penetrate cells on plant and destroy leaves, tubers and fruit
148
how is potato/tomato late blight transmitted?
produces spores which are transmitted in the wind
149
how is potato/tomato late blight treated?
-no cure
-only have prevention (resistant strains or chemicals)
150
what are the economic impacts of potato/tomato late blight?
causes millions of pounds of damage every year
151
what are the different fungal diseases?
-black sigatoka
-ring worm
-athletes foot
152
what is the causal agent of black sigatoka?
fungi
153
what are the symptoms of black sigatoka?
hyphae which penetrate leaves and turn them black
154
how is black sigatoka transmitted?
spores that travel through wind or water
155
how is black sigatoka treated?
-no cure
-only have prevention (resistant strains, use fungicides to control spread)
156
what are the economic impacts of black sigatoka?
get 50% reduction in yield
157
suggest the effect of black sigatoka on the population of East Africa
-increased malnutrition leads to increased disease and death
-shortage of other foods as people buy other foods instead of bananas, leads to increased food prices
158
what problems are likely to affect the control of the black sigatoka disease on large plantations of Cavendish bananas?
these bananas are clones of each other so if one gets infected then they all get wiped out
159
what is the causal agent for ring worm?
fungi
160
what are the symptoms of ring worm?
circular patterns that are dry and itchy on skin
161
how is ring worm transmitted?
direct skin to skin or through fomites
162
what are the treatments of ring worm?
antifungal creams
163
what are the economic impacts of ring worm?
none
164
what is the causal agent for athletes foot?
fungus (feeds on skin between toes)
165
what are the symptoms of athletes foot?
cracking, scaling, itchy and sore skin
166
how is athletes foot transmitted?
fomites
167
what is the treatment for athletes foot?
antifungal creams and sprays
168
what are the economic impacts of athletes foot?
none
169
what are monoclonal antibodies?
Lab-made antibodies that mimic natural antibodies, used as targeted therapy for specific kinds of cancer
170
how do monoclonal antibodies work?
-Recognizing and finding specific proteins on cancer cells or target proteins on immune system cells
-Binding to specific antigens on target cells, similar to how natural antibodies work
-Blocking the virus's ability to enter cells
171
how do monoclonal antibodies detect plant diseases?
either by identifying the presence of the pathogen in the plant (by testing for the presence of pathogen DNA) or the molecules (proteins) produced by either the pathogen or the plant during infection
172
what is the order that happens when a pathogen tries to enter the body?
-primary defences
-primary responses (non-specific)
-secondary responses (specific)
173
describe primary defences
-barriers to prevent pathogen entry
-these are non specific
-we also have expulsive reflexes
174
what are some examples of expulsive reflexes?
vomiting, sneezing, coughing, diarrhoea
175
what are some examples of primary defences?
-eyes are cleansed by tears by chemicals called lysosomes
-nasal cavity has hairs and mucus to trap organisms
-skin is an impervious barrier
-vagina has acidic secretion which inhibits growth of pathogens
-stomach has acidic juices that kill many microorganisms
-trachea and bronchi have a mucous layer that traps microorganisms
-mouth cavity has saliva which contains digestive enzymes
176
what are primary responses?
non specific responses that respond once a pathogen has gotten past the primary defences
177
what are the different primary responses?
-blood clotting
-fever
-inflammatory response
-phagocytosis
178
describe blood clotting
If there is damage to the skin and capillaries: platelets come into contact with collagen in the skin or the wall of the damaged blood vessel and adhere to it
179
what two substances do platelets secrete during blood clotting?
-thromboplastin
-serotonin
180
what does thromboplastin do?
it is an enzyme that catalyses the cascade of reactions (fibrinogen --> fibrin --> mesh)
181
what does serotonin do?
causes blood vessels to contract reducing blood supply to the area
182
describe the process of blood clotting
1. injured tissues and platelets causes the conversion of the blood protein prothrombin to thrombin
2. thrombin splits fibrinogen to form fibrin
3. fibrin fibres form a mesh over wound, trapping red blood cells and platelets
4. bleeding stops
5. clot hardens and becomes smaller
6. new cells grow the repair wound site
7. enzyme plasmin is released to dissolve clot
183
what does an inflammatory response cause?
pain, heat, redness and swelling of tissues
184
what cells are activated in an inflammatory response?
mast cells
185
what are mast cells and why are they activated in an inflammatory response?
they are a type of white blood cell that is activated in response to pathogens
186
where are mast cells found?
in mucosal surfaces of the gut and lung, in the skin, and around the blood vessels
187
what happens once mast cells are activated in an inflammatory response?
they release the chemicals histamine and cytokines
188
what do histamines do in an inflammatory response?
-blood vessels dilate and become more permeable causing localised heat and redness
-blood vessel walls become more permeable/leaky, so more blood plasma is forced out (tissue fluid) which causes swelling (odema) and pain
189
what do cytokines do in an inflammatory response?
attract white blood cells (phagocytes) to the site which dispose of pathogens by phagocytosis
190
what is the normal body temperature?
37 degrees celcius
191
what is the body temperature maintained by?
hypothalamus in brian
192
how does a fever work?
-pathogens reproduce optimally at or below the average body temperature
-so the pathogen triggers cytokines to signal to your hypothalamus to increase the temperature
-this inhibits pathogen reproduction
193
describe the process of phagocytosis in neutrophils
1. The phagocyte is attracted to the pathogen by the chemicals it is producing
2. The phagocyte can recognise the pathogen as being no self
3. The phagocyte is able to engulf the pathogen and forms a phagosome
4. A lysosome contains digestive enzymes
5. A lysosome will move towards a phagosome and fuse with it forming a phagolysosome
6. The digestive enzymes will then hydrolyse the pathogen inside the phagolysosome
7. If this was a neutrophil this whole process would take 10 minutes and waste minerals are pushed out of the body
194
describe the process of phagocytosis in macrophages
1. The phagocyte is attracted to the pathogen by the chemicals it is producing
2. The phagocyte can recognise the pathogen as being no self
3. The phagocyte is able to engulf the pathogen and forms a phagosome
4. A lysosome contains digestive enzymes
5. A lysosome will move towards a phagosome and fuse with it forming a phagolysosome
6. The digestive enzymes will then hydrolyse the pathogen inside the phagolysosome
7. If this is a macrophage another process occurs after hydrolysis of the pathogen
8. The antigens from the surface of the pathogen are combined with glycoproteins from the cytoplasm of the macrophage
9. When the antigens are combined with glycoproteins they are known as MHC (Major Histocompatibility Complex)
10. The MHC complex moves the antigens towards the cell surface membrane of the macrophage
11. When the antigens are on the cell surface membrane the macrophage becomes an Antigen presenting cell (APC)
12. The APC can then stimulate other cells in the immune system to respond
195
what do cytokines do?
-cell signalling molecules
-inform other phagocytes when there is a pathogen present
-can increase body temperature
-can stimulate the specific immune response
196
what do opsonins do?
-bind to pathogens and 'tag' them so they can be easily recognised by phagocytes
-phagocytes have receptors for common opsonins
197
what are the two ways in which bacteria can be classified?
shape and type of cell wall (gram positive or gram negative)
198
what is the purpose of callose in the plasmodesmata?
blocks passage of pathogen from infected cells to healthy cells
199
define antigen
an identifying chemical on the surface of a molecule that triggers the immune response (glycoprotein)
200
define antibodies
type of glycoprotein made by the B cells of your immune system in response to an antigen
201
define immune response
biological response that protects you by recognising and responding to antigens and then destroying them
202
define immune
protection against infectious diseases
203
what are white blood cells called?
leucocyte
204
what are the different types of white blood cells?
-lymphocyte
-phagocyte
205
what does a phagocyte do?
specialised white blood cells that build up at the site of infection- engulf and destroy pathogens
206
what are the types of lymphocytes?
-B lymphocyte
-T lymphocyte
207
what are the types of B lymphocyte?
-plasma cell
-B memory
-B effector
208
what does a plasma cell do?
a type of B lymphocyte that produces antibodies
209
what are the types of T lymphocyte?
-T helper
-T killer
-T memory
-T regulatory cells
210
what are the types of phagocytes?
-neutrophil
-macrophage
211
describe neutrophils
-smaller
-60% of all white blood cells
-short lived
-multi lobed nucleus
-attracted by histamines
-used for basic phagocytosis
212
describe macrophages
-larger
-lymph nodes, lung, liver
-involved in antigen presentation
-more complex and slower process
-round nucleus
-cut up pathogen to produce antigen presenting cell
213
what does antigen presentation trigger?
triggers specific immune response along with T helper cells
214
what are lymphocytes?
-specialised white blood cells that are involved in the specific immune response
-they are smaller than phagocytes
-have a nuclei that fills most of the cell
215
where do lymphocytes originate from?
-bone marrow
-they are specialised cells derived from haematopoietic stem cells
216
where do B cells originate from?
they mature in the bone marrow
217
where do T cells originate from?
they mature in the Thymus gland (in front of the heart)
218
what is clonal selection?
the theory that exposure to a specific antigen selectively stimulated the proliferation of the lymphocytes with the appropriate antibody to form numerous clones of these specific antibody forming cells (clonal expansion)
219
when is clonal selection used?
this is used when the T helper cell is binding the specific antigen
220
when is clonal expansion used?
this is used when ever the cells are replicating by mitosis
221
what is clonal expansion?
the mass proliferation of antibody producing cells by clonal selection
222
what is cell mediated immunity?
-immune response mediated by activating T helper cells
-these then lead to the other B and T cells being activated and propagated
-the cytokines produced are given the name interleukins
223
what is the role of T helper cells?
trigger specific immune response by producing interleukins
224
describe the process of cell mediated immunity
1. an APC has an MHC presented on the surface
2. T helper cells bind to the MHC using CD4 receptors as they are complimentary shapes to the antigen
3. the T helper cell releases interleukins (cell signalling molecule) which stimulates the activation of other cells:
-activates B cells
-activates T cells
-stimulates and attracts more microphages
225
what B cells are activated by the interleukins released by the T helper cells?
-B memory
-B effector
-Plasma
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what is it called when B cells are activated?
clonal expansion (mitosis)
227
what do B memory cells do?
Immunological memory: second infection means B memory will replicate and form B cells specific to the antigen
228
what do B effector cells do?
divide to form more B effector and plasma cells
229
what do plasma cells do?
make antibodies and release them into the blood, these antibodies are short lived
230
what is it called when plasma cells release antibodies into the blood?
humoral immunity
231
what T cells are activated by the interleukins released by the T helper cells?
-T memory
-T killer
-T regulator
232
what do T memory cells do?
Immunological memory: second infection means T memory will replicate and form T cells specific to the antigen
233
what do T killer cells do?
kills infected cells by producing perforin which makes holes in cell membrane and then injects them with hydrogen peroxide
234
what do T regulator cells do?
-regulate immune response by suppression, once the pathogen is gone they stop the immune response
-ensure that you recognise your self cells
-prevent autoimmune diseases
235
describe the humoral immune response
-the B cells are associated with the humoral response
-B cells are activated by T cells
-this causes antibodies to be produced and circulate
-those antibodies will bind to any of the foreign antigen they find, this could be on a pathogen or on a body cell that has become an antigen presenting cell
236
what are the main cells involved in humoral immunity?
B cells
237
where do cells develop in humoral immunity?
bone marrow
238
are there antibodies in humoral immunity?
yes
239
how are pathogens identified in humoral immunity?
antibodies are specific to the antigen
240
how are pathogens killed in humoral immunity?
antibody disables them or they can be engulfed
241
how do cells divide once they are stimulated in humoral immunity?
clonal expansion
242
what are the main cells involved in cell mediated immunity?
T helper
243
where do cells develop in cell mediated immunity?
thymus gland
244
are there antibodies in cell mediated immunity?
no
245
how are pathogens identified in cell mediated immunity?
antigens are presented on macrophage APC
246
how are pathogens killed in cell mediated immunity?
activates T killer cells
247
how do cells divide once they are stimulated in cell mediated immunity?
by mitosis
248
describe both the primary and secondary response to a disease
Primary response: Takes time to find pathogen and for lymphocytes to replicate so there's a slower production of antibodies= symptoms are caused. If survive symptoms, then B and T memory cells remain for immunological response
Secondary response: B memory cells rapidly divide to form plasma cell clones so correct antibody is produced quickly= no symptoms
249
where are antibodies produced?
they are produced by plasma cells
250
describe the shape of antibodies
Y shaped glycoproteins called immunoglobulins that have a complimentary shape to the antigen
251
what are autoimmune diseases?
condition that results from an autoimmune response
252
when does an autoimmune response occur?
an autoimmune response occurs when the immune system acts against its own cells and destroys healthy tissues in the body
253
what are some examples of autoimmune diseases?
lupus and arthritis
254
how do autoimmune diseases occur?
-tend to be genetic
-could be an abnormal response to a pathogen or normal body MOs
-could be T regulator cells not working properly
255
how can autoimmune diseases be treated?
immunosuppressant drugs can be used to treat them, but they also suppress the normal immune system
256
what is rheumatoid arthritis?
-chronic progressive disorder
-causing inflammation in the joints and resulting in painful deformity and immobility, especially in the fingers, wrists, feet and ankles
257
what is the cure for rheumatoid arthritis?
-no cure
-can only be treated with anti-inflammatory drugs, steroids, pain relief or immunosuppressants
258
what is lupus?
-poorly understood condition that affects many parts of the body and causes symptoms ranging from mild to life threatening
259
what is the cure for lupus?
-no cure
-can only be treated with steroids, anti inflammatory or immune suppressants
260
label an antibody
*SEE PAPER FLASHCARD*
261
why do antibodies have variable regions?
-gives antigen specificity
-have different amino acid sequences therefore different shapes
262
what is the difference between the light chain and the heavy chain in antibodies?
light chain is shorter polypeptides and the heavy chain is longer polypeptides
263
why do antibodies have disulfide bridges?
-hold chains together
-allow flexibility when binding to antigen
264
why do antibodies have constant regions?
-same in all antibodies
-so can bind to phagocytes
265
what are the different roles of antibodies?
1.phagocytosis
2.neutralization
3.agglutination
4.act as anti toxins
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how do antibodies carry out phagocytosis?
antibody of the antigen/antibody complex act as an opsonin, this makes it easier for the phagocytes to engulf it
267
how do antibodies carry out neutralization?
-blocks viral binding sites and coats bacteria
-this stops pathogens from invading cells
268
how do antibodies carry out agglutination?
causes complexes to stick together which prevents replication and spread of pathogen
269
how do antibodies act as anti toxins?
antibodies bind to the toxin and make it harmless
270
what are vaccines?
a way of artificially activating the immune system to produce antibodies
271
what can vaccines contain?
-whole live organisms
-killed or inactive bacteria or viruses
-attenuated versions
-harmless toxin
-antigen extracted from pathogen
-genetically engineered antigens
-genetically engineered RNA
272
what vaccination contains whole live microorganisms?
small pox vaccine
273
what vaccination contains killed or inactive bacteria or viruses?
cholera vaccine
274
what vaccination contains attenuated versions?
TB vaccine
275
what vaccination contains harmless toxins?
tetanus vaccine
276
what vaccination contains antigens extracted from pathogens?
flu vaccine
277
what vaccination contains genetically engineered antigens?
hepatitis B vaccine
278
what vaccination contains genetically engineered RNA?
COVID vaccine
279
why was eradicating small pox successful?
-stable pathogen so does not mutate
-live vaccine is more effective
-easy to produce as its cheap and high availability
-easy storage as its freeze dried and heat stable
-infected people easy to identify and cooperative
-easy to administer as no booster is needed
-no other reservoir of infection as its only a human host
280
describe artificial immunity
this is vaccines:
-injecting small artificially weakened pathogens into the body to allow an immune response
-if real disease is encountered there's an immunological memory so body is ready to fight off disease
281
describe natural immunity
-pathogen is encountered naturally which gives natural activation of the immune system involving T cells and B cells
OR
-antibodies are received through the mother's milk or placenta
282
what are the different types of eradication programmes?
-herd vaccination
-ring vaccination
283
how does a herd vaccination work?
-vaccinate most/all people
-stops infection spreading within population
284
how does a ring vaccination work?
-vaccinate all people around victim
-contains spread within ring
-stops transmission
-traces and isolates contacts; travel restrictions; make disease notifiable
285
what is acquired immunity?
immunity that develops during your lifetime
286
what are the types of acquired immunity?
active and passive immunity
287
what is active immunity?
when you produce your own antibodies
288
what is passive immunity?
when you do not produce your own antibodies
289
what are the types of active immunity?
-natural
-artificial
290
what are the types of passive immunity?
-natural
-artificial
291
what is active natural immunity?
antibodies developed in response to an infection
292
what is active artificial immunity?
antibodies developed in response to a vaccination
293
what is passive natural immunity?
antibodies received from mother, through breast milk
294
what is passive artificial immunity?
antibodies received from a medicine, from a gamma globulin injection or infusion
295
what are the advantages of active natural immunity?
-long term immunity
-memory cell production
296
what are the disadvantages of active natural immunity?
-get symptoms which can be fatal
-immune response takes time
297
what are the advantages of active artificial immunity?
-don't get symptoms
-long term immunity
298
what are the disadvantages of active artificial immunity?
-people can have reaction to vaccine
-needle phobia
-immune response takes time
-might need boosters
299
what are the advantages of passive natural immunity?
-immediate protection to everything your mother has immunity to
-lasts until baby can make its own antibodies
300
what are the disadvantages of passive natural immunity?
-short term
-no memory cell production
301
what are the advantages of passive artificial immunity?
-immediate protection
302
what are the disadvantages of passive artificial immunity?
-short term
-may have a reaction to vaccine
-no memory cell production
303
what's an example of artificial passive immunity?
receiving an injection of a serum containing antibodies e.g. against tetanus
304
what's an example of artificial active immunity?
receiving an injection of a weakened strain of a disease causing bacterium
305
what's an example of natural active immunity?
catching and recovering from a disease, such as measles
306
what's an example of natural passive immunity?
babies feeding on breast milk
307
why do we need new medicines?
-pathogens become resistant to existing drugs
-new diseases emerge
-new vaccines are needed
-existing vaccines can be improved
308
how are new medicines discovered?
-by accident
-traditional medicines
-observation of wildlife
-modern research
309
what is streptomycin and what is the source of the medicine?
an antibiotic in TB and sourced from bacteria
310
what is penicillin and what is the source of the medicine?
it's an antibacterial and sourced from Penicillium (fungus)
311
what is insulin and what is the source of the medicine?
it is an antidiabetic and sourced from pigs/cows
312
what is aspirin and what is the source of the medicine?
it is an analgesic/anti-inflammatory and sourced from bark of willow trees
313
what is an example of a medicine made from plants?
digoxin
314
where is digoxin from and what does it do?
digoxin from foxgloves slows heart rate, increases it's filling time and improves coronary circulation
315
describe the process of antibiotic resistance
1. bacteria mutate giving it a selective advantage
2. high number of bacteria, a few of them are resistant to antibiotics
3. antibiotics kill bacteria causing illness as well as good bacteria protecting the body from infection
4. the resistant bacteria now have preferred conditions (more resources) to grow and take over
316
what is synthetic biology?
involves redesigning organisms for useful purposes by engineering them to have new abilities
317
what are some examples of synthetic biology?
-develops populations of bacteria to produce drugs that are rare
-genetically modified mammals to produce therapeutic proteins in milk
-nanotechnology to deliver drugs to specific sites in cells
318
what is pharmacogenetics?
personalised medicine- science of interleaving knowledge of drug actions with personal genetic material because it is known that genotypes and drugs interact
319
what is bioinformatics?
the application of tools of computation and analysis to capture and interpret biological data
320
why are complex computer programmes used to design drugs?
-they can build up 3D models of molecules in the body
- to search through enormous libraries of chemicals
-to isolate any chemical with a potentially useful action against a specific group of features of a pathogen
321
why are the genomes of pathogens and genes linked to cancer analysed?
enables scientists to target their novel drugs to attack any vulnerabilities
322
why must biodiversity be maintained for durgs?
to make sure we do not destroy a plant, animal or microorganism which could give us the key to a life saving drug
323
what long term measures can be used to reduce antibiotic resistance occurring?
-minimising use of antibiotics
-good hygiene in hospitals
324
it is known that genotypes and drugs interact, what is the main example of this?
in approximately 30% of all breast cancers there is a mutation in the HER2 gene- by analysing breast tumors and treating those with mutations doctors can reduce deaths
325
how do antibiotics damage bacteria?
they interfere with the metabolism of bacteria without affecting the metabolism of human cells- selective toxicity
326
what are thought to be the two main causes of antibiotic resistance?
-mutation
-bacteria reproduce very rapidly
327
where is MRSA found?
on skin or in the nose
328
what does MRSA cause?
boils, abscesses and potentially fatal septicemia
329
when a person has MRSA when do problems start?
when it mutates to produce methicillin resistant strains which can cause problems in hospitals
330
where is antibiotic resistance a particular problem?
-hospitals
-care homes
331
why is antibiotic resistance a particular problem in hospitals and care homes?
antibiotics are often needed but they can't be used if the pathogen becomes resistant
332
what are the two high profile examples of antibiotic resistance?
-MRSA
-C.Difficile
333
where is C.Difficile found?
in the gut
334
what does C.Difficile cause?
damage of lining of intestines, leading to diarrhea, bleeding and even death
335
when a person has C.Difficile when do problems start?
when commonly used antibiotics kill off much of the 'helpful' gut bacteria, it survives, reproduces and takes hold rapidly
