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Biology > 4.1.1 - Communicable diseases > Flashcards

4.1.1 - Communicable diseases Flashcards

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1
Q

What is a pathogen ?

A
  • Microorganism that causes disease

- Lives in hosts

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2
Q

What are bacteriophages ?

A

Viruses that can attack bacteria

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3
Q

What are communicable diseases ?

A

Any disease transmitted from one person or animal; contagious

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4
Q

What are the four groups of microorganisms ?

A
  • Bacteria
  • Fungi
  • Viruses
  • Protoctista
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5
Q

Diseases caused by bacteria

A
  • Tuberculosis
  • Bacterial meningitis
  • Ring rot in plants
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6
Q

Diseases caused by viruses

A
  • HIV/ AIDS
  • Influenza
  • Tobacco mosaic virus
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7
Q

Diseases caused by fungi

A
  • Black sigatoka
  • Ringworm
  • Athletes foot
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8
Q

Diseases caused by protoctista

A
  • Malaria

- Potato/ tomato blight

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9
Q

What are prokaryotic pathogens ?

A

Bacteria

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10
Q

What are eukaryotic pathogens ?

A

Fungi

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11
Q

How do bacteria damage hosts ?

A
  • Multiply readily

- Damage cells by releasing waste products and/or toxins

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12
Q

How do fungi damage hosts ?

A
  • Hyphae release extracellular enzymes e.g. celluloses to digest plant tissue
  • Causes decay and leaf death —> no photosynthesis
  • May produce toxins
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13
Q

How do viruses damage hosts ?

A
  • Invade living cells where genetic material in virus takes over the biochemistry of the host cells
  • Makes more copies
  • Host cell bursts, releasing viruses
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14
Q

How do protoctista damage hosts ?

A

Enter host cells and feed on contents before breaking over cells

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15
Q

What are the three shapes of bacteria ?

A
  • Cocci
  • Spirillum
  • Bacilli
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16
Q

What is the function and shape of cocci ?

A
  • They are spherical prokaryotes that occur singularly, in pairs, in chains and in clusters
  • They have the lowest SA:V ratio enabling them to survive in dryer environments
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17
Q

What is the shape and function of spirillum ?

A
  • They are spiral prokaryotes, which range from comma like shapes, to coils to spirochetes.
  • They move with a corkscrew motion, and meet less resistance from surrounding water
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18
Q

What is the shape and function of bacilli ?

A
  • Bacilli are rod shaped prokaryotes that are normally solitary
  • They have the greatest SA:V ratio enabling them to take up nutrients from dilute solutions more efficiently
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19
Q

What is the bacterial cell wall like in gram positive bacteria ?

A
  • Thick peptidoglycan cell wall traps crystal violet in the cytoplasm
  • Alcohol rinse does not remove the crystal violet, which masks the safranin dye
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20
Q

What is the bacterial cell wall like in gram negative bacteria ?

A
  • Thin peptidoglycan cell wall between the plasma and outer membrane.
  • Crystal violet is easily rinsed away, revealing the red safranin dye
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21
Q

How do bacteria cause disease ?

A
  • They produce toxin and cause symptoms by cell damage.

- Damage cell membranes, enzymes or genetic material

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22
Q

What are exotoxins ?

A
  • Exotoxins are produced inside mostly gram-positive bacteria as part of their growth and metabolism.
  • They are secreted or released following lysis
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23
Q

What are endotoxins ?

A

Endotoxins are part of the outer portion of the cell wall of gram-negative bacteria. They are liberated when the bacteria die

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24
Q

Are viruses eukaryotic or prokaryotic ?

A
  • Neither

- They are dead

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25
Q

What are bacteriophages ?

A

They are viruses that can infect and set in motion a genetic takeover of bacteria

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26
Q

Are viruses cells ?

A
  • They are not cells

- They are very small infectious particles consisting of a nucleic acid enclosed in a protein coat

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27
Q

What type of genetic material can they have ?

A

They can be DNA viruses or RNA viruses, depending on whether their genome is single or double stranded

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28
Q

Describe the lycogenic cycle

A
  • The phage infects the cell
  • The phage DNA becomes incorporated into the hosts genome
  • The cell divides, and prophage DNA is passed on to the daughter cells
  • Under stressful conditions, the prophage DNA is excised from the bacterial chromosomes and enters the lytic cycle
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29
Q

Describe the lytic cycle

A
  • Phage DNA replicates and phage proteins are made
  • New phage particles are assembled
  • The cell lyses releasing the newly made phages
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30
Q

What can viruses be described as ?

A

Obligate intracellular parasites

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31
Q

What does Obligate intracellular mean ?

A

They can replicate only within a host cell

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32
Q

What are fungi ?

A
  • They are heterotrophs.

- Unable to make their own food like plants or to ingest food like animals

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33
Q

How do fungi absorb their nutrients ?

A

They secrete hydrolytic enzymes that breakdown molecules in their surroundings and absorb the products of that digestion

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34
Q

What are the common fungal bodies ?

A
  • Yeasts

- Multicellular filaments

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35
Q

What is mycois ?

A

The general term for an infection caused by a fungal parasite

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36
Q

What are protists ?

A
  • They are a group of eukaryotic organisms

- They were all once filled under the kingdom protista but are now recognised as polyphyletic

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37
Q

What are protist diseases in humans caused by ?

A

They are caused by animal-like protists, protozoa, which make us sick when they become human parasites

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38
Q

What causes malaria ?

A
  • Plasmodium protozoa

- They spread through their hosts via tiny infectious cells called sporozoites

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39
Q

How may protoctista enter the body ?

A

Through vectors such as mosquitoes

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40
Q

How may protoctista enter through the body directly ?

A

Polluted water

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41
Q

How can plant diseases affect us ?

A
  • They may starve us, economies may struggle and jobs would be lost
  • Plant diseases threaten ecosystems too - entire species can be threatened
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42
Q

What are some pathogens that cause plant diseases ?

A
  • Ring rot
  • Tobacco mosaic virus
  • Potato/tomato blight
  • Black sigatoka
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43
Q

What is ring rot ?

A

A bacterial disease of potatoes, tomatoes and aubergines caused by the gram positive bacteria Clavibacter michiganensis

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44
Q

What effect does ring rot have on plants ?

A
  • It damages leaves, tubers and fruit
  • It can destry up to 80% of the crop and there is no cure
  • Once bacterial ring rot infects a field it cannot be used to grow potatoes again for at least two years
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45
Q

What is Tobacco Mosaic Virus ?

A

TMV is a virus that infects tobacco plants and around 150 other species including tomatoes, peppers, cucumbers, petunias and delphiniums

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46
Q

What effect does TMV have on plants ?

A

It damages leaves, flowers and fruit, stunting growth and reducing yields, and can lead to an almost total crop loss.

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47
Q

Treatment for TMV

A

Resistant crop strains are available but there is no cure

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48
Q

What is potato/tomato blight ?

A

It is caused by the fungus like protoctist oomecyte Phytophthora infestans

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49
Q

What effect does potato/tomato blight have on plants ?

A

The hyphae penetrate host cells, destroying leaves, tubers and fruit, causing millions of pound of crop damage a year

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50
Q

Treatment for potato/tomato blight

A

There is no cure but resistant strains, careful management and chemical treatments can reduce infection risk

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51
Q

What is black sigatoka ?

A

It is a banana disease caused by the fungus Mycospaerella fijiensis, which attacks and destroys the leaves

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52
Q

What effect does black sigatoka have on plants ?

A
  • The hyphae penetrate and digest the cells, turning the leaves black
  • If plants are infected it can cause a 50% reduction in yield.
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53
Q

Treatment for black sigatoka

A

Resistant strains are being developed - good husbandry and fungicide treatment can control the spread of the disease but there is no cure

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54
Q

How can animal diseases affect us ?

A

They have a profound effect on human health and wellbeing and on national economies

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55
Q

What is Tuberculosis ?

A

A bacterial disease of humans, cows, pigs, badgers and deer commonly caused by mycobacterium tuberculosis and M.bovis

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56
Q

What does Tuberculosis do ?

A

It damages and destroys lung tissue and suppresses the immune system, so the body is less able to fight off other diseases

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57
Q

What is the relationship between TB and HIV/AIDS ?

A

People affected by HIV/AIDS are much more likely to develop TB infections

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58
Q

Treatment for TB

A

In people TB is both curable by antibiotics and preventable by improving living standards and vaccinations

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59
Q

What is bacterial meningitis ?

A

It is a bacterial infection of the meninges of the brain which can spread into the rest of the body causing septicaemia and rapid death

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60
Q

What are meninges ?

A

The protective membranes on the surface of the brain

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61
Q

What is septicaemia ?

A

Blood poisoning

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62
Q

Who does bacterial meningitis affect ?

A

It mainly affects very young children and teenagers (15-19)

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63
Q

What are the symptoms of bacterial meningitis ?

A

A blotchy red/purple rash that does not disappear when a glass is pressed against it is a symptom of septicaemia

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64
Q

Treatment for bacterial meningitis

A
  • Antibiotics will cure the disease if delivered early

- Vaccines can protect against some forms of bacterial meningitis

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65
Q

What is HIV/AIDS ?

A

It is caused by the human immunodeficiency virus which targets T helper cells in the immune system of the body

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66
Q

What does HIV/AIDS do to the immune system ?

A

It gradually destroys the immune system so affected people are open to other infections as well as some types of cancer

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67
Q

What is HIV ?

A

It is a retrovirus with RNA as its genetic material

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68
Q

What enzyme does HIV contain ?

A

Reverse transcriptase

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69
Q

What is the role of reverse transcriptase ?

A

Transcribes the RNA to a single strand of DNA to produce a single strand of DNA in the host cell

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70
Q

How is the HIV passed along ?

A
  • The virus is passed from one person to another in bodily fluids.
  • Most commonly through unprotected sex, shared needles etc
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71
Q

Treatment for HIV

A

There is yet no vaccine and no cure, but anti-retroviral drugs slow the progress of the disease to give many years of healthy life

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72
Q

Who is at a particularly high risk of HIV/AIDS ?

A

Women and girls

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73
Q

What increases the infection rate of HIV/AIDS ?

A

Traditional practices such as FGM

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74
Q

How does FGM increase the infection rate of HIV/AIDS ?

A
  • If the same equipment is used multiple times then this can spread the infection.
  • Women who have undergone FGM are more vulnerable to infection during intercourse
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75
Q

What is influenza ?

A

A viral infection of the ciliated epithelial cells in the gas exchange system

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76
Q

What does influenza do ?

A

It kills the ciliated epithelial cells, leaving the airways open to secondary infection

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77
Q

Who does influenza affect ?

A
  • Young children, old people and people with chronic illnesses
  • Humans, pigs and birds including chickens
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78
Q

What causes deaths from influenza ?

A

Severe secondary bacterial infections such as pneumonia

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79
Q

What are the three strains of influenza ?

A
  • A
  • B
  • C
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80
Q

Which influenza viruses are the most virulent ?

A
  • A viruses

- They are classified further by the proteins on their surfaces

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81
Q

What happens when viruses mutate ?

A

When there is a major change in the surface antigens, this heralds a flu epidemic as there are no antibodies available

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82
Q

Treatment for influenza

A

There is no cure

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83
Q

What is zoonosis ?

A

A disease which people can catch from animals

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84
Q

How can humans be affected by zoonoses ?

A

The virus mutates and becomes capable of infecting people

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85
Q

How dangerous can zoonoses be ?

A

Very serious as few people have natural immunity to them

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86
Q

What is malaria ?

A

Caused by the protoctista plasmodium and spread by the bites of infected mosquitoes

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87
Q

What does malaria invade ?

A

It invades the red blood cells, liver and even the brain

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88
Q

Describe the plasmodium parasite

A
  • The plasmodium parasite has a complex life cycle with two hosts, mosquitoes and people
  • They reproduce inside the female mosquito
  • The female needs to take two blood meals to provide her with protein before she lays her eggs - and this is when the plasmodium is passed on to people
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89
Q

Treatment for malaria

A

There is no vaccine against malaria and limited cures, but preventative measures can be effective

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90
Q

How can mosquitoes be destroyed ?

A

They can be destroyed by insecticides and by removing the standing water where they breed

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91
Q

How can mosquito bites be prevented ?

A

Simple measures such as a mosquito nets, window and door screens and long sleeved clothing can prevent them biting people and spreading the disease

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92
Q

What is ringworm ?

A
  • A fungal disease affecting mammals including cattle, dogs, cats and humans.
  • Different fungi affect different species
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93
Q

What does ringworm cause ?

A
  • It causes grey-white, crusty, infectious, circular areas of skin
  • Looks unsightly and may be itchy
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94
Q

Treatment for ringworm

A

Antifungal creams

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95
Q

What is athletes foot ?

A

A human fungal disease caused by Tinia pedia, a form of human ring worm that grows on and digests the warm, moist skin between the toes

96
Q

What does athletes foot cause ?

A

It causes cracking and scaling, which is itchy and may become sore.

97
Q

Treatment for athletes foot

A

Antifungal creams are an effective cure

98
Q

What are the two main types of transmission ?

A

Direct and indirect transmission

99
Q

What is direct transmission ?

A

Here the pathogen is transferred directly from one individual to another

100
Q

What are the forms of direct transmission ?

A
  • Direct contact
  • Inoculation
  • Ingestion
101
Q

What is direct contact ?

A
  • Kissing or any contact with the body fluids of another person
  • Direct skin to skin contact
  • Microorganisms from faeces transmitted on the hands
102
Q

What is inoculation ?

A
  • Through a break in the skin
  • From an animal bite
  • Through a puncture wound or through sharing needles
103
Q

What is ingestion ?

A

Taking in contaminated food or drink, or transferring pathogens to the mouth from the hands

104
Q

What is indirect transmission ?

A

This is where the pathogen travels from one individual to another indirectly

105
Q

What are the forms of indirect transmission ?

A
  • Fomites
  • Vectors
  • Inhalation
106
Q

What are fomites ?

A

Inanimate objects such as bedding, socks, or cosmetics that can transfer pathogens

107
Q

What are vectors ?

A
  • A vector transmits communicable pathogens from one host to another
  • They are often but not always animals
  • Water can also act as a vector of disease
108
Q

What is inhalation ?

A
  • Minute droplets of saliva and mucus are expelled from your mouth as you talk, cough or sneeze.
  • If these droplets contain pathogens, when healthy individuals breathe the droplets in they may become infected
109
Q

How can you reduce infection rates between animals and humans ?

A

Minimise close contact with animals and washing hands thoroughly following any such contact

110
Q

What are the factors affecting the transmission of communicable diseases in animals ?

A
  • Overcrowded living and working conditions
  • Poor nutrition
  • A compromised immune system
  • Poor disposal of waste provides breeding sites for vectors
  • Climate change can introduce new vectors and diseases
  • Culture and infrastructure can increase transmission
  • Socioeconomic factors, e.g. a lack of trained health workers and insufficient public warning when there is an outbreak of disease
111
Q

How do plants spread diseases ?

A
  • Diseases spread rapidly through plant communities, plant pollen and seed
  • They also have a less well developed immune system than humans
112
Q

Describe direct transmission in plants

A
  • This involves direct contact of a healthy plant with any part of a diseased plant.
  • Examples are TMV, tomato and potato blight and black sigatoka
113
Q

What are the forms of indirect transmission in plants ?

A
  • Soil contamination

- Vectors

114
Q

Describe soil contamination in plants

A
  • Infected plants often leave pathogens or reproductive spores from protoctista or fungi in the soil, these can infect the next crop
  • Some pathogens can survive the composting process so the infection cycle can be completed when contaminated compost is used
115
Q

How is wind a vector ?

A

Bacteria, viruses and fungal or oomecyte spores may be carried by the wind

116
Q

How is water a vector ?

A
  • Spores swim in the surface film of water on leaves

- Raindrop splashes carry pathogens and spores

117
Q

How are animals vectors ?

A
  • Insects and birds carry pathogens and spores from one plant to another as they feed
  • Insects such as aphids inoculate pathogens directly into plant tissues
118
Q

How are humans vectors ?

A

Pathogens and spores are transmitted by hands, clothing, fomites, farming practices and by transporting plants and crops around the world

119
Q

What are the factors affecting the transmission of communicable diseases in plants ?

A
  • Planting varieties of crops that are susceptible to disease
  • Over crowding increases the likelihood of contact
  • Poor mineral nutrition reduces resistance of plants
  • Damp, warm conditions increase the survival and spread of pathogens and spores
  • Climate change – increased rainfall and wind promote the spread of diseases; changing conditions allow animal vectors to spread to new areas; drier conditions may reduce the spread of disease
120
Q

Why are plants targets for microorganisms ?

A
  • They manufacture sugars in photosynthesis and convert this into wide variety of compounds such as proteins and oils
  • These proteins and oils are a rich source of nutrients for microorganisms
121
Q

What is the role of passive defences ?

A

Prevent entry

122
Q

What are active defences ?

A

They are induced when a pathogen is detected

123
Q

Name the passive defences a plant has

A
  • Cell wall
  • Waxy cuticle
  • Bark
  • Stomatal closure
  • Chemicals with anti pathogenic properties
124
Q

Name the active defences a plant has

A
  • Production of callose
  • Strengthen cell walls with additional cellulose and lignin
  • Tylose formation
  • Wide range of chemicals produced
  • Necrosis
125
Q

Callose as an active defence

A

Blocks plasmodesmata and sieve plates in the phloem, sealing off the infected part

126
Q

Tylose as an active defence

A
  • Balloon like swelling that fills the xylem vessel.

- When tylose is fully formed it blocks the vessel

127
Q

Necrosis as an active defence

A
  • Deliberate cell suicide

- By killing cells surrounding the infections, pathogens access to water and nutrients is limited

128
Q

Chemicals produced as a part of plants active defences

A
  • Terpenoids
  • Phenols
  • Alkaloids
  • Defensins
  • Hydrolysis enzymes
129
Q

What are terpenoids ?

A

Essential oils with anti-fungal and antibacterial properties

130
Q

What are phenols ?

A
  • Have antibiotic and anti-fungal properties

- Tannins bind to salivary proteins and digestive enzymes, deactivating them

131
Q

What are alkaloids ?

A
  • Nitrogen-containing compounds that have a bitter taste to inhibit herbivores feeding
  • Inhibit protein synthesis
  • Also inhibit or activate enzyme action
132
Q

What are defensins ?

A
  • Small cysteine-rich proteins with anti-microbial properties
  • Act upon molecules in plasma membrane of pathogens
133
Q

What are hydrolytic enzymes ?

A
  • Found in spaces between cells

- Include chitinases, glucanases and lysozymes

134
Q

Describe the process of a plant recognising and dealing with an attack

A
  • Receptors in the cells respond to molecules from the pathogens, or to chemicals produced when the plant cell wall is attacked
  • This stimulates the release of signalling molecules that appear to switch on genes in the nucleus
  • This in turn triggers cellular responses, which include producing defensive chemicals, sending alarm signals to unaffected cells to trigger their defences, and physically strengthening the cell walls
135
Q

What do plants produce when attacked by a pathogen ?

A

Callose

136
Q

What is callose ?

A

It is a polysaccharide made up of beta-1,3 link and beta-1,6 linkages between the glucose monomers

137
Q

How does callose initially take part in the defence mechanism ?

A
  • Within minutes of the initial attack, callose is synthesised and deposited between the cell walls and the cell membrane in cells next to the infected cells.
  • This prevents the pathogens entering the plant cells around the site of infection
  • Large amounts of callose continue to be deposited in cell walls
138
Q

What is a specific immune response?

A

The immune system ‘remembers’ an antigen after an initial response leading to an enhanced response to subsequent encounters

139
Q

What are antibodies?

A

Y-shaped glycoproteins made by B cells of the immune system in response to the presence of an antigen

140
Q

What shape are antibodies ?

A

Y-shaped

141
Q

How does the sequence of amino acids affect an antibody?

A

The sequence of amino acids determines the shape of the variable region (sequence of amino acids) and so which antigen is detected

142
Q

How many polypeptide chains does an antibody contain?

A

4

143
Q

What type of molecule is an antibody?

A

Protein

144
Q

What sort of protein are antibodies?

A

Globular

145
Q

What is formed when an antibody binds to an antigen?

A

An antigen-antibody complex

146
Q

What is the relationship between the two light chains of antibodies?

A

They are identical

147
Q

What is the relationship between the two heavy chains of antibodies?

A

They are identical

148
Q

How many binding sites are there on an antibody? Where are they?

A
  • 3
  • Two antigen binding sites
  • One receptor site that allows the body to recognise the antibody as self
149
Q

How are all antibodies in the body similar?

A

They share the same common region

150
Q

What type of bonding occurs between the heavy and light strands in antibodies?

A

Disulphide

151
Q

How are the heavy strands attached in antibodies?

A

Disulphide bonds

152
Q

How many light strands are in an antibody?

A

2

153
Q

How many heavy strands are in an antibody?

A

2

154
Q

What is the difference between the light and heavy chains of an antibody?

A

The light chains are much shorter than the heavy chains

155
Q

What is the relationship between the variable region and the antigen?

A

They have complementary shapes

156
Q

What allows for sulphide bonding?

A

The amino acid cysteine

157
Q

Why do antibodies have a hinge?

A

Allows antibodies to flex slightly and accommodate differently sized antigens

158
Q

How many amino acids form a binding site?

A
  • 110
159
Q

How do antibodies defend the body? (4 reasons)

A
  • Act as opsonins so the antigen is ‘tagged’ and easily engulfed
  • Act as antitoxins, binding to toxins produced by pathogens to render them harmless
  • Cause agglutination (clumping together) of pathogens which have antigen-antibody complexes, preventing them from spreading through the body and makes it easier for phagocytes to engulf several pathogens at once
  • Prevents pathogens from effectively invading a host
160
Q

Where do T-cells mature?

A

The thymus gland

161
Q

Where do B-cells mature?

A

Bone marrow

162
Q

What is the function of B plasma cells?

A

To produce antibodies

163
Q

Name the 4 types of T cells

A
  • Killer T cells
  • Helper T cells
  • Memory T cells
  • Regulator T cells
164
Q

Name the 3 types of B cells

A
  • B Plasma cells
  • B effector cells
  • B memory cells
165
Q

What are T helper cells ?

A
  • They produce interleukins
  • The interleukins stimulate the activity of B cells, which increases antibody production, stimulates production of other types of T cells and attracts and stimulates macrophages to ingest pathogens with antigen-antibody complexes
166
Q

What do T helper cells have on their surface membranes ?

A

CD4 receptors

167
Q

What are interleukins ?

A

They are a type of cytokine (cell-signalling molecules)

168
Q

What are T killer cells ?

A
  • These destroy the pathogen carrying the antigen.

- They produce perforin

169
Q

What does perforin do ?

A

It kills the pathogen by making holes in the cell membrane so it is freely permeable

170
Q

What are T memory cells ?

A

They live for a long time and are a part of the immunological memory

171
Q

What do T memory cells do when they meet an antigen for the second time ?

A

If they meet an antigen a second time, they divide rapidly to form a huge number of clones of T killer cells that destroy the pathogen

172
Q

What are T regulator cells ?

A

They stop the immune response once a pathogen has been eliminated, and make sure the body recognises self antigens and does not set up an autoimmune response

173
Q

What are plasma cells ?

A

They produce antibodies to a particular antigen and release them into circulation

174
Q

What are B effector cells ?

A

They divide to form the plasma cell clones

175
Q

What are B memory cells ?

A
  • They live for a long time and provide the immunological memory
  • They are programmed to remember a specific antigen and enable the body to make a very rapid response when a pathogen carrying that antigen is encountered
176
Q

What is cell mediated immunity ?

A

T lymphocytes respond to the cells of an organism that has been changed in some way

177
Q

What is cell mediated immunity important against ?

A

Viruses and early cancers

178
Q

What happens in cell mediated immunity ?

A
  • Macrophages engulf and digest pathogens in phagocytosis
  • They process the antigens from the surface of the pathogen to form an Antigen Processing Cell (APC)
  • The receptors on some of the T helper cells fit the antigens
  • These T helper cells become activated and produce interleukins, which stimulate more T cells to divide rapidly by mitosis
  • They form clones of identical activated T helper cells that all carry the right antigen to bind to a particular pathogen
179
Q

What can the cloned T cells do ?

A
  • Develop into T memory cells, which give a rapid response if this pathogen invades the body again
  • Produce interleukins that stimulate phagocytosis
  • Produce interleukins that stimulate B cells to divide
  • Stimulate the development of a clone of T killer cells that are specific for the presented antigen and then destroy infected cells
180
Q

What is humoral immunity ?

A
  • The body responds to antigens found outside the cells and to APCs
  • They humoral immune system produces antibodies that are siluble in the blood and tissue fluid and are not attached to cells
181
Q

What do B lymphocytes have on their surface membrane ?

A

immunoglobin M (IgM)

182
Q

What does a B cell do when a pathogen enters the body ?

A
  • A B cell with complementary antibodies to the antigens on the pathogen will bind to those antigens.
  • It will the engulf and process the antigens to become an APC
183
Q

What happens in humoral immunity ?

A
  • Activated T helper cells bind to the B cell APC. This is clonal selection - The point at which the B cell with the correct antibody to overcome a particular antigen is selected for cloning
  • Interleukins produced by the activated T helper cells activate the B cells
  • The activated B cell divides by mitosis to give clones of plasma cells and B memory cells. This is clonal expansion.
184
Q

What is the primary immune response ?

A

Cloned plasma cells produce antibodies that fit the antigens on the surface of the pathigen, bind to the antigens and disable them, or act as opsonins or agglutinins

185
Q

How long can a primary immune response take ?

A
  • Days or even weeks, this is why we get ill
  • The symptoms are the result of the way our body reacts when the pathogens are dividing freely, before the immune response is fully operational
186
Q

What is the secondary immune response ?

A
  • Some cloned B cells develop into B memory cells.
  • If the body is infected by the same pathogen again, the B memory cells divide rapidly to form plasma cell clones
  • These produce the right antibody and wipe out the pathogen very quickly, before it can cause the symptoms of disease
187
Q

What does an autoimmune disease mean ?

A

Sometimes the immune system stops recognising self cells and starts to attack healthy body tissue

188
Q

Why does autoimmune disease occur ?

A
  • There appears to be a tendency in some families that sometimes the immune system responds abnormally to a mild pathogen or normal body microorganism
  • Even in come cases the T regulator cells do not work effectively
189
Q

What can be used to treat autoimmune diseases ?

A

Immunosuppressant drugs, which prevent the immune system working, may be used as treatments

190
Q

What is a disadvantage of using immunosuppressant drugs ?

A

They deprive the body of its natural defences against communicable diseases

191
Q

Define immunity

A

Being able to kill pathogens if infected before getting symptoms

192
Q

Define active immunity

A

Achieved when immune system is activated and manufactures its own antibodies

193
Q

Define passive immunity

A

Achieved when antibodies are supplied from another source

194
Q

Define natural immunity

A

Achieved through normal life processes

195
Q

Define artificial immunity

A

Achieved through medical intervention

196
Q

Natural active immunity

A

Achieved as a result of infection

197
Q

Active artificial immunity

A

Achieved as a result of vaccination

198
Q

Passive natural immunity

A

Antibodies are provided by the placenta or via the breast milk

199
Q

Passive artificial immunity

A

Provided by infection of antibodies made by another individual

200
Q

What are vaccinations ?

A

Deliberately exposing the body to antigenic material to trigger long-term immunity (through activation of the specific immune response leading to memory cells)

201
Q

What may vaccines contain ?

A
  • Killed or inactivated bacteria and viruses
  • Attenuated strains of live bacteria or viruses
  • Toxin molecules that have been altered and detoxified
  • Isolated antigens extracted from the pathogen
  • Genetically engineered antigens
202
Q

Explain the main steps of vaccination

A
  • The pathogen is made safe in one of a number of ways so that the antigens are intact but there is no risk of infection
  • Small amounts of the safe antigen are injected into the blood
  • The primary immune response is triggered by the foreign antigens and your body produces antibodies and memory cells as if you were infected with a live pathogen
  • If you come into contact with a live pathogen, the secondary immune response is triggered and you destroy the pathogen rapidly before you suffer symptoms of the disease
203
Q

How long do vaccines provide artificial active immunity for ?

A
  • May last a year, a few years or a lifetime

- Can get booster vaccine

204
Q

What is an epidemic ?

A

When a communicable disease spreads rapidly to a lot of people at a local or national level

205
Q

What is a pandemic ?

A

When the same diseases spreads rapidly across a number of countries and continents

206
Q

What can prevent an epidemic ?

A

Mass vaccinations at the start of the epidemic

207
Q

What has to happen to vaccines in order for them to be effective ?

A

They have to be changing so they can stay effective

208
Q

What is herd immunity ?

A

When a significant number of people in the population have been vaccinated, this gives protection to those who do not have immunity

209
Q

What are some common medicines ?

A
  • Painkillers
  • Anti-inflammatories
  • Anti-acids
210
Q

What is penicillin ?

A

The first widely used, effective, safe antibiotic capable of curing bacterial diseases

211
Q

Where does penicillin come from ?

A

Comes from a mould called Penicillium chrysogenum, famously discovered by Fleming in 1928

212
Q

How was it discovered ?

A

Fleming saw it growing on his Staphylococcus spp. cultures

213
Q

Where are most drugs derived from ?

A

They are derived from or based on bioactive compounds in plants, microorganisms or other forms of life

214
Q

What is the source of penicillin ?

A

Commercial extraction originally from mould growing on melons

215
Q

What is penicillins action ?

A
  • Antibiotic

- The first effective treatment against many common bacterial diseases

216
Q

What is the source of docetaxel/paclitaxel ?

A

Derived from yew trees

217
Q

What is docetaxel/paclitaxel’s action ?

A

Treatment of breast cancer

218
Q

What is the source of aspirin ?

A

Based on compounds from willow bark

219
Q

What is aspirins action ?

A
  • Painkiller
  • Anticoagulant
  • Antipyretic
  • Anti-inflammatory
220
Q

What is the source of prialt ?

A

Derived from the venom of a cone snail from the oceans around australia

221
Q

What is prints action ?

A

New pain killing drug 1000 times more effective than morphine

222
Q

What is the source of vancomycin ?

A

Derived from a soil fungus

223
Q

What is vancomycins action ?

A

One of the most powerful antibiotics

224
Q

What is the source of digoxin ?

A

Based on digitoxin, originally extracted from foxgloves

225
Q

What is digoxins action ?

A

Powerful heart drug that is used to treat atrial fibrillation and heart failure

226
Q

How does biodiversity affect medicines ?

A

We have to maintain biodiversity to make sure that we do not destroy a plant, animal or microorganism which could give us the key to a life saving drug

227
Q

What is personalised medicine ?

A

Medicine with a combination of drugs that work with your individual combination of genetics and disease

228
Q

Define pharmacogenomics

A

The science of interweaving knowledge of drug actions with personal genetic material

229
Q

Which gene causes 30 % of breast cancers ?

A
  • HER2

- Caused by a mutation in the gene

230
Q

What drugs shut down the activity of the HER2 gene ?

A
  • Trastuzumab (herceptin)

- Lapatinib

231
Q

How much can doctors reduce deaths from breast cancers and how ?

A
  • Can reduce deaths from breast cancer by 50%
  • They do this by analysing breast tumours and treating those who have a mutation in the HER2 gene with the relevant drugs
232
Q

What can we do with genetic engineering and synthetic biology ?

A

We can develop populations of bacteria to produce much needed drugs that would otherwise be too rare, too expensive or unavailable

233
Q

What does synthetic biology enable us to do ?

A

It enables us to use bacteria as biological factories

234
Q

What is nanotechnology ?

A
  • It is another strand of synthetic biology

- Tiny, non natural particles are used for biological purposes

235
Q

Give an example of where nanotechnology is used

A

To deliver drugs to very specific sites within the cells of pathogens or tumours

Biology (30 decks)

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