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BIOLOGY A LEVEL > CHAPTER 12 - COMMUNICABLE DISEASES > Flashcards

CHAPTER 12 - COMMUNICABLE DISEASES Flashcards

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1
Q

What are communicable diseases caused by

A

infective organisms called pathogens

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1
Q

What are classed under the term pathogens

A

Bacteria, viruses, fungi, protoctista

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2
Q

What are vectors

A

A medium that carries a pathogen from one organism to another eg. water or insects

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3
Q

What type of organism is a bacteria

A

Prokaryotic - no nucleus or membrane bound organelles

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4
Q

Do all bacteria cause disease?

A

no - only a small proportion

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5
Q

What are the shapes of bacteria

A

Rod Shaped - bacili
Spherical - cocci
Comma shaped - vibrios
Spiralled - Spirilla
Corkscrew - spirochaetes

Chain of bacteria - Strepto….
Cluster of bacteria - Staphylo..

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6
Q

How can bacteria be classified?

A

By their shapes and by their cell walls

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7
Q

What are the two types of cell walls

A

Gram positive and gram negative

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8
Q

What is the difference between gram positive and gram negative bacteria

A

How the different cell walls react differently

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9
Q

What colour do Gram-positive bacteria look after gram staining

A

Purple-blue eg. MRSA

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10
Q

What colour do Gram negative bacteria look after gram staining

A

Red eg. E.coli

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11
Q

What are viruses

A

Non-living infectious agents

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12
Q

What is the basic structure of a virus

A

Genetic material (either DNA or RNA) surrounded by a protein

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13
Q

What happens when a virus invades a cell

A

The genetic material of the virus takes over the biochemistry of the host cell to make more viruses

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14
Q

What adaptions do viruses have which makes them a successful pathogen

A

Reproduce rapidly
Evolve by developing adaptions to their host

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15
Q

What are the viruses that attack bacteria

A

Bacteriophages

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16
Q

What are bacteriophages used for

A

To identify and treat some diseases and now very important in scientific research

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17
Q

What type of organisms are protoctista (Protista)

A

Eukaryotic

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18
Q

What is a example of a disease transmitted by a protist

A

Malaria

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19
Q

How do fungi cause disease

A

Most fungi saprophytic, but some are parasitic

Parasitic fungi cause disease, stopping plants from photosynthesising - killing them

Produce millions of spores which travel over large distances

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20
Q

How do viruses directly damage host tissue

A

Viruses take over the cell metabolism; Viral genetic material gets into the host cell and is inserted into the host DNA.

Virus uses host cell to make new viruses which then burst out of the cell, destroying it and infecting others (pg 304)

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21
Q

How do Protoctista damage host tissue

A

Take over cells and break open as new generation emerge, but dont take over genetic material.

Simply digest and use the cell contents as they reproduce

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22
Q

How do Fungi directly damage host tissue

A

Digest living cells and destroy them

Combined with response of body to the damage caused by the fungus gives symptoms of disease

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23
Q

How do bacteria indirectly damage host tissues

A

Produce poisons or toxins that that damage host cells by breaking down the cell membranes or damage or inactivate enzymes so cells cannot divide

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24
Q

How do fungi indirectly damage host cells

A

Produce toxins that cause disease

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25
Q

Explain what is meant by the term “communicable diseases”

A

Disease that can be passed from one organism to another

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26
Q

Give four ways in which pathogens can attack cells of their host organism and cause disease

A

Take over cell metabolism, viral genetic material inserted into host DNA

take over cell and
digest contents (e.g., some Protista)

completely digest living cells and destroy them (e.g., fungi)

produce toxins which poison or damage host cells, some toxins break down cell membranes or
inactivate enzymes or prevent cell division (e.g., most bacteria)

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27
Q

Explain the difference between the way viruses and protists can cause disease

A

Viruses insert genetic material into host DNA

and take over cell metabolism to make new viruses before breaking out of cell

protists take over cells and feed on cell contents

and divide before breaking out of the cell

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28
Q

Suggest why viruses are described as the ultimate parasite

A

Viruses only active when inside a host cell

have little structure and take over whole host cell

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29
Q

What is the cause of ring rot and what is its effects

A

Bacterial disease of potatoes tomatoes and aubergines - caused by gram positive bacterium Clavibacter michiganensis

Damages leaves tubers and fruit. Can destroy up to 80% of the crop with no cure, leaving a field unfarmable for 2 years

(pg 305)

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30
Q

What is the cause of Tobacco mosaic virus (TMV) and what is its effects

A

A virus that infects tobacco plants and 150 other species

Damages leaves flowers and fruit, leading to Total crop loss

Some crop strains are resistant but there is no cure
(pg 306)

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31
Q

What is the cause of Potato Blight and what is its effects

A

Caused by a Fungus-like protoctist oomycete (from fungal lineage)

The hyphae penetrate host cells, destroying leaves, tubers and fruit causing millions of £s worth of crop damage per year

No cure but resistant strains and careful management and chemical treatment can mitigate infection risk

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32
Q

What is the cause of black Sigatoka and what is its effects

A

Fungus disease in bananas which destroys the leaves.

The hyphae penetrate and digest cells, turning leaves black, 50% reduction in yield

Resistant strains being developed and fungicide can control spread of disease but there is no cure
(pg 306)

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33
Q

What is the cause of Tuberculosis and what is its effects

A

Bacterial disease of many species

Destroys lung tissue and supresses immune system, so body is less able to fight off other diseases

Rise in HIV/AIDS has caused more TB infections

TB is curable (by antibiotics) and preventable (living standards and vaccinations)

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34
Q

What is the cause of bacterial meningitis and what is its effects

A

Bacterial infection of the meninges in the brain (protective membranes on outer surface). Can spread to rest of body and cause septicaemia (blood poisoning)

Symptom of both is if a blotchy red/purple rash that doesn’t disappear when glass is pressed against it

Antibiotics will cure disease if delivered early. Vaccines can protect against some forms of disease

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35
Q

What is the cause of HIV and what is its effects

A

Virus which targets T helper cells in immune system.
Destroys immune system, opening people up to many other infections eg. TB, Pneumonia and some cancers

Also affects non-human primates. HIV is a retrovirus of DNA using RNA as genetic material, containing reverse transcriptase, which transcribes the RNA to a single strand of DNA, interacting with host cell

Virus is passed via bodily fluids eg. unprotected sex, needles, contaminated blood products and pregnancy to an unborn child

No cure or vaccine, but some anti-retroviral drugs slow the progress of the disease down

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36
Q

What is the cause of Influenza and what is its effects

A

Viral infection of the ciliated epithelial cells in gas exchange system. Kills them leaving airways open to secondary infection

Can be fatal, especially to vulnerable individuals. Affects mammals and birds.

3 main strains - A, B and C

A are most virulent and are classified further by proteins on there surface, and mutate regularly

An annual vaccine for vulnerable, no cure

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37
Q

What is the cause of Malaria and what is its effects

A

Caused by protist, spread by bites of infected Anopheles Mosquitos.

Parasite has complex life cycle, reproducing in female mosquito, who needs at least 2 blood meals for protein before eggs are laid

This is when the protist invades the red blood cells, liver and brain

No vaccine or cure, but controlling the vector eg. insecticides and removing standing water in which they breed can prevent spread

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38
Q

What is the cause of ring worm and what is its effects

A

Fungal disease affecting mammals, different fungi cause same disease in various animals

Causes grey-white crusty infectious circular areas of skin. Not damaging but looks unsightly and itchy

Antifungal creams are an effective cure

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39
Q

What is the cause of athletes foot and what is its effects

A

Fungal disease - form of human ring worm

Grows and digests the warm moist skin between the toes

Causes cracking and scaling, which becomes itchy and sore

Antifungal creams are an effective cure

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40
Q

Compare and contrast bacterial, viral, protist and fungal diseases of plant and animals

A

Bacterial:
Ring rot affects potatoes, aubergine, and tomatoes.
TB (affects humans, cows, badgers, deer. Bacterial meningitis affects humans.

Viral:
Tobacco mosaic virus affects tobacco plants and 150 other species.
HIV/aids affects humans and some apes.
Influenza affects mammals including humans, pigs, and birds.

Protist:
Potato blight affects potatoes and tomatoes.
Malaria

Fungal:
Black sigatoka affects bananas and plantains.
Ring worm affects cattle (other spp. Affects most animals including people).
Athlete’s foot affects human feet

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41
Q

Suggest 3 ways in which animal diseases and 3 ways in which plant diseases may be spread from one organism to another

A

Animals:
direct transmission from one animal to another via direct contact,
inoculation,
and ingestion and indirect transmission e.g., droplet infection, fomites vectors etc.

For plants
direct transmission plant to plant
and indirect transmission including soil contamination and
different types of vectors e.g., wind, water, animals, humans

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42
Q

How are pathogens directly transmitted between animals

A

Direct contact -
Kissing or any contact of bodily fluids
Direct skin-to-skin contact
Microorganisms from faeces to hands

Inoculation -
Break in the skin eg. sex
Animal bite
Puncture wound or needle sharing

Ingestion -
Contaminated food or drink

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43
Q

How are pathogens indirectly transmitted

A

Fomites -
Inanimate objects such as bedding, socks or cosmetics

Droplet infection -
Inhaling the droplets of saliva or mucus when an infected person talks, coughs or sneezes

Vectors -
eg. Mosquito or water

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44
Q

How can you reduce the impact of catching an animal disease as a person

A

Minimising close contact with animals, washing hands regularly

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45
Q

What factors increase the probability of catching an infectious disease

A

Overcrowded living and working conditions
Poor nutrition
Compromised immune system - eg. after surgery/immunosuppressants
Poor waste disposal
Climate change - more diseases and vectors
Culture and infrastructure
Socioeconomic factors - no training etc…

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46
Q

How are pathogens directly transmitted from plant to plant

A

Direct contact of healthy plant with any part of a diseased plant

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47
Q

How are pathogens indirectly transmitted from plant to plant

A

Soil contamination -
infected plants leave pathogens /spores in soil, infecting the next crop

Vectors -
Wind - spores carried
Water - spores on surface film of water on leaves or any water surface
Animals - transmitting as they feed from one plant to another, particularly aphids
Humans - hands clothing, fomites, farming, transporting plants, crops

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48
Q

What factors affect the transmission of communicable disease in plants

A

Planting variety of crops that are disease susceptible

Over-crowding increases likelihood of contact

poor mineral nutrition

Damp warm conditions

Climate change - increased rainfall, changing conditions etc…

49
Q

Explain the difference between direct and indirect transmission of communicable pathogens

A

Direct pathogen is spread directly from one organism to another

Indirect – the pathogen is spread from one organism to another through another medium, e.g. the air, a vector

50
Q

Compare and contrast direct transmissions of animal and plant diseases

A

Similarities:
being crowded close together increases risk of direct and indirect transmission. Weakened individuals more at risk of infection. Damage to protective outer layers can allow pathogens in

Differences:
Animals actively exchange body fluids (sex, kissing, bites) plants don’t. Animals transfer food and drink into body through mouth which plants don’t

51
Q

Compare and contrast indirect transmission of animal and plant diseases

A

Similarities:
animals, wind and water can act as vectors, fomite, e.g. bedding, sacks, machinery can carry disease from one individual to another, soil contamination is common indirect method of disease spread in plants and can affect animals too.

Differences:
droplet infection from coughs and sneezes doesn’t affect plants BUT droplets and splashes from one leaf to another can do.

52
Q

Suggest different approaches to control the spread of malaria

A

Treating people to reduce pool of infection using medicines against disease

or using vaccines (no really effective ones developed yet); destroying mosquitoes that spread the disease (insecticide sprays on water and homes)

preventing mosquitoes breeding

draining swamps

removing waste filled with water

preventing mosquitoes reaching people (mosquito nets over beds, screens at doors and windows)

53
Q

As plants dont heal tissue, what do they do instead

A

Seal off a wound/ diseased tissue and sacrifice it, will regrow using meristems

54
Q

How do plants respond to a pathogen attack

A

Receptors on cell respond to molecules from the pathogen or to chemicals produced when the plant cell wall is attacked

Stimulates release of signalling molecule that switches on genes in the nucleus

These genes, trigger cell responses, which include producing defensive, chemicals alarm signals and strengthening cell walls

55
Q

What are the physical barriers a plant has to a pathogen

A

Waxy cuticle of plant leaves, bark on trees, cellulose of cell walls

56
Q

What is the physical defence a plant will use and what is the chain

A

After minutes of attack, callose is synthesised and deposited between cell wall and membrane next to infected cells, acting as barriers

Callose continues to be deposited, and is lignified to make mechanical barrier thicker and stronger

Callose also blocks sieve plates to phloem sealing off infected part, preventing spread of pathogens

Callose is deposited in the plasmodesmata between infected cells, sealing them all off

57
Q

What are the chemical defences a plant will use against a pathogen

A

Insect repellant eg. pine resin

Insecticides eg. pyrethrins which act as neurotoxins and caffeine, toxic to insects and fungi

Antibacterial compounds -antibiotics eg. phenols antiseptics eg. gossypol
defensins - protiens that disrupt bacterial and fungal membranes
Lysosomes - break down bacterial cell wall

Antifungal compounds - including chitinases which breakdown fungal cell walls

Anti-oomycetes - including glucanases which beak down glucans in the call walls of oomycetes

General toxins eg. cyanide

58
Q

Describe how the plant response to a pathogen attack is triggered

A

Receptors respond to molecules from pathogens

or to chemicals produced by the plant cell wall when it is attacked

these attach to receptors, stimulating the release of signalling molecules to switch on genes in the nucleus, triggering cellular responses

59
Q

What are some non-specific defences the body has to keep pathogens out

A

Skin - covered in healthy microorganisms that outcompete pathogens and sebum, which inhibits growth

Body tracts lined with mucous membranes and lysozymes

Lysozymes in tears and urine, and in acid in stomach

Expulsive reflexes - cough and sneeze etc…

Blood clotting

60
Q

What does blood clotting do and how does it occur

A

Rapidly seals a wound

Platelets come into contact with collagen in skin or damaged blood vessel, adhering and secreting many substances, including

Thromboplastin - enzyme which triggers a cascade of reactions resulting in the formation of blood clot

Serotonin - making smooth muscle of walls of blood vessel contract, reducing blood supply to the area

Dries out into hard scab, while epidermal cells grow underneath with collagen strengthening it
(pg 316&317)

61
Q

Describe the inflammatory response

A

Characterised by pain, heat, redness and swelling of tissue

cells release histamines and cytokines

Histamines -
Dilate blood vessels, localising heat and redness, raising temp to pathogens cant reproduce

Makes blood vessels more leaky, so blood plasma is forced out, then called tissue fluid and causing swelling and pain

Cytokines -
Attract white blood cells who dispose of pathogens by phagocytosis

62
Q

How does a body get rid of pathogens when they have entered the system

A

Fevers
Phagocytosis

63
Q

How does a fever work and why is it a useful adaption

A

Cytokines stimulate hypothalamus to reset thermostat and temp goes up

Useful because -
Most pathogens reproduce best at or below 37 degrees C, so it inhibits reproduction

Immune system works faster at higher temps

64
Q

Describe the stages of phagocytosis

A

Pathogens produce chemicals attracting phagocytes

Phagocytes recognise non-self proteins on pathogen

Phagocyte engulfs pathogen and encloses it in phagosome

Phagosomes fuses with lysosome forming phagolysosome

Enzymes in lysosome digets Pathogen

Macrophage combines antigens from Cell surface membrane ad produces glycoprotein called Major histocompatibility complex (MHC), putting antigens on its own surface membrane, becoming an antigen-presenting cell (APC)

Stimulating other cells involved in SPECIFIC immune system to respond

65
Q

What do cytokines do

A

Act as cell-signalling molecules, informing other phagocytes that the body is under attack, stimulating them to move to the site of infection

Also increases body temperature and stimulates specific immune response

66
Q

What do opsonins do

A

Chemicals that bind to pathogens and tag them so they can be more easily recognised by phagocytes - which contain receptors on their cell surface membrane that bind to opsonins which then tells them to engulf the pathogen

Strongest opsonins are antibodies such as Immunoglobulin G (IgG) and IgM

67
Q

A woman gets a bad scratch from a bramble. The scratch gets very red hot and the next day it contains pus. Explain what is happening

A

Localised inflammatory response to pathogens at site of wound, mast cells activated and release histamines and cytokines

histamines cause vasodilation causing localised heat and redness

raised temperature helps prevent pathogens reproducing; histamines make blood vessels leaky forcing tissue fluid out, causing oedema and pain

cytokines attract phagocytes to site which phagocytose pathogens; accumulation of dead phagocytes and pathogens forms visible pus layer

68
Q

Describe the process of phagocytosis (textbook summary q)

A

Pathogens produce chemicals which attract phagocytes

phagocytes recognise nonhuman proteins in pathogen

this is not a response to a specific type of pathogen, simply to a cell or organism which is ‘not self’

phagocyte engulfs the pathogen and encloses it in a vacuole called a phagosome

phagosome combines with a lysosome to form a phagolysosome

enzymes from lysosome digest and destroy pathogen

69
Q

Explain how cytokines and opsonins make the process of phagocytosis more effective than it would be without them

A

Cytokines act as cell signalling molecules

that stimulate phagocytes to move to a site of infection or inflammation

Opsonins bind to pathogens

and tag them so they are more easily recognised by phagocytes

because phagocytes have receptors on their membranes which bind to common opsonins, e.g., antibodies

70
Q

What is the job of antigens

A

to identify an antigen as non-self

71
Q

What are antibodies and what do they do

A

Y-shaped glycoproteins called immunoglobulins which bind to a specific antigen on the pathogen or toxin that has triggered the immune response,

each antigen is specific to each pathogen

72
Q

What are antibodies comprised of

A

Polypeptide chains - Heavy chain and light chain, held together by disulfide bridges

2 binding regions
(pg 320)

73
Q

How do antibodies bind to pathogens

A

Bind to antigens on pathogen using lock and key mechanism

Binding site of 110 amino acids - known as variable region, giving specificity

Rest of molecule remains the same - constant region

74
Q

What is formed when an antigen binds to a antibody

A

Antigen-antibody complex

75
Q

How do antibodies defend the body

A

Antibody complex acts as an opsonin so complex is easily engulfed and digested by phagocytes

Most pathogens can no longer invade host cells once part of the antigen-antibody complex

Antibodies act as agglutins, causing clumping, preventing spread

Also acts as anti-toxins to the toxins pathogen produce

76
Q

Where do B lymphocytes mature

A

Bone marrow

77
Q

Where do T lymphocytes mature

A

Thymus gland

78
Q

What do T helper cells do

A

CD4 receptors on their cell-surface membrane, which bind to surface antigens on APC, producing interleukins

Interleukins stimulate activity of B cells, increasing antibody production, T cell production and attracts and stimulates macrophages to ingest pathogen with Antibody-antigen complex

79
Q

What do T killer cells do

A

Destroy pathogen carrying the antigen.

Produces Perforin, killing pathogen by making holes in the cell membrane so it is freely permeable

80
Q

What do T memory cells do

A

Live for a long time as part of the immunological memory

If a second invasion of pathogens occurs, they divide rapidly, forming huge number of clones of T killer cells

81
Q

What do T regulator cells do

A

Suppress immune system, acting as a control to regulate it

Stops immune system attacking own tissue after pathogen has been destroyed

82
Q

What do plasma cells do (a B lymphocyte)

A

Produce antibodies to a particular antigen and release them in circulation

Only live for a few days but produce 2000 antibodies a second

83
Q

What do B effector cells do

A

Divide to form plasma cell clones

84
Q

What do B memory cells do

A

Live for a long time and provide immunological memory,

Programmed to remember a specific pathogen and enable body to make rapid response/production of antibodies

85
Q

Describe the stages of cell mediated immunity and why it is required

A

Response to cells of an organism that have been changed in some way eg. mutation, viral infection or antigen processing

Non-specific defense system, macrophages engulf pathogen in phagocytosis, process antigens becoming an APC

Receptors on T helper cells bind to antigens, producing interleukins, stimulating division of T helper cells rapidly by mitosis

T cells will either -
Develop into T memory cells
Produce Interleukins and stimulate phagocytosis
Produce interleukins and stimulate B cells to divide
Stimulate development of clone of T killer cells that are specific for the presented antigen

(pg 322)

86
Q

What does Humeral immunity respond to and describe the stages of it

A

Responds to antigens found outside cells, eg. to pathogen, pathogen toxins or to an APC

Activated T helper cells bind to B cell APC - clonal selection, correct antibody is selected

Interleukins produced by activated T helper cells activate B cells

Activated B cells give clones of plasma cells and B memory cells - clonal Expansion

Cloned plasma cells produce antibodies, or act as opsonins or agglutinins (primary immune response)

Some cloned B cells develop into B memory cells, if the pathogen meets the same pathogen again, it can produce antibodies rapidly (secondary immune response)

(pg 323)

87
Q

What is an autoimmune disease

A

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

88
Q

What do scientists think is the cause of Autoimmune diseases

A

Genetic tendancy, abnormal response to a mild pathogen or normal microorganisms in the body, or T regulator cells dont work effectively

89
Q

What can be taken to help prevent autoimmune diseases

A

Immunosuppressant drugs, preventing immune system from working, but deprive body of its natural defences

90
Q

What body part is affected and what is the treatment for type 1 diabetes

A

Insulin-secreting cells of the pancreas (beta cells)

Insulin injections, pancreas transplants, immunosuppressant drugs

91
Q

What body part is affected and what is the treatment for Rheumatoid arthritis

A

Joints - especially in hands, wrists, ankles and feet

No cure, anti-inflammatory drugs, steroids, immunosuppressants and pain reliefs are all mitigators

92
Q

What body part is affected and what is the treatment for Lupus

A

Often affects sin and joints causing fatigue
Can attack any organ including kidneys, liver lungs or brain

No cure, Anti-inflammatory drugs, steroids, immunosuppressants are all mitigators

93
Q

Discuss the problems that could arise from treating an autoimmune disease with immunosuppressant drugs

A

In autoimmune disease immune system stops recognising ‘self’ and starts attacking healthy cells.
Immunosuppressant drugs reduce activity of immune system

preventing/reducing destruction of
healthy tissue BUT susceptibility to infection increases

as immune system less effective at
recognising pathogens

94
Q

Compare the main types of T and B lymphocytes - what are the similarities and differences

A

Similarities:
Both T and B cells form clones of active cells
both form memory cells which mean
that when they meet a pathogen a second time there is a rapid response, destroying the pathogen
before it can cause disease

Differences:
T cells stimulate B cells
T cells destroy pathogens directly
B cells produce antibodies which act as opsonins stimulating phagocytes to engulf
pathogens
T cells also regulate immune response so it stops once a pathogen is removed and doesn’t turn against body cells

95
Q

The Humoral immune systems deals well with bacterial and fungal infections but the cell-mediated immune system is more effective at tackling viral infections. Explain the biology behind this statement

A

Humoral immune system responds to antigens outside of cells

bacterial and fungal cells present
in body have antigens to which humoral system can respond

system makes antibodies to
bacterial and fungal surface antigens, forms antigen-antibody complexes so macrophages readily
engulf pathogen

Cell-mediated system responds to changes in cells

Viruses get into body
cells and take over cell metabolism – not so obvious in blood presenting antigens e.g., bacteria.

However, cell-mediated response detects changes in-virus infected cells and killer T cells attack and
destroy them.

96
Q

What is natural active immunity

A

When you meet a pathogen naturally for the first time, which your immune system forms antibodies for and destroys the pathogen antigen, producing T and B memory cells to recognise the pathogen next encounter

Active as body as itself acted to produce antibodies and/or memory cells

97
Q

What is natural passive immunity

A

Antibodies cross the placenta to baby during pregnancy, as well as in mammalian milk which is called colostrum, which is high in antibodies, which pass into bloodstream without being digested

98
Q

How is artificial passive immunity achieved

A

Antibodies are formed in one individual (often an animal, extracted and then injected into the bloodstream of another individual, giving temporary immunity

No memory cells are produced, multiple injections required

99
Q

How is artificial active immunity achieved

A

Vaccine, active because body makes own memory cells and antibodies, artificial as it isnt a natural encounter

Pathogen is made safe, so no infection but intact antigens
- Killed or inactivated bacteria
- Weakened (attenuated) strains
- Toxin molecules have been detoxified
- Isolate antigens extracted from pathogen
- Genetically engineered antigens

Small amounts of safe antigen (vaccine) are injected into blood

Primary immune response is triggered, producing antibodies and memory cells

If contact with live pathogen occurs naturally, secondary immune response is triggered rapidly, usually before you feel symptoms of disease

Boosters are sometimes required

100
Q

What is an epidemic

A

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

101
Q

What is a pandemic

A

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

102
Q

What are some diseases that cause problems at a global level that cannot yet be prevented by vaccination

A

Malaria - evasive, spending times inside erythrocytes so it is protected by self antigens

HIV - enters macrophages and T helper cells, disabling immune system

103
Q

What are some common types of medicines

A

Painkillers, Anti-inflammatories and anti-acid medicines

Cures include chemotherapy, antibiotics and antifungals

104
Q

What are some sources of medicines

A

Chance and then industrial replication eg. penicillin
3D models on key, computers, libraries etc
Derived from plants or microorganisms

105
Q

Where does penicillin come from and what is its action

A

Commercial extraction, originally from mould growing on melons

Antibiotic - first effective treatment against many common bacterial diseases

106
Q

Where does docetaxel come from and what is its action

A

Derived from yew trees

Treatment for breast cancer

107
Q

Where does aspirin come from and what is its action

A

Willow bark

Painkiller, anti-coagulant, anti-pyretic and anti-inflammatory

108
Q

Where does prialt come from and what is its action

A

Derived from venom of cone snail

Pain killing drug 1000x more effective than morphine

109
Q

Where does vancomycin come from and what is its action

A

Derived from a soil fungus

Powerful antibiotic

110
Q

Where does digoxin come from and what is its action

A

based from digitoxin, extracted from Foxgloves

Powerful heart drug to treat heart failure and atrial fibrillation

111
Q

What is one reason why scientists want to maintain biodiversity

A

Make sure we dont destroy a plant, animal or microorganism which could give us the key to a life-saving drug

112
Q

Where is the future going with medicines

A

Personalised medicine - pharmacogenetics

Human genome analysed quickly and cheaply, so a prescription or combination can be given based on persons genetic material (pharmacogenomics)

113
Q

Describe synthetic biology

A

Using genetic engineering, developing populations of bacteria to produce much needed drugs that would otherwise be too rare, too expensive or not available

Or use of nanotechnology to deliver drugs using non-natural particles to very specific sites within cells of pathogens or tumours

114
Q

What is selective toxicity

A

Antibiotics interfering with the metabolism of bacteria without it affecting metabolism of humans

115
Q

How have antibiotic resistant bacteria developed

A

Most of population die but due to Random mutation of a bacterium that causes resistance to drug, renders it ineffective

Bacteria with resistance then survive and rapidly reproduce passing on mutated allele, creating large population

Natural selection

116
Q

What are the anthropogenic causes of bacterial resistance

A

Over subscription of antibiotics
Not finishing the cycle, which allows any remaining bacteria to survive and reproduce

117
Q

How can antibiotic resistance be reduced in the long term

A

Minimising use of antibiotics, ensuring every course of antibiotics is completed to reduce risk of resistant individuals surviving and adapting

Good hygiene in hospitals and care homes and in general, reducing the spread

118
Q

How can the bacterial resistance crisis be solved

A

Development of new antibiotics using computer modelling and other sources in many places,

Funding

119
Q

Suggest why some children still die of communicable diseases in the UK, even in the 21st century

A

Some diseases so severe that patient killed before body can develop antibodies

some people do not have children vaccinated against diseases

if child immunocompromised, has a comorbidity, or neglected/malnourished will be more vulnerable to infections

bacterial disease may be resistant to current antibiotics

120
Q

Explain how vaccinations may be used to prevent rabies after a person has been bitten by a rabid dog, fox or bat

A

Most people vaccinated, so if bitten they are given course of injections to deliver antibodies (produced in another animal) directly into blood stream

antibodies form antigen–antibody complex with rabies virus, allowing phagocytes to destroy pathogen (an example of artificial passive immunity)

121
Q

Explain how vaccinations can be used to control epidemics

A

Epidemic occurs when communicable disease spreads rapidly to a lot of people at either local/ national level

in vaccination, immune system stimulated to make antibodies to a pathogen by exposure to safe form of an antigen injected into blood stream

if an epidemic begins to build, mass vaccination

can protect people in the community by building immunity to infecting pathogen and prevent pathogen spreading disease into the wider population

BIOLOGY A LEVEL (24 decks)

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