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a level biology > 4.1 communicable diseases > Flashcards

4.1 communicable diseases Flashcards

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AP® Biology flashcards
1
Q

What are 3 diseases caused by bacteria

A

Tuberculosis
bacterial meningitis
ring rot

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2
Q

What are 3 diseases caused by viruses

A

HIV/AIDS
influenza
tobacco mosaic virus

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3
Q

What are 2 diseases caused by protoctista

A

Malaria
Potato/tomato blight

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4
Q

What are 3 diseases caused by fungi

A

black sigatoka
ring worm
athletes foot

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5
Q

Why are some bacteria harmful

A

They reproduce rapidly and their presence can cause disease by damaging cells or by releasing waste products which are toxic to us

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6
Q

How do viruses cause disease

A

They have a core of genetic material, outer envelope of lipoproteins and inner protein coat.
without organelles to respire or absorb nutrients the virus can’t grow so it infects host cell to replicate and damages it

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7
Q

How do protoctista cause disease

A

They cause harm by entering the cell and feeding on its content as it grows

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8
Q

How do fungi create harm

A

In animals fungi lives in the skin and hyphae grow to the skin surface

In plants it lives in the vascular tissue and hyphae release extracellular enzymes to digest tissue

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9
Q

what are the symptoms of tuberculosis

A

Affects many parts of the body killing tissues and cells and the lungs are mostly affected
cough

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10
Q

What are the symptoms of bacterial meningitis

A

infection of the meninges; brain and spinal cord membranes become swollen and may cause damage to the brain or nerves

headache, rash

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11
Q

What are the symptoms of ring rot

A

Ring of decay in the vascular tissue of a potato tuber or tomato
accompanied with leaf wilting

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12
Q

What are the symptoms of HIV/AIDS

A

Attacks cells in immune systems and compromises immune response

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13
Q

What are the symptoms of influenza

A

Attacks respiratory system and can cause muscle pain and headaches

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14
Q

What are the symptoms of tobacco mosaic virus

A

mottling and discolouration of leaves

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15
Q

What re the symptoms of malaria

A

parasite in the blood that causes headache, fever and chills and may progress to coma or death

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16
Q

What are the symptoms of blight

A

Affects both leaves and potato tubers
watery rot of leaves which soon collapse and turn brown

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17
Q

What re the symptoms of black sigatoka

A

leaf spots in banana plants

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18
Q

What are the symptoms of ringworm

A

Circular rash caused by growth of fungus

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19
Q

What are the symptoms of athletes foot

A

growth under skin of feet particularly toes

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20
Q

define passive defenses

A

they are present before infection and prevent entry and spread of pathogens

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21
Q

what are the 7 physical plant defenses

A

cellulose cell wall
lignin thickening of cell walls
waxy cuticle
bark
stomata closure
callose
tylose

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22
Q

describe how to cell wall is a physical plant defense

A

acts as a physical barrier and contains a variety of chemicals which may activate when a pathogen is discovered

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23
Q

describe how lignin is a physical plant defense

A

the lignin thickening of cell walls are waterproof and undigestible

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24
Q

describe how waxy cuticles are a physical plant defense

A

prevents water from collecting and the absence of water protects the plant by ensuring the pathogen doesn’t survive

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25
Q

describe how bark acts as a physical defense for plants

A

it acts as a barrier and contains chemical defenses against pathogens

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26
Q

describe how stomatal closure acts as a physical defense in plants

A

guard cells close to prevent entry of pathogen

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27
Q

describe how callose acts as a physical defense in plants

A

it is a polysaccharide deposited in phloem sieve tubes blocking the flow in it and preventing spread of pathogens

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28
Q

describe how tylose acts as a physical defense against pathogens

A

it is a projection that fills the xylem vessel so that it can no longer carry water and spread pathogens
it also contains chemical toxic to pathogens e.g. terpenes

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29
Q

describe chemical defenses

A

terpenoids, phenols, alkaloids and hydrolytic enzymes that may be present before infection.
However, they require a lot of energy to be produced so they usually aren’t until a pathogen is detected

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30
Q

what occurs during active defense in plants

A

already existing defenses are fortified
thickened cell wall
increased production of chemicals
deposition of callose
oxidative bursts that can damage invading cells

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31
Q

name the 5 chemicals produced during plan defense action

A

terpenoids
phenols
alkaloids
defensins
hydrolytic enzymes

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32
Q

what is the action of terpenoids

A

they are essential oils with anti bacterial and anti fungal properties e.g. menthols in mint

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33
Q

what is the action of phenols

A

they are anti biotic and anti fungal
tannin inhibits insect attacks by binding to their salivary proteins and digestive enzymes deactivating them and can inhibit insect growth and may even cause death

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34
Q

what is the action of alkaloids

A

nitrogen containing compounds e.g. caffeine and cocaine that have a bitter taste to inhibit herbivores

they also act on metabolic reactions via inhibiting or activating enzymes e.g. some may inhibit protein synthesis

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35
Q

what is the action of defensins

A

they are small cysteine rich proteins with broad anti-microbial activity and appear to act in plasma membranes possibly inhibiting ion channels

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36
Q

what is the action of hydrolytic enzymes

A

found in spaces between cells and include:
chitinases - break down chitin in cell wall
glucanases - break down glycosidic bonds in glucans
lysosomes - can degrade bacterial cell wall

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37
Q

define direct transmission

A

passing a pathogen from host to new host with no intermediary

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38
Q

define indirect transmission

A

passing a pathogen from host to new host via a vector

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39
Q

what are the 4 direct transmissions of disease

A

physical contact

faecal

droplet infection

spores which can be carried in soil or air

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40
Q

describe physical contact transmission and what factors affect it

A

physical contact e.g. HIV athletes foot and bacterial meningitis
- hygiene and sanitisation of surfaces

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41
Q

describe faecal/oral transmission and what factors affect it`

A

faecal - oral transmission e.g. cholera and food poisoning usually by eating or drinking food infected with pathogen
- using human waste to fertilise crops
-cross-contamination of food
-washing food

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42
Q

describe droplet infection and what factors affect it

A

droplet infection e.g. tuberculosis and influenza
-cover mouth when sneezing or coughing
- masks

43
Q

Describe infection by spores and what factors can affect transmission

A

spores which can be carried in soil or air e.g. anthrax
- washing skin after soil contact
-masks

44
Q

what other factors can affect transmission of a disease

A

overcrowding
poor ventilation
poor diet
homelessness
not being exposed to that disease before and not having resistance

45
Q

what are some indirect methods of transmission

A

vectors
for example the the plasmodium parasite that causes malaria uses the anophales mosquito as a vector

46
Q

what are some example of direct transmission of disease in plants

A

soil contamination
protist or fungi in soil
e.g. TMV, tomato blight, black sigatoka

47
Q

What are some examples of indirect transmission of pathogens in plants

A

vectors such as wind, water, animals and humans

48
Q

define inflammation

A

swelling and redness of tissue caused by infection

49
Q

what are the 5 primary non-specific defenses against pathogens

A

skin
blood clotting
mucous membranes
coughing or sneezing
inflammation

50
Q

How does the skin act as a primary non-specific defense against pathogens

A

the outer layer of the skin (epidermis) consists of layers of cells most of which are keratinocytes and the keratinised layer of cells acts as a barrier to pathogens

51
Q

How does blood clotting act as a primary non-specific defense against pathogens

A

It involves calcium ions and at least 12 other clotting factors in an enzyme cascade.
once the clot has formed it begins to dry out and form a scab creating a temporary seal under which the skin is repaired

52
Q

Describe how the skin is repaired after a scab has formed

A

firstly there is a deposition of fibrous collagen under the scab and stem cells in the epidermis divide by mitosis to form new cells which migrate to the edges of the cut and differentiate to form new skin.
New blood vessels grow to supply oxygen and nutrients to the new tissues.
The tissues contract to help draw the edges together so that the repair can be completed

53
Q

describe the enzyme cascade

A

damage to the blood vessel wall exposes collagen and releases clotting factors
platelets bind to collagen and release clotting factors such as inactive thrombokinase in blood which is a factor and active thrombokinase (enzyme) and calcium ions
soluble fibrinogen in blood becomes insoluble fibrin which attaches to platelets in plug and clots

54
Q

How do mucous membranes act as primary non-specific defenses against pathogens

A

they trap pathogens that may be in the body and are wafted where it can be swallowed (if in the airways )

55
Q

How does coughing and sneezing act as a primary non-specific defense against pathogens

A

the sudden expulsion of air will carry the microorganism causing the irritation

56
Q

how does inflammation act as a primary non-specific defense against pathogens

A

mast cells detect the presence of micro organisms and release histamines which are cell-signaling substances.
this causes vasodilation and make the capillary walls more permeable to white blood cells and some proteins
blood plasma and phagocytic cells leave the blood and enter the tissue fluid and leads to increased production of tissue fluid which causes swelling (oedema)

Excess tissue fluid is drained into the lymphatic system where lymphocytes are stored and can lead to pathogens coming into contact with them and initiating an immune response

57
Q

what are other examples of primary defenses?

A

Eyes are protected by antibodies and enzymes in the tear fluid
The ear canal is lined by ear wax which traps pathogens
The female reproductive system is protected by a mucus pug in the cervix and relatively acidic conditions in the vagina

58
Q

Describe an antigen presenting cell

A

It is a cell that isolates the antigen from a pathogen and places it on the plasma membrane so that it can be recognised by other cells in the immune system

59
Q

define antigen

A

a protein on the pathogens outer membrane which is recognised as non-self (foreign) and can initiate an immune response

60
Q

describe opsonins

A

protein molecules that attach to the antigen on the pathogens surface and are a type of antibody

61
Q

What is the need for opsonins being non-specific

A

This enables them to attach to a variety of pathogen antigens

62
Q

What is the role of opsonins

A

they enhance the ability of phagocytic cells to bind and engulf the pathogens

63
Q

Describe phagocytic

A

they are the first line of secondary defence and are specialised cells in the blood and tissue fluid which engulf and digest pathogens

64
Q

Which phagocytes are the most common

A

neutrophils

65
Q

Describe neutrophils and their role

A

They are multi-lobed white blood cells which are produced in the bone marrow which travel in the blood and squeeze out of it into the tissue fluid.

Neutrophils contain a large number of lysosomes and they engulf and digest pathogens and will die soon after. They then may collect after an infection as pus

66
Q

Describe the difference between macrophages and monocytes

A

macrophages travel in the blood as monocytes and usually reside in the lymph nodes where they will mature into macrophages

67
Q

What are dendritic cells and where are they found

A

They are a type of macrophage and are found in peripheral tissues

68
Q

Describe macrophages and their role

A

They are a type of white blood cell which is produce in the bone marrow and play an important role in initiating the specific immune response against a pathogen

When a macrophage engulfs a pathogen it doesn’t fully digest it but rather saves the pathogen and and is moved to a special protein complex on the surface of the cell and becomes and antigen-presenting cell

69
Q

What does the special protein complex on the antigen-presenting cell ensure

A

That it isn’t mistaken for a foreign cell and engulfed by other phagocytes.

70
Q

How do the antigen presenting cells help with the initiation of the specific immune response

A

It increases the chance that the antigen will come into contact with the Band T lymphocytes

71
Q

Describe cytokines

A

hormone-like molecules used in cell signalling to activate an immune response

72
Q

Describe the specific immune response

A

It involves B and T lymphocytes and produces antibodies which neutralises the foreign antigen

It can also provide long-term protection by producing immunological memory through the release of memory cells.

73
Q

What are the 6 types of lymphocytes involved in the specific immune response

A

Plasma cells
B memory cells
T helper cells
T memory cells
T killer cells
T regulator cells

74
Q

define antibodies

A

a protein which is complementary and attaches to the antigen of a pathogen and neutralises it

75
Q

define interleukins

A

signalling molecules which are used to communicate between white blood cells

76
Q

What is the role of T helper cells

A

they release cytokines that stimulate Bcells to develop and stimulate phagocytosis

77
Q

What is the role of T killer cells (cytotoxic )

A

Attack and kill host-body cells which display the foreign antigen

78
Q

What is the role of T memory cells

A

Provide immunological memory

79
Q

What is the role of T regulator cells

A

They shut down the immune response after the pathogen has been successfully removed and are involved in preventing autoimmune diseases

80
Q

What is the role of plasma cells

A

They circulate in the blood manufacturing and releasing antibodies

81
Q

What is the role of B memory cells

A

Provide immunological memory

82
Q

describe three examples of using cytokines in cell communication

A

macrophages release monokines , some attract neutrophils and others stimulate B cells to differentiate

T cells and macrophages release interleukins which can stimulate clonal expansion and differentiation of B and T cells

Many cells can release interferon which inhibits virus replication and stimulates T killer cell activity

83
Q

When does an autoimmune disease arise

A

when antibodies start to attack our own antigens

84
Q

define clonal selection

A

selection of a specific B or T cell that is specific to the antigen

85
Q

define clonal expansion (proliferartion)

A

once the correct lymphocyte has been activated it must replicate to become more efficient which is done by mitotic division

86
Q

Why are antibodies described as immunoglobulins

A

they are complex globular proteins produced by plasma cells

87
Q

describe the structure of antibodies

A

they are Y shaped with disulphide bridges and hinge regions to allow flexibility

88
Q

What are the three main groups of antibodies

A

opsonins
agglutinins
anti-toxins

89
Q

Describe how opsonins work as antibodies

A

they bind to the antigen on the pathogen and then act as binding sites for phagocytic cells

90
Q

Describe how agglutinins work

A

The antibody molecule crosslinks pathogens by binding to more than one at a time and clumps pathogens together physically impeding them from carrying out their functions

91
Q

Describe how anti-toxins work

A

some antibodies bind to molecules that are released by phagocytic cells rendering them harmless

92
Q

describe how the secondary immune response differs from the first

A

The concentration of antibodies rises quicker and sooner and is usually quick enough to prevent the host from experiencing any symptoms

93
Q

Define vaccine

A

a way of stimulating an immune response so that immunity is acheived

94
Q

what are the 5 types of vaccine

A

whole live microorganisms are injected which aren’t as harmful as the real pathogen but have similar antigens cowpox and smallpox

weakened version of pathogen - measles and TB

dead pathogen - cholera

a preparation of the antigen from a pathogen - hep B

A toxoid (harmless version of toxin ) - tetanus

95
Q

Define herd vaccination

A

Using a vaccine to provide immunity to all or almost all of those at risk. Once enough people are immune the disease can no longer be spread through the population

96
Q

Define ring vaccination

A

used when a new case of a disease is reported and all the people in the immediate viccinity of the area are vaccinated

97
Q

Define active immunity

A

Where the immune system is activated and the body produces antibodies e.g infection

98
Q

Define artificial immunity

A

Immunity achieved through medical intervention e.g. vaccines

99
Q

Define natural immunity

A

immunity achieved through natural life processes

100
Q

define passive immunity

A

immunity achieved when antibodies are passed to the individual e.g. breast feeding and injection

101
Q

define antibiotic

A

chemical which prevents the growth of micro organisms and can be antibacterial or antifungal

102
Q

Define personalised medicine

A

development of designer medicine for individuals

103
Q

Define synthetic biology

A

the re-engineering of biology this could be through production of new molecules that mimic natural processes or the use of natural molecules to produce new biological systems which don’t exist in nature

a level biology (25 decks)

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