Communicable disease Flashcards
1
Q
What is a vector?
A
carry pathogens from one organism to another, but do not have the disease themselves
2
Q
What type of cell is bacteria?
A
prokaryotes
3
Q
What is the average diameter of viruses?
A
0.02-0.3 nanometers
4
Q
What are viruses that attack bacteria are known as?
A
bacteriophages
5
Q
Protoctista affect what types of organisms?
A
plants and animals
6
Q
What are the four types of communicable disease?
A
virus
fungi
bacteria
protista
7
Q
What is ring rot and what is the effect on plants?
A
bacterial disease that affects the fields, and damages leaves
8
Q
What is TMV and what is the effect on plants?
A
tobacco mosaic virus, causes loss in cholorphyll, which stunts growth of plants
9
Q
What is tuberculosis?
A
a bacterial disease in mammals which destroys lung tissue and suppresses the immune system
10
Q
What is Bacterial Meningitis and how does it work?
A
a bacterial infection, of the brain which can spread to the rest of the body
11
Q
What is HIV and how does it work?
A
human immunodeficiency virus
targets T helper cells
- contains RNA as its genetic material
- Contains the enzyme reverse transcriptase
- which produces a single strand of DNA in the host cell
12
Q
What are the three types of direct transmission?
A
- direct contact
- inoculation (through the skin)
- ingestion
13
Q
What are the three different types of indirect transmission?
A
- fomites (inanimate objects)
- droplet infection (inhilation)
- vectors
14
Q
What is a communicable disease?
A
pass from an infected person to an unaffected person
diseases caused by pathogens
15
Q
How do viruses attack an individual?
A
- attachment of virus to the host cell
- insertion of viral nucleic acid DNA or RNA
- DNA replication of the virus
- synthesis of viral protein
- assembly of virus particles
- lysis of host cell
16
Q
How does the plant disease of fungus work?
A
(like protist)
hyphae penetrate the host cell, destroy leaves and there is no cure
17
Q
How can you control the spread of fungal disease?
A
using fungicides
18
Q
What is a virus and what are some examples?
A
e.g. influenza/bird flu
smaller than bacteria and invade host cells
19
Q
What are some of the factors affecting transmission of disease in animals?
A
- lack of sanitation
- overcrowding
- diet
- ventilation
20
Q
How does direct transmission work in plants?
A
entering through roots
leaves touching etc.
21
Q
What are the factors affecting transmission of disease in plants?
A
more susceptible because they are clones of each other = monoculture
overcrowding
damp
lack of nutrient availability
climate change
22
Q
How does indirect transmission work in plants?
A
airborne transmission
23
Q
How does a plant detect pathogen?
A
the pathogen will attach to a receptor in the cell surface membrane
some defensive molecules directly attach
polysaccharides made to strengthen cell wall
24
Q
What are the two polysaccharides that are produced to by the plant to strengthen the cell wall?
A
chitin and lignin
25
How does the mechanical defense of the plants work?
produce a high level of callose
Callose is synthesised and deposited between the cell wall and membrane to prevent spread
26
What do callose papillae do?
act as barriers, preventing the pathogens entering other cells around infection
27
What does callose do to the phloem?
blocks the sieve plates, sealing off the infectious part, preventing the spread
28
Where is callose deposited?
in the plasmodesmata between the infected and non infected cells
29
How do chemical defenses in plants work?
produce chemicals such as insect repellents
30
What do insecticides do and where are they found?
e.g. pyrethrins = made in chrysanthemums, act as toxins towards insects
31
What is an example of an antibacterial produced by plants?
gossypol produced by cotton
32
What are some examples of antifungal compounds produced by plants?
e.g. = phenols
= chitinase = enzyme that break down fungal cell walls
33
What is the first line of defence?
a non specific response to keep pathogens out
natural barriers that prevent their entry
both chemical and physical
34
How are mucous membranes an example of a non specific response?
trap the pathogen and then expel themselves out or in the stomach
goblet cells = produce mucus
ciliated cells = move mucus
e.g. respiratory tract
35
How is blood clotting an example of a non specific response?
1st reaction = co factor joins to enzyme
2nd reaction = the enzyme turns the blood from soluble to insoluble so that its able to clot
36
How do inflammatory responses happen and how can they be dealt with?
histamine = dilate blood vessels, causes area to look red, plasma leaks from capillaries taking WBC with it
antihistamines = release mast cells
37
How are fevers a non specific response?
temps that go above 37 degrees, high temps inhibit pathogen reproduction
- specific immune system works faster at higher temperatures
38
What are phagocytes?
specialised white blood cells that engulf and destroy pathogens
39
What are the 2 types of phagocytes?
- neutrophils =made in the bone marrow, rapid action against pathogens
- macrophages = involved in both specific and non specific responses
40
Why do macrophages take longer to digest a pathogen?
it combines antigens from the pathogen surface membrane with special glycoproteins in the cytoplasm = Major Histocompatibility Complex (MHC)
41
What are the stages of Phagocytosis (without macrophages)?
1. Pathogens produce chemicals that attract phagocytes
2. Phagocyte recognises pathogen as a non-human, not a specific pathogen
3. Phagocyte engulfs the pathogen to form a phagosome
4. Phagosome combines with a lysosome to form a phagolysosome
5. enzymes from the lysosome digest and destroy the pathogen
42
What happens in phagocytosis with macrophages?
1. digested pathogen absorbed by phagocyte antigen combined with MHC in the cytoplasm
2. MHC antigen complex displayed on phagocyte membrane, making an antigen presenting cell
3. attracts attention of the specific immune response
4. becomes an antigen presenting cell
43
What are the two helpful chemicals for phagocytes?
1. opsonin
2. cytokines
44
What do opsonin's do?
chemicals that bind to the pathogen and 'tag' them, so they can be easily recognised by the phagocytes
(phagocytes have receptors on their cell membranes that bind to common opsonin's
45
What do cytokines do?
once the phagocyte has engulfed the pathogen, this chemical is produced ( cell signalling to other cells to move to the site of infection)
also increases body temp and stimulates specific immune response
46
What are antibodies?
Y - shaped glycoproteins called immunoglobulins
47
What is the structure of an antibody?
made up of two identical long polypeptide chains called heavy chains and two much shorter identical chains called the light chains
held together by disulphide bridges
all have a constant region that is the same in all antibodies
48
What do antibodies form when they bind to antigens?
forms an antigen - antibody complex
49
How does the antigen - antibody complex act as an opsonin?
so complex, and is easily digested and engulfed by phagocytes
50
How do antibodies act as agglutinins?
they cause pathogens carrying AAC (antigen - antibody complex) to clump
51
How do antibodies act as anti - toxins?
bind to the toxins produced by the pathogen, counteract
52
Where are B lymphocytes found and made?
Bone Marrow
53
Where are T lymphocytes found and made?
Thymus gland
54
What are t - helper cells and how do they work in the immune response?
bind to the surface of antigens on an APC
- produce interleukins (a cytokine)
- stimulate the production of other t-cells and stimulates 8-cells to divide
55
What are t - killer cells and how do they work in the immune response?
destroy the pathogen that is carrying the antigen
- produce a chemical called perforin, kills the pathogen by making holes in the cell membrane, making it freely permeable
56
What are t-memory cells and how do they work in the immune response?
live for a long time, part of the immunological memory
- when they meet an antigen for the second time, rapid response time
57
What are lymphocytes?
a type of WBC
58
What are t-regulator cells and how do they work in the immune response?
suppress the immune system (control and regulate it)
- stops the immune system, once the pathogen has been eliminated
- ensures there is no autoimmune response
59
What are the three types of B-lymphocytes?
- Plasma cells
- B effector cells
- B memory cells
60
What are Plasma cells and how do they help in the immune response?
produce antibodies to a particular antigen, and release them into circulation of the blood
61
What are B- effector cells and how do they help in the immune response?
these divide to form plasma cell clones
62
What are B-memory cells and how do they help in the immune response?
live for a long time, provide immunological immunity
- programmed to remember a specific antigen, enable rapid response when the pathogen is encountered again
63
What is meant by cell mediated immunity?
where T- lymphocytes respond to the cells of an organism that have been changed in some way
64
What happens in the first step of cell mediated immunity?
macrophages engulf and digest pathogens in phagocytosis
- the cell then becomes and APC (Antigen Presenting Cell)
65
What happens in the second step of cell mediated immunity?
the receptors on some of the t- helper cells fit to the antigens from the pathogen
- t-helper cell become activated AAC and produce interleukins
- stimulating more t-cells to divide rapidly by mitosis
66
What happens in the third step of cell mediated immunity?
the cloning of t-cells, the different pathways include:
- develop into t-memory cells
- produce interleukins, stimulate phagocytosis and mitosis of B-cells
- stimulate development of a clone of a t-killer cell, that are specific to presented antigen
67
What is humoral immunity?
when the body responds to antigens found outside the cell
produces antibodies that are soluble in the blood and tissue fluid
not attached to cells
68
How do B-lymphocytes play a role in antibody production?
- they have antibodies on their cell surface membrane (immunoglobin)
- when the pathogen enters... B-cells with complementary antibodies will bind to antigen on pathogen, phagocytosis will happen
- becomes an Antigen Presenting Cell
69
What is the first stage of humoral immunity?
activated t- helper cells bind to the B-cell APC
CLONAL SELECTION
70
What is the definition of clonal selection?
the point at which the B-cell with the correct antibody to overcome a particular antigen is selected for cloning
71
What is the second stage of humoral immunity?
interleukins produced by the activated t-helper cells activate the B-cells
72
What is the third stage of humoral immunity?
activated B- cells divide by mitosis, gives clones of plasma and memory cells = CLONAL EXPANSION
73
What is the fourth stage of humoral immunity?
plasma cells produce antibodies that fit the antigens on the surface of the pathogen (can act as opsonin's and agglutinins)
PRIMARY RESPONSE
74
What is the fifth stage of humoral immunity?
Some cloned B - cells develop into B-memory cells
- they circulate the blood, live longer than plasma cells
SECONDARY IMMUNE RESPONSE
75
What is an autoimmune disease?
when the immune system stops recognising 'self' cells and starts to attack healthy body tissue
T-regulator cells don't work effectively
76
What is natural active immunity?
the immune system produces T/B - memory cells so if you meet the pathogen a second time, the system recognises the antigens, can respond quicker
77
What is natural passive immunity?
colostrum = first milk a mammalian mother makes, very high in antibodies
78
What is an example of artificial immunity?
Vaccination (medical intervention)
79
How does a vaccination work?
injected with a weakened form (attenuated) of the pathogen to elicit immune response, and the production of antibodies of B-memory cells
80
What might a vaccination contain?
- killed on inactive pathogen
- attenuated (weakened form) strains of live bacteria/virus
- toxic molecules that have been altered or detoxified
- isolated antigens extracted from the pathogen
- genetically engineered antigens
81
What is the definition of pharmacogenetics?
interweaving knowledge of drug actions with personal genetic material
82
What is the definition of synthetic biology?
genetic engineering
83
What is meant by selective toxicity?
antibodies interfere with the metabolism of the bacteria without affecting the metabolism of the human cells
84
What is an example of an antibiotic resistant strand of bacteria?
MRSA
(accelerated natural selection)
85
How can antibiotic resistant bacteria development be minimised?
- minimise use of antibiotics
- good hygiene
86
In terms of natural selection, how has antibiotic resistance come about?
- variation in the bacterial population due to gene mutation
- some bacteria will have resistance to antibiotics, giving them a competitive advantage
- when antibiotics are used, the resistant allele is passed on to the next generation
- the frequency of the allele for antibiotic resistance increases in the population
