Infection and Response Flashcards
(100 cards)
1
Q
What are pathogens?
A
microorganisms that cause infectious disease
2
Q
What do pathogens include?
A
viruses bacteria protists and fungi
3
Q
What can pathogens infect?
A
plants or animals
4
Q
How are pathogens spread?
A
direct contact, water, air
5
Q
What are the qualities of a virus?
A
- very small
- they move into cells and use the biochemistry of it to make many copies of itself
- this leads to the cell bursting and releasing all of the copies into the bloodstream
- the damage and the destruction of the cells makes the individual feel ill
6
Q
What are the qualities of bacteria?
A
- small
- they multiply very quickly through dividing by a process called binary fission
- they produce toxins that can damage cells
7
Q
What are the qualities of protists?
A
- some are parasitic, meaning they use humans and animals as their hosts
8
Q
What are the qualities of fungi?
A
- can either be single celled or have a body made of hyphae
- they can produce spores which can spread to other organisms
9
Q
What is hyphae?
A
thread-like structures
10
Q
How can the damage that disease cause to populations be reduced?
A
- improving hygiene
- reducing contact with infected individuals
- removing vectors
- vaccination
11
Q
What are examples of viral diseases?
A
- measles
- HIV
- TMV
12
Q
What are the symptoms of measles?
A
fever and red skin rash
13
Q
How is measles spread?
A
droplet infection
14
Q
How is malaria being prevented?
A
vaccinations for young children to reduce transmission
15
Q
What are the symptoms of HIV?
A
initially flu-like symptoms, then the virus attacks the immune system and leads to AIDS
16
Q
How is HIV spread?
A
sexual contact or exchange of bodily fluids such as bloods
17
Q
How is HIV being prevented?
A
using condoms, not sharing needles, screening blood, mothers with HIV bottle-feeding
development to AIDS- use of antiretroviral drugs
18
Q
What is TMV?
A
tobacco mosaic virus, a plant pathogen affecting many species of plants including tomatoes
19
Q
What are the symptoms of TMV?
A
discolouration of the leaves, the affected part of the leaf cannot photosynthesise resulting in the reduction of the yield
20
Q
How is TMV spread?
A
contact between diseased plants and healthy plants, insects act as vectors
21
Q
How is TMV being prevented?
A
good field hygiene and pest control, growing TMV-resistant strains
22
Q
Bacterial diseases are on the rise as they are becoming…
A
resistant to antibiotics
23
Q
What are examples of bacterial diseases?
A
- salmonella food poisoning
- gonorrhoea
24
Q
What is salmonella food poisoning?
A
bacteria that live in the gut of different animals, which we ingest when we eat the meat
25
What are the symptoms of salmonella food poisoning?
fever, stomach cramps, vomiting, diarrhoea
26
How is salmonella food poisoning spread?
bacteria can be found in raw meat and eggs, unhygienic conditions
27
How is salmonella being prevented?
- poultry are vaccinated
- keeping raw meat away from cooked food
- wash hands and surfaces when handling it
- cook food thoroughly
28
What are the symptoms of gonorrhoea?
thick yellow or green discharge from the vagina or penis, pain when urinating
29
How is gonorrhoea spread?
sexually transmitted disease spread through unprotected sexual contact
30
How is gonorrhoea being prevented?
using contraception
31
What are examples of bacterial diseases?
salmonella and gonorrhoea
32
What is an example of a fungal disease?
rose black spot
33
What are the symptoms for rose black spot?
purple or black spots on leaves of rose plants, reduces the area of the leaf available for photosynthesis, leaves turn yellow and drop early
34
How is rose black spot spread?
spores of the fungus are spread in water or by wind
35
How is rose black spot being prevented?
- use of fungicides or stripping the plant of affected leaves
36
What is an example of a protist disease?
malaria
37
What is malaria caused by?
protist pathogens that enter red blood cells and damage them
38
How is malaria spread?
vector is the female anopheles mosquito in which protists reproduce sexually. when the mosquito punctures the skin to feed on blood, the protists enter the human bloodstream via their saliva
39
How is malaria being prevented?
using insecticide coated insect nets while sleeping, removing stagnant water to prevent the vectors from breeding, travellers taking antimalarial drugs to kill parasites that enter the blood
40
What are the non-specific defence systems?
- skin
- nose
- trachea and bronchi
- stomach
41
How does the skin act as a non-specific defense system?
- acts as a physical barrier
- produces antimicrobial secretions to kill pathogens
- good microorganisms known as skin flora compete with the bad microorganisms for space and nutrients
42
How does the nose act as a non-specific defence barrier?
- has hair and mucus which prevents particles from entering your lungs
43
How do the trachea and bronchi act as a non-specific defence barrier method?
- secrete mucus in order to trap pathogens
- cilia beat to waft mucus upwards so it can be swallowed
44
How does the stomach act as a non-specific defence barrier method?
- produces hydrochloric acid that kills any pathogens in your mucus, food or drink
45
What is the specific immune system?
acts to destroy any pathogens which pass through the non-specific immune system to the body
46
What is a large part of the specific immune system?
white blood cells
47
How can white blood cells act?
- phagocytosis
- produce antibodies
- produce antitoxins
48
What is phagocytosis?
engulfing and consuming pathogens
49
How does phagocytosis protect the body?
destroys pathogens, meaning they can no longer make you feel ill
50
How does producing antibodies protect the body?
each pathogen has an antigen on their surface, which is a structure with a specific complementary antibody can bind to.
once antibodies begin to bind to the pathogen, the pathogens start to clump together, resulting in it being easier for white blood cells to find them
if you become infected again with the same pathogen, the specific complementary antibodies will be produced at a faster rate, the individual will not feel the symptoms of the illness, they are said to be immune
51
How does the production of antitoxins protect the body?
neutralise the toxins released by the pathogen by binding to them
52
What do vaccinations involve?
making an individual immune to a certain disease - they are protected against it before they have been infected
53
What can be achieved by immunising a large proportion of the population?
the spread of the pathogen is reduced as there are less people to catch the disease from called herd immunity
54
What does vaccination do?
vaccinations replicated the first infection so that when the person is exposed to the real disease they do not feel any symptoms, just like in a secondary infection
55
What does the vaccine contain?
a dead or inactivated form of the pathogen, this stimulates white blood cells to produce antibodies complementary to the antigens on the pathogen
56
What are the advantages of vaccination?
- eradicated many diseases
- epidemics can be prevented
57
What are the disadvantages of vaccination?
- not always effective in providing immunity
- bad reaction can occur in response to vaccines
58
What are antibiotics?
medicines that kill bacterial pathogens inside the body, without damaging body cells. they cannot kill viruses as they use body cells to reproduce, meaning any drugs that target them would affect body tissue too.
59
What do painkillers do?
only treat the symptoms of the disease, rather than the cause
60
How can antibiotics be taken?
as a pill, syrup or directly into the bloodstream
61
What is an example of an antibiotic?
penicillin
62
Bacteria are becoming...
resistant to antibiotics
63
How can bacteria become resistant to an antibiotic?
- mutations can occur during reproduction resulting in certain bacteria no longer being killed by antibiotics
- when these bacteria are exposed to antibiotics, only the non-resistant one die
- the resistant bacteria survive and reproduce, meaning the population of resistant bacteria increases
- this means that antibiotics that were previously effective no longer work
64
How can we prevent the development of these resistant strains?
- stop overusing antibiotics
- finish whole course of antibiotics
65
What do drugs need to be tested for?
toxicity, efficacy, dose
66
Where are drugs tested?
preclinical testing and clinical trials
67
How are plants used as drugs?
the chemicals that plant use to kill pests and pathogens can be used to treat symptoms or human diseases
68
What are examples of plant drugs?
aspirin, digitalis
69
What is aspirin used for?
painkiller
70
Where does aspirin originate from?
willow
71
What is digitalis used for?
treat heart problems
72
Where does digitalis originate from?
foxgloves
73
Who discovered penicillin?
Alexander Fleming
74
How was penicillin discovered?
- Alexander Fleming was growing bacteria on plates
- He found mould ( Penicillium mould ) on his culture plates, with clear rings around the mould indicating there was no longer any bacteria there
- he found that the mould was producing a substance called penicillin which killed bacteria
75
What are preclinical trials?
use cells, tissues and live animals to test if drugs are safe and effective
76
What are clinical trials?
use volunteers and patients to test if drugs are safe and effective
77
Describe the process of clinical testing.
- it is first tested on healthy volunteers with a low dose to ensure there are no harmful side effects
- the drugs are then tested on patients to find the most effective dose
- to test how well it works, patients are split into two groups with one group receiving the drug and one receiving a placebo so the effect of the new drug can be observed
- these can be single-blind or double blind.
78
The results from clinical need to be..
peer reviewed by other scientists to check for repeatability
79
What are monoclonal antibodies?
identical antibodies, that have been produced from the same immune cell. as a result of their ability to bind to only one protein antigen, they can be used to target chemicals and cells in the body and so have many different medical uses, e.g. pregnancy testing
80
How are monoclonal antibodies produced?
- Scientists obtain mice lymphocytes, which have been stimulated to produce a specific antibody
- they are combined with tumour cells, to form a cell called a hybridoma
- hybridoma can divide to produce clones of itself, which all produce the same antibody
- the antibodies are collected and purified
81
What are the uses of monoclonal antibodies?
pregnancy tests, measuring the levels of hormones or chemicals, in research and treatment of certain diseases
82
What hormone is present in the urine of women who are pregnant?
human chorionic gonadotrophin hCG
83
How are monoclonal antibodies used in pregnancy tests?
- there are two sections of the stick
- the first section has mobile antibodies complementary to the hCG hormone - these antibodies are also attached to blue beads
- the second section has stationary antibodies complementary to the hCG hormone which are stuck down to the stick
- the individual urinated on the first section, and if hCG is present it binds to the mobile antibodies attached to blue beads to form hCG/antibody complexes
- they are carried in the flow of liquid to the second section
- the stationary antibodies then bind to the HCG/antibody complexes
- as they are each bound to a blue bead, results in a blue line
- this indicates that you are pregnant
84
How are monoclonal antibodies used in laboratories?
- they can be used to measure and monitor levels of hormones or chemicals in the blood
- the monoclonal antibodies are modified so that they will bind to the molecule you are looking for
- antibodies are also bound to a fluorescent dye
- if the molecules are in the sample then the antibodies bind to it, and the dye can be observed
- an example is screening donated blood for HIV infections
85
How are monoclonal antibodies used in the treatment of disease e.g. cancer?
cancer cells have antigens on their cell membranes known as tumour markers, which can be targeted.
86
What are the three ways monoclonal antibodies can be used to treat cancers?
a. producing monoclonal antibodies that bind to the tumour markers in order to stimulate the immune system to attack the cell
b. using monoclonal antibodies to bind to receptor sites on the cell surface membrane of the cancer cells, this means growth-stimulating molecules cannot bind, stopping the cell from dividing
c. using monoclonal antibodies to transport toxic drugs, chemicals, or radioactive substances as they can only bind to cancer cells
87
What are the advantages of monoclonal antibodies?
- only bind to specific cells meaning healthy cells are not affected
- they can be engineered to treat many different conditions
- now able to produce mouse-human hybrid cells to reduce the chance of triggering an immune response
88
What are the disadvantages of monoclonal antibodies?
- difficult to attach monoclonal antibodies to drugs
- expensive to develop
- produced from mice lymphocytes, often triggered an immune response when used in humans
89
What are the common signs of plant disease?
- stunted growth : nitrate deficiency
- spots on leaves : black spots fungus on roses
- areas of decay: black spot fungus on roses, blights on potatoes
- abnormal growths : crown galls caused by bacterial infection
- malformed stems or leaves: due to aphid infestation
- discolouration: magnesium deficiency, TMV
- pests on leaves: caterpillars
90
You can identify the disease of the plant by..
- gardening manual or website
- observing infected plant in a laboratory
- monoclonal antibodies to identify pathogen
91
What can nitrate deficiency cause?
stunted growth
92
What do nitrates do ina plant?
nitrates in the soil convert sugars made in photosynthesis into proteins, needed for growth
93
What does magnesium deficiency cause?
chlorosis
94
What does magnesium do in a plant?
mg needed to make chlorophyll
pigment is green and is vital in photosynthesis
if less is being made then parts of the leaves appear green and yellow which is known as chlorosis
95
Plants have a number of..
physical, chemical and mechanical adaptations
96
Why are physical defences needed in plants?
prevent the invasion of microorganisms
97
What are examples of physical defences?
- tough waxy cuticle stops entry into leaves
- cellulose cell walls form a physical barrier into the cells
- layer of dead cells around stems (bark) which stop pathogens entering, the dead cells fall off with the pathogens
98
Why are chemical defences needed in a plant?
to deter predators or kill bacteria
99
What are examples of chemical defences?
- poisons deter herbivores
- antibacterial compounds kill bacteria, such a mint plant and witch hazel
100
What are examples of mechanical defences?
- thorns and hairs make it difficult and painful for animals to eat them
- some leaves can droop or curl when touched which allows them to move away and move insects off their leaves
- mimicry to trick animals, some animals droop to look like unhealthy plants so that animals avoid them, plants can have patterns that appear to look like butterfly eggs, so butterflies do not lay their eggs here in order to avoid competition,
species from the ice plant family have a stone and pebble like appearance in order to avoid predation.
