B3- Infection and Response Flashcards

1
Q

Define pathogen

A

A microorganism that enters the body and causes harm

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2
Q

What type of disease do pathogens cause

A

Communicable

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3
Q

Can plants and animals be impacted by pathogens

A

Yes

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4
Q

How do bacteria make people feel ill

A

Producing toxins

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5
Q

Are viruses cells

A

No

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6
Q

Where do viruses live inside you

A

Inside body cells (the host cell)

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7
Q

What makes you feel ill with a virus

A

The damage of the host cell

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8
Q

What are protists

A

Single-celled eukaryotes

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9
Q

What are parasites

A

They live on or inside other organisms and can cause them damage. They are often transported by the vector which doesn’t get the disease itself

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10
Q

What is an example of a protist

A

A mosquito carrying malaria

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11
Q

What are the 4 types of pathogens

A
  • Protists
  • Bacteria
  • Fungi
  • Virus
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12
Q

What are the 3 ways in which pathogens can be spread

A
  • Water
  • Air
  • Direct contact
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13
Q

What are the 3 viral diseases you need to know

A
  • Measles
  • HIV
  • Tobacco mosaic virus (TMV)
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14
Q

What are symptoms of measles

A
  • Red skin rash

- Fever

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15
Q

What are potential complications of measles

A
  • Pneumonia

- Encephalitis

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16
Q

What is encephalitis

A

A brain infection

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17
Q

What is pneumonia

A

Lung inflammation caused by bacterial or viral infection, in which the air sacs fill with pus and may become solid. Inflammation may affect both lungs (double pneumonia) or only one (single pneumonia).

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18
Q

How is HIV transferred

A

Sexual contact by the exchange of body fluids

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19
Q

What are the initial symptoms of HIV

A

Flu like for the first few weeks

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20
Q

How long after the initial symptoms of HIV will it be until the person experiences them again

A

A few years

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21
Q

What is crucial about the time in between the first symptoms and the next ones (HIV)

A

It’s when HIV can be controlled by antiretroviral drugs

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22
Q

What does the HIV virus attack

A

The body’s immune system

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23
Q

When does HIV turn into AIDS

A

When the body’s immune system can’t cope with other infections or cancers

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24
Q

What does TMV infect

A

Plants

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25
What are the symptoms of TMV
- A Mosaic pattern on the leaves | - Parts of the leaves become discoloured
26
What does the discolouration in leaves cause
Less cell growth because it can't carry photosynthesis
27
What is rose black spot
A fungus
28
What are the symptoms of rose black spot
- Purple or black spots | - Leaves turn yellow and drop off
29
What plants can get rose black spot
Rose plants
30
How does rose black spot spreads through the environment
Water or wind
31
What is malaria caused by
A protist
32
Who is the vector for malaria
A mosquito
33
What are the symptoms of malaria
Repeating episodes of fever
34
What are the two bacteria diseases you need to know
- Salmonella | - Gonorrhea
35
Salmonella is a type of bacteria that causes _ _
Food poisoning
36
What are the symptoms of salmonella
- Fever - Stomach cramps - Vomiting - Diarrhea
37
How is gonorrhea caught
Sex | STD
38
What type of pathogen is salmonella
Bacteria
39
What type of pathogen is gonorrhoea
Bacteria
40
What are the symptoms of gonorrhea
- Pain while urinating | - Thick yellow or green discharge
41
How is gonorrhea treated
Antibiotics
42
How can people prevent the spread of gonorrhoea
Use conodms
43
What are the 4 main things you can do to prevent the spread of diseases
- Be hygienic - Destroying vectors - Isolating infected people - Vaccination
44
What are features of your body's immune system
- Skin - Mucus - Hairs - Hydrochloric acid
45
What is the most important part of the immune system
White blood cells
46
What do white blood cells do to foreign cells. What is this called
Engulf and digest them. Phagocytosis
47
What are the pros to vaccines
- Control diseases | - Epidemics prevented
48
What are the cons to vaccines
- Don't always work | - Bad reaction
49
Define monoclonal antibodies
Produced in the lab using mouse lymphocytes
50
What are is the process of monoclonal antibodies using mice
Mouse (using the mouse spleen) ○ Inject antigens into the mouse ○ White blood cells/ lymphocytes produce antibodies specific to this antigen ○ Combine white blood cell / lymphocyte with a tumour cell and this is called a hybridoma ○ Hybridoma can rapidly divide making lots of antibodies ○ Antibodies are isolated, harvested and purified
51
What is a communicable disease
A disease caused by a pathogen which can | be passed between animals or plants eg. flu
52
What is a pathogen
A disease-causing microorganism e.g. | bacteria
53
How do bacteria cause disease?
Once inside the body, they divide rapidly by binary fission. They kill cells and produce harmful toxins
54
How do viruses cause disease
They invade and reproduce inside living | body cells, leading to cell damage
55
Give three ways in which pathogens can be | spread
● By air - flu, tuberculosis and the common cold are spread by droplet infection. ● By water - fungal spores in water spread plant diseases. ● By direct contact - common in plant diseases and sexually transmitted infections
56
Give four ways in which the spread of pathogens | can be reduced
● Hygiene - handwashing, disinfectants, tissues. ● Reducing contact with infected individuals - quarantine. ● Removing vectors - use of pesticides and insecticides, removal of habitats. ● Vaccination.
57
Why is it especially important to prevent the spread | of viral diseases
Scientists have not yet developed cures for | many viral diseases
58
What is measles
Measles is a serious viral disease that can cause blindness and brain damage. The main symptoms are a fever and a red skin rash.
59
How is measles spread
By air - through the inhalation of droplets | from coughs and sneezes
60
What is HIV/AIDS
HIV is a virus which attacks and damages the immune system until it can no longer function properly. AIDS is the condition resulting from a long-term HIV infection. There is no cure or vaccine for HIV/AIDS
61
How is HIV spread
Direct sexual contact and the exchange | of bodily fluids eg. blood, breastmilk
62
How can the spread of HIV/AIDS be prevented
``` ● Use of condoms ● Screening of blood for transfusions ● Not sharing needles ● Bottle-feeding by HIV-positive mothers ● Use of antiretroviral drugs to prevent the development of AIDS ```
63
What is tobacco mosaic virus
A plant pathogen which causes leaf discolouration when cells are damaged. Affected areas cannot photosynthesise, reducing the crop yield. As there is no treatment, farmers grow TMV-resistant crop strains to avoid infection
64
How is tobacco mosaic virus spread
Contact between infected and healthy plants. Insects may act as vectors which transfer the virus between different plants
65
What is salmonella
A type of bacteria found in raw meat, poultry and eggs. If they enter the body via food poisoning, they can affect natural gut bacteria
66
What are the symptoms of salmonella food poisoning
``` ● Fever ● Abdominal cramping ● Vomiting ● Diarrhoea May be fatal in very young or elderly populations due the risk of dehydration ```
67
How can the spread of salmonella be limited?
● Vaccinating animals intended for consumption ● Keep raw meat away from cooked meat ● Disinfect hands and surfaces after contact with raw meat ● Thoroughly cook meat
68
What is gonorrhoea
A sexually transmitted bacterial infection caused by unprotected sex with an infected individual. Early symptoms include yellow/green discharge from genitals and painful urination, although it may be symptomless. Its spread can be controlled through the use of antibiotics (no longer penicillin as many strains are resistant) and using condoms
69
What is rose black spot
A fungal disease which causes purple or black spots to develop on rose leaves. It reduces the area of the leaf which is available for photosynthesis and causes leaves to turn yellow and drop prematurely
70
How is the rose black spot fungus spread
Fungal spores are spread by the wind | and in water
71
How can the rose black spot fungus be treated?
● Using fungicides | ● Destroying infected leaves
72
What is malaria
Malaria is a disease caused by protist pathogens. The disease is carried from host to host by mosquitoes, and the protists enter the human bloodstream when they feed. Symptoms include fever and shaking, and it may also be fatal in some cases
73
How can the spread of malaria be reduced
``` ● Using insecticides ● Using insect nets to avoid bites ● Prevent mosquito breeding by removing stagnant water ● Antimalarial drugs ```
74
How does the skin prevent pathogens from entering | the body?
● Acts as a physical barrier. ● Scab formation after skin is cut/wounded. ● Antimicrobial secretions which can kill pathogens. ● Healthy skin flora compete with pathogens and act as an additional barrier
75
How does the respiratory system prevent pathogens | from entering the body
● Nose - has hairs and mucus which trap pathogens. ● Trachea and bronchi - have mucus that traps pathogens. Ciliated cells move mucus to the mouth so it can be swallowed.
76
How does the stomach prevent pathogens infecting | the body
● Secretes hydrochloric acid - kills any pathogens | present
77
How does phagocytosis protect us against disease
White blood cells (phagocytes) ingest and destroy | pathogens so they cannot infect more cells
78
How does antibody production protect us against | disease?
White blood cells produce antibodies which are complementary to a specific antigen on a pathogen. The binding of antibodies to antigens causes pathogens to clump together, making them easier to destroy. In the case of a second infection, the correct antibodies can be produced rapidly, preventing the person getting the same disease again
79
How does antitoxin production protect us against | disease
Antitoxins bind to toxins released by pathogens and | neutralise them
80
What is a vaccination
Contains a dead or inactivated form of the pathogen which stimulates white blood cells to produce complementary antibodies to the pathogen. In the case of a second infection, memory cells can rapidly produce the correct antibodies and prevent illness
81
What is herd immunity
If a sufficiently high proportion of a population are immune to a disease (especially through vaccination), the spread of this disease will be limited
82
What are the advantages of vaccinations
● They have eradicated many deadly diseases eg. smallpox. ● Many epidemics can be prevented by vaccinations. ● Herd immunity protects those who cannot have vaccinations
83
What are the disadvantages of vaccinations?
● Not guaranteed to work - might not protect against multiple strains of a pathogen. ● May be side effects or adverse reactions
84
What drugs are used to cure some bacterial diseases
Antibiotics - they can kill bacterial pathogens inside | the body
85
How do antibiotics work
Antibiotics eg. penicillin kill bacterial pathogens inside the body, but do not kill human cells. Whilst some antibiotics kill a wide range of bacteria, it is important that the right antibiotic is used for specific bacteria
86
Why can antibiotics not be used to treat viral | diseases
Antibiotics have no effect on viral pathogens as they live inside the host’s (human) cells. Therefore, it is difficult to design drugs that would kill the virus and not destroy human cells at the same time.
87
What is antibiotic resistance
Antibiotic resistance occurs when mutations lead to individual bacteria being resistant to an antibiotic. These bacteria are able to survive, reproduce and pass on their alleles, leading to a greater proportion of antibiotic-resistant bacteria. This is concerning as some types of bacteria are becoming resistant to all known antibiotics, so the diseases that they cause cannot be cured
88
How can we prevent antibiotic resistance
● Avoid overuse and unnecessary use of antibiotics - eg. antibiotics are often used for viral infections. ● Finish antibiotic courses - to ensure all bacteria is killed.
89
What effect do painkillers have on infectious | diseases?
Painkillers can only treat the symptoms but do not | kill pathogens
90
What plant is the heart drug digitalis extracted from?
Foxgloves
91
What painkiller originates from a compound | found in willow bark
Aspirin
92
What antibiotic was discovered by Alexander | Fleming from a type of mould?
Penicillin
93
What are the four qualities of a good medicine
● Effective ● Safe ● Stable ● Able to be taken in and removed easily
94
What three main factors are tested for when | developing new drugs
● Toxicity ● Efficacy ● Dose
95
How is preclinical testing carried out
In a laboratory - uses cells, tissues and live animals
96
How is clinical testing carried out?
Uses healthy volunteers and patients. Firstly, the drug is tested at a low dose on healthy people - then tested on patients and on a larger scale to find the optimum dose. Often, one group receive a placebo (not the test drug) and the other group receive the actual drug, in order to assess its efficacy.
97
What is the difference between a single-blind and | a double-blind trial?
In a single-blind trial, only the doctor knows whether the patient is receiving the drug or the placebo. In a double-blind trial, neither the patient nor the doctor knows. Double-blind trials help remove bias on the part of the doctor
98
What is a peer review
Where the results of drug trials are checked over by | scientists knowledgeable in this field
99
What are monoclonal antibodies (mAbs)
● Antibodies that are clones from one parent cell ● Specific to one type of antigen
100
Describe how monoclonal antibodies are produced
1. Specific antigen injected into an animal (e.g. mouse). 2. B-lymphocytes producing complementary antibodies extracted. 3. B-lymphocytes fuse with myeloma cells to form hybridoma cells - these cells can divide and produce antibody. 4. Hybridoma cells cultured. 5. Monoclonal antibodies collected and purified
101
Outline the uses of monoclonal antibodies
● Detection of pathogens ● Location of cancer cells and blood clots ● Treatment of cancer ● Used in pregnancy test kits
102
What are myeloma cells
Type of tumour cell
103
Outline the uses of monoclonal antibodies
● Detection of pathogens ● Location of cancer cells and blood clots ● Treatment of cancer ● Used in pregnancy test kits
104
What do pregnancy kits test for
hCG in urine
105
What does a pregnancy test consist of
A stick containing monoclonal antibodies (mAbs) specific to hCG: ● mAbs attached to a blue bead (free to move) ● mAbs fixed to the test stick
106
Describe what happens to the test stick if a woman | is pregnant
``` ● hCG in urine binds to mAbs attached to a blue bead. ● mAbs with hCG diffuse up dipstick. ● mAbs fixed to the stick bind to hCG. ● Blue line forms ```
107
Describe what happens to the test stick if the | pathogen is not present
No hCG in urine so a blue line is not | formed.
108
What is the advantage of using monoclonal | antibodies to test for pathogens
● Specific to one particular antigen ● Very accurate ● Quick results
109
Why can monoclonal antibodies be used to target | cancer cells?
● Cancer cells have specific antigens called ‘tumour markers’ on their membranes. ● mAbs are specific to one type of antigen so can be targeted to ‘tumour markers’ without damaging other cells
110
Describe how monoclonal antibodies can be used to | diagnose cancer
● mAbs tagged to a radioactive substance. ● mAbs injected into the patient’s bloodstream. ● mAbs bind to ‘tumour markers’ on cancer cells. ● Emitted radiation is detected using a specialised scanner enabling doctors to determine the location of cancer cells.
111
How can monoclonal antibodies be used to target | drugs to cancer cells
● mAbs attached to an anti-cancer drug. ● mAbs injected into the patient’s bloodstream. ● mAbs bind to ‘tumour markers’ on cancer cells. ● Anti-cancer drug destroys cancer cells
112
Why are cancer treatments that use monoclonal | antibodies favoured over traditional treatments?
● Radiotherapy and chemotherapy target rapidly dividing cells. ● Healthy cells (e.g. hair follicle cells, bone marrow cells) are damaged as a consequence, producing unpleasant side effects. ● mAbs only target cancer cells, reducing damage to normal cells.
113
How can monoclonal antibodies be used to locate | blood clots?
● mAbs tagged to a radioactive substance. ● mAbs target and bind to specific proteins in blood clots. ● Radiation emitted by mAbs is detected, enabling the location of blood clots to be identified
114
How do aphids cause damage to plants?
They use their sharp mouthparts to extract sap from the plant phloem, weakening the plant. They are also vectors who can transfer pathogens from diseased plants to healthy plants
115
How can we reduce the number of aphids
● Chemical pesticides | ● Biological pest control - using ladybirds
116
Why do plants need a good supply of nitrate | ions?
Nitrate ions are required to convert sugars into proteins which are required for the plant to grow. As a result, the growth of the plant will be stunted if there is not an adequate supply of nitrates.
117
Why do plants need a good supply of magnesium | ions
Magnesium ions are required to synthesise chlorophyll, which absorbs light energy during photosynthesis. As a result, the leaves cannot photosynthesise properly and they turn yellow (chlorosis)
118
What are the symptoms of disease in plants
``` ● Stunted growth (lack of nitrate ions) ● Spotted leaves (eg. rose black spot fungus) ● Decay/rotting ● Growths ● Malformation of stems/leaves ● Discolouration ● Presence of pests ```
119
What are three ways in which plant disease | can be identified
● Reference to a gardening website or manual ● Laboratory testing ● Monoclonal antibody test kits
120
Give examples of physical defence responses | used by plants
● Cellulose cell walls ● Tough waxy cuticle on leaves ● Outside layer on stems/bark on trees ● Leaf fall
121
Give examples of chemical defence responses used | by plants
● Antibacterial chemicals | ● Poisons
122
Give examples of mechanical defence responses | used by plants
● Thorns and hairs to deter animals ● Leaves that droop/curl on contact ● Mimicry to trick animals