3. Infection and Response Flashcards

1
Q

What are pathogens?

A

Microorganisms that cause disease.

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2
Q

What are communicable diseases?

A

Diseases that are infectious and can easily spread.

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3
Q

Why can bacteria make you feel ill?

A

They produce toxins which damage your cells and tissues.

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4
Q

Why do viruses make you feel ill?

A

They reproduce rapidly inside your body. They live inside cells and replicate themsleves using the cells’ machinery to produce many copies of themselves. The causes the celll to burst, releasing all the new viruses. The cell damage makes you feel ill.

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5
Q

What are protists?

A

Single-celled eukaryotes that are parasites. They live on or inside other organisms and can cause them damage. The are often transferred to the organism by a vector, which doesn’t get the disease itself.

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6
Q

What are fungi?

A

Single-celled or have a body made up of hyphae. These hyphae can grow and penetrate human skin and the surface of plants causing disease. Can produce spores which can be spread to others.

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7
Q

How can pathogens be spread?

A
  1. Water.
  2. Air.
  3. Direct contact.
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8
Q

How is measles spread?

A

By droplets from an infected person’s sneeze or cough.

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9
Q

What are symptoms of measles?

A

Red skin rash and fever.

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10
Q

How can measles be fatal?

A

If there are complications, it can lead to pneumonia or encephalitis.

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11
Q

How can the spread of measles be prevented?

A

Being vaccinated.

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12
Q

How is HIV spread?

A

Sexual contact or by exchanging bodily fluids such as blood (eg. when sharing needles).

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13
Q

What are symptoms of HIV?

A

Flu-like symptoms for a few weeks.

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14
Q

How can the symptoms in the first few weeks be controlled?

A

Taking antiretroviral drugs. Will stop the virus replicating.

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15
Q

What is late stage HIV infection, or AIDS?

A

When your body’s immune system is badly damaged that it can’t cope with other infections or cancers.

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16
Q

What is tobacco mosaic virus?

A

Virus that affects many species of plants, eg. tomatoes.

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17
Q

What does tobacco mosaic virus cause?

A

Mosaic pattern on the leaves of plants. Parts of the leaf become discoloured.

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18
Q

How can TMV affect a plants growth?

A

As the leafs have been discoloured, the plant can’t carry out photosynthesis as well.

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19
Q

What is rose black spot?

A

A fungus that causes purple or black spots to develop on the leaves of rose plants. The leaves then can turn yellow and drop off.

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20
Q

Why does rose black spot affect growth?

A

As the leaves turn yellow and drop off, less photosynthesis can happen.

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21
Q

How does rose balck spot spread?

A

Through the environment in water or by the wind.

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22
Q

How can rose black spot be treated?

A

Using fungicides or stripping the plant of it’s affected areas. These leaves are then destroyed so that it can’t spread to other plants.

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23
Q

What is malaria and how does it spread?

A

Disease caused by a protist. Part of the malarial protists life cycle takes place in a mosquito. Mosquitoes are vectors and will pick up the protist when feeding on an infected animal. Everytime the mosquito feeds on another animal, it infects it by inserting the protist into the animal’s blood vessels.

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24
Q

What are symptoms of malaria?

A

Repeating episodes of feaver.

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25
Q

How can the spread of malaria be reduced?

A

Stopping the mosquitoes from breeding, using insecticides and mosquito nets.

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26
Q

What is salmonella?

A

A type of bacteria that causes food poisoning.

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27
Q

What are symptoms of salmonella?

A

Fever, stomach cramps, vomiting and diarrhoea.

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28
Q

What causes the symptoms of salmonella?

A

Toxins produced.

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29
Q

How can you get salmonella?

A

Eating food that has been contaminated with Salmonella bacteria.

30
Q

How is the spread of salmonella controlled in the UK?

A

Vaccinating poultry against the bacteria.

31
Q

What is gonorrhoea?

A

A sexually transmitted disease caused by bacteria.

32
Q

How is gonorrhoea spread?

A

By sexual contact.

33
Q

What are the symptoms of gonorrhoea?

A

Pain when urinating, thick yellow or green discharge.

34
Q

How is gonorrhoea treated?

A

Originally with antibiotic called penicillin, but has become trickier now as strains have become resistant to it now.

35
Q

How can you prevent the spread gonorrhoea?

A

Barrier method of contacteption.

36
Q

How can the spread of disease be reduced or prevented?

A
  1. Being hygienic.
  2. Destroying vectors (insecticides or destroying habitats).
  3. Isolating infected individuals.
  4. Vaccination.
37
Q

What defence systems does your body have against pathogens?

A
  1. Skin acts as a barrier. Also secretes antimicrobial substances which kill pathogens.
  2. Hairs ans mucus in your nose trap potentially pathogenic particles.
  3. Trachea and brochi secrete mucus to trap pathogens. Lined with cilia which waft the musus up the back of the throat where it can be swallowed.
  4. Stomach produced hydrochloric acid which can kill pathogens.
38
Q

What is phagocytosis?

A

When white blood cells engulf foreign cells and digest them.

39
Q

Describe how antibodies protect against disease?

A

When white blood cells come across a foreign antigen they will start to produce proteins called antibodies to lock onto the invading cells so that they can be found and destroyed by other white blood cells. Antibodies are then produced rapidly and carried around the body to find all similar bacteria or viruses. If the person is infected with the same pathogen again, the white blood cells will rapidly produce the antibodies to kill it.. Now naturally immune.

40
Q

How do white blood cells protect the body against bacteria?

A

Produce antitoxins which counteract the toxins produced by the invading bacteria.

41
Q

What are vaccinations and how do they work?

A

Involve injecting small amounts of dead or inactive pathogens which carry antigens which cause your body to produce antibodies to attack them even though the pathogen is harmless. If live pathogens appear after that, the white blood cells can rapidly mass-produce antibodies to kill off the pathogen.

42
Q

What are pros of vaccines?

A
  1. Help to control lots of communicable diseases.

2. If a large percentage of the population are vaccinated, epidemics can be prevented.

43
Q

What are cons of vaccines?

A
  1. Don’t always work. Sometimes don’t give you immunity.

2. Can sometimes have a bad reaction to a vaccine but these are rare.

44
Q

What are painkillers?

A

Drugs that relieve pain. However they don’t kill the pathogen, they only reduce the symptoms.

45
Q

What are antibiotics?

A

They kill or prevent the growth of bacteria without killing your own body cells.

46
Q

Why is it difficult to develop drugs that kill viruses?

A

Viruses reproduce using your body cells, so it is diffucult to destroy the virus without killing the body’s cells.

47
Q

Why is it important to avoid overprescribing antibiotics?

A

Bacteria can mutate causing them to become resistant. If you have an infection, the bacteria might be resistant to the antibiotics. This means that when you treat the infection only the non-resistant strands will be killed. Thie individual resistant strand will survive and reproduce and the population of the resistant strand will increase. Avoiding overprescribign antibiotics will slow down the rate of developing resistant strains.

48
Q

Whart chemicals do plant produce that can be used as drugs to treat human diseases and relieve symptoms?

A
  1. Aspirin - Used as a painkiller to lower fever from a chemical in willow.
  2. Digitalis - Used to treat heart conditions from a chemical found in foxgloves.
49
Q

What drug was extracted from microorganisms?

A

Penicillin.

50
Q

How are drugs made these days?

A

On a large scale in the pharmaceutical industry. Synthesised by chemicals in labs.

51
Q

What is the first stage of preclinical testing?

A

Drugs tested on human cells and tissues in the lab. But you can’t use this to test drugs that affect whole or multi body systems.

52
Q

What is the second stage in preclinical drug testing?

A

Drug tested on live animals to test for efficacy (whether it works and produces the effects you are looking for), toxicity (how harmful it is) and the best doosage (concentration that should be given).

53
Q

What are British laws on preclinical animal testing?

A

Any new drug must be tested on two different liive mammals. Some people think this is cruel but others believe this is the safest way.

54
Q

What is the third stage of drug testing?

A
  1. The drug is tested on human volunteers.
  2. First the drug is tested on healthy volunteers to make sure it doesn’t have any harmful side-effects. A very low dose is given at first and this is gradually increased.
  3. The drug is then tested on people with the illness. The optimum dose is then found.
  4. To test how well the drug works the patients are randomly put into two groups. One is given the new drug and the other is given a placebo.
  5. The clinical trial is blind.
  6. The results are then published once they’ve gone through peer review.
55
Q

What is a placebo?

A

A substance that doesn’t do anything so the doctor can see the actual difference the drug makes - allows for the placebo effect.

56
Q

What is a double blind trial?

A

Neither the patient nor the doctor knows who has the placebo and who has the real drug until the results have been gathered. So they aren’t subconciously influenced by their own knowledge.

57
Q

What are monoclonal antibodies?

A

Produced from lots of clones of a single white blood cell. This means that all the antibodies are identcal and will only target one specific protein antigen.

58
Q

How are monoclonal antibodies made?

A

Mouse is injected with chosen antigen. Mouse B-lymphocyte cells are fused with tumour cells to create a hybridoma. These cells can be cloned to create lots of identical cells which all produce the same antibodies. They can then be collected and purified.

59
Q

Why are monoclonal antibodies really useful?

A

They will only bind to the certain molecule which means you can use them to target a specific cell or chemical in the body.

60
Q

How do pregnacy testing kits work?

A

They detect HCG hormone as this is only found in the urine of a pregnant woman.
The bit of the stick has some antibodies to the hormone with blue beads attached. The test strip has some more antibodies to the hormone stuck onto it.
1. If you are pregnant:
- The hormone binds to the antibodies on the blue beads.
- The urine moves up the stick carrying the hormone and the beads.
- The beads and hormone bind to the antibodies on the strip.
- The blue beads get stuck on the strip turning it blue.
2. If not pregnant:
- The urine moves up the stick carrying the blue beads but they are unable to stick on the test strip so it doesn’t go blue.

61
Q

How can monoclonal antibodies be used to treat cancer?

A

Cancer cells have anti-gens on their cell membrane called tumour makers. Monoclonal antibodies can be made that will bind to these markers. An anti-cancer drug can be attached to these monoclonal antibodies. The antibodies are given to the patient through a drip. They antibodies target specific cells as they only bind to the tumour markers. The drug kills the cancer cells but not any normal body cells.

62
Q

What can monoclonal antibodies be used for?

A
  1. Bind to hormones and other chemicals in the blood to measure their levels.
  2. Test blood samples in laboratories for certain pathogens.
  3. Locate specific molecules on a cell or in a tissue.
63
Q

How can monoclonal antibodies be used to locate specific molecules on a cell or in a tissue?

A
  1. Monoclonal antibodies are made that will bind to the specific molecule you are looking for.
  2. The antibodies are then bound to a fluorescent dye.
  3. If the molecules are present in the sample you are analysing, the monocolonal antibodies will attach to them, and they can be detected using the dye.
64
Q

What are some advantages of monoclonal antibodies?

A

Cancer treatment - only targets specific cells unlike others which can affect normal body cells. - so side effects should be lower.

65
Q

What is a problem with monoclonal antibodes?

A

Cause more side-effects than originally expected. Can cause fever, vomiting and low blood pressure. Meaning they are not as widely used.

66
Q

Whar are the two main mineral ions plants need?

A
  1. Nitrate ions - to make proteins and therefore growth. A lack of nitrates causes stunted growth.
  2. Magnesium ions - for making chlorophyll, which is needed for photosynthesis. Plants without enough magnesium suffer from chlorosis and have yellow leaves.
67
Q

What are common signs of plant disease?

A
  1. Stunted growth, 2. Spots on the leaves, 3. Patches of decay, 4. Abnormal growths, 5. Malformed stems or leaves, 6. Discolouration.
68
Q

What are ways of looking up plant disease signs?

A
  1. Gardening manual or website.
  2. Taking the infected plant to a laboratory.
  3. Using testing kits to identify the pathogen using monoclonal antibodies.
69
Q

What are plants physical defences?

A
  1. Waxy cuticle on leaves and stems to provide a barrier.
  2. Cell walls made of cellulose surrounding the plant cell wall forming a physical barrier.
  3. Layers of dead cells around their stems, act as a barrier. eg, bark.
70
Q

What are plants chemical defences?

A
  1. Produce antibacterial chemicals which kill bacteria.

2. Produce poisins which can deter herbivores.

71
Q

What are plants mechanical defences?

A
  1. Thorns and hairs. Stops animals from touching or eating them.
  2. Droop or curl when something touches them.
  3. Mimic other organisms - tricks organisms into not eating them.