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Biology (Triple) > Infection And Response > Flashcards

Infection And Response Flashcards

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1
Q

How are infections caused?

A

Infections are caused whenever a foreign pathogen invades an organism.

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2
Q

What are the four main types of pathogen?

A

1) Virus
2) Bacteria
3) Fungi
4) Protists

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3
Q

What is a virus and how do they attack the body?

A

Viruses are tiny non-living particles that can reproduce rapidly within the body. They invade host cells and use them to make new virus particles. Once the new viruses are made, they cause the cells to burst. The cell damage makes us feel ill.

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4
Q

What is bacteria and how does it attack the body?

A

Bacteria are small living cells that either damage cells directly or by producing toxins. Bacteria can rapidly reproduce in the appropriate conditions: warm, moist areas with a good supply of oxygen. The toxins released by bacteria can damage cells and tissues, making us feel ill.

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5
Q

What are fungi and how do they attack the body?

A

Some fungi are single-celled organisms that have a body made up of hyphae (threat-like structures). The hyphae are able to grow and penetrate tissues, such as human skin or the surface of plants. The hyphae produce spores that can spread to other plants and animals.

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6
Q

What are protists and how do they attack the body?

A

Protists are single-celled eukaryotic organisms. Many are parasites, meaning that they live on or inside other organisms. They are often transferred to the host organism by a vector, such as an insect or mosquito. They make us feel ill by damaging our tissues.

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7
Q

What are the three ways an infectious disease can spread?

A

1) Air
2) Water
3) Direct contact

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8
Q

How can a disease spread by air?

A

Some pathogens are released into the air inside droplets when an organism coughs or sneezes. These droplets can then be inhaled by other organisms.

The flu or common cold are spread this way.

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9
Q

How can diseases spread by water?

A

Some pathogens contaminate water supplies. Organisms drinking this contaminated water can be infected by pathogens.

Cholera is a disease spread this way.

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10
Q

How can diseases be spread by direct contact?

A

Some pathogens live on the surface of other organisms, such as the skin. If infected skin touches a surface, some of the pathogens can transfer from the infected skin onto the surface.

The pathogen then spreads to other people who also touch that surface. Athlete’s foot is spread in this way.

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11
Q

How can the spread of infections be prevented?

A
  • Vaccinations
  • Isolating
  • Being hygienic
  • Protecting against vectors
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12
Q

How can infections be prevented by vaccinations?

A

Vaccinations can make people immune to infection. The more individuals that are vaccinated, the less likely the disease is to spread.

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13
Q

How can isolation prevent infections?

A

By Isolating infected individuals, we prevent contact with other organisms.

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14
Q

How does being hygienic prevent infections?

A

By being hygienic, we can destroy pathogens or wash them away so that they are not spread.

Using antibacterial products to clean surfaces, washing our hands and sneezing into a handkerchief are all hygienic measures to prevent the spread of infection.

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15
Q

What are vectors?

A

A vector is an organism that carries pathogens without being infected.

Some protist diseases are carried by vectors.

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16
Q

What can be used to protect against vectors?

A

Mosquito nets

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17
Q

What are some examples of viruses?

A
  • TMV (Tobacco mosiac virus)
  • Measles
  • HIV (Human immunodeficiency virus)
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18
Q

What is TMV (Tobacco mosaic virus)?

A

It is a pathogen that affects plants, such as tomatoes.

The unique ‘mosiac’ pattern of the discolouration of the plant stunts the growth of the affected plant, because photosynthesis cannot take place.

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19
Q

What are measles?

A

Measles is a virus that can be fatal if complications arise. For this reason, most young children are vaccinated against measles. Measles is spread by breathing in droplets from sneezes and coughs.

Symptoms include a fever and red skin rash.

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20
Q

What is HIV (Human immunodeficiency virus)?

A

HIV is spread by sexual contact or the exchange of bodily fluids (e.g. blood from sharing needles). Initially, HIV causes a flu-like illness. However, unless antiretroviral drugs are used successfully, the HIV virus enters the lymph nodes and attacks the body’s own immune cells.

AIDS is caused by HIV. It is the name given to life-threatening infections that can happen when a person’s immune system has been badly damaged by HIV.

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21
Q

What are some examples of Bacteria?

A
  • Salmonella
  • Gonorrhoea
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22
Q

What is salmonella?

A

If food has not been cooked properly or has been prepared in unhygienic conditions, then we may ingest salmonella bacteria that cause food poisoning.

The bacteria release toxins, causing fever, stomach pain, vomiting and diarrhoea.

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23
Q

What is gonorrhoea?

A

Gonorrhoea is a sexually transmitted disease. Its symptoms include pain when urinating and a thick yellow or green discharge from the vagina or penis.

Barrier methods of contraception, such as condoms, can be used to stop the bacteria spreading from person to person.

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24
Q

What is an example of fungi?

A
  • Rose Black Spot
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25
Q

What is rose black spot?

A

Rose Black spot can be spread in water or in the air. It causes purple or black spots on the leaves of rose plants. Eventually, the leaves discolour and fall off. This makes it harder for plants to photosynthesise and plant growth slows. Removing and destroying discoloured leaves and using fungicides can treat affected plants.

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26
Q

What is an example of protists?

A

Malaria

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27
Q

What is malaria?

A

Malaria is spread by the female anopheles mosquito. If a mosquito is carrying malaria, then it transfers the infection into a person’s bloodstream when it bites them. Malaria leads to recurring and severe fevers, which can cause death.

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28
Q

What are non-specific defenses preventing?

A

Any pathogens from entering the body and causing harm.

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29
Q

What are the body’s non-specific defenses?

A
  • Stomach acid
  • Mucus
  • Skin
  • Tears
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30
Q

How is stomach acid designed to prevent pathogens entering the body?

A

Glands in the stomach wall produce hydrochloric acid, which destroys any pathogens that enter the stomach.

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31
Q

How does skin prevent pathogens entering the body?

A

Skin is a waterproof barrier that pathogens cannot pass through. Good bacteria live permanently on our skin, covering the surface and preventing pathogens from growing on our skin.

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32
Q

How does mucus prevent pathogens from entering our body?

A

Mucus is produced in the respiratory system and traps the particles and bacteria entering our airways.

33
Q

How do tears prevent pathogens from entering the body?

A

Tears contain enzymes that destroy any pathogen that makes contact with our eye.

34
Q

What happens if a pathogen passes the non-specific defenses?

A

The immune system is activated.

35
Q

What are the different functions of the immune system?

A
  • Antibodies
  • Antitoxins
  • Phagocytosis
36
Q

How do antibodies work?

A

White blood cells recognise foreign antigens on the surface of pathogens and produce protein molecules called antibodies.

Antibodies are specific to particular pathogens.

37
Q

How do antitoxins work?

A

Some bacteria produce toxins that can damage cells and tissues. The immune system responds to this by producing antitoxins, which neutralise the toxins released by the bacteria and prevent them from causing harm.

38
Q

How do phagocytosis work?

A

A white blood cell finds the pathogen and engulfs it by changing shape. The white blood cell ingests and and digests the pathogen, destroying it.

39
Q

What are antigens?

A

Antigens are proteins found on the surface of cells. White blood cells can recognise foreign antigens on the surface of pathogens and produce molecules called antibodies.

40
Q

Why do antibodies and antigens have a complementary shape?

A

Antibodies have a complimentary shape to the antigen and lock onto the pathogen, effectively ‘tagging’ them.

41
Q

What happens when antibodies lock onto pathogens?

A

This causes the microorganisms to cluster, allowing other white blood cells to come and ingest them.

42
Q

How do vaccinations work?

A

A vaccination injects a dead or inactive form of a pathogen into the blood. The white blood cells will recognise the foreign antigens and produce antibodies against them.

Some of these white blood cells remain in the blood as memory cells. If the same pathogen invades the body, the memory cells can: produce antibodies faster, produce more antibodies (so that antibody concentration remains in the body longer).

43
Q

Why might an antibody produced to target salmonella bacteria not work against a bacteria that causes gonorrhoea?

A
  • Antibodies have a different complimentary shape to the antigen.
  • Antibodies are specific to particular shapes of pathogens, so an antibody produced to target salmonella won’t work against a bacteria that causes gonorrhoea.
44
Q

What are antibiotics?

A

Antibiotics (such as penicillin), are drugs developed to cure infections caused by bacteria. Some antibiotics work by destroying the cell wall of the bacteria so that they can’t replicate.

45
Q

Why don’t antibiotics affect viruses?

A

Antibiotics do not destroy viruses because viruses stay inside host cells and are not living cells.

46
Q

What is antibiotic resistance?

A

Some bacteria cannot be killed by antibiotics.

47
Q

Why is MRSA a “superbug”?

A

It is resistant to many antibiotics.

48
Q

How can you prevent strains of resistant bacteria from developing?

A
  • Doctors should only prescribe antibiotics if they are needed and not for minor infections or viral infections.
  • Patients should complete their course of antibiotics to ensure all bacteria are killed.
49
Q

What is the process of bacteria becoming resistant to antibiotics?

A
  • Within a population of bacteria, some will have random mutations. The mutated bacteria are resistant to antibiotic, so they can survive, whole the non-resistant bacteria dies.
  • The non-resistant bacteria can reproduce rapidly because of its competition has been destroyed by the antibiotic. When resistant bacteria reproduce, they produce genetically identical copies. These copies will all be resistant to antibiotics.
50
Q

How were drugs made/extracted from in the past?

A

Many drugs were taken from plants and microorganisms.

51
Q

How are drugs made nowadays?

A

Drugs are synthesised by chemists in the pharmaceutical industry.

52
Q

Where and when did digitalis originate?

A

The heart drug digitalis orginates from foxgloves (a plant) which was first used 200 years ago by William Withering.

53
Q

Where does aspirin originate from?

A

The painkiller aspirin originates from willow trees.

54
Q

Who discovered penicillin?

A

Alexander Fleming

55
Q

How is penicillin made?

A

The antibiotic penicillin is made from penicillium mould.

56
Q

Why are scientists always trialling new bacteria?

A

For when new strains of resistant bacteria appear.

57
Q

What are painkillers used for?

A

Painkillers are used to relieve the pain caused by an infection. They don’t cure diseases or kill pathogens, they just relieve the symptoms.

58
Q

What are used to treat viral infections?

A

Antiviral drugs

59
Q

What are the three main criteria of testing drugs?

A

Toxicity - Is the drug safe?
Efficacy - Does the drug work?
Dose - How much of the drug is needed?

60
Q

What are the two stages to testing drugs in laboratories?

A
  • Preclinical testing
  • Clinical testing
61
Q

What is preclinical testing?

A

Scientists carry out early stage testing on human cells and tissues grown in the laboratory or on live animals.

Testing on animals is useful for working out how toxic a drug is to cells.

In the UK, new medicines have to undergo tests on two different live mammals.

Many drugs fail at this stage if they damage cells or do not work.

62
Q

What is clinical testing?

A

Clinical trials test drugs on healthy volunteers and patients to check that they are safe. They usually use low doses of the drug.

If a drug is found to be safe at low doses, there are more clinical trials to work out the optimum dose for the drug.

63
Q

What are double-blind tests?

A

In clinical trials, some patients are given a placebo. Whether a patient gets the drug or the placebo is randomly chosen. Neither the patient nor the decor knows who has received which.

64
Q

What is the equation for effectiveness of drug testing?

A

Effectiveness = (no. of individuals whose symptoms were relieved ÷ number if tested individuals) x 100

65
Q

How are monoclonal antibodies produced?

A

They are produced from clones of cells (often white blood cells).

66
Q

Why do monoclonal antibodies target specific chemicals of cells in the body?

A

Monoclonal antibodies are specific to one binding site on one protein antigen.

67
Q

What are the different ways monoclonal antibodies are used for?

A
  • Identifying chemicals in blood.
  • Pregnancy tests
  • Treating diseases
68
Q

What are the side effects of treating patients using monoclonal antibodies?

A

Fevers, low blood pressure and vomiting.

69
Q

Why are monoclonal antibodies used for identifying chemicals in blood?

A
  • They can identify molecules in a tissue or cell by binding to them with a fluorescent dye.

-Identify the levels of hormones in the blood.

  • Be used to test blood samples for pathogens, such as HIV.
70
Q

How are monoclonal antibodies used in pregnancy tests?

A
  • Pregnant women produce a hormone called HCG.
  • Monoclonal antibodies cam be used in pregnancy tests to bind to the HCG hormone’s antigen.
  • If the urine contains HCG, the antibodies bind and shows a positive result.
71
Q

How are monoclonal antibodies used for treating diseases?

A
  • We can attach anti-cancer drugs to the monoclonal antibodies. When they bind to the cancer cells, they can deliver the drugs directly to the tumours.
  • This is an effective cancer treatment because the antibodies cannot bind to or damage any normal human body cells.
72
Q

What are lymphocytes?

A

White blood cell

73
Q

What are the different ion deficiency conditions?

A
  • Magnesium deficiency
  • Nitrate deficiency
74
Q

What is magnesium deficiency?

A

There isn’t enough magnesium in the soil, which causes plant leaves to turn yellow.

Magnesium is required for the production of chlorophyll. Without this, it causes chlorosis, meaning that the plant cannot photosynthesis well or produce enough glucose to grow.

75
Q

What is nitrate deficiency?

A

Nitrates are needed for the production and synthesis of proteins.

Without proteins, plants cannot grow, because of this, nitrate deficiency causes stunted growth.

76
Q

How can plants be infected?

A
  • Tobacco Mosaic Virus (TMV)
  • Pests (insects)
  • Fungal disease
77
Q

What are the 3 different plant defences against infections?

A

Chemical
Mechanical
Physical

78
Q

What are the different signs of having a plant disease?

A
  • Areas of decay (rot)
  • Discolouration
  • Malformed seems or leaves
  • Growths
  • Stunted growths
    ,- Presence of pests
  • Spots on leaves
79
Q

What are the three different ways of identifying plant disease?

A
  • Laboratory
  • Testing kit
  • Gardening manual

Biology (Triple) (6 decks)

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