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GCSE AQA Combined Science Biology 9-1 > Topic 3 - Infection and Response > Flashcards

Topic 3 - 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 pathogens?

A

Pathogens are microorganisms that cause diease

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3
Q

What are the four main types of pathogen?

A
  • Viruses
  • Bacteria
  • Fungi
  • Protists.
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4
Q

What is a virus?

A

A virus is a tiny, non-living particles that can reproduce rapidly within the body. They invade host cells and inserts its own DNA into the host cell’s DNA, which is copied and used to make new viruses. One the new viruses are made, they cause the cells to burst. The cell damage makes us feel ill.

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5
Q

What are bacteria?

A

Bacteria are small living cells that either damage cells directly or by producing toxins. They reproduce rapidly in warm conditions and 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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6
Q

What are fungi?

A

Fungi are eukaryotic organisms and can be either muticellular or unicellular. Muticellular fungi have long thread-like structures called hyphae. The hyphae are able to grow and spread through soil and penetrate tissues, like human skin or surface of plants. The hyphae produce spores that can spread to other plants and animals.

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7
Q

What is an example of a fungal disease?

A

Rose black spot

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8
Q

What is rose black spot?

A

Rose black spot is a bacteral disease which causes purple or black spots to form on the leaves plants, especially roses. Eventually, the leaves can begin to turn yellow and drop off, which reduces photosynthesis

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9
Q

How does rose black spot spread?

A

Rose black spot is transported either through the water or by the wind

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10
Q

How is rose black spot treated?

A

Rose black spot is treated by either chopping off infected leaves and destroying them so it can’‘t spread or spray the plant with fungicides

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11
Q

What are protists?

A

Protists are eukaryotes and are either unicellular organisms or multicellular organisms. However, a large majority are unicellular. Many protists are parasites, meaning 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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12
Q

What is malaria caused by?

A

Malaria is caused by parasitic protists, meaning it needs a host to survive

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13
Q

How is malaria spread between hosts?

A

Through vectors

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14
Q

How can we reduce the spread of malaria?

A
  • Stop the mosquito vectors from spreading the protists
  • Destroy the mosquito breeding sites
  • Kill the mosquito with insecticides
  • Use mosquito nets
  • Use mosquito repellent
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15
Q

How do pathogens spread?

A
  • Air
  • Direct contact
  • Contaminated food and water
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16
Q

How can disease be spread through air?

A

Some pathogens are released into the air inside droplets when an organism sneezes or coughs. These droplets can be inhaled by other organisms e.g. influenza, measles

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17
Q

How can disease be spread through direct contact?

A

Some pathogens live on the surface of other organisms e.g. (the skin). If infected skin touches a surface, some of the pathogens can transfer from the skin to the surface. The pathogen then spreads to other people who also touch that surface e.g athlete’s foot

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18
Q

How can disease be spread through food and water?

A

Some pathogens contaminate water supplies. Organisms drinking this contaminated water can be infected by pathogens e.g cholera, salmonella

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19
Q

How can you reduce the spread of disease?

A
  • Vaccination
  • Preventing contact with vectors (mosquito nets) / killing vectors (insecticides)
  • Being hygienic - washing hands, cleaning cookery items (knives, chopping boards)
  • Quarantining/ Isolating yourself if infected
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20
Q

How does vaccination prevent spread of disease?

A

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

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21
Q

How does preventing contact with vectors prevent spread of disease?

A

If protist diseases are carried by vectors (organisms that carry pathogens without being infected), then using nets or pesticides can prevent contact with vectors.

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22
Q

How does being hygienic prevent spread of disease?

A

Being hygienic, you can destroy pathogens or wash that away that they are not spread. You can also use antibacterial product to clean surfaces, along with sneezing into handkerchiefs to prevent spread of infection.

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23
Q

How does isolation prevent spread of disease?

A

By being isolated to other people, contact with other organisms is prevent. This stops the infection from spreading.

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24
Q

Are viruses cells and living?

A

No

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25
Q

How do viruses reproduce?

A

As they cannot reproduce themselves, they have to get inside another organisms cell where they can use the cells own machinery to make copies of themselves and hen when the time is right, burst the cell so then the new viruses have to find new cells to take over.

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26
Q

Whhy do viruses make us feel ill?

A

As they damage our bodies

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27
Q

What are three examples of diseases caused by viruses?

A

Measles, HIV and TMV.

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28
Q

What is measles?

A

Measles is a virus, that include red and rash skin along with a fever as symptoms. Young children are vaccinated against it, as it could be fatal.

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29
Q

How is measles spread?

A

Measles are spread by breathing in droplets from sneezes and coughs.

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30
Q

What does HIV stand for?

A

Human Immunodeficiency Virus

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31
Q

What does HIV refer to?

A

HIV refers to the virus not the disease

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32
Q

What is HIV?

A

Human immunodeficiency virus (or HIV) causes a flu-like illness. HIV enters the lymph nodes and attacks the body’s own immune cells, unless antiretroviral drugs are used properly. AIDS is caused by HIV, it happens when the infected person’s immune system has been badly damaged by HIV.

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33
Q

How is HIV spread?

A

HIV is spread by sexual contact (unprotected) or exchange of body fluids (blood).

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34
Q

What does TMV stand for?

A

Tobacco Mosaic Virus

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35
Q

What organism does TMV affect?

A

Plants (mainly tobacco and tomato plants)

36
Q

What is TMV?

A

Tobacco mosaic virus (or TMV) is a pathogen that affect plants, like tobacco. The unique ‘mosaic’ pattern of the discolouration of the plant stunts the growth of the affected plant, because photosynthesis can’t take place.

37
Q

Are bacteria unicellular or multicellular?

A

Unicellular

38
Q

Do bacteria reproduce rapidly? Why?

A

Bacteria reproduces rapidly because of the good food supply

39
Q

What can bacteria produce?

A

Bacteria can produce toxins and make us feel il by damaging our cells and tissues

40
Q

What are some examples of diseases caused by bacteria?

A

Salmonella and gonorrhoea

41
Q

What is salmonella?

A

Salmonella happens when food has not been cooked properly or the food has been made in unhygienic conditions, which might lead to the ingestion (eating) of salmonella particles

42
Q

What can salmonella cause?

A
  • Stomach cramps
  • Food poisoning
  • Vomiting
  • Fever
43
Q

How is gonorrhea spread?

A

Gonorrhea is a sexually transmtted disease

44
Q

What are symptoms of gonorrhea?

A
  • Pain when urinating
  • Thick yellow-green discharge
45
Q

How is gonorrhea treated?

A

Usually by penicillin but now a lot of gnorrhea strains are resistant to penicillin. So now we’re having to use rarer and more expensive antibiotics

46
Q

What are non-specific defences?

A

They are designed to prevent any pathogens from entering the body and causing harm.

47
Q

What are our non-specific defences?

A
  • Tears
  • Mucus
  • Stomach acid
  • Skin.
48
Q

How do tears defend our body?

A

Tears contain enzymes that destroy any pathogens that make contact with our eye.

49
Q

How does mucus defend our body?

A

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

50
Q

How does stomach acid defend our body?

A

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

51
Q

How does our skin defend the body?

A

The skin foms a protective layer covering the body. The outer layer of the skin consists of dead cells and is difficult for pathogens to penetrate. The skin also produces an oily substance called sebum which can kill bacteria.

52
Q

What are the different functions of white blood cells?

A

Producing antibodies, antitoxins and the process of phagocytosis.

53
Q

What are antigens?

A

An antigen is any substance that your body sees as foreign, which then causes your immune system to produce antibodies against it. For example, the toxins and cell walls of pathogens would be considered antigens.

54
Q

Why do white blood cells produce antibodies?

A

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

55
Q

Why are antitoxins produced?

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.

56
Q

What is phagocytosis?

A

A white blood cells finds the pathogen by detecting the chemicals being released from it and engulfs it by changing shape. The white blood cell ingests (absorbs) and digests the pathogen, destroying it through the use of enzymes .

57
Q

What are antibodies?

A

Antibodies are protein molecules produced by white blood cells. They bind to specific antigens and act as a signal to our immune system to destroy the antigen (or the pathogen it is part of)

58
Q

How do antibodies work?

A

The white blood cells find antigens on the surface of cells. White blood cells recognise the foreign antigens on the surface of pathogens and produce protein molecules called antibodies. Antibodies have a complementary shape to the antigen and lock onto the pathogen, effectively ‘tagging’ them. This causes the micro-organisms to cluster, allowing other white blood cells to come and ingest them.

59
Q

What are two key features of antibodies?

A

They are extremely specific and they an remain in the blood for a long time

60
Q

pros and cons of vaccinations

A

…………….

61
Q

What is the process of vaccination?

A

A dead or inactive form of a pathogen is injected into the blood. White blood cells recognise the foreign antigens and produce antibodies against them. Some white blood cells remain in the blood as memory cells. If the same pathogen invades the body again, the cells are able to produce antibodies faster and produce more antibodies, meaning that the antibody concentration remains in the blood for longer. Next time the same pathogen infects the vaccinated person, it will be destroyed by the immune system before illness is caused.

62
Q

What is herd immunity?

A

If a large percentage of the population is immune to a disease, it will make it very hard for a pathogen to spread.

63
Q

What are antibiotics?

A

Antibiotics are drugs developed to cure infections caused by bacteria.

64
Q

How do some antibiotics work?

A

They destroy the cell wall of the bacteria so that they can’t replicate.

65
Q

Why don’t antibiotics affect viruses?

A

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

66
Q

How are antibiotics specific?

A

Specific antibiotics are prescribed by medical doctors for specific diseases. The use of antibiotics has greatly reduced the number of deaths from infectious bacterial diseases.

67
Q

How have antibiotics benefitted the number of deaths?

A

The use of antibiotics has greatly reduced the number of deaths from infectious bacterial diseases.

68
Q

What is antibiotic resistance?

A

Some strains of bacteria are resistant to certain antibiotics. This means that these antibiotics cannot kill them.

69
Q

How can antibiotic resistance be stopped?

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 make sure that all bacteria are killed.

70
Q

What is MRSA?

A

MRSA is often called a ‘superbug’ as it is resistant to many antibiotics.

71
Q

What can happen if some bacteria mutate against antibiotics?

A

Some bacteria will have random mutations (change in DNA) in a population of bacteria. The mutated bacteria are resistant to antibiotics, so they can survive against it, whilst the non-resistant bacteria die. The resistant bacteria can reproduce rapidly because their competition has been destroyed by the antibiotics. When the resistant bacteria reproduce, they produce genetically-identical copies. These copies will all be resistant to the antibiotics.

72
Q

How were drugs extracted from the past?

A

They were extracted from plants and micro-organisms.

73
Q

Where does the heart drug digitalis originate from?

A

Digitalis originates from foxgloves which is a plant.

74
Q

Where does the painkiller aspirin originate from?

A

Aspirin originates from willow trees.

75
Q

Where is the antibiotic penicillin made from and who discovered it?

A

Alexander Fleming discovered penicillin, which is made from the penicillium mould.

76
Q

How are drugs made now?`

A

Drugs are synthesised (made) by chemists in the pharmaceutical industry, and the ingredients of these drugs may be chemicals extracted from plants.

77
Q

What are the different types of drugs being developed today?

A

Antiviral drugs, antibiotics and painkillers.

78
Q

What are antiviral drugs?

A

As viruses are found inside cells, it’s hard to destroy them without damaging the body’s cells and tissues. We use antiviral drugs to treat these viral infections.

79
Q

Why are antibiotics still being developed as of now?

A

Scientists are always trialling new antibiotics for when new strains of resistant bacteria appear.

80
Q

What are painkillers?

A

Painkillers are used to relieve the pain caused by an infection. They do not cure diseases or kill pathogens, but they do relieve the symptoms.

81
Q

Why do drugs have to be tested and trialled?

A

To check if the drug is safe (not toxic or harmful), how much of it is needed and if it works (efficient).

82
Q

What is the first stage of testing drugs?

A

Preclinical testing - scientists carry out early stage testing on human cells and tissues grown in the laboratory. This is also done on live animals. Testing on animals is useful to work 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.

83
Q

What is the second stage of testing drugs?

A

Clinical testing - 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 (best) dose for the drug.

84
Q

What is a double-blind trial?

A

During clinical trials, some patients are given a placebo (an alternative that does not contain any of the drug). Whether a patient gets the drug or the placebo is randomly chosen. Neither the patient nor the doctor knows who has received which.

85
Q

What are the two main features of a double-blind trial?

A

Unbiased - these trials make sure it’s a fair test. If the patient or doctor knew what they were taking, the outcomes of the trial could be different.
Identical conditions - all the conditions are kept identical across the two groups so that only the drug has an impact on a patient’s health.

86
Q

What is malaria caused by?

A

Malaria is caused by parasitic protists, meaning it needs a host to survive

GCSE AQA Combined Science Biology 9-1 (7 decks)

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