Topic 9: Disease, Defence and Treatment Flashcards

1
Q

What is a pathogen?

A

A microorganism that causes disease.

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2
Q

What is an example of a non-pathogenic microorganism?

A

Gut bacteria that helps digest food

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3
Q

What are 4 types of pathogen?

A

Bacteria
Viruses
Protists
Fungi

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4
Q

What are 5 features of bacteria cells?

A
Cell membrane
Cell wall
Cytoplasm
loose loops of DNA
No nucleus
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5
Q

What is the structure of a virus?

A

A virus contains some genetic material surrounded by a protein shell.

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6
Q

What are 5 ways diseases spread?

A
Direct contact or body fluids
Infection by air
Water
Insects
Contaminated food
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7
Q

What is the name of the virus that causes AIDS (acquired immune deficiency syndrome)?

A

Human immunodeficiency virus (HIV).

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8
Q

How is HIV spread?

A

Unprotected sex

Sharing needles/other drug injection equipment

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9
Q

What are the symptoms of AIDS?

A

HIV weakens the immune system:
Fever
Flue-like symptoms
Rash

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10
Q

How can the spread of HIV be prevented?

A

Safe sex - (don’t be silly wrap ur willy - George)
Avoiding sharing needles
Wearing surgical gloves when treating bleeding

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11
Q

What is HIV?

A

A virus that damages the cells in your immune system and weakens your ability to fight everyday infections and disease.

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12
Q

What is the cell wall of a bacteria made of?

A

A substance called murein.

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13
Q

What is chlamydia?

A

A sexually transmitted bacterial disease.

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14
Q

How is chlamydia transmitted?

A

Unprotected sex.

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15
Q

What are 4 symptoms of chlamydia?

A

Pain when urinating
Unusual discharges from sex organs
Painful testicles
Bleeding between periods

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16
Q

What are the treatments for chlamydia?

A

Can be treated with antibiotics.

If left for too long, problems such a sterility can occur.

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17
Q

How can chlamydia be prevented?

A

Wear a condom during sex.

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18
Q

What causes malaria?

A

A single-celled parasite of the species Plasmodium, carried by mosquitoes.

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19
Q

What are the symptoms of malaria?

A

High temperature
Sweats and chills
Headaches
Vomiting and diarrhoea

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20
Q

How can malaria be prevented?

A

Mosquitoes nets, insect-repellent
Antimalarial tablets
Treating homes with insecticide

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21
Q

What are 5 bodily defences?

A
Skin - acts as a barrier
Stomach acid - kills ingested pathogens
Mucus - trap pathogens 
Sweat - contains antimicrobial chemicals
Blood clots - prevent pathogen entry into wounds
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22
Q

What are the 2 features of the ‘preventing entry stage’ of the immune system?

A
  1. The skin is a barrier against pathogens, most the body is covered by it.
  2. If the skin is broke, blood will clot the wound to seal the gap.
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23
Q

If a pathogen passes the ‘preventing entry stage’ of the immune system, what happens?

A

The immune system kills the pathogens when they enter inside the body.

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24
Q

What are the 2 types of white blood cells that kill pathogens?

A

Phagocytes and lymphocytes.

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25
Q

What are phagocytes?

A

White blood cells that ingest (engulf) microorganisms and digest them.

26
Q

What are lymphocytes?

A

White blood cells that produce chemicals called antibodies which destroy microorganisms, antibodies called antitoxins neutralise any poisons produced by the pathogen.

27
Q

How do white blood cells detect ‘foreign’ cells in the body?

A

By recognising molecules on their cell surfaces (antigens).

28
Q

What are antigens?

A

Molecules on the surface of all cells that are recognised by the immune system.

29
Q

How do antigens help white blood cells detect foreign cells?

A

All cells in your body have an identical pattern of antigens, therefore white blood cells can easily detect the foreign cells.

30
Q

What are 2 methods in which lymphocytes destroy pathogens?

A

They either create antibodies to destroy the pathogens

or stick the pathogens together so that the phagocytes can ingest a lot at once.

31
Q

What is the 4 step method of phagocytes engulfing pathogens?

A

They detect the pathogen, engulf it, then enzymes within it

destroy the pathogen and the harmless remains of the pathogen leave the phagocyte.

32
Q

What are the 2 types of pathogen vaccines can protect against?

A

Bacteria and viruses.

33
Q

What are memory cells?

A

Memory cells are lymphocytes that after removing a pathogen, stay in the immune system, ready to rapidly fight off that pathogen if it enters the body again.

34
Q

What is the body’s defence system?

A
  1. Antigens are detected by the white blood cells.
  2. Phagocytes attack, lymphocytes start to develop an antibody against the antigens (may take a while, so you may grow ill due to pathogens).
  3. Lymphocytes begin producing correct antibody which also forms memory cells.
  4. Antibodies start to work against pathogen.
  5. If body is ever infected by these pathogens again memory cells rapidly produce the correct antibody which prevent symptoms to occur.
35
Q

What is vaccination?

A

A vaccine can produce immunity against a disease before you encounter it.

36
Q

What is in a vaccine?

A

The microorganisms that cause the disease but they have been killed (or sometimes weakened).

37
Q

Why are booster vaccines needed?

A

To ensure enough memory cells are produced to be able to fully fight off the disease.

38
Q

Why might parents choose to have their child vaccinated?

A

Vaccines save lives and will prevent some diseases.

39
Q

What are 3 reasons why parents might not choose to have their child vaccinated?

A
Vaccines include injection - may hurt/scare young children
Side effects (minor) - like itching / inflammation
40
Q

What type of pathogen do antibiotics only kill?

A

Bacteria (mainly) and fungi.

41
Q

How do antibiotics work?

A

They slow down or stop the growth of bacteria without damaging the host cells which can cure bacterial diseases.

42
Q

What type of microorganism produces penicillin?

A

A fungus called penicillium.

43
Q

What is semisynthetic penicillin?

A

Penicillin that has been modified chemically.

44
Q

What is synthetic penicillin?

A

Penicillin that has been produced from scratch chemically rather than being produced naturally by fungus.

45
Q

What is MRSA and why is it difficult to treat?

A

A type of bacteria resistant to several widely used antibiotics meaning infections with MRSA are harder to treat than others.

46
Q

What are 3 ways to prevent MRSA?

A

Hospital staff and visitors must take hygiene precautions.
Equipment sterilised thoroughly
Patients entering hospital screened for MRSA.

47
Q

What 2 measures are taken to slow natural selection?

A

Doctors avoid prescribing antibiotics wherever possible

Doctors vary prescriptions of antibiotics as much as possible to avoid antibiotics becoming ineffective.

48
Q

What are the 4 stages in the development of new drugs?

A
  1. Drug is tested on human cells grown in a lab.
  2. Drug is tested on animals, side effects monitored.
  3. Drug tested on healthy volunteers (beginning in low doses).
  4. Drug tested on people with disease after optimum dosage is found.
49
Q

What is a placebo?

A

A substance which looks the same and is ideally indistinguishable from the actual drug but has no effect when taken.

50
Q

What are placebos used for?

A

To test the effectiveness of a new drug by providing a comparison point.

51
Q

What is a blind trial?

A

Patients are not told if they are in the trial group or the placebo/control group for drug testing.

52
Q

What is a double blind trial?

A

The patient and the doctor and not told which is the placebo or trial group to eliminate bias.

53
Q

What are monoclonal antibodies?

A

A type of treatment which relies on the immune system. It copies a type of antibody so scientists can obtain large quantities of a specific one.

54
Q

How do lymphocytes produce monoclonal antibodies?

A

They are activated and produce antibodies that are specific to a pathogen.
They then divide so that lots of antibodies can be made at once.

55
Q

How are monoclonal antibodies produced in a lab? (7 step method)

A
  1. The antigens are injected into a mouse.
  2. The mouse’s lymphocytes produce antibodies specific to that antigen.
  3. Some spleen tissue containing lymphocytes is collected from the mouse.
  4. These cells are fused with myeloma cells to form hybridoma cells.
  5. The hybridoma cells are grown in a culture medium and produce the antibodies.
  6. The antibodies are extracted from the culture medium by centrifugation, filtration and chromatography.
56
Q

Where are lymphocytes most common?

A

The spleen.

57
Q

What are myeloma cells?

A

Cancerous white blood cells.

58
Q

What are hybridoma cells?

A

The fused myeloma cells and spleen cells.

59
Q

How can monoclonal antibodies be used to detect disease like: chlamydia, HIV and malaria?

A

Immunoassays.
Specific monoclonal antibodies that are attached to fluorescent dyes can be added to bodily fluids. If a patient’s blood displays the detectable (colour) change, the antigen must be present.

60
Q

How are monoclonal antibodies used in tissue and organ translplants?

A

They can identify different tissue types, which helps find the correct donors. They can detect how similar the antigens on the surface of cells are to the patient, avoiding rejection.

61
Q

How are monoclonal antibodies used to help chemotherapy?

A

Ones specific to cancer cells can have a drug attached to them that will kill the cells (which won’t damage healthy cells).

62
Q

How are monoclonal antibodies used to monitor the spread of malaria?

A

They can detect the malarial parasite antigens (via a detectable chemical being attached), allowing scientists to diagnose malaria to patients that have no symptoms.