4.1 Disease Flashcards

1
Q

What is a disease?

A

A condition that impairs the normal function of an organism.

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2
Q

What is a pathogen and give examples.

A

An organism that causes disease eg bacteria fungi virus and protoctists.

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3
Q

What is a communicable disease?

A

A disease that can spread between organisms.

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4
Q

What pathogen type is Tuberculosis and who does it effect?

A

A bacterium.
Affects animals mostly humans and cattle.

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5
Q

What pathogen causes Bacterial Meningitis and who does it affect?

A

Bacterium.
Affects humans.

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6
Q

What pathogen causes ring rot and who does it effect?

A

Bacterium.
Tomado and potatoes.

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7
Q

What pathogen causes HIV/AIDS and who does is affect?

A

Virus.
Affects humans.

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8
Q

What pathogen causes influenza and who does it affect?

A

Virus.
Affects animals including humans.

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9
Q

What pathogen causes Tobacco mosaic virus and who does it affect?

A

Virus.
affects plants.

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10
Q

What pathogen causes black sigatoka and who does it affect?

A

Fungus.
Banana plants.

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11
Q

What pathogen causes ringworm and who does it affect?

A

Fungus.
Cattle.

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12
Q

What pathogen causes athletes foot and who does it affect?

A

Fungus.
Humans.

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13
Q

What pathogen causes tomato/ potato late blight and who does it affect?

A

Protoctist.
Tomatoes and Potatoes.

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14
Q

What pathogen causes malaria and who does it affect?

A

Protoctist.
Affects animals mainly humans.

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15
Q

What is direct transmission of disease?

A

When a disease is transmitted directly from one organism to another.

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16
Q

How can direct transmission occur?

A

Droplet infection
Sexual intercourse
Touching an infected organism

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17
Q

Give two examples of direct transmission diseases.

A

HIV
Athletes foot

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18
Q

What is indirect transmission?

A

When a disease is transmitted from one organism to another via an intermediate.

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19
Q

How can indirect transmission occur?

A

Through another organism (vectors)
Air
Water
Food

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20
Q

What are two examples of indirect transmission diseases ?

A

Potato/tomato blight
Malaria

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21
Q

What factors affect transmittion and why?

A
  1. Living conditions
    - because overcrowded conditions increase transmission of communicable diseases.
  2. Social factors
    - In humans only. Factors like income and the area people live in increase transmission of diseases.
  3. Climate
    - Warm and humid climates can aid spore and vector transmission.
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22
Q

What are the different animal primary defences to pathogens?

A

Skin
Mucous membranes
Blood clotting
Inflammation
Wound repair
Expulsive reflexes

23
Q

What are the different plant primary defences against pathogens?

A

Physical defences like waxy cuticles, cell walls and callose.
Chemical defences like toxic chemicals that stop insects.

24
Q

What is the immune response?

A

The body’s reaction to a foreign antigen.

25
Q

What are antigens?

A

Proteins or polysaccharides found on the surface of cells. When the pathogen enters the body the antigens on its surface are recognised as foreign and this activates the immune system.

26
Q

What is the first stage in the immune response and describe it and explain it.

A
  1. Phagocytosis
  • The phagocyte recognises antigens on pathogen.
  • Phagocytes cytoplasm moves around pathogen engulfing it. This is made easier with the presence of opsonins.
  • Pathogen is not contained in phagosome in cytoplasm of phagocyte.
  • Lysosome fuses with phagosome and enzymes in it break down pathogen.
  • Phagocyte then presents pathogens antigens on its surface to activate other immune system cells (its acting as a Anitgen-presenting cell APC)

Neutrophils are an example of a phagocytes.

27
Q

What is the structure and function of a phagocyte?

A

A white blood cell that carries out phagocytosis.
Has lots of lysosomes for pathogen digestion.

28
Q

What is the second stage in the immune response. Describe and explain it.

A
  1. T lymphocyte activation.
  • Receptors bind to complementary antigens on APC’s and activates the T lymphocyte( this process is know as clonal selection)
  • T lymphocyte then undergoes Clonal expansion where it divides to produce clones of itself
  • Some then become memory cells.
29
Q

What is the structure of T lymphocytes?

A

A white blood cell with receptors on its surface that bind to antigens on APCs.
Every T lymphocyte has different receptors on its surface.

30
Q

What’s the function of T helper cells?

A

Releasing substances to activate B lymphocytes and T killer cells.

31
Q

What is the function of T killer cells?

A

To attach and kill cells infected with a virus.

32
Q

What is the function of T regulatory cells?

A

To suppress the immune response from other white blood cells which helps stop immune system from attacking body cells.

33
Q

What is the third stage in the immune response? Describe and explain it

A
  1. B lymphocyte activation and plasma cell production.
  • When antibody on surface of B lymphocyte meets complementary antigen it binds to it forming antigen-antibody complex.
  • Each B lymphocyte binds to a different antigen!
  • This binding along with the chemicals released from T helper cells activates the B lymphocyte (clonal selection example)
  • The B lymphocyte then divides by mitosis into plasma cells and memory cells ( clonal expansion example)
34
Q

What is the fourth stage in the immune response?

A
  1. Antibody production.
  • Plasma cells (clones of the B lymphocytes) secrete loads of antibodies into the blood.
  • These bind to antigens on surface of pathogens to from antigen-antibody complexes. This helps signal to destroy the pathogens.
35
Q

Draw and describe the structure of antibodies.

A

Antigens are glycoproteins. Made of 4 polypeptide chains two heavy ones and two light ones. Each chain has a variable region and a constant region.

Check book for drawing.

36
Q

What three ways do antibodies help clear infections?

A
  1. Agglutinating pathogens
  2. Neutralise toxins
  3. Prevent pathogen binding to human cells.
37
Q

Explain the primary immune response. and describe what it’s like.

A
  • When pathogen enters body for first time it activates the immune system.
  • Slow as not many B lymphocytes that can make antibody needed.
  • Eventually enough antibodies will be made to overcome disease but until then the person will show symptoms.
  • After this the T and B lymphocytes produce memory cells which remain in body this gives people immunity as they can now respond quickly to a secondary infection.
38
Q

Explain the secondary immune response.

A
  • If same pathogen enters body again immune system responds faster and stronger.
  • This is because clonal selection happens faster.
  • No symptoms are then shown as pathogen is gone.
39
Q

Why can’t immunity be maintained forever?

A

As Memory T and B lymphocytes have a limited lifespan. Once they have died the person is susceptible to the pathogen attacking again.

40
Q

Give 4 differences between primary and secondary immune response.

A
  1. Primary is slow but Secondary is fast.
  2. Primary has symptoms secondary doesn’t have symptoms.
  3. In primary the pathogen enters for the first time but in secondary it enters for the second time.
  4. In the primary response B and T lymphocytes are activated but in secondary its memory cells.
41
Q

What is active immunity?

A

Type of immunity you get when your immune system makes its own antibodies after being stimulated by an antigen.

42
Q

What is natural active immunity?

A

When you become immune after catching a disease.

43
Q

What is artificial active immunity?

A

When you become immune after being given a vaccine containing harmless doses of an antigen.

44
Q

What is passive immunity?

A

A type of immunity you get from being given antibodies made by a different organism. Your immune system doesn’t produce any antibodies of its own.

45
Q

what is natural passive immunity?

A

When a baby becomes immune due to the antibodies, it receives from its mother through the placenta and breastmilk.

46
Q

What is artificial passive immunity?

A

this is when you become immune after being injected with antibodies from someone else.

47
Q

Compare active and passive immunity.

A
  1. Active immunity requires exposure to the antigen, whereas passive doesn’t.
  2. Active immunity takes a while for the protection to develop, whereas in passive immunity protection as immediate.
  3. active immunity is long-term protection passive immunity is only short term.
  4. in active immunity memory cells are produced in passive immunity they’re not.
48
Q

what is an autoimmune disease?

A

When the immune system treats, self-antigens as foreign antigens, and produces an immune response against the organisms own tissues. A disease resulting from this response is an autoimmune disease.

49
Q

What are two examples of autoimmune diseases?

A
  1. Lupus
  2. Rheumatoid arthritis
50
Q

What is a vaccine?

A

A weakened, dead or free floating antigen that is injected or taken orally. It gives you immunity without any symptoms as your body can produce memory cells.

51
Q

What is the difference between vaccination and immunisation.

A

Vaccination is the administration of antigens into the body whereas immunisation is the process of developing immunity. Vaccination causes immunity but not the same thing.

52
Q

Give two examples of routine vaccines and when they are given.

A
  1. The MMR at 1 yrs old
  2. The meningitis C vaccine at 3 months
53
Q

What is an antibiotic and what was the first one?

A

Chemicals that kill or inhibit growth of bacteria.
First one was penicillin.

54
Q

What causes antibiotic resistance?

A

Only the super resistant bacteria can survive in the host who is being treated with antibiotics. Causes the allele for the antibiotic resistance to be passed on.

Caused mainly by people not taking the full course of antibiotics.