Diseases - 4.1 Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

What is a pathogen?

A

A microorganism that causes disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is a communicable disease

A

A disease that can be transmitted from one organism to another

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What diseases are caused by bacteria?

A
  • Tuberculosis (A)
    -Meningitis(A)
    -Ring rot (P)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What diseases are caused by viruses?

A

-HIV (A)
-Influenza (A)
-Corona virus (A)
-Tobacco mosaic virus (P)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What diseases are caused by protostists?

A

-Malaria (A)
-Blight (P)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What diseases are caused by fungi?

A

-Athletes foot (A)
-Ringworm (A)
-Black sigatoka (P)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is an antibiotic?

A

A drug that slows bacteria growth or kills bacteria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the primary reasons for the development of antibiotic resistance?

A

-Over prescription of antibiotics
-Patients not completing the course of antibiotics
-Routinely using antibiotics in farming

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How are pathogens transmitted?

A
  • Direct physical contact (reduce by hand washing, cleaning surfaces, etc)
  • Faecal - oral transmission usually by eating food or water contaminated by the pathogen, eg cholera (reduce by washing fresh food and treatment of drinking water)
  • Droplet infection ( reduce by covering mouth when coughing, etc)
  • Transmission by spores - they can be carried in the air or in soil (reduce by washing hands after contact with soil)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is a vector?

A

An organism that carries a pathogen from one host to another. This is indirect transmission- eg the plasmodium that causes malaria enters a host via a bite from a mosquito

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the role of T helper cells?

A

Release cytokines that stimulates B cells to develop and stimulates phagocytosis by phagocytes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the role of T killer cells?

A

Attack and kill host body cells that display the foreign antigen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the role of T memory cells?

A

Provide long term immunity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the role of T regulator cells?

A

Shut down the immune response after the pathogen has been successfully removed. Also involved in preventing autoimmunity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the role of plasma cells?

A

Circulate in the blood to manufacture and release antibodies

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the role of B memory cells?

A

Remain in the body for years and act as the immunological memory

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What happens in clonal selection in the specific immune response?

A

The specific antigens on the pathogen are detected by T and B lymphocytes that carry a specific receptor molecule on their plasma membrane that is complimentary to the shape of the antigen. This is where a T helper cell is clonally selected

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What happens in clonal expansion in the specific immune response?

A

Once the correct lymphocytes have been activated they must increase in number to become effective so divide by mitosis. The T helper cells also secretary cytokines which attract B cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What happens during differentiation during the specific immune response?

A

T and B lymphocytes develop into a range of useful cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What are the three main groups of antibodies?

A

-Agglutinins
-Opsonins
-Antitoxins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

How do Opsonins work?

A

Bind to the antigens in a pathogen which acts as a binding site for phagocytic cells so they can bind more easily to destroy the pathogen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

How do agglutinins work?

A

It cross links pathogens by binding an antigen in one pathogen with one binding site and then an antigen in another pathogen with its other binding site. This clumps together the pathogens which impedes them from carrying out some of their functions and makes it easier for them to be engulfed by phagocytosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

How do antitoxins work?

A

Directly bind to toxin molecules decreased by pathogen to neutralise them and prevent damage to cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

State three factors that would affect the speed of transmission in plants

A

-climate change
-wind
-overcrowding of crops
-warm humid conditions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

How is influenza virus most likely to be transmitted between humans?

A

Respiratory droplets

26
Q

Sate four different types of vector that can transmit a communicable disease

A

-water
-wind
-animals (mosquitos)
-humans

27
Q

State three passive physical defences that prevent plants being infected by pathogen

A

-cellulose cell wall
-bark
-waxy cuticle
-thorns

28
Q

State three active physical defences a plant would use against a invading pathogen

A
  • Callose synthesised and deposited between plasma membrane and cell wall (callose blocks sieve plates in phloem)
  • callose deposited in plasmodesmata between infected cells and their neighbours
    -lignin added to cell walls
    -tyloses block xylem vessels
29
Q

State three chemical defences a plant would use against an invading pathogen

A
  • hydrolytic enzymes (chitinases , tannins, etc)
  • antibacterial compounds ( phenols, alkaloids, etc)
30
Q

Describe the role of the skin as a primary non specific defence

A

-dead outer layer of keratin prevents pathogen entry
-skin flora outcompete pathogens for space
-oil secretions inhibit pathogenic growth

31
Q

Describe the role of mucus membranes as a primary non-specific defence

A
  • mucus traps pathogen
    -mucus contains lysosomes
    -phagocytes engulf and digest pathogens in mucus
32
Q

What enzyme catalyses the conversion of prothrombin to thrombin?

A

Thromboplastin

33
Q

Describe the role of thrombin in the clotting process

A

Causes the conversion of fibrinogen into insolvable fibrin fibres to block the wound

34
Q

Describe the process of inflammation as a secondary non-specific response

A

-mast cells release histamines
-histamines increase the permiability of capillaries so that plasma leaks into tissue fluid (causes pain and swelling)
-arterioles vasodilation so more blood can reach the infected area (causes heat and redness)
-neutrophils are attracted to the area so more phagocytosis happens

35
Q

Describe the process of phagocytosis

A

Phagocyte engulfs pathogen into a phagosome. Lysosomes fuse with the phagosome to form a phagolysosome. Enzymes, hydrogen peroxide and nitric acid break down the pathogen

36
Q

What is the name of small proteins that act as cell signalling compounds?

A

Cytokines

37
Q

How are neutrophils adapted for their role?

A

-Have a lobed nucleus so they can squeeze through capillaries
-Plasma membrane have receptors for opsonins
-Many mitochondria for respiration
-Many ribosomes to make enzymes
-Many lysosomes
-Many Golgi apparatus

38
Q

Why are opsonins non-specific?

A

So that opsonins can attach to any type of pathogen to help phagocytosis so the phagocyte has something to bind to. They have to be non-specific to bind to many different pathogens

39
Q

Define autoimmunity

A

The destruction of self tissue as the body’s immune system mistakes its own healthy tissues as foreign and attacks them

40
Q

Give examples of autoimmune diseases

A

-Rheumatoid arthritis
-Lupus
-Type 1 diabetes

41
Q

What is the role of T regulatory cells

A

Dampen down the immune response (stops it). Prevents autoimmunity

42
Q

How does an antigen presenting cell lead to a large number of T helper cells?

A

Antigen presenting cell binds specifically to Th cell (clinal selection)
This selected Th cell then increases in number by mitosis (clonal expansion)

43
Q

How are B lymphocytes activated and what is their role?

A

A T helper cell binds specifically to a B lymphocyte, B lymphocyte differentiates into plasma cell
Plasma cells release antibodies specific to particular antigen

44
Q

How do T killer cells destroy a virally infected cell?

A

They release performing which punch holes in membranes of infected cell. It then floods in hydrolytic enzymes , nitric acid and hydrogen peroxide

45
Q

What is the difference between an antigen and an antibody

A

An antigen is found on the surface of a pathogen and antibodies are produced by plasma cells - they are specific to the antigen

46
Q

How are plasma cells specialised for their role?

A

They produce antibodies - they ave lots of ribosomes, Golgi, RER and mitochondria

47
Q

How do opsonins function

A

They bind to an antigen on the pathogen which creates a binding site for the pathogen to attach to so it is marked for destruction by a neutrophil which binds to the constant region of the opsonin so the pathogen can be destroyed by phagocytosis

48
Q

How do agglutinins function?

A

One of the binding sites on the antibody binds to one antigen on a pathogen and the other binding site binds to a different antigen which cross links them. This clumps them together so they are easier to phagocytose

49
Q

How do antitoxins function?

A

They bind specifically to toxins produced by the pathogen so they neutralise them

50
Q

How does the structure of an antibody enable it to preform its function?

A

-It has variable regions specific to antigen (shape complimentary to shape of antigen)
-Has a hinge region so it is flexible to bind with more than one antigen
-The disulphide bridges hold the four polypeptide chains together
-The constant region may have a shape that can be recognised by neutrophils

51
Q

Why does it take several days for the primary immune response to become effective?

A

After infection the pathogen must be detected and attacked by macrophages, clonal selection must take place of T and B cells, they must then reproduce in clonal expansion, hen they must differentiate into plasma cells to produce specific antibodies to the antigens. Each step takes time

52
Q

Why is the secondary immune response so much faster than the primary immune response?

A

There are already T memory and B memory cells in the blood meaning that the correct T and B memory cells are clonal lay selected and can differentiate very quickly into the correct T helper, T killer and plasma cells, meaning plasma cells can produce antibodies faster and in greater quantity.
This means pathogen is wiped out before symptoms are experienced and the levels of antibodies stayed higher for longer

53
Q

What is natural active immunity - give example

A

The body’s own response to a new pathogen so memory cells are produced - antibodies made in immune system in response to infection

54
Q

What is natural passive immunity - give example

A

Antibodies provided through placenta and breast milk so no memory cells produced

55
Q

What is artificial active immunity - give example

A

The injection of an antigen so immune response occurs meaning memory cells produced

56
Q

What is artificial passive immunity - give example

A

ANTIBODIES are injected that have been made by another organism so no memory cells produced

57
Q

Why does passive immunity only provide short term immunity?

A

Antibodies are supplied which are proteins so will to last long in body and may be attacked by our own antibodies from our immune system

58
Q

What is an epidemic?

A

A rapid spread of disease through a high proportion of the population

59
Q

What is the difference between heard vaccination and ring vaccination?

A

-Heard vaccination is where almost everyone is vaccinated
-Ring vaccination only vaccinates people around the site of the outbreak to prevent spread of disease to the whole population

60
Q

How can a microorganism become resistant to an antibiotic?

A

Bacteria that survive a treatment will be slightly resistant to the antibiotic and the antibiotic will select the resistant individuals which can reproduce. Some of their offspring may be more resistant so resistance evolves

61
Q

parasite definition

A

An organism that lives inside a host and gets its nutrition at the expense of that organism