Communicable Diseases Flashcards
1
Q
What time of disease can be passed from one person to another?
A
Communicable
2
Q
What do vectors do?
A
Carry organisms from one organism to another
3
Q
What are the 2 ways in which bacteria can be classified?
A
- Shapes
- Cell walls
4
Q
What are the shapes of bacteria?
A
Rod, Spherical, Comma, Spiralled, Corkscrew
5
Q
What do gram positive bacteria look like under the microscope?
A
Purple-blue
6
Q
What do gram negative bacteria look like under the microscope?
A
Red
7
Q
Give an example of gram negative bacteria…
A
E.coli
8
Q
Give an example of gram positive bacteria…
A
MRSA
9
Q
Why is gram staining useful?
A
The type of cell wall affects how bacteria react to different antibiotics.
10
Q
What are bacteria?
A
Prokaryotes
11
Q
What are fungi?
A
Eukaryotes
12
Q
What are protoctista?
A
Eukaryotes
13
Q
How do plant diseases threaten people?
A
When crop plants fail, people may starve, economies may struggle and jobs are lost.
14
Q
What pathogen is Ring rot?
A
Bacterial disease
15
Q
What does ring rot do to plants?
A
Damages leaves, tubers.
16
Q
What are the effects of ring rot on future growth?
A
Field is infected so it cannot be used to grow potatoes for at least two years.
17
Q
Name 4 plant diseases.
A
- Ring rot
- Potato blight
- Black sigatoka
- TMV
18
Q
What is affected by black sigatoka?
A
Bananas
19
Q
What is black sigatoka caused by?
A
A fungus
20
Q
What does black sigatoka do?
A
Attacks and destroys leaves. Hyphae penetrate and digest cells, turns leaves black.
21
Q
Are there any cures for black sigatoka?
A
Resistant strains being developed and fungicide treatment can control spread of disease.
No cure.
22
Q
What is potato blight caused by?
A
Protoctista
23
Q
What does potato blight cause?
A
Destroy leaves and tubers.
24
Q
Is there a cure for potato blight?
A
No cure.
Resistant strains available, careful management can reduce infection risk.
25
What does TMV stand for?
Tobacco mosaic virus
26
What is TMV caused by?
A virus.
27
What does TMV do?
Damages leaves, flowers, stunting growth and reducing yields.
28
Are there any cures for TMV?
No cure.
Resistant cures available.
29
Name 7 animal diseases...
- Tuberculosis (TB)
- Bacterial meningitis
- HIV/ AIDs
- Influenza (flu)
- Malaria
- Ring worm
- Athletes foot
30
How are pathogens transmitted directly?
Direct contact
Inoculation
Ingestion
31
How can pathogens be transmitted by direct contact?
Skin-to-skin contact
| Body fluids contact
32
How can pathogens be transmitted by inoculation?
Through break in skin
| Animal bite
33
How can pathogens be transmitted by ingestion?
Contaminated food or drink
34
How are pathogens transmitted indirectly?
Fomites
Droplet infection
Vectors
35
How can pathogens be transmitted by fomites?
Intimate objects
36
How can pathogens be transmitted by droplet infection?
Droplets of saliva and mucous are expelled from mouth when you talk or cough.
37
How can pathogens be transmitted by vectors?
One host to another.
| Water can act as vector.
38
Give 5 factors affecting the transmission of communicable diseases in animals
- Overcrowded
- Poor nutrition
- Poor disposal of waste
- Climate change
- Socioeconomic factors
39
How can pathogens be directly transmitted between plants?
Contact of a healthy part with a diseased part
40
How can pathogens be indirectly transmitted between plants?
Soil contamination
Vectors
41
How can soil contamination lead to transmission of diseases of plants?
Infected plants leave pathogens or reproductive spores from fungi or protoctista in the soil. These can infect the next crop.
42
Name 4 vectors...
- Wind
- Water
- Humans
- Animals
43
Give 5 factors affecting transmission of communicable diseases in plants
- Crops which are susceptible to disease
- Over crowding
- Poor mineral nutrition
- Climate change
- Damp, warm conditions
44
What do plants produce high levels of as a mechanical defence?
Callose
45
What is the physical defence of plants?
Callose
46
What does callose do?
1) Deposited between cell walls and cell membranes
2) Lignin is added, giving a stronger mechanical barrier
3) Callose blocks sieve plates
4) Callose is deposited in the plasmodesmata between infected cells and their neighbours
47
Give 5 chemical defences of plants
1) Insect repellents
2) Insecticides
3) Antifungal compounds
4) General toxins
5) Antibacterial compounds
48
Give an example of an insect repellent...
Citronella from lemon grass
49
Give an example of an insecticide...
Caffeine (toxic to insects and fungi)
50
Give an example of an antifungal compound...
Chitinases (break down chitin in fungal cell walls)
51
Give an example of a general toxin...
Chemicals can be broken down to form cyanide compounds which is toxic
52
Give an example of an antibacterial compound...
Lysosomes
53
What are the non-specific defences of the body to keep pathogens out?
Barriers, blood clotting, inflammatory response
54
What are the barriers to the body?
- Lysozymes in tears and urine
- Skin covers body, produces sebum which inhibits growth of pathogens
- Body tracts lined with mucous membranes which secrete mucous and trap microorganisms
55
What are the two important substances secreted when you cut yourself?
Thromboplastin
| Serotonin
56
What is thromboplastin?
Enzyme which triggers a cascade of reactions resulting in a blood clot.
57
What is serotonin?
Makes smooth muscle contract, so they narrow and reduce the supply of blood to the area.
58
What is inflammation characterised by?
Pain, heat, redness, swelling
59
What do mast cells release?
Histamines and cytokines
60
What are mast cells activated by?
Damaged tissue
61
What are the role of histamines in the inflammatory response?
- Make blood vessels dilate, causing localised heat and redness. Raised temperature prevents pathogens reproducing.
- Make blood vessel walls more leaky, so blood plasma is forced out. This forms tissue fluid and causes swelling and pain.
62
What are the role of cytokines in the inflammatory response?
Attract phagocytes for phagocytosis.
63
What are the non-specific defences of the body to get rid of the pathogen?
Fevers
| Phagocytosis
64
What does fevers do to get rid of the pathogen?
When pathogen invades body, cytokines stimulate hypothalamus to reset the thermostat and the temperature goes up.
This is good because specific immune system works quicker and most pathogens reproduce quickest below 37 degrees.
65
Give the stages of phagocytosis?
1) Phagocyte attracted to pathogen by chemicals produced by the pathogen.
2) Phagocyte binds to pathogen.
3) Phagocyte engulfs pathogen to form a phagosome.
4) Lysosomes move towards phagosome and combine with it forming a phagolysosome.
5) Lysosomes secrete lysozymes which hydrolse the pathogen.
6) Digested pathogen is absorbed by phagocyte.
7) Antigens combine with MHC in the cytoplasm.
8) MHC/ antigen complex is displayed on phagocyte membrane, making an antigen presenting cell.
66
What does MHC stand for?
Major histocompatibility complex
67
What are opsonins?
Bind to pathogen and tag them so more easily recognised by phagocytes.
68
What can cytokines act as?
Cell signalling molecules
69
Give 3 ways that antibodies defend the body?
1) Antigen antibody complex acts as an opsonin.
2) Acts as agglutinins.
3) Pathogens cannot effectively invade body cells if part of a complex.
70
What is the structure of an antibody?
4 polypeptide chains
- 2 light
- 2 heavy
- Held by disulphide bridges
2 antigen binding sites
Receptor binding site
Hinges
Variable region
Constant region
71
Antibodies are Y shaped glycoproteins called...
... immunoglobulins
72
What are the main types of B cells?
- Plasma cells
- B memory cells
- B effector cells
73
What are B effector cells?
Divide to form plasma cell clones
74
What are plasma cells?
Produce antibodies
75
What are B memory cells?
Provide immunological memory, very rapid response if pathogen carrying antigen is encountered again
76
What are the main types of T cells
- T killer
- T helper
- T memory
- T regulator
77
What are T killer cells?
Produce perforin which make membranes freely permeable
78
What are T regulator cells?
Supress the immune system.
Makes sure an autoimmune response is not set up.
79
What are T memory cells?
Part of immunological memory.
If meet an antigen again, divide to form clones of killer cells.
80
What are T helper cells?
Have receptors CD4 on the cell surface membrane which bind to surface antigens on APCs.
They produce interleukins. They stimulate B cells, which increase antibody production and other T cells.
81
What are interleukins?
Type of cytokine
82
What is a cytokine?
Cell signalling molecule
83
What are the steps of cell mediated immunity?
1) Non-specific defence engulf and digests pathogens by phagocytosis. They produce APCs.
2) The receptors on some T helper cells fit the antigens. These T helper cells become activated and produce interleukins, which stimulate more T cells to divide by mitosis. Forms a clone of T helper cells.
3) Cloned T cells may...
- Develop into T memory cells
- Produce interleukins which stimulate phagocytosis
- Produce interleukins which stimulate B cells to divide
- Stimulate development of a clone of T killer cells
84
What are the steps of humoral immunity?
1) Activated T helper cells bind to the B cell APC. This is clonal selection.
2) Interleukins produced by the activated T helper cells activate the B cells.
3) The activated B cell divides by mitosis to give clones of plasma cells and B memory cells. This is clonal expansion.
4) Cloned plasma cells produce antibodies that fit the antigens on the surface of the pathogen, they bind and disable them, or act as opsonins or agglutinins. This is the primary immune system.
5) Some cloned B cells develop into B memory cells. If the body is infected by the same pathogen again, B memory cells divide to form a clone of plasma cell which produce the specific antibody. This is the secondary immune response.
85
What is clonal selection?
The point at which the B cell with the correct antibody to overcome a particular antigen is selected for cloning.
86
What is an autoimmune disease?
Immune response stops recognising self cells and starts to attack healthy cells of the body.
87
Name 3 common autoimmune diseases...
Type 1 diabetes
Lupus
Rheumatoid arthritis
88
What body part does lupus affect?
Skin and joints
| Any organ
89
What is the treatment for lupus?
No cure
Anti-inflammatory drugs
Steroids
Immunosuppressant drugs
90
What is the treatment for Type 1 diabetes?
Insulin injections
Pancreas transplants
Immunosuppressant drugs
91
What body part does Type 1 diabetes affect?
Beta cells of the pancreas
92
What body part does Rheumatoid Arthritis affect?
Joints in particular in the hands, wrists, ankles and feet
93
What is the treatment for Rheumatoid Arthritis?
```
No cure
Anti-inflammatory drugs
Steroids
Pain relief
Immunosuppressant drugs
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