Module 4:Communicable Diseases

Question 1

What is a communicable disease?

Answer 1

A communicable disease is passed from one organism to another.

Question 2

Can I delete cards?

Answer 2

Apparently not

Question 3

Why are pathogenic bacteria harmful?

Answer 3

Most produce toxins that poison or damage host cells. They do this by: interrupting cell membranes, inactivate enzymes or interfere with genetic material.

Question 4

What are the different shapes of bacteria?

Answer 4

Rod shaped, spherical, comma shaped, spiralled and corkscrew.

Question 5

What are the two types of bacteria?

Answer 5

Gram +ve (Appear purple-blue after staining)

Gram -ve (Appear red after staining)

Question 6

What is an antibiotic?

Answer 6

A compound that kills or inhibits the growth of bacteria.

Question 7

What is the name of a rod-shaped bacteria?

Answer 7

Bacilli

Question 8

What is the name of a spherical bacteria?

Answer 8

cocci

Question 9

What is the name of a comma-shaped bacteria?

Answer 9

vibrio

Question 10

What is the name of a spiral-shaped bacteria?

Answer 10

sprilla

Question 11

What is the name of a corkscrew-shaped bacteria?

Answer 11

spirochaete

Question 12

What is the name of a virus that infects bacteria?

Answer 12

Bacteriophage

Question 13

What does different type of cell wall change about it’s treatment?

Answer 13

Different antibiotics are useful.

Question 14

What are protocista (protista)?

Answer 14

Eukaryotic organisms with a wide variety of feeding methods. They tend to either be single-cellular or a large colony of cells.

Question 15

What are Fungi?

Answer 15

Fungi are eukaryotic organisms that are often multi-cellular. Although thrush is single celled. They cannot photosynthesize and-so digest their food extracellularly and then absorb the nutrients. Some are saprophytic (feeding off dead matter). Some are parasytic.

Question 16

Why are fungi lethal to plants?

Answer 16

Fungal infections tend to effect the leaves of a plant, preventing photosynthesis, which then prevents aerobic respiration, killing the plant quickly.

Question 17

How do fungi reproduce?

Answer 17

They produce lots of spores, which allows for the rapid spread of the fungi.

Question 18

What 3 types of pathogen directly damage host tissue?

Answer 18

Viruses, protoctista and fungi.

Question 19

How do protoctista directly damage host tissues?

Answer 19

Take over cells and break them open as a new generation emerge. They don’t take over the genetic material, they digest and use the cell contents as they reproduce.

Question 20

How do fungi directly damage host tissues?

Answer 20

Fungi digest living cells and destroy them. The bodies response to this causes the symptoms of the disease.

Question 21

Why do plant diseases threaten humans?

Answer 21

They can cause famine and lead to the economy struggling, leading to loss of jobs. Further destruction of an ecosystem can occur.

Question 22

What is Ring Rot?

Answer 22

A bacterial disease of potatoes, tomatoes and aubergines. Caused by a gram +ve bacteria. It damages the leaves, tubers and fruit. No cure. Can destroy up to 80% of crops. To prevent spread don’t grow crops in infected field for two years. (Ring of rot in tubers)

Question 23

What is the tobacco mosaic virus?

Answer 23

A virus that infects tobacco plants and 150 other species. e.g tomatoes and peppers
It damages the leaves, flowers and fruit. Stunts growth and reduces yields, can lead to almost total crop loss. No cure but resistant crop strains available. (Causes mosaic pattern)

Question 24

What is potato blight?

Answer 24

Fungus-like protoctista. Their hyphae penetrate host cells, destroy leaves, tubers and fruit. No cure. Resistant strains and careful management, chemical treatment can reduce infection risk. (Discolouration and becomes brown)

Question 25

What is Black sigatoka?

Answer 25

pathogenic fungus. Attacks and destroys leaves. Hyphae penetrate and digest host cells, causing the leaves to turn black. If plants infected 50% reduction of crop yield. Resistant strains, good husbandry and fungicide control are used to control the spread. There is no cure.

Question 26

What are the 3 types of Direct Transmission?

Answer 26

Direct Contact, Inoculation, ingestion

Question 27

Direct Contact:

Answer 27

Direct skin to skin contact. Microorganisms from faeces transmitted onto hands.

Question 28

Inoculation:

Answer 28

Direct transmission through a break in the skin. e.g from animal bites. Or through a puncture wound.

Question 29

Ingestion:

Answer 29

Contaminated food or drink directly transferring pathogens to the mouth and digestive system.

Question 30

What are the 3 types of indirect transmission?

Answer 30

Fomites, Droplet Infection, Vectors

Question 31

Fomites:

Answer 31

Inanimate objects that can transfer pathogens

Question 32

Droplet Infection:

Answer 32

Miniature droplets of saliva and mucus expelled from the mouth or nose containing pathogens.

Question 33

Vectors:

Answer 33

A vector transmits communicable pathogens between organisms. Can be biotic and abiotic.

Question 34

How to limit interspecies transmission?

Answer 34

Minimising close contact can reduce infection rates. Washing hands thoroughly.

Question 35

What are the factors affecting the transmission of communicable diseases in animals:

Answer 35

overcrowding, poor nutrition, poor disposal of waste, climate change affecting vector populations, culture (traditional medicine), Socioeconomic factors (lack of trained medical staff)

Question 36

What are the factors affecting the transmission of communicable diseases in plants:

Answer 36

Susceptible varieties, over-crowding (increases likelihood of direct contact), malnutrition, damp and warm conditions, climate change (increased rainfall and wind promote spread of disease) .

Question 37

What are the two types of indirect transmission between plants?

Answer 37

Soil contamination and Vectors

Question 38

How does soil contamination spread disease between plants?

Answer 38

Infected plants leave pathogens or reproductive spores in the soil. These remain and can infect the next crop.

Question 39

What are the different vectors that can spread disease between plants?

Answer 39

Wind, Water, Animals, and Humans (or their fomites e.g contaminated equipment)

Question 40

What is tuberculosis?

Answer 40

A bacterial disease that damages lung tissue and suppresses the immune system. TB is curable with anti-biotics and preventable with vaccinations.

Question 41

What is Bacterial Meningitis?

Answer 41

A bacterial infection of the meninges in the brain. It can spread to the rest of the body and cause septicemia. Mainly affects young people. Can be cured with antibiotics if found early. Can be vaccinated against.

Question 42

What is HIV/AIDS

Answer 42

(Human Immunodeficiency virus) targets T-helper cells. The immune system is destroyed and so the infected are susceptible to other diseases. Retrovirus with RNA genetic material. uses reverse transcriptase to produce a strand of DNA in the host cell. DNA interacts with the host cell DNA.

Question 43

What is influenza

Answer 43

Viral infection of ciliated epithelial cells. Leaves airways open to secondary infection. Secondary infections tend to be lethal.

Question 44

What is Malaria

Answer 44

Caused by a protoctista. spread through the bites of mosquitoes. Reproduce in female mosquito. No vaccine and limited cures. Main method is to kill vectors with insecticides.

Question 45

What is Ring worm.

Answer 45

A fungal disease the affects mammals. Grey-white, crusty, infectious circular areas of skin. Not damaging. Can be cured with anti-fungal cream.

Question 46

What is Athlete's foot?

Answer 46

Fungal disease- form of ring worm- digests warm moist skin between toes - causes cracking and scaling. Anti-fungal creams used as cure.

Question 47

What do opsonins do?

Answer 47

Opsonins mark antigens on pathogens to signal the phagocytes and aid the phagocyte binding to the pathogen

Question 48

What is an antigen?

Answer 48

An antigen is a molecular tracer on the outside of a cell or virus that is used for cell signaling. And will illicit an immune response.

Question 49

What are antibodies?

Answer 49

Y-shaped glycoproteins (immunoglobulins) on the surface of lymphocytes that bind to the antigens on a pathogen to stop it from functioning.

Question 50

Agglutination:

Answer 50

one antibody binds to two pathogens - clumping the pathogens together - facilitating phagocytosis.

Question 51

Antibodies in neutralisation:

Answer 51

Antibodies act as anti-toxins and are complimentary to the toxin, binding and causing the toxin to be less harmful.

Question 52

Blood clotting cascade

Answer 52

Platelets contact collagen or cell walls - Secrete thromboplastin and serotonin. serotonin contracts smooth muscle in arteries and reduces blood supply. thromboplastin catalyses with a calcium ion and prothrombin to form thrombin. thrombin catalyses firbinogen into fibrin- forms fibres for a blood clot.

Question 53

6 stages of viral life cycle

Answer 53

``` Attach to cell surface membrane inserts viral nucleic acid replicate nucleic acid synthesis of viral protein assembly of virus lysis of host cell. ```

Question 54

Active immunity

Answer 54

Specific production of antibodies/ anti-toxins | Either through natural/ vacination

Question 55

What do cytokines do?

Answer 55

Signal lymphocytes to an area.

Question 56

Passive immunity

Answer 56

Maternal or artificial} antibodies provided from externally

Question 57

Primary response:

Answer 57

1st pathogen entry - triggers phagocytes and t-effector cells Symptoms include fever and swelling - histamines released to reduce pathogen replication through more extreme temperatures.

Question 58

T helper cells

Answer 58

produce interleukins (cytokine) - stimulate B cell to secrete antibodies - attracts other t cells and antibodies

Question 59

T killer cells

Answer 59

Kill pathogens by producing perforin that forms a hole in the infected/pathogenic plasma membrane.

Question 60

T memory cells

Answer 60

Immunological memory - remain in the blood for a long period of time - divide rapidly in second infection - forms many t-killer cells

Question 61

T regulator cells

Answer 61

Prevent autoimmune response by repressing immune system after all the pathogens have been destroyed.

Question 62

What is the role of phagocytes?

Answer 62

TO consume the invader and recognise the antigens.

Question 63

B effector cells

Answer 63

Divide to form plasma cell drones

Question 64

B plasma cells

Answer 64

Secrete antibodies/antitoxins

Question 65

Secondary response

Answer 65

2nd pathogen entry B-memory cells stimulate the creation of specific monoclonal antibodies no symptoms

Question 66

Neutrophils

Answer 66

multi-lobed nucleus granular phagocytes that release antimicrobial factors in specialized granules - extruded by nucleic acids - for neutrophil extracellular traps.

Question 67

Lymphocytes

Answer 67

B & T little to no cytoplasm Large nucleus

Question 68

Eosinophils

Answer 68

Bilobed nucleus - contains enzymes and proteins - granular (200 granules)

Question 69

Basophil

Answer 69

Bilobed nucleus - cytoplasmic granules - glycogen storage - release cytokines, histamines, and leukotrienes.

Question 70

Monocyte

Answer 70

Secrete chemokines - recognise 'danger signals'

Question 71

Outline phagocytosis

Answer 71

phagocyte signaled to invader by cytokines. phagocyte makes contact with invaded. phagocyte engulfs the invader. the phagosome fuses with the lysosomes to form a phagolysosome. the invader is broken down with perforin contents spill out and useful material used. Waste products packaged into vesicles and leaves through exocytosis.

Question 72

Plant physical defences to disease:

Answer 72

Callose is synthesised and deposited between cell walls and membrane. Callose papillae act as barriers, preventing pathogens from entering the plant cells. Lignin makes the mechanical barrier to the invasion thicker. Callose blocks sieve plates in the phloem, sealing off the infected part of the plant. Callose deposited in plasmodesmata between infected cells and their neighbours to seal off infected cells.

Question 73

Outline the physical defence process in plants.

Answer 73

Entry into the cells triggers detector molecules. When the pathogen's enzymes breakdown the cell wall the products are recognised. This stimulates signal molecules to alert the nucleus. Polysaccharides and defensive chemicals synthesised. Defensive molecules stimulate neighboring cells and some attack the pathogen and cellulose blocks pathways.

Question 74

Plant chemical defences.

Answer 74

- insect repellent (citronella) - insecticides (Pyrethrins) - antibacterial compounds (Saponins and caffeine) - toxins - anti-oomycetes (glucanase)

Question 75

Human non-specific defences:

Answer 75

Skin - physical barrier - produces sebum which inhibits pathogen growth Mucous membranes - trap microorganisms and contain lysosomes that break down cell walls( also contain phagocytes) Expulsive reflexes. Inflammation

Question 76

Macrophage phagocytosis difference:

Answer 76

When the pathogen has been digested, the macrophage combines antigens from the pathogen surface membrane with glycoproteins called the major histocompatibility complex. The MHC complex moves the pathogen antigens across the macrophage's surface, becoming an antigen-presenting cell. These stimulate other cells to produce antibodies.

Question 77

Inflammmation:

Answer 77

Mast cells stimulated by damaged tissue release cytokines and histamines. Histamines dilate blood vessels, causing a localised heat and redness. Histamines increase the water potential of the blood, causing blood plasma to transfer into tissue fluid. This causes increased temp and swelling. Cytokines attract white blood cells to the site.

Question 78

Where are B lymphs produced?

Answer 78

Bone marrow

Question 79

Where are T lymphs produced?

Answer 79

Thymus gland

Question 80

Cell-mediated immunity:

Answer 80

Macrophages do their thing after detecting abnormal cell antigens. Used to treat cancer and viruses. Macrophage -> APC -> stimulates T helper cells -> cloning (into t memory cell, produce interleukins that stimulate phagocytosis or B cell division, into T-killer cells)

Question 81

Humoral immunity:

Answer 81

A B cell with complimentary antibodies bind to the pathogen and engulf pathogen. Becomes APC. T helper cells binds to B cell APC. (This was clonal selection) Interleukins produced stimulate B cell mitosis. (clonal expansion.) Cloned cells produce antibodies to disable the pathogen. (KEY FACTOR IS THE ACTION OF ANTIBODIES IN THE LYSIS AND DEATH OF PATHOGENIC ORGANISMS)

Question 82

What is an autoimmune disease?

Answer 82

The immune system begins to attack healthy body tissue. Treated with immunosuppressant drugs. - but make patient susceptible to other diseases. e.g Lupus

Question 83

Principles of vaccination:

Answer 83

Pathogen is made safe by maintaining antigens but eliminating the risk of infection. Small amounts injected into the blood. Primary immune response triggered. Contact with pathogen will now trigger secondary response, destroying pathogen rapidly.

Question 84

In what ways can antigens be put into a vaccine safely?

Answer 84

Killed or inactivated pathogen Weakened (attenuated) pathogen Genetically engineered antigens produced antigens isolated

Question 85

What are the sources of medicine?

Answer 85

Plants Microorganisms Personalised medicine (Pharmacogenetics) Synthetic Biology

Question 86

Examples of drugs extracted from plants?

Answer 86

Penicillin -> mould on melons -> antibiotic | Aspirin -> willow bark -> Pain Killer

Question 87

Synthetic biology:

Answer 87

Using genetic engineering, colonies of bacteria can be produced to produce antibodies.

Question 88

Anti-biotic resistance

Answer 88

Bacteria culture reproduce. Genetic variation due to mutation. Exposure to antibiotics. More resistant bacteria survive. Less competition. Higher population of more resistant bacteria.

Question 89

MRSA:

Answer 89

Bacteria 30% population have it on their skin Can cause boils, abscesses, and potentially septicemia. Treated with methicilin and penicillin-like antibiotics, however some strains are resistant.

Question 90

C. difficile:

Answer 90

Bacteria In guts of 5% of pop Produces toxins that could damage the lining of the intestines. Dangerous when overused antibiotics kill healthy gut bacteria.