Biology Module 7 - Infectious Diseases

Question 1

What is a Vector

Answer 1

An organism that can transport or propagate a pathogen before implanting into an organism (by nature).

Question 2

What is a Prion

Answer 2

Created from abnormal PrPC gene which causes protein to fold abnormally, leading to holes in the brain and eventual death.

Question 3

What is a Virus (example)

Answer 3

Made of a protein coat (DNA/RNA), they require a host to replicate through transduction. (Influenza Type A)

Question 4

What is bacteria (animal and plant example)

Answer 4

Unicellular etc, killed by antibiotics. E.g. E. Coli in animal intestines cause food poisoning. Black rot damages plant health)

Question 5

What is a Protozoan (example)

Answer 5

Unicellular eukaryotic organism, produce asexually from binary fission. Most live in water with flagellum’s. Plasmodium causes malaria.

Question 6

What is a fungi (animal and plant example)

Answer 6

Diverse group of eukaryotes, gain nutrients from decomposing matter, live on dead tissue or as parasites like living. Tinea on feet and white blister disease.

Question 7

Macro-parasites (examples)

Answer 7

Multicellular eukaryote. 2 kinds; end parasites live inside hosts and extoparasites act as vectors carrying pathogens to infect the host. Tapeworms live in vertebrate intestines causing weight loss and pain.

Question 8

Insects and mites (plant example)

Answer 8

Can damage be vectors to pathogens. Citrus leafer miner lays eggs in plant, larvae then mine in the leaf for nutrients, creating swivly tunnels.

Question 9

Nematodes (plant example)

Answer 9

Common in soil and few act as pathogens. Root knot nematode affects tomatoes by attacking its roots to create lumps until the plant dies.

Question 10

Phytoplasm (plant example)

Answer 10

Related to bacteria but doesn’t have a cell wall. Inhabit the phloem tissue, creating mottles and stealing nutrients on tomatoes and others.

Question 11

Epidemic example

Answer 11

Equine Influenza / Horse flu in Australia 2007. Transmitted by nasal, horses were quarantined when moved and produced a vaccine.

Question 12

Example of vector transmission

Answer 12

Malaria: The protozoan enters the mosquito after drinking, it develops in mosquito and is extracted as saliva when injecting into human.

Question 13

Common symptoms of foodborne disease

Answer 13

Nausea, vomiting, stomach cramps and diarrhoea.

Question 14

Example of bacteria food poisoning

Answer 14

Salmonella: found in animals, infection from eating undercooked food - term food poisoning comes from toxins released by bacteria.

Question 15

Examples of viruses in food

Answer 15

Shellfish: from raw cool temperatures and hepatitis comes from shellfish; fatigue, stomach pain and yellowing skin - vaccine for travellers.

Question 16

Examples of parasites in food

Answer 16

Trichinella spiralis: intestinal roundworm from consuming pork that’s undercooked. Symptoms are; eye swelling, aching muscles, takes 2-8 weeks to appear.

Question 17

Pasteurs swan flasks

Answer 17

Disproves the theory of spontaneous generation. Uses meat broth to show how bacteria from the air comes to develop.

Question 18

What’s needed for successful pathogen infiltration?

Answer 18

Enter the host. Multiply in their tissue. Resist hosts defence system. Damage the host.

Question 19

Types of pathogens

Answer 19

Prion, virus, bacteria, protozoan, fungus and macroparasites.

Question 20

Transmission routes for pathogens.

Answer 20

Airborne, waterborne, vector-borne, faeco-oral (resist harsh environments - e. Coli in stomach acid), soil-borne, sexual, bloodborne, vertical (mother to child).

Question 21

Phytopthora Cinnamomi: Plant retaliation and effect.

Answer 21

Dangerous fungus, grows in warm damp soil on roots and spreads via spores. It blocks the nutrients getting to plants.
Plants use physical barriers (stomata, waxy cuticle) to prevent further damage. Chemically, enzymes can break pathogen or self destruct parts.

Question 22

Tobacco mosaic virus effect and plant retaliation.

Answer 22

Infects tobacco and solanaceae family (tomatoes, peppers). Causes mottling or yellowing, disrupting chlorophyll which inhibits growth.

Question 23

1st lines of defence

Answer 23

Skin, eyelashes and hair are physical barriers to prevent entry.
Tears, sweat, oil, stomach acid and mucus are chemical barriers to reduce pathogen activity.

Question 24

2nd line of defence

Answer 24

Fever, vomiting, phagocytosis, lymph system and complement system attempt to reduce pathogens spread.

Question 25

3rd line of defence

Answer 25

B / T cells. B cells form as plasma, with assistance of T cells they record new antigens and create antibodies specific to dealing with them. Memory B/T cells will then remember the pathogen and how to destroy it again.

Question 26

Acquired resistance

Answer 26

Gained/developed as a result of vaccinations (artificial).

Question 27

Natural resistance

Answer 27

Developed throughout our life time as we cross different pathogens.

Question 28

Passive immunity

Answer 28

Gained antibodies temporarily, from placenta to foetus, breast milk and antibodies in certain vaccinations (hepatitis).

Question 29

Example of passive acquired immunity

Answer 29

Immune serum globulin provides antibodies to protect against the pathogen. This is a passive acquisition since the memory of the pathogen is recorded for next time.

Question 30

What is immunisation

Answer 30

Process of immune system making lymphocytes or antibodies to fight infection - can be natural or artificial.

Question 31

What is innate immunity?

Answer 31

Nonspecific defence mechanism that occurs every time a pathogen enters. New or old the mechanisms always include the same physical/chemical barriers (1st/2nd(?) lines of defence).