C12 Flashcards
What are the 4 Types of pathogen
Bacteria, Viruses, Fungi, Protoctista
What are the 2 ways in which we can classify bacteria
By Shape - Rod, Spherical, Comma, Spiralled, Corkscrew
By cell wall - Gram Positive (blue), Gram negative (Red)
What’s the base structure of a virus
Non living, Genetic material surrounded by proteins
How does a virus infect
Takes over the genetic material of host cell
Why are viruses the ultimate parasite?
Reproduce rapidly, Infect bacteria, Take over the whole cell for food
Are protoctista single or multicellular?
Both, some single cells and some cells grouped into colonies
What is a parasite
Use host as a source for food
How do fungi eat food?
Saprophytes - Feed on dead and decaying matter
When fungi reproduce, what do they produce?
Millions of tiny spores that can spread long distances, e.g through the wind (A type off vector)
What are the 2 ways a pathogen acts on a cell
Damaging cell directly - E.g. viruses take over cell metabolism. Fungi digest living cells and destroy them.
Producing toxins which damage tissues - Bacteria produce toxins, some of these inactivate enzymes, some interfere with genetic material
Give an example of a bacterial, fungal and viral disease in PLANTS
Bacterial - Ring rot
Viral - Tobacco mosaic virus
Fungal - Potato Blight, Black Sigatoka
Give an example of a Bacterial disease that acts on humans. Explain how it works and how it can be cured.
Bacterial meningitis - Brain, can spread to rest of the body. Blotchy red rash. Antibiotics can be used
Tuberculosis - Damages and destroys lung tissues and suppresses immune system. Makes body less able to fight other diseases. TB is durable through antibiotics
How does ring rot operate and what is its cure. (If any)
Damages the leaves, tubers and fruit. No cure
How does TMV work
Damages Leaves, flowers, fruit and stunts growth, reducing yield.
Name 3 ways in which a pathogen can transfer directly
Contact - Kissing, Skin to skin
Inoculation - Through break in skin
Ingestion - Taking in contaminated food or drink
Name three ways in which a pathogen can transfer indirectly
Fomites - Bedding etc
Droplet infection - Saliva and mucus spit out of mouth
Vectors - For example mosquitoes
Give an example of how We can minimize the transfer of disease from animals to humans
Minimize in close contact, washing hands after touching the animals
Name as many factors as possible affecting the transmission of communicable disease in animals
Overcrowded living and working conditions, poor nutrition, compromised immune system, poor disposal of waste, climate change, culture an infrastructure, lack of trained health workers
What are two ways plants can be affected indirectly?
Soil contamination
Vectors
Plants can be affected indirectly by vectors explain four types of vecrors they can be affected by
Wind - Can carry bacteria viruses fungus and spores
Water - Spores swim in the surface film of water on leaves. Splashes can cause transmission
Animals - Insects and birds and carry pathogens two plants as they feed
Humans - Pathogens and spores can be transferred By hands

Name of many factors affecting the transmission of communicable diseases in plants
Planting varieties of crops that are susceptible to disease, overcrowding, poor mineral nutrition, damp warm conditions, climate change
- All increase the risk of developing a communion disease
Explain in as much detail as possible the 3 steps in which a plant recognizes an attack
- Receptors on cells respond to molecules from pathogens
- Stimulates the release of signaling molecules that switch on genes in the nucleus
- Triggers cellular response, such as chemicals being produced
How does Callose aid pathogen defense
- When attacked, plants produce high levels of Callose. Callose is synthesized deposited between cell walls and cell membranes of cells around the infected ones. It acts as a barrier, preventing pathogens entering the plant around the site of infection.
- Callose is continuously added, blocks sieve plates in the phloem , Sealing off the infected part
- Callose is deposited in between the infected cells and Neighbor’s, stopping the spread
Name four examples of chemical defenses
Insect repellent’s, insecticides, antibacterial compounds, antifungal compounds, Anti Oomycetes, general toxins
Name for non-specific defenses keeping pathogens out
Skin, mucous membranes, lysozymes, coughs and sneezes
Explain the blood clot cascade
- Tissue is damaged and platelets are activated which release thromboplastin.
- Thromboplastin catalyses the formation of thrombin from prothrombin and calcium
- Thrombin catalyses the formation of fibrin from fibrinogen. Fibrin then forms a clot.
Explain the inflammatory response
- Mast cells are activated by damaged tissues and release cytokines and histamines.
- Histamines make blood vessels dilate, causing heat and redness. Blood plasma leaks put, becoming tissue fluid
- Cytokines - attract white blood cells to site, get rid of pathogens via phagocytosis.
How does a fever work?
When pathogen invades, cytokines stimulate hypothalamus to reset the thermostat, therefore temp goes up.
