Chapter 12 Pathogens And Plants Flashcards by Vinay Ladwa

What are pathogens? What is communicable disease?

Pathogens- organisms which cause disease
Communicable- caused by pathogens which can be passed between organisms

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What are bacteria? How are they sorted and cause disease?

Prokaryotes which are classified by shape- e.g rod, corkscrew or by cell wall, gram positive or negative
They secrete toxins, natural waste products produced as part of the bacteria functioning, which break down cell membranes, disrupt enzymes, and interfere with DNA

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What are viruses and how do they cause disease?

Non living genetic material surrounded by proteins
They invade cells- inserting virus genetic material into the hosts DNA, take over the metabolism/ biochemistry of a cell to make more viruses, burst, then spread
Bacteriophages take over bacteria

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What are protoctista? How do they cause disease?

Eukaryote which break into cells, steal nutrients, replicate by themselves, and burst the cell open

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What are fungi and how do they cause disease?

Eukaryotes, saprotrophs, which digest cells to destroy them, and also secrete toxins

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What is ringrot and what is it caused by?

Disease of potatoes, tomatoes and aubergines
Gram Positive Bacteria

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What is tobacco mosaic virus and what is it caused by?

Disease of tobacco plants and tomatoes, which stunts growth, no cure
Virus

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What is potato blight and what causes it?

Affects potatoes
Protoctist, acts like fungi by penetrating host cells, no cure

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What is black Sigatoka and what causes it?

Disease of banana trees, destroys leaves
Fungus- digest cells, fungicide to help

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What is tuberculosis?

Disease which damages lung tissue, increased likelihood with low immune system
Bacteria

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What is meningitis strep?

Bacterial infection of the meninges, can cause blood poisoning so death
Signs= blotchy rash that doesn’t disappear under a glass
Cured via antibiotics and vaccines

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What is HIV?

Virus that targets T helper cells, gradually destroys the immune system, Virus interacts with host DNA
No vaccine, antivirals slow spread

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What is influenza?

Disease of ciliated epithelium, often a secondary infection
Virus

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What is malaria?

Disease caused by a Protoctist, through mosquitoes, spread to human blood via bites
Controlled via controlling spread of mosquitoes
Pathogen called PLASMODIUM

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Give two examples of fungal diseases for animals?

Ringworm- cattle, cats, scratchy circles. Antifungal cream
Athletes foot- digesting warm skim, antifungal cream

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What are examples of direct transmission between humans?

Direct contact e.g kissing, skin to skin
Inoculation- through breaks in the skin
Ingestion- from hands in mouth

What are examples indirect transmission in animals?

Fomites- sharing bed sheets
Droplets
Vectors- organisms that spread disease without become affected

What are examples of transmission in plants

Direct- healthy plant touching unhealthy
Indirect- soil contamination, spores travelling through wind, water,

What factors affect transmission of communicable disease?

Overcrowding
Poor nutrition
Climate change
Culture
Variety

What is the process of recognising a pathogen in plants?

Receptors respond to chemical from either the pathogens, or from when pathogens attack the cell wall
Stimulates the release of signalling molecules which switches in genes that can produce a cellular response e.g chemical production, alarm other cells

What is a plants physical defence mechanism against pathogens?

Produces callose, formed from B-glucose 1,3 and 1,6 linkages
Deposited between cell walls and membranes next to infected to prevent pathogens entering neighbouring cells
Blocks off sieve plates and plasmodesmata to help prevent pathogens spreading

Cellulose cell wall as a physical barrier, lignin for water proofing
Waxy cuticle to prevent water collecting on the surface
Guard cells close stomata

What are chemical plants responses to pathogens?

Terpenoids- antibacterial and antifungal
Alkaloids- nitrogenous , prevents being fed on, so less exposure to pathogens

How can vaccinations prevent epidemics turning into pandemics ?

At the beginning of an epidemic, mass vaccination , may need to be changed regularly to be effective
Herd immunity, when enough people have it, gives protection to who hasn’t stopping spread

Why has malaria and HIV not had a vaccine?

Malaria evasive- hides inside erythrocytes
HIV disables immune system as disrupts T helper cells

What are some examples of where medicines come from?

Organisms: Aspirin from Willow bark, Penicillin from mould Synthesis with help from computers Modifying current medication

Medically, why is biodiversity important?

Lots of new medicines from plants and fungi Deforestation, loss of coral reefs, loss of habitats Means there are species which have gone extinct which could have held the key to treating diseases of the future

What is pharmacogenetics?

Personalised medicine- a combination of drugs which work on one's individual genome and disease e.g Herceptin and HER2 breast cancer gene,

What is synthetic biology?

Using genetic engineering to develop bacteria to produce drugs which are otherwise too expensive, rare or unavailable Or synthesis of new genes/organism Also nanoparticles to deliver drugs

Why is over use of antibiotics a problem?

Antibiotics work by targeting the functioning of a bacteria e.g of translation/transcription/synthesis of DNA/cell wall If a mutation occurs with a different way of the above, if successful, passes on to daughter cells To whole population Especially a problem if not needed, like in feeds Acts as a selection pressure and so leaves only those resistant surviving which would otherwise not be at an advantage

What happened with MRSA and C.difficile?

MRSA in nose, but in body causes problems, treated with antibiotics but now resistant C difficile in gut, not normally a problem, but antibiotics killed healthy bacteria, so took over gut

What is the difference between vaccination and immunisation?

Vaccination- inject antigen Immunisation- process of developing immunity

Outline a method for testing callose in plants at different temperatures.

Baseline callose first. Aseptic technique Infect same species of plant, ideally clones, same disease, same time, same pH water, same soil type, same light intensity 20,30,40,50 degrees heaters, set times Take samples from the plant, multiple and from multiple locations, but same for all 3 Microscope and graticule for amount

How do retroviruses replicate?

Insert RNA into cell Reverse transcriptase to make single stranded DNA from RNA strand, then DNA polymerase to make double strand and helix Attached to host DNA Enables synthesis of RNA which can be released