b5 - communicable diseases

what is health

a state of physical and mental well being

what are the two types of disease

communicable and non communicable

what are risk factors for disease

• bad diet
  - stress
  - life situations

what can happen to a person with several diseases

the diseases can interact and mutliply the effects of both, making it worse for the patient

what can communicable diseases be caused by

pathogens such as bacteria, viruses, fungi and protists

how do bacteria make you sick

by producing toxins

how do viruses make you sick

invading live host cells and hijacking the cell's internal machinery to replicate themselves

how can pathogens be spread

direct contact, air and water

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why are bacteria grown in the lab

for investigating the action of disinfectants and antibiotics

what is the maximum temperature that cultures should be incubated in schools and colleges and why

25 degrees celsius to reduce the likelihood of pathogens growing that might be harmful to humans

how often do bacteria divide

once every 20 minutes

what do bacteria need for cell division

• nutrients
  - suitable temperature

how can the spread of diseases be prevented

• simple hygiene measures
  - destroying vectors
  - isolation of infected individuals
  - by vaccination

what type of pathogen are measles

virus

how are measles spread

droplets

what are the symptoms

fever and rash, can be fatal

measles cure

no cure

how is spread of measles prevented

• isolation of patients
  - vaccination

what type of pathogen is HIV

a virus

what does HIV cause

flu like illness

how is HIV controlled

antiretroviral drugs

what does HIV do to the body

attacks the body's immune cells

what is late stage HIV infection called

AIDS

what happens to the body when it has AIDS

it can no longer deal with other infections or cancers

how is HIV spread

sexual contact or exchnage of bodily fluids

how are bodily fluids exchanged non sexually

when drug users share needles

what type of pathogen is TMV

virus

what does TMV stand for

tobacco mosaic virus

how is tobacco mosaic virus spread

contact and vectors

what does TMV do to a plant

reduces photosynthesis and damages leaves

TMV cure

no cure

how is the TMV spread prevented

field hygiene and pest control

how is salmonella spread

undercooked food and poor hygiene

symptoms of salmonella

• fever
  - abdominal cramps
  - diarrhoea
  - vomiting

why do people with salmonella vomit

due to the toxins the bacteria secretes

how is the spread of salmonella controlled in the UK

poultry are vaccinated against salmonella

what type of pathogen is salmonella

bacteria

what type of pathogen is gonorrhea

bacteria

how is gonorrhea spread

STD

what are the symptoms of gonorrhea

• thick yellow/green discharge from the penis/vagina
  - pain on urination

treatment for gonorrhea

antibiotics

what is the issue of treating gonorrhea with anitbiotics

many strains are resistant

how is the spread of gonorrhea prevented

using condoms and limiting sexual partners

what plant disease causes crown galls

agrobacterium tumefaciens

what type of pathogen is rose black spot

fungal

how is rose black spot spread

• wind
  - water

what does rose black spot do to a plant

damages leaves so they drop off (photosynthesis is thus reduced)

how is the spread of rose black spot controlled

• removing affected leaves
  - fungicide chemical sprays

what is malaria cuased by

parasitic protists, bite of female mostquitoes

what type of pathogen is malaria

protist

what does malaria do to the body

attacks blood and liver cells

what are the symptoms of malaria

fevers and shaking, can be fatal

how is malaria treated

some drugs are effective if given early

issue with malaria drugs

some strains are becoming resistant

how is the spread of malaria prevented

• preventing vectors from breeding
  - using mosquito nets to prevent people from being bitten

what does rose black spot look like

purple or black spots develop leaves, which turn yellow and drop early

how does the body protect against the entry of pathogens

skin (barrier and antimicrobial), the nose, the trachea, the bronchi and the stomach

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how do white blood cells protect against pathogens

• phagocytosis
  - making antibodies
  - making antitoxins

what can plants be infected by

viral, bacterial and fungal pathogens and insect pests

symptoms of disease in plants

• stunted growth
• spots on leaves
• areas of decay (rot)
• growths
• malformed stems or leaves
• discolouration
• the presence of pests.

how can identification of plant disease be made by

• refernce to a gradening manual
  - taking infected plants to a laboratory to identify the pathogen
  - using test kits with monoclonal antibodies

what can nitrate ion deficiency lead to in plants

stunted growth

what can magnesium ion deficiency cause in plants

chlorosis

what are nitrate ions needed for

protein synthesis and therefore growth

what are magnesium ions needed for

to make chlorophyll

how do plants protect themselves from disease physically

• cellulose cell walls
  - tough waxy cuticles
  - layer of bark/dead cells

chemical plant defences

• antibacterial chemicals
  - poisons to deter herbivores

plant defences against herbivore

• thorns
  - hairs
  - touch me nots
  - mimicry