B5 Flashcards
Define disease
A disorder to the body or mind that negatively affects an individual’s health
Describe cholera
- caused by Vibrio cholerae (bacterium)
- spread via drinking water or washing in water contaminated with infected faeces
- symptoms: diarrhoea, vomiting
can be reduced by:
- access to clean water
- improved sanitation
Describe tuberculosis
- caused by Mycobacterium tuberculosis (bacterium)
- it is an airborne bacteria, which is spread by droplet infection
- symptoms: lung damage, chesty cough, wheezing
Can be reduced by:
- improved hygiene
- isolation of infected individuals
- increased ventilation
Describe chalara ash dieback
- caused by fungus
- spread via airborne spores
- symptoms: dark lesions on bark, blackened leaves
Can be reduced by:
- control movement of ash trees
- kill infected
- replant with different species
Describe malaria
- caused by plasmodium (protist)
- spread by mosquito vectors
- symptoms: damage to re blood cells, liver damage
Can be reduced by:
- mosquito nets
- insect repellant
- cover arms and legs
Describe stomach ulcers
- caused by Helicobacter pylori (bacterium)
- transmitted orally by eating infected foods / drink
- symptoms: stomach pain, vomiting, nausea
Can be reduced by:
- access to clean water
- improved hygiene and sanitation
Describe ebola
- caused by Ebola (virus)
- spread by direct contact with bodily fluids
- symptoms: fever, diarrhoea, vomiting, internal bleeding
Can be reduced by:
- improved hygiene
- isolating infected individuals
- sterilisation of areas
Describe the lytic pathway
- virus binds to specific receptors in host cell
- virus injects its DNA, which replicates using host cell machinery
- new viral structures assembles
- host cell ruptures, releasing new viruses
Describe the lysogenic pathway
- Virus binds to specific receptors on host cell
- Viral DNA injected into host cell and becomes integrated into who cell genome
- viral DNA replicates each time cell divides
- trigger caused activation of viral DNA
- switches to the lytic pathway
Describe HIV
- caused by human immunodeficiency (virus)
- spread via contact with bodily fluids
- destroys white blood cells, making the individual susceptible to other diseases such as AIDS
Can be reduced by:
- using barrier methods of contraception
- blood screening
Describe chlamydia
- caused by Chlamydia (bacterium)
- spread through direct contact
- can result in infertility
Can be reduced by:
- using barrier method of contraception
- screening
Why are chemicals produced by plants useful?
They produce physiological effects on the body so can be used in medicines to treat disease
Why are plant defence systems important?
- plants to producers so all organisms higher up in the food chains rely upon their survival and ability to fight disease
- important in maintaining human food security
How can plant diseases be detected and identified in the field?
- observations of symptoms
- analysis of the distribution of infected plants can indicate the type of pathogen involved and its mode of transmission
- Changing environmental conditions to eliminate other causes such as nutrient deficiencies
How can plant diseases be detected and identified in the lab?
- detection of foreign antigens in a sample plant tissue using monoclonal antibodies
- analysis of DNA to identify any pathogen DNA in a tissue sample
