Communicable diseases Flashcards
what type of pathogen is tobacco mosaic virus
a virus
symptoms of TMV and how does this affect plants
- causes mosaic pattern of discoloured patches on the leaves
- this restricts the plants growth as it cant photosynthesize or produce sugars for growth in the discoloured patches
how is TMV spread
- through contact between healthy and diseased plants
- by insects
how can farmers prevent the spread of TMV
- Good field hygiene
- pest control
disadvantages of TMV
- remain infectious in soil for 50 years
- can reduce the yield of crop
what type of pathogen causes measels
virus
symptoms of measles
- red rash
- fever
how is measles spreaded
- the inhalation of infectious coughs and sneezes
how is measles prevented from spreading
- people are vaccinated against it at a young age
- an infected person is isolated
what type of pathogen causes HIV
virus
how is HIV spread
- through sexual contact
- through sharing body fluids e.g needles
- from a mother to a child via breast milk
symptoms of HIV and how it affects the body and develops into AIDS
- at first the patient develops flu like symptoms such as fever, tiredness and aches but it disappears over a few weeks
- over time the immune system becomes weaker and damaged as the illness remain hidden in the immune system
- when the immune system becomes so weak it cant deal with infections or certain cancers it means that the person has developed aids
why is AIDS so dangerous
- as it make a person more prone to diseases and gives them a higher risk of getting cancer
how can HIV be treated and how does it work
- can be treated with antiretroviral drugs, this stops the virus from replicating which stops the disease from developing, so the virus does not damage the patients immune system
disadvantages of antiretroviral drugs
- countries with a high level of HIV cannot access these drugs
what type of pathogen causes salmonella
bacteria
how is salmonella spread
- eating undercooked food or food contaminated with salmonella bacteria from raw meat
symptoms of salmonella
- fever
- stomach cramps
- vomiting
- diarrhoea
what does salmonella do when it enters the body
- disrupts the natural gut bacteria inside your stomach causing food poisoning
how can salmonella be prevented
- cooking chicken thoroughly
- vaccinating chickens
- avoid washing raw chicken
- washing hands and surface after dealing with raw chicken
how to reduce the symptoms of salmonella
- drinking lots of water
what pathogen causes gonorrhoea
bacteria
how is gonorrhoea spread
unprotected sexual contact
symptoms of gonorrhoea
- pain whilst urinating
- yellow-green discharge
how to prevent gonorrhoea
- avoid unsafe sex
- use barrier method
- people who have had unsafe sex should test for gonorrhoea so they can be treated with antibiotics before they pass it on
treatment for gonorrhoea and its disadvantage
- penicillin- however lots of gonorrhoea strains have become resistant to penicillin and this has resulted in doctors to use more expensive and rare treatment
how can gonorrhoea affect babies
- can cause them to go blind and have a severe eye infection
what type of pathogen causes agrobacterium tumefacien
bacteria
what does agrobacterium tumefacien do to plants
- causes crown galls which are loads of specialised cells that grow between roots and shoots
- modifies plants
what causes agrobacterium tumefacien in plants
- when bacteria insert plasmids into the cell causing masses of undifferentiated genetically modified cells to grow
how can bacteria be treated
- with antibiotics and this kills them or stops them from growing
disadvantages of antibiotics
- bacteria is becoming more resistant to antibiotics causing more people to die from bacterial diseases
what type of pathogen causes rose black spots
fungi
symptoms of rose black spots
- black or purple spots on leaves
- yellow leaves which the drop off
what does rose black spots do to a plant
- causes them to not grow properly as it can not photosynthesize in the spots that are affected
how is rose black spots spread
by wind or water
treatments of rose black spots
- chop off infected leaves
- spray the plant with fungicide
what pathogen is malaria caused by
protist
how is malaria spread
mosquitos
symptoms of malaria
- fevers
- headaches
- recurrent episodes (when the symptoms go and then come back)
what causes recurrent episodes in malaria
when the protist burst out of the red blood cell
prevention of malaria
- reduce the number of mosquitos by destroying their breeding site or killing them with insecticide
- use mosquito repellents
- drain water so they stop breeding or spray it with insecticide ( they breed in in still water)
how does malaria affect the body
- affects the liver
- damages red blood cells
what are pathogens
microorganisms that can cause infectious disease
how do bacteria cause a person to be ill
- they divide rapidly once its in the human body and split into two through the process called binary fission
- bacteria the release harmful chemicals called toxins
- the toxins then damage our cells and make us feel ill
how do bacteria cause a person to be ill
- they divide rapidly once its in the human body and split into two through the process called binary fission
- bacteria the release harmful chemicals called toxins
- the toxins then damage our cells and make us feel ill
how do viruses make us feel ill
- viruses invade a host cell as they cant reproduce by themselves
- the virus then reproduces inside the host cell
- this is very damaging to the cell
- when the virus leaves the cell it can cause the cell to burst open and die and causing us to be ill
- this releases the replicated viruses and make them find new cells
main symptoms of bacteria and viruses
- headaches
- high temperatures
- rashes
characteristics of bacteria
- can be used to make food and medicine and treat sewage
- important to the environment (as decomposers) and in the body
- they are unicellular
- can be treated with antibiotics
- can reproduce by themselves
characteristics of viruses
- smaller than bacteria
- they have regular shapes
- can cause disease to every type of organism
- not living
- cannot be killed by antibiotics
- cant reproduce by themselves
what is health
health is a state of physical and mental well being
what are communicable diseases
are diseases that can be passed on from one person to another
what are non communicable diseases
are diseases that cannot be passed on from one person to another
factors that can affect your health
- diet - e.g by not eating the right nutrients or not eating enough can cause type 2 diabetes, starvation or malnutrition
- stress - e.g by having too much stress can result in health disease certain cancers and mental health problems
- lifestyle situations - can cause communicable and non communicable dieseases
examples of lifestyle situations
- gender
- where you live
- ethnic group
- levels of free health care
4 ways health problems interacts
- viruses living in cells can cause them to change resulting in cancer
- defects in the immune system can cause them to not work properly and make people more prone to communicable diseases
- physical and mental health are linked
- malnutrition is linked to health problems
how are pathogens spread
- through the air as tiny droplets when a person coughs or sneezes
- direct contact
- contaminated food or water
how to stop diseases (6 ways)
- hygiene
- killing vectors
- reducing direct contact e.g condoms
- quarantine or isolation
- vaccinations
- providing people with clean drinking water
what is a culture medium and what does it contain
- a culture medium is a liquid or gel that contains nutrients to culture microorganisms
what nutrients are need for bacteria to grow
- carbohydrates (for energy)
- nitrogen (to make proteins)
- minerals
why do you have to make sure your petri dish is uncontaminated
- to reduce the risk of mutations which can form dangerous pathogens
- to help see the effect of chemicals on pathogens
how to prevent contamination
- sterilize the petri dish, bacterial nutrient broth and the agar gel
- sterilize the inoculating loop (which transfers bacteria) by passing it through a bunsen burner
- when the bacteria is inside the petri dish we use adhesive tape to stop the lid from falling off and for any unwanted bacteria entering
- flip the petri dish upside down in the incubator to stop any moisture drip down onto the bacteria disrupting its colonies
why do school labs incubate bacteria at 25 degrees
to reduce the risk of harmful bacteria growing
why do hospitals incubate bacteria at 37 degrees
to increase the rate of growth of the bacteria so that they can identify the bacteria quickly
effects on bacterial growth REQUIRED PRACTICAL
1) clean the bench with disinfectant to kill any microorganisms that could contaminate the bacteria
2) sterilise the inoculating loop by passing it through a busen burner
3) open a sterilise agar gel plate near a bunsen burner flame and the flame kills the bacteria in the air
4) use the loop to spead the bacteria evenly over the plate
5) place the sterile filter paper discs containing antibiotics onto the plate
6) incubate the plate at 25 degrees
what is the zone of inhibition and how to calculate the area of it
the zone of inhibition is where the bacteria has not grown
area = pi x radius squared
what affects the growth rate of bacteria
- temperature
- pH levels
- available nutrients
- oxygen levels
how to calculate the number of bacteria
number of bacteria = 2n (n is the rounds of division) x the starting population
how to prevent bacterial growth
- raise or lower the temperature
- use chemicals to kill them
- using antibiotics to kill them or prevent them from growing
how does the skin prevent entry of pathogens
- acts as a barrier and prevents bacteria and viruses from reaching beneath the tissue
- if you cut or damage your skin platelets form a clot and dries into a scab this stops pathogen=s from getting in and stops you from bleeding to death
- your skin has sebaceous glands which produces sebum and this kills bacteria
- your skin has an extra layer of microorganisms which acts as ana extra barrier and prevents entry of microorganisms
how does the digestive system prevent the entry of pathogens
- the hair and mucus in your nose traps pathogens from the air
- the trachea and bronchi also contains mucus which traps pathogens from the air and the tubes contain cilia which waft the mucus to the back of the throat where it is swallowed
- stomach walls produce hydrochloric acid which kills the bacteria in the food and the mucus you swallow
3 ways your white blood cells protect you against disease
- phagocytosis- your white blood cells engulfs microorganisms that enter your body and ingests the pathogen, digesting and destroying them
- your white blood cells produce antitoxins which neutralises the toxins
- your white blood cells produce antibodies which lock onto certain types of antigens, causing the microorganism to be trapped so your white blood cell can digest them
how do your white blood cells boost your immunity
- if the same pathogen re enters the body your white blood cells would respond quick as it has made the antibodies before
- this quick response stop a person from getting ill and having the same disease
symptoms of plant ilnesses
- areas of decay/rotting- black spot fungus
- stunted growth- nitrate deficiency
- discolouration (yellow)- chlorosis
- discolouration (black spots)- black stop fungus
- discolouration (mosaic pattern)- TMV
- malformed stem/leaves- Aphids
- Growth on lower stem- Bacteria infections
what are aphids and what do the do
aphids are small insects which feed from the phloem taking sugars away from the plant, they also act as vectors by transferring pathogens from diseased plants to healthy plants
what do aphids cause to plants
- they make plants suffer from ranges of defficiencies
how to treat aphids
- insecticides
- enclosed spaces
- aphid eating insects e.g ladybugs
what is chlorosis caused by and what does it do to the plant
its caused by a lack magnesium ions in the soil, this makes it hard for the plant to make chlorophyll this makes the leaves turn yellow (known as chlorosis) and inhibits growth as the plant cant photosynthesize fully
what does a lack of nitrate ions in the soil do to plants
it stunts their growth as they wont have enough nitrate ions to convert into sugars by photosynthesis to be converted into proteins for growth in protein synthesis
physical barriers in plants
- tough waxy cuticle- stops the entry of pathogens
- bark and layers of dead cells, which fall of , taking the pathogens with them
- the cellulose cell walls prevent invasions by microorganisms
- leaves fall, taking away any infected leaves
chemical barriers in plants
- antibacterial chemicals- protect them against invading pathogens and bacterial infections
- poisons to deter herbivores
mechanical barriers in plants
- thorns and hairs to deter animals from eating or touching them
- leaves that drop or curl when touch
- mimicry to trick animals into not eating or laying eggs on them by mimicking an unhealthy plant
