B5 - Communicatible diseases Flashcards
What is a pathogen?
A micro organism that can cause illness or disease
What is the process called how bacteria grow and how does it work?
Binary fission
1) cell replicates its genetic material
2) cell then splits into two
List 6 ways is which diseases can be spread.
- airborne
- direct contact
- waterborne
- vector
- std’s
- breaks in the skin
What is the method for growing bacteria?
1) sterilise the inoculating loop by heating it until red hot and then leaving to cool
2) dip the sterilised loop into a suspension of bacteria you want to grow
3) then use it to make zig zig streaks across the surface of the agar
4) place the lid immediately on the Petri dish to avoid contamination
5) tape the edges shut (but not all the way round as to not cause anaerobic bacteria) to prevent movement of micro organisms in or out of the Petri dish.
6) incubate the culture at around 25 degrees (never above as you don’t want to grow human pathogens) for several days
7) observe your findings
Name three safety issues that must be kept in mind when growing bacteria?
- never culture plates at no more than 25 degrees to stop human antigens from growing
- keep Petri dishes closed once bacteria has grown
- avoid contamination as much as possible
What is mean division time?
The average time needed by species of bacteria to divided by binary fission
How to work out mean division time?
1) calculate how many times the bacteria divides in the time given - must have the same units
2) calculate the number of bacteria in the population using the equation ( bacteria at beginning x 2^number of divisions)
When testing the effects of disinfectants and antibiotics, what shows how effective the antibiotic/ disinfectant was?
The zone of inhibition ( the size of the circle where it has killed bacteria )
What were the discoveries of Dr Semmelweis?
-realised that dead bodies and sick people could spread diseases
-he introduced simple hygiene to hospitals in Vienna and death rate fell.
Why is nitrogen needed in plants?
Helps growth/ produced proteins
Why is phosphorus needed in plants?
Healthy roots
Why is magnesium needed in plants?
Chlorophyll production
How can you prevent bacterial growth?
Low temp, high temp, disinfectant, antisceptic, anitbiotic
Name a few types of viruses and how they’re transmitted.
-measles - airborne
-HIV/aids - bodily fluids in sex
-tobacco mosaic(plants) - physical contact
Name some bacteria and how their transmitted?
Salmonella- passed through food chain
Gonorrhoea- transmitted during sex
Malaria - spread by mosquitos
Name some types of funguses and how their transmitted?
Athletes foot- direct contact
Rose black spot- airborne in moisture
Describe what happens in malaria?
-mosquito bites a human and releases malaria-causing parasites into the human.
-They travelled the liver and damage liver cells
-they also infect the human’s blood cells.
-they make lots of copies of themselves which causes the red blood cells to burst releasing them into the blood.
-the mosquito then bites the human again, taking the parasite into its body to reinfect someone else.
What treatment Is there for malaria?
-If diagnosed quickly can be treated with lots of drugs.
-however not always effective as some mosquitoes have become resistant to medicines
-also many drugs aren’t available in countries most effective
-most techniques focus on prevention
What are some of the human defences?
Earwax, mucus, tears, hydrochloric acid in stomach, skin, platelets.
What is the name of the process when white blood cells ingest microbes and kill them?
Phagocytosis
Describe phagocytosis?
1) phagocyte detects bacterium toxins
2) phagocyte extends its cytoplasm around the bacterium
3)phagocyte engulfs bacterium
4) enzymes released to digest bacterium
5) white blood cell gets rid of it to be used or destroyed
What is an antibody?
- white blood cells can release
Chemicals called antibodies which stick to microbes and help to kill them. - antibodies are very specific for a particular antigen(little lumps on a pathogen).
-they look like big Ys with a weird shape at the tips
Describe how white blood cells ability to make antibodies help them to kill pathogens.
1) the antibodies collide with and bind with the antigens to form a pathogen anitbody complex.
2) the phagocyte is drawn to the pathogen
3) the phagocyte ingest the pathogen-antibody complex
What are anti toxins and what do they do?
-An anti-toxin is a chemical that white blood cells release to stop toxins from working.
-like antibodies different antitoxins are needed to deal with different toxins.
What are the symptoms and treatment for measles?
Symptoms = Cough, red eyes, runny nose, white spots inside cheek
Treatment = no treatment but there are vaccines.
Symptoms and treatment for HIV / aids.
Symptoms = fever, headache, rash, sore throat, will progressively weaken immune system
Treatment = no cure but can be prevented
Tobacco mosaic symptoms and treatment.
Symptoms = discoloured leaves
Treatment = no cure
Salmonella symptoms and treatment.
Symptoms = diarrhoea, nausea, stomach cramps
Treatment = electrolyte replacement and rehydration
Gonorrhoea symptoms and treatment
Symptoms = pain urinating, discharge from genitals
Treatment = antibiotics or preventation
Athletes foot symptoms and treatment.
Symptoms = Rashes, itchy patches
Treatment = creams and sprays
Rose black spot symptoms and treatment.
Symptoms = black marking on leaves
Treatment = remove infected leaves
Malaria symptoms and treatment
Symptoms = headaches, fever
Treatment = medicine or prevent getting bitten by mosquitoes
How does the number of antibodies differ between the first and second exposure to an antigen (1st one is a vaccine)
- for second one the gradient at start is steeper
- more antibodies are produced (higher peak)
- second one decreases slower (shallower gradient)
