Fighting Disease Flashcards
What are viruses?
> not cells (1/100 of a bacterium)
> they invade your cells and use your cell’s machinery to reproduce and break out of your cell
> this cell damage is what causes you to feel unwell
What prevents pathogens from entering the body?
> skin, and hairs and mucus in the respiratory tract prevent lots of pathogens from entering the body
> platelets clot the blood when you cut yourself, preventing pathogens from entering
In what 3 ways does a white blood cell defend against infection?
> engulfs the pathogens
> produces antibodies
> produces antitoxins
Describe the process of a white blood cell producing antibodies?
> each invading cell has a unique antigen
> when the WBC comes across a foreign antigen, it produces specific antibodies to lock onto and kill the invading cells
> antibodies are then produced rapidly and sent around the body to kill the invading cells
> if person is infected with same pathogen again they will rapidly produce the antibodies to kill it= natural immunity.
What is bacteria?
> v. Small cells that can reproduce rapidly within the body
> make you feel ill by : damaging cells+ producing toxins.
What does a vaccination involve?
> injecting a small amount of dead or inactive microorganisms into the body
> as contains the antigens causes the body to produce antibodies without you feeling unwell
> this means that your body can rapidly produce the correct antibody if the live pathogen enters.
Why do booster injections sometimes need to be given?
> some vaccinations can wear off, so need to be given to increase level of antibodies again.
What are the advantages of vaccination?
> it prevents infectious diseases that were once common
> it prevents epidemics as even if some are not vaccinated, if the majority is then it is more difficult to become infected.
What are the disadvantages of vaccination?
> it does not always provide immunity
> it can have side effects caused by a bad reaction.
Why are painkillers ineffective in preventing infection?
Because they only relieve pain without actually tackling the pathogens
What do antibiotics do?
> they kill and prevent the growth of bacteria without killing your own body cells.
> they are specific
Why is it difficult to produce anti-vital drugs?
Because viruses reproduce using body cells so are difficult to kill without killing the body cells
Why must doctors not over-prescribe antibiotics?
To slow down the rate of development of resistant bacteria.
Describe the process of the creation of a resistant strain of bacteria
Bacteria can mutate, some of theses mutations can cause them to become resistant to antibiotics
> if you treat an infection like this, you will only kill the non-resistant strain, causing the resistant strain to multiply and increasing its population
How can you test the action of bacteria ?
Pour hot agar jelly ( containing carbs, sugars and minerals needed for bacteria to grow) into a Petri dish.
> when cooled use an inoculating loop to transfer bacteria into the agar jelly,
> place a paper disc soaked in antibiotic onto the agar jelly. The resistant strains will grow near to the disc but the rest will just grow around .
