Microbiology and the Immune System Flashcards
What is a micro-organism?
A living organism which is so small that it can only be seen with a microscope
What are the 4 types of microorganisms?
Viruses
Bacteria
Fungi
Protists
What are protists?
one cell
from the kingdom Protista
eukaryotic (contains a nucleus)
Features of bacteria?
- cell wall made of merien and not cellulose
- cell membrane
- DNA floats in cytoplasm
- cytoplasm in middle
What are the features of viruses?
- protein coat
- coiled up genes in middle
- even smaller than bacteria
What is bacterial growth dependant on?
Temperature
Warm temps are ideal
Too cold and the growth will be slow
Too high and the bacteria will die
What is agar?
Jelly that contains nutrients that can grow bacteria
What is a large group of bacteria called?
Colonies
Explain the process of aseptic technique
1 - loop is flamed to kill bacteria
2 - stopper is removed from bacterial tube
3 - mouth of tube is flamed, no bacteria drifts out of tube
4 - loop is dipped in bacteria
5 - mouth of tube is flamed again, stopper is replaced, stops bacteria getting into the tube
6 - lid of petri dish is raised slightly so traces can be put on, plate is not completely off to prevent bacteria in the air getting onto the agar
7 - loop is flamed again, repeat process if necessary
What is penicillin?
It is an antibiotic that treats bacteria, it is a fungus.
What is an antibiotic?
A chemical used in medicine to destroy bacteria.
What are the 3 conditions for optimum penicillin growth?
- Temperature between 23-28*
- pH of 6.5
- correct oxygen level (fungus is aerobic so needs oxygen for respiration and growth)
Why are the nutrients added to the fermenter until growth has actually started?
Fungus only produces penicillin when nutrient levels are low
What happens after the penicillin has been brewing for 200hrs?
The liquid is drained, filtered and chemically treated to extract the penicillum.
What does the stirrer in a fermentor do?
Mixes ingredients, otherwise they settle at the bottom
Why is a cooling jacket used in a fermentor?
The reaction produces heat, but we need the conditions to stay within 23-28*
Why is a pressure relief valve used in a fermentor?
Otherwise pressure would increase to dangerous levels and growth of fungus would stop.
What is a pathogen?
An organism that causes disease.
5 ways pathogens can spread?
- direct contact or bodily fluids
- aerosol infection
- water
- insects
- contaminated food
What is AIDS?
acquired immune deficiency syndrome, caused by human immune deficiency virus.
How is AIDS spread and what can we do to prevent it?
- spread by bodily fluids We can prevent it by - safe sex - avoid sharing needles - wear surgical gloves when dealing with bleeding
What is chlamydia?
Chlamydia trachomatis
- transmitted by unprotected sex
- treated by antibiotics
What is malaria?
A tropical disease spread by flies or mosquitoes
What is the name of the parasite responsible for malaria?
Plasmodium
How can we prevent malaria?
- use mosquito nets
- draining swampy areas
- treating homes with insecticides
- taking anti-malarial tablets
What are pathogens killed by?
white blood cells
What are phagocytes?
Ingest micro-organisms and digest them, they will attack any cell.
What are lymphocytes?
They produce antibodies that destroy micro-organisms, antitoxins neutralise any poison produced by the pathogen. (antibodies are specific to pathogens)
What are antigens?
They are in white blood cells
- recognise foreign bodies
- we have identical antigens
What happens when a pathogen is detected?
1 - antigens detected by white blood cells
2 - phagocytes attack, lymphocytes develop antibodies (pathogens will grow in this time, worsening symptoms)
3 - lymphocytes produce right antibodies + memory cells that will produce the antibody if pathogen repeats
4 - antibodies usually wipe out pathogen
5 - memory cells = response will be more rapid, person will be immune to the disease
What are vaccines?
Vaccines protect us from bacterial and viral diseases
How do vaccines work?
- They are made of dead or weakened pathogens with antigens
- Lymphocytes will react and build up memory cells +immunity
- to build up more memory cells, boosters are sometimes needed
Disadvantages of vaccines?
- vaccination involves injection, which can hurt and panic young children
- usually some have side effects, even though they are minor they may put people off the idea of having them
What are superbugs?
Evolved resistance to antibiotics (eg MRSA)
How do you slow the natural selection/mutation of superbugs?
- doctors to avoid prescribing antibiotics when possible
- vary the types of antibiotics
How do you prevent the spread of superbugs in hospitals?
- patients screened for MRSA
- rigorous with personal hygiene
- visitors wash hands and use hand sanitisers
- safety measures when dealing with open wounds
How are monoclonal antibodies made?
1- the antigen that the antibody is to be used is injected into the mouse
2- the mouse white blood cells will produce antibodies specific to that antigen
3- spleen tissue containing white blood cells is collected from mouse
4- they are fused with myeloma (cancer cells) to form hybridoma cells, which divide and grow
5- hybridoma cells are collected and grown in a culture medium
6 - hybridoma cells grow and divide indefinitely and produce large amounts of the monoclonal antibody specific to the original antigen
7- antibodies extracted from culture medium by centrifugation (spinning), filtration and chromatography
4 ways monoclonal antibodies can be used?
- more specialised/safe chemotherapy treatment
- helps diagnose AIDS
- allowing malaria to be detected before symptoms show, to help track spread of disease
- used to identify tissue type for transplants
What are the 4 processes in pre-clinical testing?
1- the drug is tested on human cells outside the body
2- the drug is tested on animals
3- tested on healthy volunteers
4- tested for optimum dosage
What is clinical testing?
The drug is trialled on those with said disease, to see if the new drug is more effective than current treatments
