Notes : 6.13 - 6.15 Antibiotics Flashcards
(27 cards)
Quickly clarify what each cell has on their cell surface.
- Pathogens : Antigens
- Phagocytes : Receptors but when they become APC the have : Antigens
- T cells : Receptors
- B cells: Receptors but when they become APC the have : Antigens
What is active immunity
- Occurs when your body makes its own antibodies after being stimulate by an antigen.
What is passive immunity
When you have been given ready made antibodies that have been produced by another organism.
example of active natural immunity
Getting ill and you make your own antibodies
Example of active artificial
Getting vaccinated which a harmless form of an antigen
Example of passive natural
Breastfeeding - babies receive antibodies from their mother when they breastfeed
Example of passive artificial
Like an antidote - So an antibody injection to treat disease.
How can we compare active and passive immunity, like which one may be considered better ?
- Active immunity gives you long term protection as you develop memory cells but takes a while for the protection to develop.
- Passive immunity gives you short term immunity but the protection is immediate.
Blurt everything you know about vaccines
- They contain antigens - This will help to stimulate the primary immune response against a pathogen without the pathogen actually infecting your cells. This results in your body producing memory cells and you so you become immune to the pathogen without getting any symptoms of the disease.
- Some vaccines may contain many different antigens to protect against different strains of the pathogens. - which is due to antigenic variation.
What is the evolutionary race idea based upon.
- Overtime our immune systems have evolved to increase our defence against pathogens.
- However pathogens have also envelopes to become at infecting us/evading our immune systems.
- This struggle between pathogens and their hosts to outdo each other is known as an evolutionary race.
How is HIV support the theory of the evolutionary race ?
- HIV has a high rate of mutation in the genes which code for its antigens. This means that different strains of HIV will show slight differences in the shape of their antigens (antigenic variation). Memory cells that have formed from one HIV strain therefore may not detect the presence of antigens from other HIV strains.
- HIV replicates inside T lymphocytes and destroy the cells when they burst out of them. This disrupts the person’s immune response because their T cell levels will be too low to produce an effective immune response against the virus.
- HIV disrupts antigen presentation in host cells which prevents the activation of T helper cells.
How does M.Turberculosis support the evolutionary race theory ?
- When M. tuberculosis gets inside the lungs, it is engulfed by phagocytes, however they produce
substances that prevent the lysosome fusing with the phagocytic vacuole. This means the bacteria aren’t broken down and they can survive and replicate inside the phagocyte - disrupts antigen presentation in host cells which prevents the activation of T helper cells.
Define the term bacteriocidal.
Antibiotics that kill bacteria
Define the term Bacteriostatic.
Antibiotics that prevent the growth of bacteria/multiplication of bacteria
What are antibiotics ?
- Chemicals that kill or inhibit the growth of micro-organisms.
How do antibiotics work to kill and inhibit the growth of bacteria ?
- They can prevent bonds forming between the murein (peptidoglycan) molecules which make up the cell wall. This weakens the cell wall and prevents bacterial cells from growing properly. If water enters the bacterial cell by osmosis, the weakened cell wall cannot withstand the increased hydrostatic pressure and can burst (lysis), killing the bacteria.
- They can bind to bacterial ribosomes and prevent them from carrying out translation. This prevents the synthesis of protein’s, which catalyse important metabolic reactions. If these metabolic reactions do not take place, the bacterial cell cannot grow and asexually reproduce properly.
Why do antibiotics affect bacterial cells and not human cells ?
- Eukaryotic cells (human cells) do not have a cel wall and we have different sized ribosomes (80s) .
- So antibiotic can not affect the cell wall like they do in bacteria cells as there is no cell wall and they also can’t bind to our 80s ribosomes as they are a different size.
Why do antibiotics have no effect on viruses ?
Because viruses have no cell wall or ribosomes.
What are HAIs
- Hospital acquired infections
- They are infections which are transmitted in hospitals
How do HAIs spread ?
As a result of poor hygiene practices.
- And can easily spread in hospitals because patients have weakened immune systems and are around other ill people .
How can HAIs be prevented ?
- good hygiene practices, such as hand washing and sterilising surgical equipment.
Why are infections caused by antibiotic resistance dangerous ?
-As they can not be treated with antibiotics.
What measures have hospitals put in place to prevent the development of antibiotic resistance ?
- The rotated use of different antibiotics
- Taking the full course of antibiotics
- Avoiding overuse of antibiotics (e.g. for minor infections or for viral diseases).
- Doctors shouldn’t prescribe antibiotics to prevent infection
Examples of antibiotic resistant bacteria
MSRA
