Unit 2 Topic 4Aii Medicine and Drugs Flashcards
How do bacteria reprodue
binary fission (asexual reproduction in bacteria)
- bacteria splits in half
- under ideal condition, bacteria can split into two cells every 20 mins
How are bacteria used in experiments
cultured in experiments to investigate potential medciein
Define culture
large number of certain microorganism grown under desirably controlled lab conditions for scientific investigations
What are bacteria survival and reproduction conditions
- nutrients (glucose for respiration, amino acids for protein synthesis)
- oxygen / no oxygen (those respiring aerobically, no oxygen for those anaerobic)
- optimum temperature and pH (enzymes controlling metabolic processes to function optimally)
- water (hydrolysis reactions, solvent)
What are the precautions of culturing bacteria in experiments
- risk of arising a pathogenic mutant strain from completely harmless microorganisms
- risk of contamination of culture by pathogenic microorganisms from the environment
- risk of contamination of culture from microorganism from air or skin into the culture
- risk of contamination to the envrionment from the culture
What is antimicrobial
substances that kill microbes (bacteria, prevent growth of microbes)
Plants and its antimicrobial properties
- evolved and developed range of chemical defences against microbes which invade and cause disease (antiseptic compounds, antibiotics)
What are the uses of plant’s antimicrobial properties
- exploited to develop new drugs to treat bacterial and fungal diseases
- produce plant extract containing antimicrobial chemicals to test its effect on growth of bacteria
Cotton’s antimicrobial properties
produce gossypol
- antiseptic that kills bacteria attacking cotton seeds
Willow bark’s antimicrobial properties
salicylic acid
- used as a cosmetic BHA
- chemically engineered into acetylsalicylic acid (aspirin) for painkilling
- Salicylic acid was extracted and purified and use for pain relief -> led to the development of aspirin in the form of a small white tablet
Cinchona tree’s antimicrobial properties
Example: Quinine sourced from the cinchona tree, used to prevent and treat malaria, allowing loggers and developers to work in the Amazon Basin
Example of mold’s antimicrobial properties
Example: Penicillin developed from mold, used in killing bacteria. Penicillin breaks down the cell wall (beta-lactam ring) of bacteria, killing the bacteria.
What is antibiotics
Alter the metabolic pathways of bacteria ( just one type ) -> antibiotics can also directly kill bacteria
* Only treats bacterial infections but not viral infections
Virus are not living, parasitic and they replicate within a host cell
Advantages of the antimicrobial properties of plants
1.Enable humans to be more successful at treating diseases, increasing life expectancy
2.Ensuring exact and reliable dosage of medication
- By allowing the production of medication with a known concentration of the active ingredient
- the levels of chemicals in any part of a plant varies with the age of the plant, season, time…
3.Allow analysis of chemical structure of active ingredients, enabling scientists to create synthetic versions
- Reducing the need to remove large amounts of plant material from environment
- Modifications carried out in the lab to make the active ingredient more effective
What is William Withering and digitalis soup
- Found that foxgloves contained active ingredient (digitalis glycosides) for treatment of dropsy ( swelling of tissues by accumulation of fluid ) and heart failure
- Found that foxgloves are poisonous to humans, hence made different concentrations of digitalis -> digitalis soup
- Experimented on patients and found the most effective concentration that treats the patient without poison
- Creating the drug digoxin
How does digoxin work
- Causing the heart muscles to contract quickly and forcefully/ slowing heartbeat/ decreasing the size of the heart to increase the heart output
- Patient produces large quantities of urine as kidneys recovered to remove excess fluid and their heartbeat became stronger and more regular
Limitations of William Withering’s development
- did not purify and identify ingredients in this test (randomly mix concentration and feed to patients)
- no pre-clinical trials
- small sample size
- did not test on healthy people first
- no use of placebo / double-blind trials
- not ethical: many side effects, patients almost died
What are factors to be considered in drug testing
- effective (cure prevents relievs)
- safe (non-toxic, benefits > harm, no unacceptable side effects)
- stable (stored under normal conditions)
- easily taken into and removed(
Drug research
- Potential models of the drugs modeled using computers (Fit new structures into the active site of enzymes/ receptors that are important in disease processes)
- Patent gives the inventor the right to be the only one to produce and sell their invention for the next 20 years
- Drug is tested on human cell/ tissue culture/ whole organs in a lab
What should be done for drug development
- Design a suitable delivery system for the drug (ie. nasal spray, oral tablet, liquid medicine)
- The drug has to be stable such that there is no risk of it breaking down to form something toxic or inactive before it works
- Drugs are tested on animals to see if the drugs get into the cells easily, if they are chemically changed, excreted safely
Phases of clinical trials
phase 1: testing on small number of healthy volunteers
phase 2: testing on slightly larger group of volunteers suffering from the target disease (100-500)
phase 3: testing on an even larger group of volunteer patients
(past paper) Three-phase testing can be used to check for the safety and effectiveness of these chemicals. Describe the roles of phase 1 and phase 2. (3)
- to test for side effects
- to determine safe / minimum dosage / concentration
- to determine if it is more effective than existing treatments
What are the purposes and aims for each phase of clinical trials
phase 1
- side effects, correct dosage
phase 2
- double-blind trial with a placebo
- see how drug affects the disease in real patients
phase 3
- double-blind trial with a placebo
- effectiveness and safety of the new drug
- identify any unexpected adverse side effects
What is placebo
One group receives the drug and the other group receives a placebo, which looks identical but contains no active ingredient
- patients are not tol which group they are in
- compare with treatment group to prevent false result in the effectiveness of drugs due to placebo
