A.S Biology Unit 2.16.2 Antibiotic Resistance

aimee1234's version from 2015-04-11 10:46


Question Answer
How can an adaptation like antibiotic resistance become more common in a population because of natural selection?1.Individuals within a population show variation in their characteristics. 2.Predation, disease and competition create a struggle for survival. 3.Individuals with better adaptations are more likely to survive, reproduce, and pass on the alleles that cause the adaptations to their offspring. 4.Over time, the number of individuals with the advantageous adaptions increases. 5.Over generations this leads to evolution as the favourable adaptations become more common in the population.
How do poulations of antibiotic resistant bacteria evolve by natural selection?1.Some individuals in a poulation have alleles that give them resistance to an antibiotic. 2.The population is exposed to that antibiotic, killing bacteria without the anibiotic resistant allele. 3.The resistant bacteria survive and reproduce without competition, passing on the allele that gives antibiotic resistance to their offspring. 4.After some time most organisms in the population will carry the antibiotic resistance allele.
Why is it becoming increasingly difficult to treat TB?1.TB is a lung disease caused by bacteria 2.N. of people dying from TB decreased with the development of specific antibiotics that killed the bacterium and the number of people catching TB dropped due to a vaccine. 3.Recently some populations of TB bacteria have evolved resistance to the most effective antibiotics. Natural selection has led to populations that are resistant to a range of different antibiotics - the populations (strains) are multidrug-resistant. 4.To try to combat the emergence of resistance, TB treatment now involves taking a combination of different antibiotics for about 6 months 5.TB is becoming harder to treat as multidrug-resistant strains are evolving quicker than drug companies can develop new antibiotics.
Why is it becoming more difficult to treat MRSA?1.MRSA is a strain of the Staphylococcus aureus bacterium that has evolved to be resistant to a number of commonly used antibiotics, including methicillin. 2.Staphylococcus aureus causes a range of illnesses from minor skin infections to life-threatening diseases such as meningitis and septicaemia 3.The major problem with MRSA is that some strains are resistant to nearly all of the antibiotics that are available. 4.Also, it can take a long time for clinicians to determine which antibiotics, if any, will kill the strain each individual is infected with. During this time the patient may become very ill and even die. 5.Drug companies are trying to develop alternative ways of treating MRSA to try to combat the emergence of resistance

Recent badges