B14-evolution And Genetics

Question 1

How does antibiotic resistance develop?

Answer 1

(same steps that allow us to explain all evolution by natural selection)
Variation (due to mutation)-When dividing, some individual bacteria may develop a mutation that makes them slightly more resistant to an antibiotic.
Competition-The more resistant bacteria are less likely to be destroyed
by the antibiotics
Survival of the fittest-The more resistant bacteria survive while the other
bacteria are destroyed.
Reproduction-The more resistant bacteria are able to reproduce
(especially as the level of competition has now dropped,
since all the other bacteria have been destroyed!). The
new population are all likely to be more resistant to
antibiotics

Question 2

How can we prevent resistant strains developing?

Answer 2

Don’t overuse antibiotics doctors no longer use antibiotics to treat non-serious infections (e.g. mild throat or ear infections)+since antibiotics don’t affect viruses we shouldn’t request antibiotics to treat an illness that doctors believe caused by virus
patients finish course medicine every time so all bacteria killed by antibiotic so none survive to mutate+form resistant strains
Important restrict agricultural use as prevents spread of antibiotic resistance from animal to human pathogens (70% human antibiotics used on animal farms in USA)

Question 3

What is MRSA?

Answer 3

MRSA (methicillin-resistant Staphylococcus aureus) is an antibiotic resitant bacteria

Question 4

Why is a resistant bacteria a problem

Answer 4

population of the resistant strain increases by natural selection+will then spread coz ppl are not immune to it and there is no effective treatment so people will die from mild diseases

Question 5

What can be done to reduce the spread?

Answer 5

Doctors don’t prescribe antibiotics inappropriately, patients use the correct antibiotics prescribed and patients complete each course of antibiotics.
-medical staff should wash their hand w/soap+water or use alcohol gel between patients visits and wear disposable clothing or clothing that is regularly sterilised
-hospitals should have high standards of hygiene so that they are really clean
-patients who become infected w/antibiotic resistant bacteria should be looked after in isolation from other patients
Visitors to hospitals+care homes should wash their hands as enter+leave

Question 6

What do these resistant strains mean for the future

Answer 6

Development new antibiotics=costly +slow and is unlikely to keep up with the emergence of new resistant strains

Question 7

Classification

Answer 7

Is the organisation of living things into groups of similarities.

Question 8

How are organisms classified

Answer 8

Traditionally, living things have been classified into groups depending on their structures and characteristics in a system described by Carl Linnaeus known as the natural classification system who classified organisms into kingdom, phylum,class, order, family, genus and species.

Question 9

Kingdoms

Answer 9

contain lots of organisms with many differences but a few important similarities

Question 10

How many kingdoms are there

Answer 10

Now most scientists accept a 3 domain, 6kingdom model to give the 6kingdoms the prokaryotes were split into archaebacteria,ancient bacteria-like organisms and the eubacteria.

Question 11

Species is

Answer 11

The smallest group of clearly identified organisms in Linnaeus’ classification where members are very similar and is a group of organisms that can breed together+produce fertile offspring.

Question 12

How are organisms named

Answer 12

by the binomial system of genus and species