It is impossible to think of a world without the contribution
of the chemical industry, from everyday items like shampoo
and television, to major advances in medicine and energy.
has come a long way since the days when herbalists and
folk remedies were the only option, but substances obtained
from plants and fungi are still used when treating and
preventing infections. Penicillin, one of the earliest
and best known antibiotics, is a chemical
produced naturally by a fungus called Penicillium, an
ascomycete. This fungus feeds on rotting dead animal
or plant material. It produces penicillin as a strategy
to compete with the bacteria that also feed on dead
organisms. Bacteria naturally grow and multiply faster
than the fungus unless they are inhibited by this naturally
Other common antibiotics such as streptomycin, neomycin
and tetracycline also occur naturally. We can grow the
fungi in culture and extract the antibiotics from them.
These chemicals either destroy micro organisms or inhibit
their growth. They are most effective against bacteria,
but can also be useful in treating infections caused
by other micro organisms such as viruses. Diseases caused
by viruses can be more difficult to treat than those
caused by bacteria. However, scientists are continually
developing more and more effective antiviral agents.
Unfortunately antibiotics don’t always win the
battle against micro organisms. Every time a bacterium
reproduces there is a chance that a mutation occurs
- a change in the DNA code of the bacterium. Most mutations
are a disadvantage to bacteria, but some may give individual
bacteria the ability to resist particular antibiotics.
To compound this, the more we use antibiotics to treat
infections, the more likely it is that resistant strains
of bacteria evolve. Some species of bacteria - for example
Mycobacterium tuberculosis which causes tuberculosis
- have developed multi-drug resistance, making them
particularly difficult to treat. Viruses can mutate
faster than bacteria, so the problem of drug resistance
is even greater with viral infections.
So where does the chemistry come in to the story?
Well, in the past we used to simply extract an antibiotic
from a culture of fungus and use it to treat bacterial
infections without worrying about resistance. Today,
however, we are aware that micro organisms can develop
resistance to our antibiotics. To combat this, research
chemists working for pharmaceutical companies need to
understand the chemical composition of naturally occurring
antibiotics and exactly how they affect micro organisms.
With this knowledge they can develop
synthetic antibiotics that will treat previously
resistant bacteria, and are more effective in the treatment
of viruses. Where in the past, tuberculosis could be
treated with penicillin, the treatment today involves
a cocktail of several different drugs.
So how do research chemists develop these synthetic
The first step in the investigation of a naturally
occurring antibiotic is finding out its chemical formula.
Neomycin has the molecular formula C12H26N4O6. Streptomycin
is C21H29N7O12. Tetracycline is C22H24N3O8. Penicillin
is R-C9H11N2O4S where R is a side chain with several
different possibilities. Sounds complicated, but that’s
the easy bit! Next the chemists discover how these atoms
were connected together into molecules - find out the
structural formula. Then they find out how the molecules
actually work: exactly which part of the antibiotic
molecule interferes with the life of the bacterium.
Each step in the process seems more challenging. Using
this knowledge the chemists are able to develop synthetic
chemicals that resemble or mimic the naturally occurring
antibiotics. These are molecules with similar 3D shapes
to one or other naturally occurring antibiotic. During
this development, the synthetic antibiotics must be
thoroughly tested to ensure that they are effective
against bacteria or viruses and, importantly, that they
have no harmful side effects on patients. Only when
they have passed all the tests can they be licensed
for medical or veterinary use.
It’s really important that we all act responsibly
with these new antibiotics; just discontinuing treatment
when we feel better is irresponsible. Even though we
may think that we’ve recovered, a residual infection
can give rise to mutated micro organisms, ones that
have developed resistance to the antibiotic. Failure
to follow the prescribed treatment can have the same
result. If a patient is supposed to take the tablets
3 times a day but forgets to do so, they will have a
lower concentration of the antibiotic in their bloodstream;
low enough to allow some bacteria to survive and mutate.
So there you have it: chemistry doesn't just answer
the big questions of history, but is vital to the world
we live in, affecting some of the most important aspects
of our daily lives.
The synthesis of new polymers has revolutionised the
20th century. They can be seen in virtually every aspect
of our everyday lives. Polymers occur naturally, but
scientists have been making synthetic polymers since
the early 1900s. They are in the clothes we wear, the
packaging our food comes in, our furniture and the electrical
equipment we use.
The word 'polymer' is derived from the Greek polys
meaning 'many' and meros meaning 'part'. Polymers
are very large molecules, with a very high molecular
mass. Rubber, for example, is made up of huge molecules
with thousands of covalently bonded atoms. These huge
molecules consist of monomers that are linked together
through a process called polymerisation.
The types of synthetic polymers that are used in industry
are continually changing: compare the different plastic
bottles there are! Bacterial polymers have also been
created: these are totally biodegradable, but they are
currently very expensive to produce.
degree in chemistry can lead to many diverse vocations
including biochemistry, materials science, pharmacology
and biotechnology. Less obvious careers range from being
a patent examiner or water purification chemist, to
food technologist or veterinarian. Alternatively, you
could choose to become a colourist or perfumer! To find
out more about careers in chemistry, visit Chemsoc,
the Royal Society of Chemistry’s chemical science