Tutor profile: Sarah K.
Subject: Biomedical Science
Whats the biggest threat to human health?
This is another question that has many possible answers but one things scientists are worried about is multi-resistant strains of bacteria. Until the 20th century diseases caused by bacterial infections, such as pneumonia and diarrhoea, where the number one cause of death in the world. The first antibiotic to be mass produced was penicillin and it so transformed medicine in the 20th century that it was called 'the wonder drug'. Between the 1960s and 1980s many classes of new antibiotic were discovered and in the western world, death from bacterial infections has become a thing of the past. Now we face two problems. Firstly, many strains of bacteria are becoming resistant to the antibiotics we have making some infections difficult if not impossible to treat. Secondly, no new classes of antibiotics have been discovered since the 1980s. Therefore many scientists and medics believe that antibiotic resistance will be one of the biggest health care challenges we face in the coming decades as we may lose our ability to treat bacterial infections.
Subject: Basic Chemistry
How do glow sticks work?
Glow sticks are essentially a miniature contained chemical reaction. They emit light when to chemicals inside them react. Inside a glow stick is a small glass vial containing one chemical (usually hydrogen peroxide) whilst surrounding it is another chemical (usually a phenyl oxalate ester) as well as a fluorescent dye. Fluorescent dyes are chemicals that can absorb energy and then emit that energy in the form of light. When the glow stick is bent the glass vial snaps and the two chemicals are mixed together. The reaction between the two chemicals releases energy. This energy is absorbed by the fluorescent dye causing electrons in the fluorescent dye to jump to a higher energy state (i.e. further from the nucleus of the atom). When the electrons return to their normal energy state, energy is lost in the form of light and this is the glow that we observe.
Are Virus' Living things?
This is a debatable one. Many scientists disagree on whether virus' are living things but there are several factors to consider. 1. Living things reproduce. All (other) living things are able to reproduce by replicating their DNA. Virus have DNA (or RNA) that can be copied in order to create more virus thereby suggests that they are living things too. However, virus's do not have the machinery to copy their DNA themselves, instead they insert their DNA into a host cell and it is the host cell that replicates the virus' DNA. Therefore not all scientists agree that virus' fulfil the criteria of being able replicate since they a rely on a host cell to do so. 2. Living things have cells. All (other) living organisms consist of cell(s). Whether single cellular or multicellular organisms, they have one or more cells surrounded by a cell membrane. Virus' on the other hand do not have a cell membrane they simply have a protein coat that surrounds and protects their genetic material. For this reason virus' might not be considered living. 3. Living things use energy. All living organisms use energy. Virus' do not use energy when outside of the cell and once inside the cell it is the hosts energy that is used to replicate the virus' DNA. Therefore for this reason some scientists believe that virus' do not fulfil the criteria of using energy.
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