Did you know?
Did you know?

Scientists preparing for a private Mars 2018 mission are looking at how the astronauts’ poo could line the walls of the spacecraft to protect against radiation.


‘New Scientist’, 1 March 2013

Originally published:

‘Big Picture: Space Biology’


Polymerase Chain Reaction

Polymerase Chain reaction.


PCR cycles

Polymerase Chain Reaction (PCR) is a three step process used to reproduce a section of DNA in large quantities and involves the use of the enzyme taq (thermos aquaticus) polymerase extracted from bacterial thermophiles. The three processes involved in PCR are 1) Denaturisation, 2) Annealing and 3) Elongation.

PCR step 1

During the first stage, DNA is heated to approximately 97 degrees in order to split the hydrogen bonds between the two DNA strands into two separate DNA strands. It is said when the DNA splits to form two separate nucleotide strands  due to heating at a high temperature such as 97 degrees ,the DNA has undergone denaturisation. This is also the reason why taq polymerase is used to amplify the DNA as usually when we replicate DNA when new cells are produced, the enzyme DNA polymerase found in our bodies helps us to copy our DNA. However, this enzyme cannot withstand very high temperatures and if heated up to 97 degrees, this enzymes would denature and cease to function.

PCR step 2- Annealing
PCR step 2- Annealing

Primers, a short chain of nucleic acids that are complementary part of the nucleic acid chain, are then attached to the start of the chain you want to copy. (Annealing)

pcr step 3 again

pcr step 3

The taq polymerase then comes along in the third stage of PCR and using the primer as a starting point, uses free nucleotides to form a complementary chain which ends up being identical to the chain you wanted to copy.

This process produces double the number of DNA molecules than the number that we started off with before the process began. For example, if you start with one molecule of DNA, after one cycle  of PCR you will end up with 2 molecules of DNA, then 4, then 8, then 16, then 32 molecules and so on (see the diagram below).

For more information on how PCR works, please watch the following videos: (you will have to create an account to access this video, but it is very good).

Also, have a look at this page:

A short introduction of a very short introduction: My chapter by chapter summary of Jonathan Howards book ‘Darwin, a very short introduction’ Part 1 / 2.

darwin intro book darwin tree of life i think

Today, I’m just going to summarise 1 out of 2 of the 9 chapters in the book ‘Darwin, a very short introduction’ by Jonathan Howard. Here we go:

Darwin led a relatively simple life in the fact that he had only lived in three places during his career in science, first spending 5 years travelling around the world on the Beagle where his theory of evolution first began, before settling in London and for the remainder of his life, a few miles near the South of London.

Darwin also kept a biography and detailed private notes on his discoveries and theories which, thanks to this, we are now able to know about evolution. As Darwin’s time was a time  it was a traditional celebration of a great man’s death , along with this he wrote letters to many scientists who kept them

Darwin was born in 1809 in a town called Shrewsbury, Shropshire where his father, Erasmus Darwin , was a doctor and his mother was the daughter of the founder of pottery , Josiah Wedgwood , although he was raised by his sister as his mother died when Darwin was 8 years old.hmsbeagle

Darwin went to Edinburgh university as a medical student but left the field of medicine and transferred to Cambridge university, with the wish of becoming a priest but Cambridge was the place where he began to take a great interest in Science and which led to Darwin , at the age of 22, to go on what would be over 100  years later a famous expedition on the HMS Beagle.

During the first 5 years on the Beagle, Darwin wrote developed his theory of evolution in the form of  900 private notes and although he didn’t intend to publish his notes, he ended up publishing his work. In 1839,he published a document called ‘Journal of Researches’ where he described what had taken place during his voyage in the HMS Beagle and what he had discovered , which then went on to become a popular travel book in the 19th century before again publishing geological results in the form of three volumes of text.

At the same time as the Journal of Researches was published, he married his cousin Emma Wedgwood and then had their first child in 1841. At 1842, Darwin’s health began to deteriorate and he would display symptoms  of nausea, insomnia and intestinal pains, all of which did not stop him from continuing to work . Some say that the disease Darwin suffered from for 45 years before his death was called Chagas disease, some Crohns disease and some cyclical vomiting disease(have a look at this link for more information: , )just like Charles Darwin’s Origin of species book was the first  at the time it was publishes, there’s obviously a bit of speculation as to what he had suffered from for such a long time. It could have been as a result of psychological trauma following the death of many of his children during his lifetime.

17 years late in 1859, Darwin eventually published ‘The Origin of Species By Means Of Natural Selection Or The Preservation of Favoured Races in the Struggle For Life’ where, as you may have learnt at school once upon a time, produced a reaction from the public and scientists alike and were mentioned in newspapers, magazines and in scientific assemblies. The concepts were Darwin described also challenged religious beliefs that God made the plants and animals on Earth as they were and according to scientists, Darwin did not produce enough evidence to support evolution by natural selection.

if you had an idea chalres Darwin

Darwin’s work has influence many scientists and ordinary people alike in his day and continues to do so even now. Darwin had inherited his family’s wealth so that he would never have to work a day in his life if he wanted to and the money he received from the books he published meant that he lived and died a rich man, even though there was no recognition from the Royal Society of his work until after his death.


Hominid evolution through time, Drawing

evolution 2

Fun fact !

Did you know?
Did you know?

Did you know that…

Women wake up from anaesthesia nearly twice as fast as men?


Tong et al. Anesthesiology 1999;91:1283-7.

Originally published :

‘The Big Picture Little Book of Fast Facts

I absolutely love this fact but the question I want to know is why women wake up so quickly from anaesthesia compared to men?

If you think you know the answer to my question, feel free to post a comment on why you think this is the case.

Chronic fatigue breakthrough offers hope for millions

I thought this article was interesting and I would like to share this with you all.

Taken from the New Scientist, 2 July 2015 article:

The website link to the article is as follows:


  HAVING a condition that no one understands is bad enough. Having one that many also doubt the existence of is worse. Yet that has been the unenviable fate of millions of people diagnosed with chronic fatigue syndrome.

CFS first entered the medical lexicon in 1988 to describe a cluster of symptoms without an obvious cause that doctors were seeing in the Lake Tahoe area of Nevada. The principal symptom was debilitating tiredness, but people also complained of sore throats, headaches, muscle pain and various other manifestations of general malaise.

The lack of a clear biological cause, the fuzziness of the symptoms and the fact that many of the people diagnosed were young professionals opened the door to a smear campaign. The media were quick to dub CFS “yuppie flu”.

Although it has shaken off some of its more pejorative nicknames in recent years, CFS has struggled to lose the stigma. People with the syndrome still say they are not taken seriously, blamed for their illness, or accused of malingering. Treatments are often psychiatric, which are a great help to many but unintentionally add weight to the idea that CFS has no physical cause.

Over the years, medical groups have launched campaigns to have CFS taken more seriously. The latest was in February, when the US Institute of Medicine proposed making a clean break with the past by renaming it systemic exertion intolerance disease. This has not caught on as yet.

The unsatisfactory state of affairs is largely a reflection of the fact that we do not have a good biological explanation for CFS. That has not been for lack of trying, but even here the disease seems to be a magnet for controversy. A paper published in 2009 in Science claimed to have found an association between CFS and a mouse virus. The paper was later retracted after other teams failed to replicate the result.

Now there is hope of a breakthrough. Researchers in Norway have been trialling a drug normally used to knock out white blood cells in people with lymphoma and rheumatoid arthritis. Two thirds of the people who took it experienced major remission of CFS symptoms, essentially returning to normal life, with bursts of vitality unthinkable while they were ill (see “Antibody wipeout relieves symptoms of chronic fatigue syndrome“).

The discovery – which sprang from a serendipitous observation – offers more than just the promise of a much-needed treatment. It also suggests that the symptoms are somehow caused by antibodies originally produced to fight off an infection. The researchers speculate that they might disrupt blood flow, leaving muscles drained of energy.

If correct, this brings the scientific story full circle. CFS was initially suspected to be a “post-viral” syndrome – the lingering after-effects of an infection with Epstein-Barr. More importantly, it could offer people diagnosed with CFS both physical relief and psychological closure.

There are wider implications too. Pain and fatigue without an obvious cause account for a large percentage of visits to the doctor, and usually have an unsatisfactory outcome. On top of that, there are many other conditions – Morgellons, for example – that struggle for credibility. If the CFS mystery is finally solved, that offers hope to countless others struggling with unexplained symptoms. It may take another serendipitous discovery, but science is good at those.

This article appeared in print under the headline “Revitalised”               

[Taken from the New Scientist, 2 July 2015 article:

The website link to the article is as follows: ].