Report: Sir Paul Nurse - the 2nd Annual Lecture

The Great Ideas of Biology (a report by Christine Ransome-Wallis)
Professor Sir Paul Nurse, Nobel Laureate, President of the Rockefeller University, New York and graduate of Birmingham University.
 
Sir Paul was introduced by Professor Michael Overduin who described him as ranking with the greats of the original Lunar Society.

Biology was a large subject, Sir Paul explained to the capacity audience, and he aimed to break his talk down into five areas – the cell, the gene, evolution by natural selection, life as chemistry and biological organisation. Biology is a subject that makes lists; “we don’t have grand ideas like physicists”.
 
The Cell: The doctrine of all life is that is it composed of cells. A cell is the smallest unit exhibiting characteristics of life, biology’s atom. Technology begat discovery and the microscope was used during the 17th century to look at small things. Hooke came up with the name ‘cells’ in 1665 – after monks’ cells. By 1800, cells were seen everywhere. Physicists and chemists began to suggest that cells were the basic unit of life, and this was clear by 1839 – but they were wrong as to where cells come from. It was 1858 before Virchow identified that the cell was the simplest structural functional unit of life and this discovery was a major landmark.  Scientists studied plant cells, animal cells, cell-fusion and, once cell division was understood, it was clearly recognised as the basis of growth and division of all living organisms. By the 1880s, it was accepted that all living organisms came from a single cell.
 
The Gene: Living organisms can reproduce, generating offspring resembling their parents. The academic monk Gregor Mendel in what is now the Czech Republic studied how characteristics were handed down from parents to children. Crossing plants in his monastery garden in the 1860s, his realisation that particles contained units of information led to his identification as the father of genetics. The idea of the gene was the most outstanding contribution to biology during the last century. In 1944, DNA marked the birth of molecular genetics with its double helix structure to encode information and replicate itself.
 
Natural Section: Charles Darwin was the first publicly to postulate the theory that organisms evolve due to natural section, although before him his grandfather Erasmus, a successful doctor in Lichfield and member of the Lunar Society, was an enthusiastic supporter of evolution, and even Aristotle had commented upon it. Charles was more scientific and systematic but was clear that natural section was a mechanism for evolution. Reproduction has to be based on heredity with possibility for changes. Living things have to reproduce and, as they are all a bit different, variants are genetically determined and so are inherited from generation to generation. Natural selection occurs as a consequence of natural factors, which leads to survival of the fittest. Genetic changes accumulate in the population and bring about evolutionary change.
 
Life as Chemistry: This suggests that all growth, the ability to think, etc. is going on in all living things. During the 19th century the idea developed that specific microbes produced specific chemicals and biologists believed that vital phenomena in living organisms were due to forces other than physics and chemistry. Sir Paul suggested that understanding life’s activity in terms of chemistry had its origins in fermentation as the basis of life. The identification of enzymes gave scientists the confidence to understand it and the work looking at fermentation and its role with life formed the basis of biochemistry. Chemistry needs a particular environment and the cell divides into lots of environments but it is a well-organised state, not anarchic, so all different environments are connected to different chemistries at different times. Modern biologists are comfortable with the idea that life can be explained in terms of chemistry, so long as the cell is considered as a chemical machine.
 
Biological Organisation is not individual chemical reactions but purposeful behaviour and special organisation, suggested Sir Paul. DNA encodes information and genes regulate themselves. We can connect genes and proteins like a circuit board of a radio. Oscillations can encode signals and dynamics into a biological system. Pre-1900 physics could be understood but then Einstein came along.
 
Sir Paul concluded by saying it may be some time before we fully understand the complexities of biological organisation but the basis of this emerging idea allows us to look for ways that can transform molecular interactions, biochemical activities and biophysical mechanisms into logical and informational structures and processes. Considering the cell as a logical and computational machine shifts biology away from common sense and familiarity towards something more abstract.