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DNA Organization Is Fractal

How would you pack spaghetti in a basketball (07/28/2004) such that you could get to any strand quickly?  You might try the “fractal globule” method.  You form little knots, or globules, on each strand.  These become like beads on a string.  Now you fold the beads into globules, and then fold those into higher-level globules.  […]

Chemistry Nobel Celebrates Cell Complexity

A discovery rivalling the elucidation of the genetic code is the structure of the ribosome – the “molecular machine” that translates the DNA code into proteins.  Untangling the complexity of this multi-part system won three scientists the Nobel Prize for Chemistry (see BBC News).  The winners are Venkatraman Ramakrishnan, Thomas Steitz and Ada Yonath.   […]

Molecular Machines on Parade

Scientific papers continue to exhibit the exquisite mechanisms in the cell for handling all kinds of situations, through the operation of molecular machines.  Here are a few recent examples from this week’s issue of Nature (Sept 3, 2009). Molecular sieve:  What happens when a cell gets bloated?  Too much water entering a cell can increase […]

Emergence of Genetic Code Touted

Most origin-of-life researchers have acknowledged the extreme improbability of the genetic code arising by chance.  Their approaches to get around this problem have varied considerably since the Miller experiment succeeded in generating a few amino acids.  Despite the celebrations that 1953 experiment generated (05/02/2003), it did not even begin to approach the problem of solving […]

Your Throat Has Tasteful Antennae

Our airways are lined with cells that have beating oars called motile cilia.  Like galley slaves on a Roman ship, they beat in coordinated waves, setting up currents that propel dust and foreign matter out toward the mouth.  Scientists just found out another amazing capability of these motile cilia: they can “taste” toxic chemicals and […]

Return of the Peppered Mice

Slight changes in the coat color of deer mice is the latest triumph of evolutionary theory.

Plants Use Hourglass Mechanism

Plants need to know when to flower and produce seed.  They can read the sunshine, but what about plants living in shade or cloudy conditions?  It turns out they have two mechanisms for telling time: a light meter and an hourglass.  If the light meter doesn’t switch on, the hourglass lets the plant know it […]

DNA Translator More Complicated Than Thought

One of the most remarkable molecular machines in your body, the ribosome, is coming to light, nanometer by nanometer, as scientists find new ways to peer into the inner workings of the “black box.”     Science Daily reported on work at Berkeley that has given the clearest imagery yet.  “Ribosomes, which number in the […]

Protein Function: It’s All in the Fold

Most chemical reactions involve atoms or molecules bumping into one another and exchanging electrons.  Proteins, by contrast, derive their immense functional repertoire from their shapes.  Several recent studies explore the amazing potential for strength, motility and catalysis that derives from the way proteins fold. Clots:  A picture of fibrin graces an article in Science Daily.  […]

Did Evolution Create Genetic Proofreading?

Protein manufacture in the cell is such a critical operation, there are numerous error-checking mechanisms the cell uses to get it right.  One of the most amazing is the careful association of DNA codons with amino acids, and the “proofreading” or “spell checking” that ensures fidelity.  How could spell checking evolve?     Science Daily […]

Epigenetics Rising in Consciousness of Geneticists, Embryologists

The old story of genetics was that all the information is in genes, and when sperm and egg unite, it’s only the combination of genes from parents that affect the offspring.  That view has been under challenge for years now as geneticists and embryologists find more and more evidence for additional heritable factors that affect […]

Selfish Gene Mutates, Dies a Metaphorical Death

Richard Dawkins proposed in his book The Selfish Gene that a gene, being the target of natural selection and unit of replication, is the entity most likely to get passed on to posterity; as such, it is “selfish” in that the rest of the organism is really only incidental to its immortality.  Dawkins expanded this […]

Nanotech Blurs Line With Biophysics

Machines on the molecular scale – in the literature these days, one needs to dig to find whether a news article is talking about man-made machinery or the living cell.  Both employ laws of physics to do work.  Notice how seamless the connection is in the following examples. Kinesin tightrope walk:  Scientists at Northwestern University […]

Biological Big Bang: Another Explosion at the Dawn of Life

Eugene Koonin and two friends from the NIH went tree-hunting.  They examined almost 7,000 genomes of prokaryotes.  They found trees all right – a whole forest of them.  They even found 102 NUTs (nearly universal trees) in the forest.  Unfortunately, it’s not what they wanted to find: a single universal tree of life that Darwin’s […]

More Going On in the Brain Than We Realize

The news story about a girl who can see in both eyes with half a brain has stunned neurophysiologists (see New Scientist and Live Science).  Somehow, the remaining parts of her brain underwent a massive reorganization of the circuits involved in vision.  “It was quite a surprise to see that something like this is possible,” […]
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