Category Archives: Students

Items for students and others, interested in learning about science and engineering and the application of science in our lives. We post many of the general interest items here.

2009 Nobel Prize in Chemistry: the Structure and Function of the Ribosome

graphic image of the components of a cell

Cross section of a cell by the Royal Swedish Academy of Sciences. A ribosome is about 25 nanometters (a millionth of a millimeter) in size. A cell contains tens of thousands of ribosomes.

The Nobel Prize in Chemistry for 2009 awards studies of one of life’s core processes: the ribosome’s translation of DNA information into life. Ribosomes produce proteins, which in turn control the chemistry in all living organisms. As ribosomes are crucial to life, they are also a major target for new antibiotics.

This year’s Nobel Prize in Chemistry awards Venkatraman Ramakrishnan, Thomas A. Steitz and Ada E. Yonath for having showed what the ribosome looks like and how it functions at the atomic level. All three have used a method called X-ray crystallography to map the position for each and every one of the hundreds of thousands of atoms that make up the ribosome.

Inside every cell in all organisms, there are DNA molecules. They contain the blueprints for how a human being, a plant or a bacterium, looks and functions. But the DNA molecule is passive. If there was nothing else, there would be no life.

The blueprints become transformed into living matter through the work of ribosomes. Based upon the information in DNA, ribosomes make proteins: oxygen-transporting haemoglobin, antibodies of the immune system, hormones such as insulin, the collagen of the skin, or enzymes that break down sugar. There are tens of thousands of proteins in the body and they all have different forms and functions. They build and control life at the chemical level.

Details from the Nobel Prize site (which continues to do a great job providing scientific information to the public openly).
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2009 Nobel Prize in Physiology or Medicine

This year’s Nobel Prize in Physiology or Medicine is awarded to three scientists who have solved a major problem in biology: how the chromosomes can be copied in a complete way during cell divisions and how they are protected against degradation. The Nobel Laureates have shown that the solution is to be found in the ends of the chromosomes – the telomeres – and in an enzyme that forms them – telomerase.

The long, thread-like DNA molecules that carry our genes are packed into chromosomes, the telomeres being the caps on their ends. Elizabeth Blackburn and Jack Szostak discovered that a unique DNA sequence in the telomeres protects the chromosomes from degradation. Carol Greider and Elizabeth Blackburn identified telomerase, the enzyme that makes telomere DNA. These discoveries explained how the ends of the chromosomes are protected by the telomeres and that they are built by telomerase.

If the telomeres are shortened, cells age. Conversely, if telomerase activity is high, telomere length is maintained, and cellular senescence is delayed. This is the case in cancer cells, which can be considered to have eternal life. Certain inherited diseases, in contrast, are characterized by a defective telomerase, resulting in damaged cells. The award of the Nobel Prize recognizes the discovery of a fundamental mechanism in the cell, a discovery that has stimulated the development of new therapeutic strategies.

Scientists began to investigate what roles the telomere might play in the cell. Szostak’s group identified yeast cells with mutations that led to a gradual shortening of the telomeres. Such cells grew poorly and eventually stopped dividing. Blackburn and her co-workers made mutations in the RNA of the telomerase and observed similar effects in Tetrahymena. In both cases, this led to premature cellular ageing – senescence. In contrast, functional telomeres instead prevent chromosomal damage and delay cellular senescence. Later on, Greider’s group showed that the senescence of human cells is also delayed by telomerase. Research in this area has been intense and it is now known that the DNA sequence in the telomere attracts proteins that form a protective cap around the fragile ends of the DNA strands.

Many scientists speculated that telomere shortening could be the reason for ageing, not only in the individual cells but also in the organism as a whole. But the ageing process has turned out to be complex and it is now thought to depend on several different factors, the telomere being one of them. Research in this area remains intense.

The 3 awardees are citizens of the USA; two were born elsewhere.
Read more about their research at the Nobel Prize web site.

Molecular biologist Elizabeth Blackburn–one of Time magazine’s 100 “Most Influential People in the World” in 2007–made headlines in 2004 when she was dismissed from the President’s Council on Bioethics after objecting to the council’s call for a moratorium on stem cell research and protesting the suppression of relevant scientific evidence in its final report.

Webcast of Dr. Elizabeth Blackburn speaking at Google:
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Test it Out, Experiment by They Might Be Giants

Put It to the Test is one of the songs on the great new Album and animated DVD from They Might Be Giants: Here Comes Science.

Are you sure that thing is true, or did someone just tell it to you.
Come up with a test. Test it out.
Find a way to show what would happen if you were incorrect. Test it out.
A fact is just a fantasy unless it can be checked.
Make a test. Test it out.

A fun song on fundamentals of experimenting to the scientific method.

Movie Aims to Inspire College Students With Tales of Successful Minority Scientists

African American women are still rare in many science professions, despite their increasing representation in undergraduate science classes. The documentary – Roots to STEM: Spelman Women in Science—seeks to explore how these women were able to succeed and to hold them up as role models.

Tarsha Ward remembers begging her mother for a stethoscope so she could be the star of career day at her kindergarten class in Charleston, S.C. Her mother presented her with something that proved more prophetic: a white lab coat.

“For me that was the beginning of a career,” said Ward, who is working toward her doctorate in biomedical sciences at Morehouse School of Medicine in Atlanta, Ga., focused on cancer research. “Ever since then everything was about science.”

“If you get into a bind you have to think it out yourself,” she said. “A Ph.D. has really taught me to think on my own. You’re here thinking in the midnight hours and there’s no book to tell you what’s right. You just have to see if it works.”

Such struggles have already paid off. “In seven months, I published my first paper. I worked on it day and night,” said Ward, a 2004 Spelman graduate. “I (loved) the fact that I could find something no one else could find and actually publish it.”

Read the full press release

Friday Fun: Hammer and Feather Drop on Moon

Gravity acts in the same way on a feather and hammer. The reason the hammer falls faster on earth is due to air resistance (well and if you try outside – wind could blow the feather too).

At the end of the last Apollo 15 moon walk, Commander David Scott performed a live demonstration for the television cameras. He held out a geologic hammer and a feather and dropped them at the same time. Because they were essentially in a vacuum, there was no air resistance and the feather fell at the same rate as the hammer, as Galileo had concluded hundreds of years before – all objects released together fall at the same rate regardless of mass. Mission Controller Joe Allen described the demonstration in the “Apollo 15 Preliminary Science Report”:

During the final minutes of the third extravehicular activity, a short demonstration experiment was conducted. A heavy object (a 1.32-kg aluminum geological hammer) and a light object (a 0.03-kg falcon feather) were released simultaneously from approximately the same height (approximately 1.6 m) and were allowed to fall to the surface. Within the accuracy of the simultaneous release, the objects were observed to undergo the same acceleration and strike the lunar surface simultaneously, which was a result predicted by well-established theory, but a result nonetheless reassuring considering both the number of viewers that witnessed the experiment and the fact that the homeward journey was based critically on the validity of the particular theory being tested.

Neil Degrasse Tyson: Scientifically Literate See a Different World

From the interview of Neil Degrasse Tyson from 3 July 2009.

“If you are scientifically literate the world looks very different to you. Its not just a lot of mysterious things happening. There is a lot we understand out there. And that understanding empowers you to, first, not be taken advantage of by others who do understand it. And second there are issues that confront society that have science as their foundation. If you are scientifically illiterate, in a way, you are disenfranchising yourself from the democratic process, and you don’t even know it.”

I agree, and, as I have said before, when a society allows a scientific illiteracy to continue then the potential for abuse by those that manipulate those that are scientifically illiterate leaves the society vulnerable to making very bad choices.

Smokers with High Blood Pressure and High Cholesterol Lose 10 Years

By examining data from the Whitehall Study researchers have found smokers with high blood pressure and high cholesterol in middle age died 10 years earlier than the others after reaching age 50. This is independent of changes after later in life (quiting smoking, etc.). Life expectancy in relation to cardiovascular risk factors: 38 year follow-up of 19,000 men in the Whitehall study

At entry, 42% of the men were current smokers, 39% had high blood pressure, and 51% had high cholesterol. At the re-examination, about two thirds of the previously “current” smokers had quit smoking shortly after entry and the mean differences in levels of those with high and low levels of blood pressure and cholesterol were attenuated by two thirds. Compared with men without any baseline risk factors, the presence of all three risk factors at entry was associated with a 10 year shorter life expectancy from age 50 (23.7 v 33.3 years). Compared with men in the lowest 5% of a risk score based on smoking, diabetes, employment grade, and continuous levels of blood pressure, cholesterol concentration, and body mass index (BMI), men in the highest 5% had a 15 year shorter life expectancy from age 50 (20.2 v 35.4 years).

Conclusion Despite substantial changes in these risk factors over time, baseline differences in risk factors were associated with 10 to 15 year shorter life expectancy from age 50.

Another conclusion: if you don’t want to live a shorter life, don’t smoke. Not a new idea but given how many people continue to smoke it seems some don’t understand this conclusion.

3D Printing is Here

photo of objects printed using a 3D printer

Photo by Jessica Sabo at the at 2009 Annual ASEE Conference.

The Future of Printing is 3D [I removed the broken link]

At this year’s annual ASEE Conference in Austin, one of the main topics of conversation started with the question, “have you seen the 3D printer?”. The company Stratasys, Inc. has created their Dimension 3D Printers. Their latest innovation is their line of uPrint machines, which are less costly (prices starting at $14,900)
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Jesse Roitenberg, the representative from Stratasys at the conference, explained the benefits of using 3D printing as opposed to building models by hand:

“With a 3D printer, you are actually able to create an object as you had designed it. Once the object is created, the designer is then able to hold, test and verify the design. The object created is more accurate and the process is less time consuming.”
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The Dimension 3D printers have been used in both educational facilities and the workplace, benefiting everyone from engineers to middle school science teachers. Below is a video of Jay Leno explaining how he was able to use the 3D printer to recreate an old steam engine car part.

Norman E. Borlaug 1914-2009

The Father Of the Green Revolution

Norman E. Borlaug, 95, an American plant pathologist who won the Nobel Peace Prize in 1970 for starting the “Green Revolution” that dramatically increased food production in developing nations and saved countless people from starvation, died Saturday at his home in Dallas.

“More than any other single person of this age, he has helped provide bread for a hungry world,” the Nobel committee said in honoring him. “Dr. Borlaug has introduced a dynamic factor into our assessment of the future and its potential.”
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In his lecture accepting the Nobel Prize, he said an adequate supply of food is “the first component of social justice. . . . Otherwise there will be no peace.”
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In 1977, Dr. Borlaug received the Medal of Freedom, the highest civilian honor of the U.S. government.

Billions Served: Norman Borlaug interviewed by Ronald Bailey

As a matter of fact, Mother Nature has crossed species barriers, and sometimes nature crosses barriers between genera–that is, between unrelated groups of species. Take the case of wheat. It is the result of a natural cross made by Mother Nature long before there was scientific man. Today’s modern red wheat variety is made up of three groups of seven chromosomes, and each of those three groups of seven chromosomes came from a different wild grass. First, Mother Nature crossed two of the grasses, and this cross became the durum wheats, which were the commercial grains of the first civilizations spanning from Sumeria until well into the Roman period. Then Mother Nature crossed that 14-chromosome durum wheat with another wild wheat grass to create what was essentially modern wheat at the time of the Roman Empire.

Durum wheat was OK for making flat Arab bread, but it didn’t have elastic gluten. The thing that makes modern wheat different from all of the other cereals is that it has two proteins that give it the doughy quality when it’s mixed with water. Durum wheats don’t have gluten, and that’s why we use them to make spaghetti today. The second cross of durum wheat with the other wild wheat produced a wheat whose dough could be fermented with yeast to produce a big loaf. So modern bread wheat is the result of crossing three species barriers, a kind of natural genetic engineering.
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I see no difference between the varieties carrying a BT gene or a herbicide resistance gene, or other genes that will come to be incorporated, and the varieties created by conventional plant breeding. I think the activists have blown the health risks of biotech all out of proportion.
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the data that’s put out by the World Health Organization and [the U.N.’s Food and Agriculture Organization], there are probably 800 million people who are undernourished in the world. So there’s still a lot of work to do.

I am a bit more cautious about supporting genetic engineering in our food supply but I agree with him that we need to remain focused on the lives of hundreds of millions of hungry people (which is far too often ignored). I am worried about the risks to the environment and human health. I am also worried about the concentration of food plants in a greatly reduced genetic varieties that are more productive in general but increase the risks of massive food failures (due to limited genetic varieties).

40 New Species Found in Papua New Guinea

The rat is not afraid of humans, which could make it vulnerable. Photo by the BBC.

Yet another discovery of dozens of new species has been made. The rat that’s the size of a cat: 40 new species in ‘lost world’ at a remote volcano in Papua New Guinea.

In the kilometre-deep crater of Mount Bosavi, they found a habitat teeming with life which has evolved in isolation since the volcano last erupted 200,000 years ago.

Among the new species was the the Bosavi Woolly Rat. One of the biggest rats in the world, it measures just over 32 inches from nose to tail and weighs 3lb. The silvery grey mammal has dense fur and its teeth suggest it has a largely vegetarian diet and probably builds nests in tree hollows or underground.
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It is estimated that along with the giant rat and cuscus the expedition found about 16 species of frogs, one species of gecko, at least three species of fish, at least 20 of insects and spiders and possibly one new species of bat.
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Further evidence of the rich wildlife of the tropical location came with the discovery of the Bosavi Silky Cuscus. This animal, which resembles a small bear, is a marsupial that lives up in trees, feeding on fruits and leaves.

Weighing in at some 4.5lb, it has thick silky fur adapted for the mountain environment in which it lives. Dr Helgen has identified it as a new subspecies in the group of strange marsupials known as cuscuses.
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The habitat in the area is currently regarded as pristine, but less than 20 miles to the south of Mount Bosavi extensive logging operations are happening.