Photosynthesis, What a Blessing

Photosynthesis is a chemical process that plants and other photosynthetic organisms fix carbon dioxide and water into glucose and release oxygen by using energy of sunlight. Glucose is a kind of sugar and it can be converted into starch, fat, proteins and other components of cells. Photosynthesis can be simply expressed in the equation listed below.

Photosynthesis is considered to be the most important chemical reaction on the earth.

This is because, firstly, oxygen in air originated from photosynthesis. Based on scientific studies, during the early days of the earth, there was no free oxygen in the atmospheres. It was the process of photosynthesis that supplied oxygen to the atmosphere. How important oxygen is to us? Without oxygen it means we cannot breathe. How long can you hold without breathing? You can test it by putting your face into water. I did it. I can hold for one minute. It is extremely difficulty for me to hold for two minutes. The Guinness world record in 2008 is 14 minutes. However, most of people would die in less than ten minutes without breathing. So you see, without oxygen, we would die very quickly.

Secondly, photosynthesis provides the material and energy source for plants, animals and humans. Plants can grow by using solar energy through photosynthesis. But Animals and humans have to eat foods that are plants or other animals to survive. How important foods are to us? Some people in our club have already talked about nutrition and healthy foods. I enjoyed your speeches and I think I have learned a lot from your speeches. Naturally I would like to choose the foods that are good for my health. However, if you had not eaten any food for three days, I bet you would completely forget about nutrition and would possibly eat grasses and worms. Without food, we could hardly survive for one week.

Thirdly, fossil fuels, including oil, coal and natural gas are the products of photosynthesis. Why are they called fossil fuels? Because they formed from plants and animals that lived on earth millions of years ago. How important fossil fuels are to us? Recent information reveals that fossil fuels, oil, natural gas and coal provide us with 86% of the energy that we are consuming. Without fossil fuels, we not only cannot drive, but the industry would completely paralyze or collapse. Our way of living would have to go back up to that of three hundred years ago. Can you adapt to that kind of life? I don’t know whether I can adapt to it or not but I prefer the present life style. So without fossil fuels we could not enjoy our present life style.

Photosynthesis provides us with Oxygen, food and fossil fuels. We human did not design or create photosynthesis. Photosynthesis is a gift of nature or a gift of God if you like to see it from the angle of religion. No matter how photosynthesis originated, isn’t it a blessing for mankind?

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The above is a speech I delivered at my Toastmasters club. This five to seven minute speech is based on Toastmasters Competent Communication Manual, Project Seven: Research Your Topic.

Genome and Creating Artificial Life

In my last speech, I talked about DNA and genes. DNA is a molecule that encodes genetic information in cells.

Genome is the entire DNA of an organism. This is to say that a genome contains all the genetic information needed to make the organism. Most of you may have heard of “Human Genome project”. Up to now, scientists have sequenced genomes of about a dozen of organisms. There are accumulated interests for scientist to understand the huge amount of genome sequencing data. Studying of genome data would help scientists better understand some basic questions about life, such as minimal genetic information needed to make or sustain a life. Such knowledge would makes it possible one day in the future that scientists can specifically design a genome, synthesize the genome and create an synthetic or artificial life.

Hers is an experiment conducted by scientists in Craig Venter Institute.

Left in the picture is a kind of bacteria. We called it A. A has its own genome X. Scientists designed a genome Y based on the blue script of another bacteria B.

Genome Y was introduced into Bacteria A and later Genome Y replaced genome X.

After the genome was replaced, all characteristics of bacteria A including its proteins, membrane and appearance changed, changed completely into bacteria B. This experiment illustrated that after transplantation of genome, a bacterial species changed into another.

This experiment itself didn’t create a new life. But it is a big step toward creating a synthetic or artificial life.

What could this technology – creating artificail life do? Unlimited! If synthetic life can be created in the future, this technology would be as revolutionary as nuclear energy and computers. One possible application of synthetic life is to create microorganism for bio-fuels production.

Some people may feel it is impossible or extremely dangerous for human being to create artificial life. Are we playing God here? As far as I am concerned, I think scientists will be able to create simple life like bacteria in 10 or 20 years, but it would be extremely difficulty or very unlikely to create complicated life like plants and animals in the near future.

Is the technology of creating artificial life horrible? No. I don’t think so. Technology itself cannot be labeled “good” or “evil”. It depends how it is used. Similar as nuclear energy, hazards the technology of creating artificial life could possibly bring about are environmental pollution because of accidental release of artificial life and production of bio-weapon by terrorists using this technology.

History has proven that the world, the society and people’s life have been getting better and better because of the development of science and technology. So it will be the case for the technology of creating artificial life as well.

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The above is one of 5 - 7 minute speeches I delivered in my Toastmasters club.

Gene and Genetic Engineering

If you think why dogs give birth to dogs, cats give birth to cats, or an apple seed grows into an apple tree, you are thinking basic questions of Genetics. That phenomenon is called heredity. Why are we humans? The answer is simple: we are humans because our parents are humans. Our parents passed the information of humans to us and based on that kind of information we developed into humans. The information our parents passed to us is called Genetic Information. A unit of the genetic information is called a gene.

Genes exist in the sequence of DNA, a large molecule contained in the cells. DNA is composed of four bases, A, T, G, C. Different genes have different lengths and sequences.

Genes are softwares, or programs of an organism. They determine how an organism looks, how it takes its food, how it fights infection, and sometimes how it behaves. Change of a gene can mean death, illness or characteristic change to an organism.

The technique involving direct manipulation of genes is called genetic engineering.

One example of application of genetic engineering is Bt cotton. Bt represents Bacterial Toxin, a kind of protein encoded by Bacteria Bt gene. Bt is toxic to some insects. Bt gene is a bacteria gene. Cotton or other plants don’t naturally have the gene. Scientists have isolated the Bt gene from bacteria and transferred it into some cotton plants. The cotton plants that obtain the Bt gene are called genetically modified cotton or Bt cotton. Bt cotton can produce bacterial toxin, which can kill pests that eat the cotton. Nowadays, Bt cotton has widely planted in USA, China and India. Application of Bt cotton can increase yield, save farm labor and avoid pesticide contamination.

Another example of application of genetic engineering is Gene Therapy, a technique of directly using genes to treat or prevent diseases. Recently, scientists in University of Washington injected genes that produce color-detecting proteins into two color-blind monkeys and cured the color-blind monkeys. The two monkeys have been able to see red and green for the first time.

Genetic engineering has already emerged as a powerful technique in agriculture and medicine. It is expected that genetic engineering will provide revolutionary technology to solve energy, environmental, and global warming problems in the future.

Someone says that the 20th century is the century of physics and 21st century is the century of biology. I believe it.

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The above is one of 5-7 minute speeches that I delivered in my Toastmaster Club.