Stem Cells Breakthrough & Seeds of Hope

Stem Cells: Seed of hope?
Stem Cells Breakthrough

After watching these videos, we had to answer some questions:


Why are stem cells considered so valuable for medical research?
Because stem cells are pluripotent (they can transform into many different specialized cells) and can fix many diseases.

Why did the researchers have to narrow the spectrum of genes within stem cells?
Because, by doing that, they could reproduce them from skin cells, having a much wider spectrum afterwards. As in the beginning, 20000 genes is too much, the possible combinations had to be narrowed.

What are the sources of stem cells and the advantages and disadvantages associated with using each?
Stem cells used for this kind of investigations are the one that embryos have. The advantages could be that you could eventually regenerate any kind of cell, and potentially heal an organ. Disadvantages could include that, apparently to produce one of those cells and organs, you have to create life, use what you and then need and destroy it. It is also possible to obtain stem cells from organs that still ave some residual stem cells, mainly the spinal cord. Another possibility is to create them with the gene combination obtained.

What are the three cases presented at the beginning of the second video?
A hockey player whose spinal cord was damaged. Diabetes in a young man. Two girls who were cousins had a genetic disorder (Tay- Sachs disease)

How might a stem cell be used to treat spinal cord injuries?
They have to insert the stem cell in the damaged spinal cord, and then wait for it to make the "bridge" and communicate both sides of the cord.

Explain the outcome of the experiment with injured rats presented in the second video?
Rats whose spinal cord was damaged, were treated and then they could almost walk normally.

What issues surround the debate over of stem cell research?
Ethic issues. The importance of preserving life.

What issue do you think needs to be debated as we make decisions about stem cell research?
The importance of having the power to create life carries a huge responsibility, and how can we be sure than this knowledge will be used only for the good of the people. and not create weapons or something that could damage humanity in the future.

Genetic Tool Kit

What do homeobox genes code for in animals?

They produce basic body parts, such as wings, legs and heads, in all animals.

Why are homeobox (also called homeotic) genes called the master control genes, or master switches?

Because the research indicates that animals descended from a single common ancestor that passed along to them a set of homeobox genes, used to build a wide variety of forms from just a few basic body plans.

What other organisms besides fruit flies have homeobox genes?

Every animal has homeobox genes.

What did the experiment with fruit flies and mice show?

That every animal may have evolved from a common ancestor, which means that evolution is a simpler process than it was thought.

What does the presence packages of information suggest about evolution?

That genes are the same, but external factors determine different evolution conditions, which makes organs differentiate among animals. This means that evolution is triggered by external factors such as food, weather, etc.

How has evolution tinkered with genes of animals?

Evolution can be considered to be the process in which new combinations of genes are created, commonly triggered by external changes.
What role has embryos played in the study of evolution?

They have been the main study object because during this stage genes start to be expressed and scientist can study the similes between different species.

VIDEO

Gene Control

Why did the German scientist decide to study the fruit flies at the larval stage?

Because it is a fast-breeding insect and sometimes, a mutation occurs and legs come out of the fly's head. These mutations occurs during the larval stage of the fly, so that's why the scientist need to study the fly from the larval stage, and see the complete development of the fly.

How does the mother fly activate the control genes?

When the mother lies the eggs, she leaves different chemical messages at either end of the egg. One indicates that this will be the head and the other one the tail. Inside the egg, the chemicals will activate a specific gene, called the control gene.

What is the role of control genes?

The control gene controls the activity of other genes in time and space, so they control at which point or in which region another gene is expressed.

Which of the two species are closer to humans?

The zebrafish is closer to us in terms of control genes and body plans.

VIDEO

The Embryo Takes Shape video

What directs the sequence of events that turn a blob of cells into an embryo with specialized tissues and organs?

The process of Gastrolation, in which the cells form three layers: The lower layer becomes the lungs, liver and digestive tract, the middle layer turns into the heart, muscles, bones and blood, while the top layers develops into the nervous system, skin and hair.

The narrator says that “cells talk to each other.” What does that mean?

It means that cell communicate with each other by chemical messages with the "intention" of organizing themselves.

How do cells in different parts of the embryo become different kinds of cells and organs?

It depends on the genes. There are specific parts of the genes that activate. This parts make a cell differ from another. The process of differentiation is also related to Gastrolations, which was explained previously.

What kinds of proteins are found in different cells and organs?

It depends on the the function of each protein and organ/cell. For example, Hemoglobin is found in blood forming part of erythrocytes with the function of carrying oxygen to different organs and parts of the body. Collagen is found in different kinds of tissues and in some organs such as skin, tendons, bones and the cornea. Actin and myosin are found in muscles. Crystalline is found in the lens of the eyes.

What tells the cells which kinds of proteins to make?

The groups of genes activated in each cell have a specific DNA, which is replicated, transcripted and finally traduced into a specific amino acid sequence. This sequence forms a large chain of aminoacids which form part of a protein. Each sequence determines a different protein.

What is the relationship between DNA, genes, and the proteins that are produced in cells?

The DNA is our genetic code. Some parts of the DNA (genes) are activated in different cells of our organism and after the process explained in the previous question, the genes determine specific proteins. Proteins are the most abundant organic macro molecule in our body.

Video

Impact of biofuels on economy presentation

Last Friday we had to present about some topics related to biofuels. First, Ugarte and Nuñez presented about the process of extraction and production. It was a really interesting presentation but some concepts were difficult to understand without previous knowledge.

Then, Gastó and I presented about the impact of biofuels on economy. We divided the impact into two great areas: a negative and a positive impact. Gastó talked first about the positive impact, mainly related to the jobs and income generated by biofuels. After him, I presented about the negative impact which is based on the raise of prices and the impossibility of poor families to afford food used for biofuels. Sugar cane, corn, soybean and agave are just some examples of crops that have raised in price. What really called our attention was the raise in the price of tortillas in mexico which has incremented as much as 400%.

Finally, Barriga and Reynolds presented about the effect of producing biofuels on land used for food or cattle.

The impact of producing biofuels on economy

According to http://biofuel.org.uk/, a biofuel is defined as any fuel whose energy is obtained through a process of biological carbon fixation. Biofuels can be produced through different kinds of crops and may differ in their chemical structure, but they all have similar methods of obtention. some of the most used crops are sugar cane, agave, grass and corn. By producing biofuels, we have two great impacts on economy: a positive and a negative one.

Positively, biofuels have expanded processing of agricultural products in rural areas, generating a widely pursued strategy for rural economic development. By adding value to farm products before they leave the area, new processing plants can create new employment opportunities and generate economic spinoffs in rural areas. In addition, farmer-owned processing facilities provide a way for producers to integrate forward and capture potential profits from processing and marketing their products. Consequently, the expansion of agricultural processing in rural areas usually receives broad-based support from commodity groups, rural development interests, and state political leaders. In recent years, the most prevalent type of new agricultural processing ventures in the Midwest and Great Plains states has been corn ethanol plants.  Like other types of agricultural processing, these biofuel ventures have generally received widespread support, and numerous studies have addressed their contributions to local or regional economies.  The rapid growth of the corn-based ethanol industry shows the potential for biofuels.  However for biofuels to make a substantial contribution to the domestic liquid fuel supply, the industry must expand beyond corn-based ethanol. As the results of a study done by the U.S. Renewable Fuel Standard (RFS), the main benefit of biofuels is the direct job creation (Approximately 400,000 jobs), which greatly helps poor people in developing countries.

On the other side we have the negative impact of biofuels on economy. Expanding biofuel affects poor people in some developing countries by making it harder to find and afford an adequate diet, according to recent World Bank research. The expansion would push up prices for many food staples. Global prices for corn and other major grains could rise by as much as 3% and the price of sugar by 8%, issue that has already happened in countries such as Brazil and the United States with an increase in corn, soybean and sugar prices by 27, 21 and 12 percentage points respectively.

So what do you prefer, fuel or food?

References: Hodur, Nancy M., F. Larry Leistritz, and Tarrand Hertsgaard.  2006.  “Contribution of the North Dakota Agricultural Products Utilization Commission Programs to the State Economy.”  Dept. of Agribusiness & Applied Economics AAE 06006, North Dakota State University.

http://www.agmrc.org/renewable_energy/biofuelsbiorefining_general/economic-impacts-of-biofuel-development

http://www.bio.org/articles/us-economic-impact-advanced-biofuels-production-1

http://biofuel.org.uk/

http://econ.worldbank.org/WBSITE/EXTERNAL/EXTDEC/0,,contentMDK:22946809~pagePK:64165401~piPK:64165026~theSitePK:469372,00.html

http://www.federalreserve.gov/pubs/ifdp/2009/967/