Here are some questions related to the last two videos we watched about Stem Cells. In this post, I present my answers.
1) Why are stem cells considered so valuable for medical research?
This is because Stem Cells are flexible and can turn into any specialized cell, that's why they're called Pluripotent.
2) Why did the researchers have to narrow the spectrum of genes within stem cells? (video 1)
Because there are over 20 thousand genes, which were narrowed to 100, then 24 and finally only 4.
3) What are the sources of stem cells and the advantages and disadvantages associated with using each?
They can be taken from embryos, or can be produced from some specific cells taken from any cell. The advantages of stem cells are obvious, as they could eventually turn into any organ and help doctors cure almost every disease. However, their main drawback is related with ethics, as an embryo must be created to extract a specific organ, which means that doctors would "kill" the embryo (there is a similar problem with abortion)
4) What are the three cases presented at the beginning of the second video?
A hockey player with a problem in his spinal cord, a man with diabetes and two cousins that had a genetic brain problem (Tay Sachs disease)
5) How might a stem cell be used to treat spinal cord injuries?
They could replace the dead cells and build a bridge along the spinal cord by communicating with the closest cells.
6) Explain the outcome of the experiment with injured rats presented in the second video?
The stem cells were placed in a section of the rat's spinal cord, and they turned into spinal cells by communicating with the nearby cells. However, the result was not completely perfect.
7) What issues surround the debate over of stem cell research?
The ethical problem related with embryos is the main issue, as in some methods a embryo is created and then it dies.
8) What issue do you think needs to be debated as we make decisions about stem cell research?
Just as with abortion, life should be respected. I think that healing diseases is something great, but it cannot go over other's life. I believe that killing an embryo to heal someone else is something selfish and it might generate deep problems in our society.
1) How has evolution tinkered with genes of animals?
Evolution can be considered to be all the new combinations of genes that are created, commonly triggered by the external changes (Climate, food availability, etc).
2) What role has embryos played in the study of evolution?
They are the developing animal, which shape and form is determined by the activated genes and the homeobox. This is the stage of development in which scientists focus their researches.
3) What did the experiment with fruit flies and mice show?
It showed that the homeobox or genetic tool kit could guide the growing process of any animal, as the genes come from common ancestors. This created a new view about the complexity of evolution.
4) What does the presence packages of information suggest about evolution?
It suggests that all animals have common genes, but their development is determined by the external factors and by the homeobox.
Genetic Tool Kit Video
As we keep learning about embryos and cells, today I present a set of questions related to Control Genes.
1) Why did the German scientist decide to study the fruit flies at the larval stage?
She decided to investigate the flies in their early stage to analyse how they developed and how the mutations occurred. Other researchers used to analyse fruit flies in their adult stage, but they couldn't understand how the genes worked nor how the mutation was produced.
2) How does the mother fly activate the control genes?
She leaves different chemical messages when she lays the eggs, and they determine the head and the tail of the growing fly and activate some gens inside the egg.
3) What is the role of control genes?
They switch on many other genes inside the cells, in order to specify their tasks. They control time and space, so the genes are activated at a determined region or organ in a specific moment of the growing process.
4) Which of the two species are closer to humans?
Zebrafish is closer. Their control genes and body plans are similar to the human beings'.
Gene Control Video
As we are starting to explore a new area, the stem cells and the ethics around them, I'll answer some questions about the video "The Embryo takes shape" to have a better knowledge of this biological process.
1) What directs the sequence of events that turn a blob of cells into an embryo with specialized tissues and organs?
It's mainly determined by the genes and by the three layers created in gastrolation. 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.
2) The narrator says that “cells talk to each other.” What does that mean?
It means that they can communicate to each other by chemical messages, which activate some specific gens in the nearby cells.
3) How do cells in different parts of the embryo become different kinds of cells and organs?
It depends on the ADN, the gens activated in each cell and the embryo layers explained in question 1.
4) What kinds of proteins are found in different cells and organs?
Collagen - Skin, tendons and bones.
Carrington - Hair.
Crystalline - Lens of the eyes.
Actin and myosin - Muscle fibers.
Hemoglobin - Carries oxygens from lungs to body.
5) What tells the cells which kinds of proteins to make?
The groups of genes activated in each cell.
6) What is the relationship between DNA, genes, and the proteins that are produced in cells?
They are all connected. The DNA is the genetical information in your cells, and genes are very small sections of these code. The genes, activated by molecules, determine which proteins are produced in each cell. Proteins are the molecules that build our bodies.
Last week, we studied the benefits and drawbacks of the implementation of biofuels in our world. It was great because we had the chance to understand the bad aspects of these sources of energy, which are usually seen as completely green and safe. During the week, we joined in pairs (I worked with Mr. Barriga) and presented about a topic. We focussed our work on the land consequences in the production of biofuels, which is mainly related with the production of food. I think we managed to perform pretty well and explained our subtopic to our class in a good way. In general, I think the presentations were all good and also, they were a great way to understand the problems and benefits of biofuels in a better way, as each group faced the topic from a different aspect or view.
If some asked me how would I evaluate my partners work, I think all the peers did a good job. Some topics were more difficult, specially the one about the production process, but Mr Nuñez and Mr Ugarte managed to present it in a good way (Maybe they could have spoken a little louder). Mr Oporto and Mr Gastó presented about the Economical Effects, contrasting the comercial benefits of biofuels and their impact in food prices.
Here are some questions related to the last two videos we watched about Stem Cells. In this post, I present my answers.
6) Explain the outcome of the experiment with injured rats presented in the second video?
