Monday, May 16, 2011

Evolution Essay

Evolution is the theory that all living forms came from ancient ancestors. Through a series of mutations, genetic drift, migration, and natural selection today’s descendants show an amazing amount of similarities and diversity. Evolution on a small scale is called microevolution, relating to the changes that occur such as insects becoming resistant to pesticides. Macroevolution refers to the grand scale. It is associated with extinction, change, stability, and lineage. At the time of its “birth”, it was a controversial subject. Charles Darwin was the first to formalize the theory of evolution, but before him there were more scientists interested in it.

Charles Darwin was born in England and originally planned to take up a career in medicine. When that didn’t work out, he switched to divinity in Cambridge. Later he took a five year excursion on the HMS Beagle. During his time on board Darwin read the “Principles of Geology” that stated there was geological evidence of ancient animals. While on the Galapagos Islands he noticed that the finches on the each island were closely related but different in big ways. When he returned, he theorized evolution based on natural selection. Twenty years later he and Alfred Russell Wallace discussed evolution openly. In 1859 he published his extremely controversial ideas. Darwin was attacked for his theory, particularly by the Church. But his ideas became widely accepted.

Darwin’s own grandfather, Erasmus Darwin, was a prestigious physician, botanist, naturalist, poet, and philosopher. He believed that all modern creatures had originated from “one living filament”, a common ancestor. Erasmus did not come up with natural selection, but he did believe in competition and sexual selection. He believed that the strongest males reserved the right to mate, therefore passing on satisfactory traits. He used an integrative method of research, bringing together multiple branches of science to come to his conclusion. Some of his ideas were alike to those of Jean Baptiste Lamarck. Lamarck is an obscure character in evolutionary history as he was ostracized and his theories were not recognized by his colleagues. He was in the army, then worked as a botanist in the royal gardens. In 1793, Lamarck was appointed professor of invertebrates. At the time there was little research on insects. He wrote a series of books about invertebrate zoology and paleontology. Although other scientists in his day hinted at the possibility of evolution, Lamarck declared it forthright. He was discredited by his peers and died a poor man. However, Charles Darwin and others respected his as a great zoologist and the forerunner of evolutionary theory. Georges Cuvier was a colleague of Lamarck’s that forsake him. He was a brilliant mind, but he did not share Lamarck’s theory of evolution, going as far as to discredit him. Cuvier had studied mummies of cats and ibises brought back from Egypt by Napoleon. Finding no difference from current day animals, he had decided evolution was false. He later studied elephants and mammoth fossils, determining that mammoths were different from living elephants in their day. This led to the important idea of extinction.

Macroevolution is evolution on a grand scale. Instead of focusing on a single branch, macroevolution focuses on that chunk of the tree. It identifies patterns and transformations, then figures out how and why it happened. Mutation, migration, genetic drift, and natural selection are basic mechanisms that apply to both micro- and macroevolution to determine these patterns.For 3.8 billion years mutations have been passing through the filter of natural selection, creating stronger and more resilient descendants.  Changes and extinctions that have happened over the years are all part of macroevolution. Some changes take place slowly, this is called stasis. An example of this is the c┼ôlacanth, a fish hauled onto a ship in 1938, it was thought to be extinct for 70 million years. Extinction is an important part of evolution. Every species has a chance that it will become extinct. Microevolution is an even more important part of the evolutionary theory. As previously discussed, it is evolution on a small scale. It is the changes in animals to adapt to their habitats and the changing environment. Microevolutionairy changes can be seen by changes in gene frequency. A few of the mechanisms that affect these changes are mutation, migration, genetic drift, and natural selection. If a random cell is mutated, for example if a  yellow bird has some purple chicks and the rest are yellow. The genes in the yellow bird would have been mutated to produce purple chicks. If the purple chicks moved to another island, and the yellow birds on that island immigrated to the island that purple birds had previously inhabited, that is known at migration, or gene flow. When a mutated gene is passed to more offspring and out numbers the original colored offspring it is called genetic drift. As for natural selection, it means that the more well equipped animals are the most likely to survive. For example if the purple birds lived in a purple tree they would be more likely to survive than their yellow relatives in a purple tree. A test for preformed on sand colored and dark colored mice, showing that each mouse matched the color of their corresponding habitats. When put in the other’s habitat, they were put into more danger.

Ideas about evolution extend to different types of science as well. Biochemistry is also interested in this topic. It shows that there is a surprising amount of evolutionary evidence within the human body, bacteria, and fungus. An e.coli bacteria can become mutated and glow under a black light, showing an evolutionary change. As human fetuses grow within their mother’s wombs they are changing in evolutionary ways. There is fossil evidence that supports the evolutionary theory. Paleontologists have found and studied different species of fossils and have concluded that some fossils found were related to fossils found prior to the dig, or after. These fossils just had changes to them, evolution it could be said.

The most convincing arguments for evolution seem to be fossil evidence and the evidence that the fossils have evolved from other, previous fossils. Seeing how Darwin’s finches different from each other although they are the same bird, it makes sense to believe that evolution is plausible. Human are even evolving. Jaws are becoming shorter and their is less room for wisdom teeth in their mouths. Looking back into history, there is also the thought about Native Americans who lived in Arizona or the indigenous people of the Arctic. Their constitutions must have been completely different to be able to survive such extreme conditions. When thinking about dogs, crows, and spiders that can procreate with different dogs, crows, and spiders in their species it’s hard not to believe in evolution. This idea of speciation is a rather convincing idea.


All Information Was Taken From

Understanding Evolution. 2011. University of California Museum of Paleontology. 22 August 2008 <http://evolution.berkeley.edu/>.

Friday, May 6, 2011

Very Brief Introductory Video for Biology!

DomoNation.com: Welcome to Biology, Biology Childrens by justpeachygreen


Like it? Create your own at DomoNation.com. It's free and fun!

Oh, how fun Biology has been this year! I will miss it. This is a introductory video for new students next year. Enjoy the briefness!

Monday, May 2, 2011

Indexing La Junta

A few weeks ago the class was visited by a man from the Animal Assistance Foundation. We were given four pages to record animals that we saw, feral, owned, or unknown. For the next two weeks I walked the normal route I took home and counted the animals that I saw.

April 14, 3:30 P.M.- 4:00 P.M.
Cats:
1 owned
5 feral
2 unknown

Dogs:
3 Owned


April 15, 3:30 P.M.- 4:00 P.M.
Cats:
0 Owned
7 Feral
2 Unknown

Dogs:
4 Owned

April 21, 3:30 P.M.- 4:00 P.M.
Cats:
7 Feral

Dogs:
3 Owned


April 22, 3:30 P.M.- 4:00 P.M.
Cats:
9 Feral

Dogs:
3 Owned

I walked the same route everyday, and there are definitely more stray cats than there were dogs. Most of the dogs that I saw galavanting  around had collars and tags. There was a large population of stray cats that live down the street from me in an empty house, this is where most of my cat data came from. I really hope that the information helps cats like the ones down the street.

Tuesday, April 26, 2011

Something Fun!

This doesn't have a lot to do with what we've been learning in class lately but I thought it was fun so here you go!

Click on the screen and follow each video to find out how much you know!! (By the way... click on Science)

Thursday, April 21, 2011

Fingerprinting

When I look at people's hands, I notice how different they are from mine. They have different lines on their palms, their cuticles are neat or torn, the shape of their nails are square or conical or spatulate. Sometimes their hands are square, long, soft, or worn like they've worked their entire lives. I can tell if their nails are blue at the moons of their nails that they have poor circulation. Palm readers have noticed these little things for centuries. Today, we can recognize people from another thing on their hand, their fingerprints.
These little swirly things on the tips of are fingers aren't just pretty designs designed to hypnotize unwitting victims, they can be used to find criminals or missing persons. In crime shows they're always dusting for prints, running print scans, or shooting people. So it's pretty interesting when you actually see it in real life. Now days they send out little packets that contain an at home fingerprinting kit and a cotton swab for your kid's cheek so you'll alway be prepared if a creeper sneaks through a window in the middle of the night and snatches your children. There are some pretty amazing things that happen now days, and there aren't as many missing kids as there used to be.

Wednesday, April 20, 2011

GATTACA

I have to be honest, ever since watching GATTACA, I've been looking for it in DNA sequences that pop up on screens and videos we've been watching lately. I wonder if it's really hiding in there somewhere.... I really liked Original Jerome. He was really spunky and who doesn't like Jude Law? I think I liked his character the most because (Jude Law) he was driven. Jerome knew what he needed to get accomplished and went ahead with it. Even when "Jerome" was faltering. I wouldn't really want to be him though, besides being female, I think that the challenges he faced were pretty terrible.

 GATTACA sparked a few questions for me. It made me think about how the world would be if they could screen your child and tell you everything that that would make him/her "invalid". I mean, sure it would be wonderful to tell if your children will have brown hair with purple eyes and be adorable. But it would be horrible to know that that same child would die at the age of 7 because of a genetic disease, or 45 because of heart failure. This knowledge would probably bring you to shelter your child and hinder its growth. Jerome/Vincent knew what his "deficiencies" were but he went on to have a fulfilling life. He pushed his boundaries, but Irene didn't. She didn't dare do anything that may incur the prediction that was made at her birth. And that would seriously suck. Today we do things that could hurt us but we do them because, somewhere we can. GATTACA's society was wrong to judge people purely on their genetic code, because they didn't know what the person's will could or would be.

I loved GATTACA. It was interesting to me that this society may exist. Recently I read a book like GATTACA called "Matched". It's about a "perfect" society. People are paired with people who best fit their genetics. Their food and medicine and exercise is monitored and set up for them. Even their jobs are chosen for them, and ALMOST their every decision is predicted. And on their 80th birthdays, they die. Every choice is made easy for them, because what they offer is the best choice. But beneath the perfect society, it's not so perfect! It's a really easy read and pulls you into its world. It made me cringe to think that someday, someone could be making my choices for me.

pGLO Transformation




Thems is spooky cats! For the past 2 days we've been working on a pGLO Transformation Lab. It's basically playing with E. coli and seeing which one glows on the 2nd day, like the cats above. Don't worry they didn't put E. coli in those cats, but it is a similar process. But they are both genetically modified.

Here's an example of the glowing sample from a lab done in another class.

So what made the bacteria glow? Well, we began the lab with 2 samples, a positive and negative solution. After about 20 minutes of work, we were dishing out samples into 4 different agar sample plates (LB+, LB/Amp/ara+, LB/Amp+, and LB/Amp-). We waited over night and in the morning checked for results. Using a little black light we ran it over the 4 samples. As you can tell from the wonderful picture to the left, LB/Amp/ara was the completely awesome glowing sample. We successfully modified the bacteria! Hurrah for playing with bacteria!

Tuesday, April 19, 2011

PCR, POV

I'm a medical technician and I need to run a DNA sequence. So I set off down the hall, happy as can be with my little sample of people skin. When I get to the lab, I suit up (put on rubber gloves), as not to contaminate the sample. I collect a bacterial colony to move into a microcentrifuge vial with a wire rod. Adding a digestive buffer to the the sample eats away at the cell wall so I can take a closer look, this takes a few hours so I twiddle my thumbs. When it's finally done "digesting" I heat inactivate the digestive enzymes using a water bath. When it's ready I move the sample to a centrifuge to be spun down into cellular debris to be removed from my sample. What I really want is the supernatant so I can move those into PCR tubes and sequence. When I've collected all the goodies i add PCR master mix. It contains water, a whole lot of nucleotides (GACT), oligonucleotide (a short nucleic acid polymer, with <50 bases) DNA primers, and  a heat-stable DNA polymerase that makes the copy DNA strand longer. I'll run a positive (the one with PCR master mix) and negative (this contains deionized water) test. After my samples are prepped, I put them in the PCR machine. Yippee!!
What the PCR does is replicate DNA. It begins by splitting the double helix, next the primer of the template is annealed(a heat treatment that causes changes), and ends when the DNA polymerase is used to extend the copy of DNA. Finally, after lots of other work... I can sequence the DNA! I add sequencing brew and turn a the PCR. When that's finished I put it in a automatic sequencer and then build the sequence. I can finally compare my sample to others. 

Thursday, March 31, 2011

The Sequencing of DNA, Old School



I really like DNA sequencing. There's something about it that just interest me. Maybe it's that you can "read" people, or the thought that you're seeing something that different people don't ever get to see. And it's all possible today because Frederick Sanger saw what other people hadn't seen before. We did a worksheet earlier this week and you can see the data I collected from it above.
The worksheet had us reading DNA and protein sequences from 3 different patients and comparing them to a normal sequence of DNA/protein. A normal sequence would be seen as:

                   "ATG GTG CAC CTG ACT CCT GAG GAG AAG TCT GCC"


At least according to the worksheet, ;). The proteins were shown as this:

                   "Met Val His Leu Thr Pro Glu Glu Lys Ser Ala"


Don't worry, it starts getting interesting from here. As you can tell from the graph above, none of the patients have a DNA sequence that perfectly matches the norm. Abby and Bob have the most "normal" of the sequences, and it may lead you to believe that they are completely ok, just a little different. But when you look at Carol, you think,"Oh wowza, she's a mutant!"

But in reality, all of these patients have a problem. With Abby, she is only has one base change, right at the first GAG/Glu. Her's is instead GTG/Val. This is called a "point mutation". It doesn't seem like a single mutation could mess anything up, but it does. It all comes down the protein sequence. The Glu is positively charged and goes along with the sequence well, but the Val is hydrophobic. That means it will probably mutate the sequence. This is seen in people with cystic fibrosis. But she could not have! :D

With Bob, he has a Truncation mutation. He only has one changed base, like Abby. But his AAG/Lys base is a TAG/stop instead. That means that his sequence stops early, 3 early in his case. This makes the protein too short.

Carol probably has skin cancer. Her type of mutation is called a Frameshift Mutation. She has a normal sequence but is missing, it's completely gone, her T from the ACT/Thr base, so instead it is a ACC/Thr. This can be caused by radiation from the sun, or other things that could kill off one of her letters.

It makes me pretty happy that I can read all that in a single sequence. It's amazing all that can happen in a human body.
Ok, now you can take a step back, stretch, and wipe that yawn off your face. You learned something!


Tuesday, February 22, 2011

Human Chromosome Webquest blog

These questions have been taken from a webquest I've been doing in Biology. I researched Narcolepsy and I think it's pretty interesting. I also looked at insomnia, but that isn't very important but it was neat to finally know what went on with it. Watch the Prezi!!!


 *What disease did you choose and what gene is/genes are associated with this disease? I chose Narcolepsy to research. The prepro-orexin gene is associated with Narcolepsy.

*On what chromosome are these genes/is this gene located? The prepro-orexin gene is located on the chromosome 17q21-22.

·      When was the disease first reported in the scientific literature? In the 1990’s.

·      What are some of the clinical symptoms of this disease? Daytime drowsiness, cataplexy (sudden weakness of muscles), and occurrences of REM during wakefulness are the clinical symptoms of Narcolepsy.

·      What lab findings (gene function or biochemical data) are associated with the disease? Narcolepsy appears at random instead of being inherited. It was thought that the cause of narcolepsy was because the body’s immune cells were attacking neurons that secrete hypocretin.

·      What type of inheritance governs this disease? There is no specific inheritance that deals with this disease. Instead it is appears randomly.

In Sickness and Health!


In Biology we've been working on the sickness and health activity where we work at being genetic counselors. The following questions are each of the stages that i passed to finish the activity. Check out the website here.


Questions

  1. Do autosomal dominant disorders skip generations? No because they need to have a female carrier. 
  2. Could Greg or his mother be carriers of the gene that causes myotonic dystrophy? His mother could be a carrier but Greg could not because he is male.
  3. Is there a possibility that Greg’s aunt or uncle is homozygous for the myotonic dystrophy (MD) gene? Yes.
  4. Symptoms of myotonic dystrophy sometimes don’t show up until after age fifty. What is the possibility that Greg’s cousin has inherited the MD gene? There is a 50/50 chance that Greg's cousin inherited MD. 
  5. What is the possibility that Greg and Olga’s children could inherit the MD gene? There isn't a chance because Greg can not be a carrier without having symptoms of the disease. 

Questions

  1. What are the hallmarks of an autosomal recessive trait? There are five hallmarks of autosomal recessive inheritance:
    1. Males and females are equally likely to be affected.
    2. On average, the recurrence risk to the unborn sibling of an affected individual is 1/4.
    3. The trait is characteristically found in siblings, not parents of affected or the offspring of affected.
    4. Parents of affected children may be related. The rarer the trait in the general population, the more likely a consanguineous mating is involved.
    5. The trait may appear as an isolated (sporadic) event in small sibships
  2. What does consanguineous mean? Why is this concept especially important when discussing recessive genetic disorders? It means people coming from the same ancestor, this is important because if two people are related then it is more likely they will receive the disease.
  3. What is it about the inheritance pattern of factor VIII deficiency seen in Greg and Olga’s pedigree that point toward it not being an autosomal recessive trait? The pattern seems to stay mostly in boys, making women carriers. 

Questions

  1. What are the characteristics of X-linked recessive inheritance? The characteristics are that they are only passed on to boys and the disease does not affect women.
  2. Why does a son never inherit his father’s defective X chromosome? The mother has to pass on the gene to her son.
  3. What is required for a woman to display a sex-linked recessive trait? She would have had to inherit it from her mother.
  4. Return to the pedigree drawn earlier for Greg and Olga; mark those persons who are carriers of the factor VIII deficiency gene. Link to Picture
  5. What is the chance that Olga carries the gene for factor VIII deficiency? Calculate the probability that she will pass it to her offspring. Will male children be affected in a different way than female children? There is a 50% chance that she will pass the VII deficiency to her children.
  6. What is the chance that Greg carries the factor VIII gene? Can he pass the gene on to his sons? His daughters? How will each be affected? There is a 25% chance that he will the gene onto his children. He wouldn't be able to pass the genes onto his children.

Questions

  1. What is the second equation? 1 of 3,000
  2. The incidence of cystic fibrosis in Hispanic Americans is 1/4500 while in African Americans cystic fibrosis is seen in 1 of every 15,000 births. What is the carrier frequency for each of these populations? 1 in every 3 women.
  3. What is the probability of two Hispanic Americans having a child with cystic fibrosis, given that there is no history of the disease in either’s family? Zero percent.
  4. Carol is an African American woman who does not suffer from CF. Both of her parents are healthy but her brother has cystic fibrosis. Carol is planning a family with her husband Marcus, who is also African American but who has no history of CF in his family. What is the probability of their having a child with CF? 50%

Questions

  1. What are some of the risks and benefits of genetic testing as it relates to legal (not medical) issues? Risks of genetic testing are that the child could miss out on job opportunities or be prejudiced. Benefits are that they can catch the disease early on and help. 
  2. Do you think an unintended consequence of genetic testing could be that people would be less liable to seek medical care out of fear that they could later be denied life or health insurance? What laws should be used to govern the use of genetic data of this type? Yes, that is a viable consequence. A law should be made to provide everyone with equal insurance rights. 

Tuesday, February 8, 2011

Eugenics!

The definition of eugenics is the following. (Taken from dictionary.com.)
–noun ( used with a singular verb )
the study of or belief in the possibility of improving the qualities of the human species or a human population, especially by such means as discouraging reproduction by persons having genetic defects or presumed to have inheritable undesirable traits(negative eugenics)  or encouraging reproduction by persons presumed to have inheritable desirable traits (positive eugenics).

For the past week or so we’ve been working on eugenics. It’s interesting to think that people used to be sterilized (neutered) because of a defect that had a possibility of being passed on in a mother or father’s chromosome. I think this is a little bit unnecessary because sometimes certain genes aren’t passed on. There is always a chance that the child won’t receive a gene for brown eyes if the mother’s eyes are dominantly blue and the father’s eyes are brown with a recessive gene for blue eyes.

A little history on eugenics now, yes? Eugenics originates in America after the Civil War. During reconstruction many immigrants were moving in. There was a decline of births in elite families and an incline in poor families. Social Darwinism was on the incline also. It basically says “survival of the fittest” and it was taken from there that the elite were the fittest. It was decided that because much money was spent on the “degenerate” poor, sterilization would be the best option for the survival and betterment of our race. They based a lot of their work on IQ tests and behavior, such as criminal activity, prostitution, and social standing. Richard Dugdale did research on a family of 700 of these degenerates. He thought that the degeneration may have been based on poor environment, but when the degenerate family was mixed with an elite family, the “degenerate” genes were passed on. From there, increased marriage restrictions occurred, and the 8th of the 18 suggestions of dealing with these types of genes was euthanasia. People were sterilized unfairly, people like Carrie Buck, who was put in a home for the “feeble-minded” with her mother, both were accused of being promiscuous and imbeciles. Carrie’s seven month daughter was also labeled feeble-minded, although later grades showed the opposite. Hitler’s eugenics seem much crueler, as he sterilized thousands of Jews and Gypsies, preferring a blond and blue eyed race. But the United States also preformed involuntary sterilizations on criminals in prisons. I can’t determine which could be worse, as they’re both involuntary. But I believe Hitler took his too far. Way too far.

I really don’t agree with eugenics, like Punnett said at the first meeting of international eugenics in 1911, “Except in very few cases, our knowledge of heredity in man at present is far to slight and far too uncertain to base legislation upon.”
They really didn’t know enough about a person’s genetic structure to be allowed to kill or neuter said person. I don’t believe that in any way should it be justified by a few defects that may not even be passed on. A few days ago, I tested my mother and sister with the little strips Mr. Ludwig handed out. They could (much to my glee) taste them. My mom said that it was a decent taste, but I think that may have been the result of her previous gum chewing. I didn’t warn my sister about what I was giving her and got a wonderful reaction from her. I had the same reaction. What does it mean? Would it have meant back in the day that we needed to be sterilized? (Just so you know what I’m talking about, it means “neutered”.) People were sterilized for the silliest reasons. At one point, it was believed that you could have a predisposition to be a criminal if you father was due to a gene that could be passed on. I heard once that you have a predisposition to like broccoli. I guess that makes sense seeing as how half the population hates vegetables. What if we sterilized people who didn’t like broccoli? I suppose it would cut down on the amount of picky children but what if all those people had  gene that made the body more susceptible to cancer cures? What if they could stop radiation? Then it’d be horrible to make sure they didn’t have any children.


Take a look at the eugenics archive to see what I'm talking about :).

Tuesday, January 18, 2011

Cloning!! And More Meiosis



I have to say, I love this Biology Unit. I love learning about the mechanics of the machine that is our body. It's interesting (to me at least) to know that meiosis is what starts the baby making process! Learning about the 18 Ways to Make a Baby was really neat, and one of the ways was cloning.

Introducing, the amazing Cloning Charlie! He uses his super hero skills to divide and conquer evil. Unlike the process that goes on in cloning animals, Charlie's super powers could be compared to the production of sperm or plant mitosis.

 So, what goes into the animal cloning process? I'm not quite sure myself, but let's look at how a mouse is cloned and try and determine what in the heck is going on.

1. Meiosis here. That is how the regular splitting of cells occurs. After a woman's egg becomes fertilized it moves onto meiosis 2, the fetic and embryonic stages. But with cloning, you are going to have to exact same DNA as the creature you took the DNA from.  From here on is the recipe for cloning.

Ingredients

1 Mouse Somatic Cell
1 Mouse Egg
1 Surrogate Mouse
1 Dividing Agent (mouse sperm)

1. Extract a somatic cell from the 1st mouse. Harvest the egg from the 2nd.
2. Remove the nucleus from the egg cell. Replace with the nucleus from the somatic cell.
3. Fertilize the new egg cell.
4. Implant the egg into the surrogate mouse.
5. Hurray for babies!

Friday, January 14, 2011

A Blog About Meiosis

I think new borns are extremely weird looking. Like little aliens. At an embryonic 12 weeks, they are even more frightening. I once told my friend that I thought at that point in the gestation period they looked like predators. Like Alien Vs. Predator. They frighten me. It's hard to believe that at one point that weird little red thing was once just an even littler gamete. Beginning as gametes, then they're a zygote with a diploid, then it turns to a haploid cell. It's like mitosis, but this creates what become little kids who become adults who make more little kids. So I was curious and decided to research how to make a baby!

Step 1 (AKA Prophase 1): A diploid cell splits, making four haploid daughter cells (this is what creates genetic diversity). The paired chromosomes are called chiasmata, which are caused by genetic recombination.

Step 2 (Prometaphase 1): One kinetochore (the protein structure where chromosomes attach) forms for each chromosome and the chromosomes begin to move.

Step 3 (Metaphase 1): The two chromosomes, now bivalents, line up at the metaphase plate. At this point there is a 50/50 chance that  the daughter cells will get either the mother or father's feature.

Step 4 (Anaphase 1): The daughter cells become haploid cells after chiasmata separate (chiasmata is where the cells exchange DNA).

Step 5 (Telophase 1): The cell either reforms or starts meiosis 2.

Step 6 (Cytokinesis): This is where the two daughter cells form.


There we have it, meiosis! This process keeps happening in men, but in women it doesn't continue until an egg is fertilized. Which will be continued in a separate blog on.... meiosis II.... DUN DUN DUN!

Monday, January 10, 2011

Stem Cell Research

Important Terms:

Cell-based therapies: stems cells are induced to differentiate into a specific cell type.
Differentiation: where a unspecialized cell acquires the specialized features of a specific cell.
Embryonic stem cell line: embryonic stem cells that allow proliferation without differentiation for months to years.
Proliferation: the expansion of the number of cells from two identical daughter cells.
Plasticity: ability to be different.
Pluripotent: Having the ability to give rise to all the various cells types of the body.


Answer the following questions:

1. What are the unique properties of all stem cells?  Explain in your own words what each property means.
Stem cells are able to proliferate; splitting and reuniting, can become any cell, and can differentiate; can become a specific type of cell.

2. What are the two main kinds of stem cells used by researchers?  What are the major differences between the two types in terms of their sources and usefulness to researchers?  Give examples for each type of stem cell.
The two main kinds of stem cells used by researchers are embryonic cells and adult stem cells.

3. List some of the diseases that scientists think may be treated using stem cell research and suggest how stem cells might be used to treat each disease.
Scientists think that stem cells may be used to cure diseases such as cancer and birth defects.


4. What are the necessary characteristics that laboratory-manipulated stem cells will need to have in order to be successfully used in cell-based therapies?
The stem cells need to be unspecialized. 

Friday, January 7, 2011

What I'm Glad I Know Now That I Didn't Know Before (a break from Biology :))

 http://www.paulgraham.com/hs.html 


Let me start by asking, what are you going to do when you grow up? Are you going to move to Zambia and ride giraffes? Or don a space suit and rocket to the moon? I don't know the answer to that question, and neither do you, most probably. In Paul Graham's speech, he reassures his audience that, yes, you can have absolutely NO CLUE what you want to do when you get to college! Now, I've been told this over and over again by multiple adult people (and they should know, shouldn't they?), but it was reassuring to see it written, or typed, as it was here. This article took a stick and jammed it into my brain and played around in my mind. I found myself immensely relieved that I still have time. And slightly smug, knowing this tiny gem of wisdom. Something Mr. Graham wrote really hit me. "If I were back in high school and someone asked about my plans, I'd say that my first priority was to learn what the options were." He then goes on to say there's no rush to figure out what you want to do for the rest of your life. I agree. If you're going to do something, you should be able to do it right, and enjoy it every time you do it. I will conclude by asking another question. Are you going to worry about what you're going to do when you grow up? Or are you going to relax and find a perfect medium?

Onion Root Cell


Begin by reading the description of the five major cell phases. You will need to keep this information in mind during the activity.

Make a copy of the data sheet that appears on the second page. You will need it to answer the questions.

Proceed through the activity, identifying the phase for each cell you are shown. Pay attention to the hints if you misidentify a cell at first.


Interphase
Prophase
Metaphase
Anaphase
Telophase
Total
Number of Cells
20
10
3
2
1
36
Percent of Cells
55.5%
28.7%
8.3%
5.5%
2%
100%


When you have completed the activity, answer the following questions:

1. What percent of cells were in interphase?
55.5% were in Interphase.

2. What percent were in mitosis?
100% were in mitosis.

3. Which phase of mitosis takes the longest?
Metaphase takes the longest.

4. During which stage is the nucleolus visible as a dark spot?
In Interphase, the nucleolus is visible as a dark spot.

5. How can you recognize a cell in metaphase?
You can recognize a cell in metaphase by the “squiggles”.

Wednesday, January 5, 2011

Mitosis and Me

After taking the pre-test for the Cell Cycle, I realized that I really need to work harder this Semester. So I too a trip to visit Google, my best friend next to freetranslation.com.

1. Definition for the Cell Cycle: The process in which a cell grows and divides. Some cells take 24 hours to  go through the cell cycle (animal cells) and some do not divide at all (neurons).
Compliments of:  http://www.wisegeek.com/what-is-the-cell-cycle.htm

2. How it happens and what follows.
Interphase: G1, S, G2.
1. G1: grows in size and manufactures more
2. S (Synthesis): where the cell replicates the cell's DNA, only one copy is made.
3. G2: the cell continues to grow and produces a number of molecules
4. M: the cell's DNA condenses into chromosomes and are then are sorted into an even amount.
     They are then split into two different cells.
  • a) Interphase: The very end of the Cell Cycle, where the cell becomes two separate cells. 
  • b) Prophase: The Beginning of Mitosis: the centrosomes move towards the opposite poles of the cell. The sister chomotids become more visible as they condense. 
  • c) Metaphase: The chromatids are lined up between.
  • d) Anaphase: The chromotids begin to separate and become chromosomes and move towards the ends of the poles.  
  • e) Telophase: The chromosomes arrive at the poles, finally, and begin to grow their own nuclear membranes.
  • f) Cytokinesis: A furrow is created in the parent cell and eventually "pinches" the two new cells apart. 
And this is how cells reproduce!