Tuesday, March 15, 2011

DNA Extraction Lab

Below is the slide show Sidney and I made on Google Docs. It just briefly goes over what we did.
Check it out :)

Genetics...phenotype...genotype...

More than recently ago, we did an activity in class. We made babies. (Nonexistent babies of course.) Each of us had a partner and we conducted an activity to create a child. Later, we drew pictures of our "children" and they were proudly posted on the wall of Mr. Ludwig's classroom. This activity, I believe was done to teach us about genotype and phenotype. Both very important key words when talking about genetics. I'll start off by telling you a little bit about the activity we conducted in class...
          After we had been paired up in partners Alii and I got right down to making our baby. The way the activity worked was we had a list of different features...eyes, mouth, nose, ears, freckles, no freckles, hair color, etc. etc. We flipped coins and used pencil and paper to decide what our baby's genotype would be. I was the daddy (haha) and Alii was the mother. After the genotype was decided this helped us to know what our baby was gonna look like. Which is the phenotype.

         So these traits-eyes, mouth, hair color, etc... is controlled by two alleles. There is the dominant allele and the recessive allele. The dominant allele is referred to this way because of its ability to mask the expression of the other allele. A dominant allele is expressed with a capital letter. The recessive allele is identified with the same letter but in a lower case form. Two identical alleles, for example- TT. (Which is two alleles for tallness in plants.) are homozygous. This means that if there were two parent plants that were homozygous all the gametes produced by these parents would contain alleles for tallness (T). And all of the gametes produced by shorter plant parents would contain alleles for shortness (t). So let's say there was cross-pollination between two plants. Then this new generation would have one allele for tallness and one for shortness (Tt) Because they had two different alleles they are considered heterozygous. Even though these plants had one of each type of allele, they were all tall because (T) was the expressed allele. This makes it dominant.
         This brings us back to genotype and phenotype. Genotype refers to the alleles an individual receives at fertilization. Phenotype refers to the physical appearance of the individual. For example- a person with Genotype TT (homozygous dominant) would have the phenotype of being tall. A person with the genotype tt (homozygous recessive) would have the phenotype of being short.
           In the activity we flipped the coins to decide which allele we would give to the child...it works sort of differently in real life...but you get the point. :)
So there you go! A kind of brief overview on genetics. And how genotype and phenotype fit into all of it.

In Sickness and in Health...Case Study/Greg & Olga

This is the Pedigree that Sidney and I created for Greg and Olga. Greg and Olga are labeled. And you can see their families history.
So Im taking a risk here...the way I understand it, as long as I can prove I understood this whole "assignment" we won't have a problem. Well, obviously the easy way to do it would be to answer the questions provided on the site and show that I was indeed paying attention to what I was reading. BUT as much as I love to answer questions, I am going to just write. And describe what the heck genetic counseling is and how it applies to our friends Greg and Olga. So here we go! :)

          Let's start off with why Greg and Olga came to a genetic counselor in the first place. Greg and Olga are concerned. They want to start a family but each of them have some worries about their families medical histories. Hemophilia A is present in both of their histories and they knew it could be inherited, and they were concerned about passing it on if they had children of their own. Also, several of Greg's relatives suffered from (MD) Myotonic Dystrophy. Knowing that MD runs in families, G & O also had some concerns that they could pass that on as well.

          First we will address the worries over the possibility of Greg being an MD carrier. MD is an autosomal dominant disease. MD does not skip generations. Greg's mother has two siblings that have MD. But there is no chance that his mother has the disease. Neither Greg or his mother could not be carriers of the gene because if they were they would be sufferers of the disease. The possibility of G& O's kids inheriting MD is ZERO. Because neither of Greg's or Olga's parents had the disease, G & O can't be carriers of the gene themselves. That means they can't pass it on to their kids themselves.

        Now when G & O came into the office they also had a couple concerns about diseases that aren't as easy to weed out, Cystic Fibrosis for example. Now CF is one common RECESSIVE TRAIT. A recessive trait can skip generations. Recessive traits (this is very important) are equally likely top affect both males and females. Consanguinity is also included in here somewhere. Consanguinity is the matings between two related individuals. Consanguinity is important when talking about Recessive traits because two people who are consanguineous they have a very good chance of having similar genotype...example, recessive traits.


             If you look at G & O's pedigree we can see that Hemophilia A, Greg & Olga's main concern, is only present in males and it appears rarely. This is a very good indication that Hemophilia A is an X-linked gene. X-linked genes mostly appear in males because the mutated gene is on the X-chromosome. Males only have one X-chromosome. Unlike girls, who have two X-chromosomes. This means if a girl had a mutated gene on the X-chromosome her second "good" X-chromosome could cover it up. If G & O were to have a boy there isn't any chance that Greg could ever pass on the disease at all. For G & O to have a son Greg would have to pass on a Y-chromosome which is not affected by the disease. Because the disease effects the X-chromosome and Greg does not suffer from it there is no possibility that he has the disease. This means he could not pass it on through the X-chromosome he would give a daughter. Looking back at Olga's family history we can see that her mother and grandmother were both carriers. This means there is a chance that she would pass the mutated gene on to her child (male). OR the child could be a carrier as well (male or female)

            This an example of a case that could be brought in to a Genetic Counselor. Genetic Counseling can be very helpful if you have concerns about the child or children you hope to bring into the world.

Here is the website I used to help complete this post:
http://www.sciencecases.org/sickness_and_health/sickness_and_health6.asp

Sunday, February 27, 2011

It is very late...but here it is.

I have been a very bad blogger lately! I have been working on so many projects for Biology they all kind of just take turns getting worked on. The good news is that I have made progress and finished some stuff on Mitosis and Meiosis. The following is a link to a glog I did on Mitosis:
http://sierra3.edu.glogster.com/glog-6479-4769/

I decided since I do Glogs for EVERYTHING! I would take a break and do an "old fashion blog post" and just tell you a little bit of what I learned on Meiosis.
       First of all, what is Meiosis? Meiosis is the type of nuclear division that reduces the chromosome number from the diploid number to the haploid number, in sexually reproducing organisms. The total number of chromosomes is referred to as the diploid number. The haploid number still refers to chromosomes. But the haploid number of chromosomes is half of the diploid number. For example, in humans, the diploid number is 46. In the haploid number, you end up with 23. Gametes are the reproductive cells, often times this refers to the sperm and egg. Gametes usually have the haploid number of the chromosomes. When these gametes form and fuse they make a cell called a zygote. This is all part of the integral parts of sexual reproduction. A zygote always has the full number of chromosomes, the diploid number. In meiosis there are two unique cell divisions. Meiosis I and Meiosis II. Prophase, Metaphase, Anaphase, and Telophase are the phases of both Meiosis I and II. Crossing over occurs in Prophase I. Crossing over is very important. It is the exchange of genetic material between NONSISTER chromatids of a bivalent. Due to this swapping of material, the chromatids held together by the centromere are no longer identical. That means that when those chromatids during Meiosis II, separate, some of those daughter cells will receive chromosomes with recombined genes. The offspring will have a different sequence of alleles, due to genetic recombination. What does that mean? It means that they will have different genes than their parents. Making them, their own person. At the end of Meiosis I the two daughter cells will have one chromosome from each homologous pair. The chromosomes still consist of two chromatids. In Meiosis II, the chromosomes align at the metaphase plate and then the sister chromatids separate and become DAUGHTER chromosomes. In Telophase II spindle disappears, nuclei form. And then cytokinesis takes place. At the end of Meiosis we have four haploid daughter cells. After Meiosis II, the haploid cells become gametes in animal cells and spores in plants. And you know the rest already, those gametes form and fuse to make the zygote! For humans, Meiosis occurs only in the reproductive organs to make the gametes.
So there you go! A little bit of information on Meiosis. Very soon, I will be posting blogs on the things we have been working on more recently. Chapin, Sidney, and I are all working on our Eugenics post and it should be up soon! I will also have a blog on a case study very soon :)

Friday, January 7, 2011

Being Reflective...

        Christmas Break has recently ended and myself like many other kids all over the country are getting back to walking through halls, reading books, writing reports, typing things up, and learning all kinds of good new "stuff".  On the first day back I was presented with an opportunity to read this article. It was called What You'll Wish You'd Known. I love to read and I really love to write. This article was so enjoyable. And it presented a lot of things to the think about. It wasn't an article on biology at all but it really helped me in that class and all of my other classes, from Choir to Math. The article was in fact a speech directed at high school students. It was something unlike anything I had read before in a good way. I enjoyed it because it addressed things that I have been hearing about for a while now. Things that are important at the moment but also have a direct connection to you later. It made a shout out to something that all American high schoolers struggle with. I guess what you would call it is our placement in the world at the moment. And what our placement will be in 5, 10, 20 years. Among many other things it discussed how we as high school students shouldn't be defined as high school students. Because yes, we do have to go to school 7 hours everyday, and it could be considered a "job". But the author of this article suggested something very smart. Treating high school as a DAY job. Going and doing what you have to do at school but also working on hard problems. Pursuing things that matter. Things that will make a difference to your own life and the lives of others. Learning things that will have a real impact on your life. Putting some of the focus that we so generously give over to t.v. or Facebook into things that will be beneficial to our lives. This article made a very big impression on me. Because it had a message that meant something. It was giving anyone who read it a head start on something that some people never grasp in their lifetime. This article is beneficial to anyone who reads it. Even people who are "old".  I believe that all of us can make a difference when we focus on the hard problems. And use our own talents to "make a difference". This article gave me a big realization that all of the things I am interested in and take an opinion on are part of my future and the future of the world. This article has helped me in this past week back from break, a week that focus appears few and far between. It inspired me. It inspired me to not waste time. To make an effort in everything I do. Whether it be a blog post for bio or a poem for english class...or maybe my own personal creation I have been working on lately. It helped me to look at myself, and see if I was really being true to this world and my "placement" in it. So I have decided to make this the best semester ever. The best summer ever. The best year ever. The best lifetime ever, by getting to work to get things done.


Here is the link to the article incase you are now inspired to read it and become inspired yourself :)


http://www.paulgraham.com/hs.html

Thursday, December 16, 2010

Glog happy :) PKU

Part 2! This is another Glog on PKU. I really enjoyed making this one. And I promise that I will soon find another way to share my knowledge besides Glogs in a creative way, they are just so much fun. haha
Here you go! :)
Link:
http://sierra3.edu.glogster.com/phenylketonuria/