Mitosis Lab & Meiosis

     Today we started off by doing a lab on the different stages of mitosis in both plant and animal cells. We observed an onion root tip cells and animal cells under a microscope and drew pictures of the cells we observed going through the various stages. First interphase - DNA replication is occurring within the nucleus but physically it looks normal. The nucleus is intact and dark surrounded by cell walls. The second phase is prophase - the nucleus dissapears. The third phase is metaphase - the chromosomes line up in the middle. The fourth phase is anaphase - spindle fibers pull the two chromatids apart which forms two daughter chromosomes. And lastly telophase - a new nuclear enveloped forms around the two and if cytokinesis occurs there will be the formation of a cell wall between the two.

     After this we practiced our knowledge by looking at pictures of cells and counting the cells in each phase. This also told us how long the cells spend in each phase. Cells spend the majority of their lives in interphase.

     The mitosis I just talked about only occurs in body cells and some gametic cells. Other cells go through Meiosis. 

     Meiosis is similar, first the cells go through interphase consisting of G1, S and G2 stages, the same as in mitosis. G1 you have mom and dad DNA. In S, DNA is replicated and you have twice as much DNA. In G2 nothing really happens. Then Prophase 1 occurs, the nucleus dissapears. Then metaphase 1 - chromosomes line up in the middle, homologous structures together. Then anaphase 1 - pulled apart by spindle fibers. Telophase 1 - forms temporary nucleus and cell wall around two new cells. Prophase 2 - nucleus disappears. Metaphase 2 - line up in middle. Anaphase 2 - pulled apart. Telophase 2 - four nuclei and cell walls are formed.

    We practiced this repeatedly and noticed that almost every time we did it, a different combination of alleles came out. These random combinations are genetics, what we learned about last unit.

Unit 5 Project & Microscopes

     Today in class we started by getting our tests back. We then talked about the Unit 5 project and had time to work on them. I used this time to research the different organelles for eukaryotic plant and animal cells and prokaryotic cells. I also worked a little bit on my prezi.
     After this we learned how to properly use the two different types of microscopes in the classroom. We looked at a dog flea, cheek cell from our cheek, plant cell, and a sample taken out of one of the fish tanks in the classroom. We looked so closely that we could even see the cell walls and chloroplasts in the plant cells.

TEST DAY

We took the unit 4 test today! And I found out I got all 1s on my lab report (I think) SO I'M HAPPY YAYYYYY.

Pedigrees

     Today in class we learned how to interpret and create pedigrees, which are basically a family tree with genetics. We learned how to determine if the pedigree depicted a gene which is Autosomal (normal) or Sex-linked. We do this by determining if the gene appears more in males or if it appears in males and females about equally. We can then look at the parents genotypes (if given) and their offspring to see if the gene is dominant or recessive. We practiced with these for a while, and even did a hard problem to determine within a huge family who the carriers (heterozygous individuals) are.

Genetics AGAIN

     This class we learned about co-dominance, incomplete dominance, and sex linked genes. Co-dominance is when a single gene has more than one dominant allele and when an individual is heterozygous, both alleles will be shown. An example of this is blood type, type A and B are both dominant, so an individual with both will have AB blood, as opposed to one or the other. Incomplete dominance. Incomplete dominance is when a heterozygous offspring shows a mixture of the two alleles. For example, a red flower and a white flower have an offspring which is a pink flower. Sex-linked is when, for example, an x linked gene is passed onto a son, the son will always show that trait, even if it is recessive, because he doesnt have another X chromosome to show the dominant trait, he has a Y chromosome, however if it is passed to a daughter it doesn't always show.

Genetics #2

     This class we learned two ways to find phenotypic and genotypic ratios when we have two or more genes. We practiced these and took a quiz on them. I personally like the Fitz way because it is faster, but sometimes it is easier to see it using the Quick way. 

Genetics

Today we started learning about genetics! We did problems solving punnet squares. We also learned some basic vocabulary necessary for this unit. For example Heterozygous means having both alleles, A and a. Homozygous is two of the same alleles, either AA or aa depending on whether it is homozygous dominant or homozygous recessive. We learned about a carrier, which is a person who is heterozygous. F1 generation which is the first offspring of the parents, and F2 generation which is the offspring of F1.

Unit 3 Test

Today we took our Unit 3 DNA Test.

Hand/Flower Response

Hand and Flower Response

Flower: Transposons have inserted themselves into the genes of the flower which has caused the striped color. These are also called jumping genes, which we have read about for homework. 

Hand: This would occur when a scientist takes tissue from the pinky side of a limb bud and transplants it on the other side very early in development. This causes the limb to have a full extra set of fingers

Operon System

Today we learned about the operon system, because it is related to both the lab and protein synthesis. The operon system controls protein synthesis and signals when it should start and stop. This is only in prokaryotes. There are two types, repressible, which goes from on to off, and inducible which goes from off to on. Repressible represses the ability to make a protein until it is turned off. Inducible induces protein synthesis when turned on.

Notes Survival of the Sickest Chapter 6 / PGLO Lab

• 18th century - Edward Jenner  discovers how vaccines work b/c he notices milkmaids who get cowpox don't get small pox --> infects teens with cowpox and they don't get small pox as well 
• all humans start as one cell - less than 3% of our DNA is used to create/build cells, the rest are useless 
• useless/junk DNA isn't used to make proteins, but does cause evolution, mostly b/c of viruses
• evolution caused in part by adapting to viruses/bacteria
• genetic changes b/c errors when DNA goes from parent --> daughter cell
• other mutations can be caused by radiation
• antigenic drift- when a mutation occurs in the DNA of a virus
• antigenic shift- when a mutation acquires new genes from a related strain
• mutations = random, occur during reproduction & --> natural selection
• Jean-Baptise Lamarck- theory of inherited acquired traits
• Barbara McClintock- geneticist,"jumping gene" intentional mutations in DNA to respond to unusual events
• genes jump when under stress
• antibodies = against specific viruses and bacteria and once you have them, you always do (why vaccines work)
• retroviruses- made of RNA, turn themselves from RNA into DNA and "rewrite" the DNA, off spring inherit the retrovirus through their parents' DNA
• if the virus does't hurt,  becomes a part of the gene pool (HERVs)

Class Today:

Today in class we began our pGLO lab. We created +pGLO and -pGLO (+ having plasmid). After getting the plasmid inside the pGLO using a heat shock, we put broth into each in order to feed the bacteria. We then put +pGLO into two petri plates, one with broth and ampicillin and the other with broth, ampicillin and ara (a type of sugar). Next we put -pGLO into two petri plates as well, one with only broth and one with broth and ampicillin. We predicted that +pGLO with amp and LB would grow, because the plasmid is resistant to the amp, and it might glow. We predicted the same for +pGLO with LB, amp and ara. For -pGLO with LB and amp we predicted that it would neither grow nor glow because the ampicillin would kill of the bacteria. And for -pGLO with just LB we predicted that it would grow but not glow.

Quiz and Class Today

1. Explain the significance of Mendel.
     Mendel's experiments in the 1850s and 60s demonstrated that traits passed on from parents may not be visible in the child, however they can still be visible in their grandchildren. This shows that the variant can be passed on, but not be seen. This led to the discovery of physical DNA.

 2. Draw the structure of DNA and who created this structure.
Watson and Crick made this discovery.

3. Explain each of the five examples of variations that occur to DNA and give an example of each. 

     1. Point mutation. This is when a single pair in the DNA changes. This can have an overwhelming affect on the individual's whose DNA has this mutation. For example, in whippet dogs, one mutation can lead to an individual losing the gene that signals the body to stop gaining muscle, which leads to huge whippet dogs.
     2. Insertion.  of new base pairs can lead to variations in DNA as well. For example, 800-base pairs can be inserted into a pea to create wrinkled peas as opposed to smooth peas by changing its sugar and water content.
     3. Gene Copy Number. This is when genes are duplicated because during cell division, errors are copied. This can lead to both differences between individuals within a species, or to differences between species. Chimpanzees contain one gene for the starch digesting enzyme, whereas in humans it was duplicated so much that it led to humans having 10 copies of the gene.

     4. Duplication. This is an error in copying, commonly in species whose DNA has the same base pair eight or more times in a row. The base pair is commonly copied too many times or too few. One example is of pigs, who commonly have a base pair copied two too many times, leading to light colored pigs lacking pigmination.

     5. Regulatory Changes. These are changes in DNA that affect when and where genes are activated. This can cause severe and extreme effects such as changing body parts durning an organisms development. This is what caused changes from the very bushy teostine and the modern tall and lean cornstalk.

4. What is evo-devo? 

     A specialty within evolutionary biology that focuses on and examines the affects of important gene changes, and how those effect evolution.

5. Make a connection between human migration and the mutation of lactose intolerance.
     As humans spread out around the world, they developed different diets based on what resources were available to them. Mutations in humans to be lactose tolerant would thrive and pass down their genes to their children in areas where lactose was a large part of their diet, and this group would evolve to have a lot of people that are lactose tolerant. However, in areas with little to no lactose, this mutation would not affect their survival, and many would remain lactose intolerant.

IN CLASS:

Today in class we began constructing DNA structures with our partners. We cut out different nitrogen bases and created hydrogen bonds between each matching pair and created  phosphodiester bonds in order to complete our double helix strand of DNA.

Geneticist Video Part 2

     Today we finished the geneticist video. Alrighty.

Article/Video Response

The Journey of Man video and the Traces of a Distant Past have both taught me many things I did not know. I learned that the earliest humans existed 200,000 years ago in Africa. All people that are alive or have ever lived have been related, and are descendants of the first “mitochondrial eve.” I also learned the migratory path of Africans. This migration began 50,000 years ago, first going from Africa to Australia, and eventually spreading out into every corner of the World, the last place that was reached being South America. One of the major questions that was being asked by many geneticists and researchers is how they originally got from Africa to Australia, by land or by sea. Most of the research I have done supports the slow movement to Australia along the coast of Asia. Another common question was why they moved, curiosity because of their large, intelligent brains, or simply the need for more food and more resources. Back to the original migration, I knew nothing about how DNA could tell us this, but I learned it was through looking at mutations. These mutations act as a guide showing that people from all over the world, have the mutation of the Sanbushman. When a small group moved to Australia, their DNA continued to mutate and have markers, which are not currently present in Africans. This pattern continues and makes the journey of man very clear through DNA, even without the supporting fossil evidence. I also learned that when geneticists are testing DNA, they typically use male DNA, because male transmitted DNA has tens of millions of nucleotides, while mitochondrial only has 16,000 nucleotides. Another aspect of early human life that was mentioned in both my article and in the movie was the humans’ interaction with Neanderthals. It discussed how little to no inbreeding took place, which I found very interesting.  The movie and the articles I have read were all very interesting, and taught me a lot about human evolution in particular, and also connected back to general evolution about mutations and adaptions in genes.

Geneticist Video

Today in class we began by getting our test back and discussing the questions we missed so we can correct them on Blue Harvest. After this we discussed in groups of four what we read for homework, which was a National Geographic Article talking about evidence that all humans came from Africa and spread to different countries, and also talked about how genetics proves this as well as fossils because DNA shows that the genetic variety in Africa is about twice as high as everywhere else because they have been there the longest. After this we watched a movie about roughly the same topic. The movie starred a geneticist who wants to physically travel the route of ancient man, because despite the proof in genetics, it still seems impossible for early man to have made that trek in such a short period of time. The geneticist began in Africa with a tribe believed to be the direct descendants of the earliest humans. These tribe members have never left their area, however they have features similar to those of Asians, Europeans, and Africans. It was a really interesting movie to watch and we will be finishing it next class.