1. How does meiosis differ from mitosis? What is the ploidy number of the products in both processes?
Meiosis is a type of cell division that splits the number of chromosomes in half and results in four haploid cells.
Mitosis is asexual reproduction that results in two identical cells as the first diploid.
They differ in the cells that are produced and how they are produced. Meiosis splits chromosomes and divides it between four haploids well mitosis replicates the same chromosomes and DNA and splits into two identical diploids.
2. What is non disjunction? Give an example.
Non disjunction occurs when chromosomes don’t separate correctly during meiosis. This occurs either during Meiosis one or Meiosis two and it may result in too few or too many chromosomes in the gamates. A baby with an unusual number of chromosomes in its cells could happen and that can lead to a baby with Down Syndrome, or other developmental issues.
3. Compare contrast asexual vs sexual reproduction. Describe pros and cons of each.
Asexual reproduction only uses one organism so there is no mixing of chromosomes so the babies are genetically identical. An advantage is it is faster that sexual reproduction in most cases. However with asexual reproduction there is no genetic diversity and can make populations susceptible to disease and things like that.
Sexual reproduction uses two partners so there is mixing between the chromosomes and DNA. Organisms produced through sexual reproduction will have a better chance at survival and adapt better to the environment because natural selection and evolution and that stuff. The down side is it can take a while, like some weird creatures it can take up to 9 months like thats bazar.
4. Describe what you learned in class on Thursday either about Molly or about chimeras.
In class on Thursday we learned about Molly. Molly was a girl that was born with both her parents recessive genes and had issues with producing blood cells, they where shaped improperly, so had oxygen deficiency (issue with chromosome 6). She also needed a bone marrow transplant. She needed a donor but it was going to be extremely hard to find someone with identical DNA and genes so they genetically made a little baby that could provide bone marrow for Molly. It was a success. So now there is a little test tube baby walking around and living and Molly is fine.
Paragraph 1: One thing I learned from this activity is that all the different types of genes are much more spread out among the chromosomes than I previously thought. It seems like everything except a few exceptions (Y, 8, 14, 16, 22) are pretty diverse. Every chromosome (besides the previously mentioned exceptions) has some oncogenes and some tumor suppressors, and they all have some genes for cell survival and some for cell fate. Only 6 chromosomes have genome maintenance but it is still spread out. Something our group noticed was that all genome maintenance genes are also tumor suppressor which makes sense because they have to work together to fix the DNA and suppress the cell divination. This is probably the biggest thing I learned from this activity, I had previously thought that the genes where much more specialized.
Paragraph 2: Another thing I learned is that the different types of cancer (at least Melanoma) aren’t very restricted on the genes they attack or what chromosomes or functions or anything. In my Melanoma group we didn’t notice many patterns, the genes where not located on the same chromosomes, most of the genes where not the same except 2 of us had BRAF and two had MLL3, the same number of genes where not affected (two of us had 5 affected and 1 of us had 4 affected), and last but not least there was no pattern in the functions, we had mixed of cell fate and cell survival and two had maintenance but it didn’t seem to matter. We came to the conclusion that this means it is way easier to get cancer than we thought. This makes it seem very wide spread and not very specific to a certain gene or chromosome. Yes some came up more but it was all so randomly distributed that it seems widespread and harder to prevent because you don’t know where its attacking you cell.
Paragraph 3: One thing I learned not from this activity but from the week was about the cycle a cell goes through to divide and all the checkpoints and things. There are 4 stages: G1, S, G2, and M. G1 is the period of growth before the DNA is replicated, S is the period where the DNA is replicated, then G2 where the cell grows more now that there is new DNA and it prepares for division, and then there is M which is Mitosis and the cell divides.
Paragraph 4: The two main things that surprised me was how diverse the genes and chromosomes where and how few genes there where. I expected the chromosomes to be much more specialized, it is weird to me that all the different types of genes are seemingly spread of evenly. I also expected there to be so many more and it seems like there just aren’t that many different genes.
Paragraph 5 (question): How easy is it to get cancer and are some genes / chromosomes better at fighting it than others?