Week 2 Day 2 Double Fertilization

Unlike humans, plants have to undergo double fertilization.  Double fertilization is essential for fertility and seed production.  Double fertilization involve two "twin" sperm cells and one egg cell.  One sperm cell (haploid) join with the egg cell to produce the embryo (diploid) and the other join with a second cell in the ovary to produce the endosperm (triploid)  inside the seed.

The ovule contains a reproductive cell called the megaspore cell (diploid), which undergoes meiosis to produce four haploid megaspores, but only one typically survive out of the four.  The surviving megaspore undergoes three rounds of mitosis to produce eight haploid nuclei.  The eight nuclei is in the embryo sac.  Within the embryo sac, cell walls form between most of the nuclei.  Three cells form opposite the micropyle opening of the ovule.  Three also form near the micropyle (one of them is the egg).  Two polar nuclei remain together in one large central cell.
 
After that step, the pollen (sperms) come into action.  A pollen grain reach the stigma and begin to germinate.  Then it sends a long pollen tube through the style and ovary.  One of the two sperm cells fertilizes the egg cell.  The second sperm cell fuses with both of the polar nuclei, fertilizing them to produce an unusual triploid cell.  The endosperm serves as the embryo's food supply.

When the pollen grain reaches the stigma, the gene, FBL17 triggers the destruction of another protein that inhibits cell division.  The gene acts as a switch to trigger precursor cells to divide into twin sperm cells. 

Week 2 Day 2 Genome Chapter 2 Summary: Species

In this chapter for Genome, Ridley began with the introduction of how people used to mistaken that a human genome has 24 chromosomes.  However, more well developed studies show that human has only have 23 chromosomes because Chromosome 2 is slightly modified by fusing two ape chromosomes.  There are some religious figures believe that the human soul is somewhere near the centromere of Chromosome 2.  Many people believe that human are an ecological success because we are able to occupy 300 million tons of biomass.  However, the human and chimps genetics are 98% the same.  There must be some point in time that the split occur when a chimpanzee population "isolated" and developed a genetic mutation that prevented the two population from breeding and forming a new species.  Monogamy shaped our "division of labor".  Ridley concluded by saying that the differences between species are in the genes but genes do not totally control behavior.

Week 2 Day 5 Genome Chapter 1 Summary: Life

In the first chapter of the book Genome by Matt Ridley, Ridley introduced the word that builds up the world.  Later, he reveals the word to be RNA, not DNA.  This first chapter is the introduction to the beginning, with RNA.  RNA is more chemically active than DNA, but it is more unstable.  Perhaps many prehistoric organisms came up with DNA through the trial and error process.  Ridley briefly explained the correlation between RNA and DNA within the human genome, and some scientists' discovery in relations with RNA and DNA.  Ridley also brings up LUCA, the Last Universal Common Ancestor, which is believed to be a protozoan, rather than bacteria.  Ridley concludes this chapter with the explanation that the human genome is made up of the genetic code of DNA.

Extra Credit Blog

From first semester, I think the topic that confuse me the most is the functional groups and the topic I feel very clear on is probably the ecology chapters and the simple macromolecules.  I think my favorite lab/activity is HPLC lab because it is interesting and you can see the color change.  I think the lab/activity that is my least favorite lab is the plant pigment chromotography because I do not think my lab actually worked.  

Week 1 Day 3 BOW 1: Genome Chapter 4 Summary: Fate

In chapter 4 of the book Genome by Matt Ridley, the author specifically wrote about the genetic diseases on chromosome 4.  Ridley start off with talking about how people tend to have the wrong perception of a gene related disease.  When stating how the Wolf-Hirschhorn gene affect the disease, Ridley states it is because the person lack the gene, thus the Wolf-Hirschhorn disease occur.  Ridley then goes on into the Huntington's disease.  Huntington's disease is a mutated genetic dominant disease that occur as the sequence CAG continuously repeat itself.  If CAG is repeated more than thirty-nine times, then an individual has Huntington's disease.  Huntington's disease will cause the patient to lose balance, deteriorate the brain, jerking limbs, and occasional hallucination and delusions.  The disease cannot be cured.  The rest of the chapter describes that people with a family history of Huntington's disease has a 50% chance of getting it.  This means either you get the disease or you do not.  The chapter also explore several villages with Huntington's disease and how scientists go out into the villages to trace the ancestry as well as diagnose people with the disease.

Cell Diversity Wordle

I choose those words to represent this chapter is because I think the organelles that make up part of a cell is very important.  The cell differs from prokaryotic and eukaryotic.  Moreover, the prokaryotic cells are much simpler than the eukaryotic cells.  In addition, eukaryotic cells have a nucleus and membrane enclosed organelles, such as ER and ribosomes.  These important structures of the cells provide cells with essential process to sustain itself.  In other words, they act as a factory.  Each organelles do their own parts, but work together for the cell.  Some cells have cell wall, while others only have a cell membrane.  Some cells even have flagella to move around.  Plant cells usually have the cell wall for protection and support.  Animal cells only have the cell wall, which regulates what come out and goes in the cell, and the chloroplasts.  Other organelles, such as the mitochondria and ribosomes, provide energy and make proteins.  Lysosomes digest waste.  All organelles have some use for the cell.

Time, Love, and Memory

1. Genetic materials affect organism behavior.
I think this key idea is crucial because this links ecology to molecular biology.  Using DNA to explain behavior, scientists created a link between the two subjects.  In our biology class, we need to learn about both molecular biology and ecology.  Through this book, I further understand about ecology and how we must learn both behavior and about the genes in order to understand biology.

2. Organisms do learn from experience.
Again, this relates to ecology because it can be seen that organisms have the capacity to learn.  This is crucial because in nature an offspring might need to learn from their parents.  This key point relate to our curriculum using ecology as a backbone for me to further explore the world of animal behavior.

3. Scientific experiments are crucial in establish conclusions.
This whole book established itself on scientific experiments.  Though some may be cruel, most of the experiments do prove something.  In our class, we too conduct experiments, but we conduct them in order to understand the curriculum better.  Scientific experiments help explain a lot of confusion from just reading text and create a better understanding for students.