Genome: Chromosome 2 - Species

Until 1955, humans were thought to have consisted of 24 pairs of chromosomes until Albert Levan’s experiment. Levan concluded that humans have 23 pairs of chromosomes after counting the chromosomes in photograph books with captions stating that there were 23 pairs. While chimpanzees, gorillas, and orangutans have 24 pairs, humans are similar to apes. We humans are apes, yet we have one obvious difference: humans have one less chromosomes because a pair of ape chromosomes had fused together into us humans. Natural selection is where life forms are changing to suit our exposed physical environment. Humans are able to colonize different habitats whether it is hot, cold, high, low, marine, or desert environments. We are also the most abundant large animals living on the plant, about 6 billion of us add to about 300 million tons of biomass. Ridley ends the chapter by saying that human beings and chimpanzees are similar except for their genetic differences because genes are not sufficient, at least not in apes. Genes are recipes for anatomy and behavior, as well as natural selection.

Double Fertilization

Angiosperms, also known as flowering plants, are capable of undergoing both sexual and asexual reproduction. In sexual reproduction, angiosperms are capable of double fertilization. In the process of double fertilization, sperm cells are delivered by pollen grain to the ovule, the female reproductive organ. The ovule contains a reproductive cell called the megaspore. One megaspore undergoes three rounds of mitosis, producing eight haploid nuclei, which share the same cytoplasm, the embryo sac. These eight nuclei are then separated near the micropyle and the synergids. The egg is near the synergid while two polar nuclei are located together in the middle. In order to start double fertilization, the pollen grain starts to germinate, creating a long pollen tube through the style and ovary in which the sperm is able to reach the embryo sac. The haploid sperm cell undergoes mitosis and produces two haploid sperm cells which is then released into the embryo sac. One of the sperm cells fertilizes the egg cell which produces a diploid zygote. The other sperm cell combines and fertilizes the two polar nuclei which produces a triploid (3n) cell which then develops into an endosperm. The endosperm is then known as the embryo’s food supply.

Source: http://bcs.whfreeman.com/thelifewire/content/chp39/3902001.html

Genome: Chromosome 1 - Life

In this chapter, life began with a single word: DNA. Life consists of two different skills, the ability to replicate and the ability to create order. The key to both of these is information. Information is the instructions for building and maintaining the equipment that creates order. The author relates genes to coded recipes, with its four repeated letters A, T, C, and G. A gene has 120 different letters that are constantly being copied into a short filament of RNA, the copy being called 5SRNA. The genes are able to replicate because of proteins. The author mentions how RNA may have came before proteins because RNA is a chemical substance that links DNA and proteins together; therefore, RNA must have come before. Ultimately, genes are the same everywhere, in all organisms and life. Their genetic code are the same and wherever we go and whatever organism we see, they will have the same codes and languages.

Genome: Introduction

The introduction chapter basically talked about the twenty-three chromosomes of the human genes. Each of the twenty-two pairs of chromosomes are numbered based on their size whereas the last pair of chromosomes contained the sex chromosomes. Matt Ridley had compared the human genome to a book which I thought had made it easier to learn about the genome. He stated that the twenty-three chapters are chromosomes, each chapter with several thousand stories are the genes, each story that is made up of each paragraphs is the exons, each paragraph with words that are called the codons, and each letters is the bases.This introduction chapter also talks about how the genes can undergo replication and translation, how replication involves the four letters A,C,G, and T, and translation which involves RNA, replacing T for U. The rest of the chapter talks about how everything is made of proteins that is later on translated into a gene.

Extra Credit Blog: Reflection on First Semester

What topics really confused you?
I am still confused on the chemistry, cell, and bacteria chapters.

What topics do you feel very clear on?
I feel the best with the ecology chapters compared to all the chapters. All the other chapters, I feel like I don’t know it completely.

What lab/ activity was your favorite? Why?
Some of my favorite activities were when we planted our seeds into the jar. It was amazing to watch how my plant grew compared to everyone else’s plants. For the chromatography lab, it was interesting watching how the solvent gradually moved up the filter papers. As for the flower dissection activity, I liked being able to look through microscopes and be able to see the pollen clearly. I also liked being able to realize that our school had a lot of plant diversity when we explored our campus looking for different insects and flowers.

What lab/activity was your least favorite? Why?
My least favorite lab would be the fly lab because it felt tedious to cross each trait, yet I witnessed many flies with different traits that seemed interesting to me. My other least favorite lab would be the bacteria lab because I did not want to inhale or get any dye on my clothing. Knowing what problems could arise if I had inhaled anything made me afraid to be near the bacteria when opening it.

If you could change something about the class to make it better, for instance the type of homework (not the amount) what would it be and why?
Sometimes I don’t know which reading quizzes I need to complete and which blogs I have to finish. When we had a list of blogs to do, it made finishing the blogs so much easier knowing which ones I had to do.