This unit focuses on genetics and why individuals have the traits that they have. We started the unit by studying the cell cycle, the way that our body cells formed and the way that many asexually reproducing species reproduce. The cell cycle consists of interphase (the copying of DNA), mitosis (DNA and organelles split), and cytokinesis (the cell officially divides in two). This was one of my strengths; I was able to understand the different phases and the purpose of the cell cycle. We also learnt about asexual and sexual reproduction, and the pros and cons of both. Asexual reproduction yields tons of offspring and is possible without a mate, but there is no genetic variation and the species will not stand the test of time. Sexual reproduction has lots of genetic variation and creates competition for mates, but it requires time and energy and exposes you to parasites. I felt that this topic was fairly straightforward. Meiosis is the process in which gametes (sex cells) are formed. In humans, these are the sperm and egg cells. They are haploid, meaning that they have half the normal number of chromosomes. This is so that during recombination, the new zygote cell will be diploid. I felt strong on this topic. I feel that determining incomplete dominance from codominance as well as looking at dominant and recessive alleles in punnett squares is one of my strengths.
The Law of Segregation and the Law of Independent Assortment are definitely my weak areas. I think that if I try to draw meiosis from memory with the different alleles on each chromosome, I will be able to conceptualize the laws better. I understand the basic definitions, but don't know whether I'll be able to apply them to a specific scenario yet.
I definitely have a better understanding of genetics, punnett squares, and I feel like I am more knowledgeable about why individuals look and are the way they are. I have learnt a lot from doing the infographic; it helped me understand the concepts better when I did research and created my own graphics and diagrams. I would like to learn more about the common human genes that are more complicated than basic dominance and recessiveness. I am also interested in learning more about genetic disorders.
My VARK learning style is multimodal. My scores were visual 7, aural 6, speech/writing 5, kinesthetic 4. Kinesthetic is my lowest, because I don't tend to learn from simulations as much. These are the scores I would have expected, because diagrams and charts tend to stick in my mind. I will focus on learning and understanding diagrams from the vodcasts and the textbook; during tests I often find myself trying to visualize those.
Wednesday, November 18, 2015
Coin Sex Lab Relate and Review
In this lab we looked at how the probability of having a child with a certain trait was related to actually predicting how many children would actually have that trait. In order to illustrate how genes separate during meiosis, we used coins as props. We determined what possible genotypes we had by looking at our phenotypes; for example if a person had a phenotype of brown hair their genotype could be either BB (homozygous dominant) or Bb. One each side of the coin we wrote one allele (if an individual was heterozygous for brown hair they would write "B" on one side of the coin and "b" on the other.) When we dropped the coins onto the table, it was random which allele landed face side up. This is a simulation of meiosis. When we subsequently paired our coin with our partner's coin to find out the offspring's genotype, we simulated sexual recombination.
We did a dihybrid cross--we looked at the gene for having brown vs. blonde hair, and the gene for having brown vs. eyes at the same time. We crossed two individuals who were double heterozygous. Their genotypes were BbEe (B=brown hair, b=blonde hair, E=brown eyes, e=blue eyes). The expected phenotypic ratio was 9 brown hair brown eyes: 3 brown hair blue eyes: 3 blonde hair brown eyes: 1 blonde hair blue eyes. Our results were 8 brown hair brown eyes: 3 brown hair blue eyes: 4 blonde hair brown eyes: 1 blonde hair blue eyes. Probability says how likely something is to happen, but the certainty of something actually happening is different. Our results were close to the expected, but slightly different.
Probability is a prediction of the likelihood of an event occurring. If thousands of trials were to be done, the law of averages would ensure that the probability of getting a certain trait was met. However, if a person were to flip a coin 5 times, it is entirely possible that they could flip 10 heads in a row, even though the probability of flipping a head is 50%. Most humans don't have that many offspring compared to other species, and often times probability is inaccurate in predicting offspring's traits.
Genetics can be seen everywhere in our life. Genes are the reason why people have certain traits and the reason why people look the way that they do. I have wondered in the past why some children have completely different traits, such as blonde hair or blue eyes (autosomal inheritance), than their parents do. Now, with the knowledge of punnett squares and different alleles, I can answer that question. Also, knowing how X-linked inheritance works, I can understand why certain people I know are colorblind, even if neither of their parents are.
We did a dihybrid cross--we looked at the gene for having brown vs. blonde hair, and the gene for having brown vs. eyes at the same time. We crossed two individuals who were double heterozygous. Their genotypes were BbEe (B=brown hair, b=blonde hair, E=brown eyes, e=blue eyes). The expected phenotypic ratio was 9 brown hair brown eyes: 3 brown hair blue eyes: 3 blonde hair brown eyes: 1 blonde hair blue eyes. Our results were 8 brown hair brown eyes: 3 brown hair blue eyes: 4 blonde hair brown eyes: 1 blonde hair blue eyes. Probability says how likely something is to happen, but the certainty of something actually happening is different. Our results were close to the expected, but slightly different.
Probability is a prediction of the likelihood of an event occurring. If thousands of trials were to be done, the law of averages would ensure that the probability of getting a certain trait was met. However, if a person were to flip a coin 5 times, it is entirely possible that they could flip 10 heads in a row, even though the probability of flipping a head is 50%. Most humans don't have that many offspring compared to other species, and often times probability is inaccurate in predicting offspring's traits.
Genetics can be seen everywhere in our life. Genes are the reason why people have certain traits and the reason why people look the way that they do. I have wondered in the past why some children have completely different traits, such as blonde hair or blue eyes (autosomal inheritance), than their parents do. Now, with the knowledge of punnett squares and different alleles, I can answer that question. Also, knowing how X-linked inheritance works, I can understand why certain people I know are colorblind, even if neither of their parents are.
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