Tutor profile: Jaeyoon C.
Subject: SAT II Chemistry
I'm overwhelmed. How do I even begin?
Deep breaths. You are not alone! I remember taking this test too and feeling stressed, but with dedication, I got a perfect score within a few weeks of studying. Here are some tips: - Think carefully about when to take this test. Realistically, the test will be most suitable for a student who have completed high school chemistry. AP chemistry knowledge will certainly help, but it is not required. - Khan academy has great resources. I also have some study book recommendations. - When you are ready to start, I would suggest beginning with a practice test. This will give you an idea of expectations and where your weaknesses may be. - The key is practice, practice practice! Chemistry has equations, sure, but it is NOT a memorization science. Of the sciences, I feel chemistry is the least memorization and the most application-based. Many of the questions can be answered just by knowing how to use and understand the periodic table! - On that note, create a "master periodic table," as I like to call it, as you are studying. Jot down equations, label the electron configurations, circle the most electronegative atom, write the group names up top. On the back, write down examples and questions you repeatedly struggle with. The periodic table is your biggest friend. - Read the explanations of each question answer, whether you got it correctly or not. Resolve each and every question you get incorrect or were uncertain about. Star the particularly challenging ones and bookmark them to come back to the next week. - Leading up to test day, practice exams are your best friend. Remember to go over each question until you understand the larger concept behind it. You got this!
Subject: College Admissions
What would you say is a common mistake students make during the college application process?
I have seen many students and younger friends through their college application cycles, and I must say, the key thing is the essay! Far too often I see students paying hundreds of dollars into getting their essays manicured (and sometimes even written for them!) by a professional. From my experience, the students who have the best results and are accepted to top schools took the essay as a chance to truly reflect on themselves and genuinely write about an aspect of themselves not reflected in their academic or extracurricular activities. Please, please write your own essay, using your own words, before seeking help. I am always happy to brainstorm topics together and provide constructive feedback multiple times per essay, but it is difficult for a student to come without any basis to work with. Also, I strongly suggest that you actually turn to current/recently-graduated college students themselves for help, rather than professionals who are decades out of college. Trust me -- the essay is the only part of your application to make your own character shine and tell your story. Make it yours!
Can bacteria reproduce sexually? If so, how?
Great question! We often think of bacteria just performing asexual reproduction to make clones, but if you think about it, that doesn't give them much of an evolutionary advantage. Sexual reproduction, on the other hand, does. The short answer to your question is yes -- in the sense that sexual reproduction constitutes a gene transfer that allows one bacterium to get new genes and a change in phenotype. The long answer is that this process of "sexual reproduction" is called horizontal transfer, because the gene transfer occurs not from a bacterium to its daughter cell (vertical transfer), but between bacteria/DNA of the same "generation," so to speak. Let's look at the three main ways in which horizontal transfer takes place: conjugation, transformation, and transduction. Conjugation requires physical contact between two living bacteria. A structure called the pilus forms between the two. The pilus be thought of as a bridge through which a piece of DNA goes from one bacterium (the donor) to the other (the recipient). Transformation does not require physical contact or even two living bacteria. When bacteria die, their DNA is chopped up and these small pieces float in the environment. A living bacterium can then take up this piece of DNA and incorporate it into its own chromosome. Transduction is interesting -- it is mediated by phages, which are bacterial viruses. A phage that infected one bacterium can erroneously carry a piece of the bacterial DNA, rather than its own DNA. When this phage goes on to "infect" another bacterium by injecting the DNA, this second bacterium instead receives a piece of the first bacterium's DNA.
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