For Bi 10, a freshman biology lab class, students get to grow colonies of the microbiota found in everyday life. This includes samples from the hands, E. Coli strains and also saliva swabs! We are given 8 Petri dishes of agar mixed with growing medium, or “broth”. Agar is a yellowish clear jelly. For this first class, I got to rub my fingers all over one half of the hard, slippery surface of the jelly. On the other half of the dish, I used clean, freshly washed hands. This experiment was to see how effective hand washing with soap is.
In a similar experiment, we left a Petri dish with the cover off on our lab benches for the whole class period. This is then closed and left in a cardboard box with a Petri dish that hasn’t been exposed to the air. Ideally, when we come pick this up next week, the open dish will have collected bacteria from the air and dust and there will be colonies in it.
In another experiment, we were given the option of either spitting or licking a fresh agar plate. I chose to tap the tip of my tongue against the jelly, which left a slightly salty taste on my tongue. The saliva spot is then rubbed all around the plate with a plastic loop.
We also practiced proper streaking streaking technique with some bacterial colonies. The dish from which we got small smidges of bacteria from was done with proper streaking. This process thins out the bacteria from the original dab and isolates single bacteria which form their own small colonies in a few days. This was really hard for me because I can’t see the bacteria that I was spreading around the plate, so I’d lose track of where my last streak was.
We also started a polymerase chain reaction (PCR) process today. PCR is used to make lots of copies of target DNA strands. The double helix of each DNA strand is pulled apart into the single stranded backbones. A mix of smaller enzymes are added to the solution. Each little enzyme will attach to the half strands, in A-C and T-G pairs, to complete it into the original double helix shape. In a way, you can think of this a doubling the number of target DNA strands each PCR cycle. In order to start the reaction, a short strand of DNA first is first attached to one end of the half strands. This short strand is called the primer and is also simply mixed into the solution. We also added a buffer solution that will help the DNA multiply and for the newly formed copies to stay together better. One interesting thing was that these vials need to be kept in ice buckets.
This summer I had the incredible opportunity to do a 10-week internship at Gilead Sciences in Foster City, CA. For those unfamiliar, Gilead Sciences, Inc. is a research-based biopharmaceutical company focused on the discovery, development, and commercialization of innovative medicines.
With 45 Nobel Laureates on its Faculty Roster, it’s not surprising that research is an integral part of the Caltech undergraduate experience. One of the programs that promotes such research is the Summer Undergraduate Research Fellowship (SURF). There is no minimum knowledge or experience required to participate in a Caltech SURF. In fact, students can participate in a SURF as soon as the summer after their freshman year. It is not difficult to get a SURF. All you need to do is find a mentor who is working in an area of research that interests you and willing to mentor you through a research project. The mentor can work in a Caltech lab, at the NASA Jet Propulsion Laboratory (JPL), or at another participating institution. Once you find a mentor, you work together to write a project proposal that you later send to the SURF office for review and approval. About 98% of the SURF proposals get approved. This fellowship is a great way to explore various fields of research and obtain real, hands-on experience where you get to apply the theoretical knowledge you’ve learned in class. Not only do you get to work and learn alongside your mentor, but you also get compensated for your time. The length of the SURF is ten weeks, and it starts at the beginning of the summer. However, it is not uncommon for many students at Caltech to continue their research project throughout the academic school year.
Like many students at Caltech, I suffer from a slight boba addiction, where side effects may include over caffeination, minor sugar highs, and of course, a large toll on one’s wallet. This addiction is not helped by the fact that there are at least three boba shops within walking distance of campus. So, after an entire term’s worth of boba runs, I came back from winter break with a new year’s epiphany: it was time to get a job. Rather than try to curb my addiction, I decided to find a way to subsidize it.
Research at Caltech looks different for every student, and can often vary term by term. As a chemistry major, my course requirements are on the lighter side for a Caltech major, and many chemistry majors take advantage of the lighter course load to join research groups. This can be whenever the student wants, but many people join labs during their freshman or sophomore years. Some may work in one lab only, and some may switch between labs during the course of their undergraduate studies, depending on if their interests change.