Question of the Day: MCAT Biology
Nuclear transport is a very important concept of study in modern cellular biology. Transport of proteins into the nucleus of an organism requires energy in the form of GTP, which is attached to a protein called Ras-related Nuclear protein (RAN).
RAN is a monomeric G protein found in both the cytosol as well as the nucleus and its phosphorylation state plays an important role in the movement of proteins into and out of the nucleus. Specifically, RAN-GTP and RAN-GDP binds to nuclear import and export receptors and carries them into or out of the nucleus. They also play a role in dropping off cargo that import and export receptors hold onto. RAN's functions are controlled by two other proteins: RAN guanine exchange factor (RAN-GEF) and RAN GTPase activating protein (GAP). RAN-GEF binds a GTP onto RAN, while RAN-GAP hydrolyzes GTP into GDP. As a result, there is a RAN-GTP and RAN-GDP concentration gradient that forms between the cytosol and nucleus.
Suppose an experiment was done and the concentrations of RAN-GEF and RAN-GAP were determined, as shown below:
Given these results, what can be said about the charge of RAN in the cytosol and nucleus?
RAN is more positively charged in the cytosol than in the nucleus
RAN has equal charge in both the nucleus and cytosol
RAN's charge may fluctuate depending on the metabolic state of the cell
RAN is more positively charged in the nucleus than in the cytosol
RAN's charge state cannot be determined without further experimentation
Completely overhauled in 2015, the Medical College Admissions Test (MCAT) is a major hurdle that every aspiring medical student in the United States faces. The MCAT has garnered a reputation as a challenging exam, and for many students, the uncertainty of the new exam makes their test anxiety more acute. Whether you need MCAT tutoring in Atlanta, MCAT tutoring in Houston, or MCAT tutoring in San Francisco, working one-on-one with an expert may be just the boost your studies need.
The new MCAT is broken into the roughly familiar categories examinees have faced before, with the addition of a new social science-themed test section. These sections are as follows:
- Biological and Biochemical Foundations of Living Systems
- Chemical and Physical Foundations of Biological Systems
- Psychological, Social, and Biological Foundations of Behavior
- Critical Analysis and Reasoning Skills
Most examinees probably feel most comfortable with the first of these sections. Despite this, it is important to allocate time and effort evenly during exam preparation.
The Association of American Medical Colleges has indicated that there will be three categories within the Biological and Biochemical Foundations of Living Systems section. These are, broadly, as follows:
- Structure and function of biomolecules
- Organization of molecular and cellular components of life
- Complex organization and emergent properties of whole organisms
These are certainly broad categories, but they highlight some important changes relative to years past. It is clear that doing well in undergraduate biology and organic chemistry is the best foundation for success on the MCAT. These topics line up with typical content in any undergraduate biology or organic chemistry sequence. It also provides students with an idea of where to focus their studies. Varsity Tutors offers resources like free MCAT Biology Practice Tests to help with your self-paced study, or you may want to consider an MCAT Biology tutor.
There are also some surprises in the information from AAMC. In fact, there is now a focus that examinees may not have seen in years past, with biochemistry and biomolecules now featuring prominently. Historically, undergraduate biochemistry was not even required as a prerequisite for medical schools. Even now, it may not be part of a typical pre-medical curriculum at your institution, and is an excellent example of why it is so important to take control of your own preparation. It is critical to do your own research!
For many students, wondering where to start poses a serious challenge. You may have done your research, gathered materials, and feel that you are ready to go. But the volume of information is overwhelming! Making matters worse, many faculty or premedical advisors may be unsure of what exactly to expect on the 2015 MCAT. For students facing the inaugural exam, the challenge of any MCAT is now compounded with uncertainty. As a result, adequate preparation is more important than ever, and should be a major focus for any premedical student entering the second half of their undergraduate careers. Arguably the best way to begin preparation is to work with materials geared toward the revised MCAT, which reflects the changes to the exam in 2015. An exam like the MCAT rewards students who review by challenging themselves, completing practice questions, and interacting with others to mature their ideas and ensure the mental agility needed for MCAT success. In addition to the MCAT Biology Question of the Day and MCAT Biology tutoring, you may also want to consider using some of our MCAT Biology flashcards.
Want to start preparing for your MCAT right now? Answer our MCAT Biology question of the day! Each day, we feature a multiple-choice MCAT Biology question that you can use to assess your skill. After you choose a response, the correct answer is revealed, as well as a full explanation detailing how the question can be solved. If you answer correctly, you can feel more confident in your ability to face MCAT content. If you miss the question, it presents the opportunity for you to identify exactly where you erred in your reasoning, helping you avoid making the same mistake twice. Either way, answering our MCAT Biology question of the day can only help you continue to strengthen your MCAT knowledge, so check back every day for a new MCAT Biology question, and try out our other free MCAT Biology resources for practice tests, diagnostic tests, and other tools to help you learn this challenging material.