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Flashcards: Glia
Prions are the suspected cause of a wide variety of neurodegenerative diseases in mammals. According to prevailing theory, prions are infectious particles made only of protein and found in high concentrations in the brains of infected animals. All mammals produce normal prion protein, PrPC, a transmembrane protein whose function remains unclear.
Infectious prions, PrPRes, induce conformational changes in the existing PrPC proteins according to the following reaction:
PrPC + PrPRes → PrPRes + PrPRes
The PrPRes is then suspected to accumulate in the nervous tissue of infected patients and cause disease. This model of transmission generates replicated proteins, but does so bypassing the standard model of the central dogma of molecular biology. Transcription and translation apparently do not play a role in this replication process.
This theory is a major departure from previously established biological dogma. A scientist decides to test the protein-only theory of prion propagation. He establishes his experiment as follows:
Homogenized brain matter of infected rabbits is injected into the brains of healthy rabbits, as per the following table:
Rabbit 1 and 2: injected with normal saline on days 1 and 2
The above trials serve as controls.
Rabbit 3 and 4: injected with homogenized brain matter on days 1 and 2
The above trials use unmodified brain matter.
Rabbit 5 and 6: injected with irradiated homogenized brain matter on days 1 and 2
The above trials use brain matter that has been irradiated to destroy nucleic acids in the homogenate.
Rabbit 7 and 8: injected with protein-free centrifuged homogenized brain matter on days 1 and 2
The above trials use brain matter that has been centrifuged to generate a protein-free homogenate and a protein-rich homogenate based on molecular weight.
Rabbit 9 and 10: injected with boiled homogenized brain matter on days 1 and 2
The above trials use brain matter that have been boiled to destroy any bacterial contaminants in the homogenate.
A scientist shows that PrPC in normal nervous cells helps speed nervous transmission. What other structures help speed nervous transmission?
All glial cells
Astrocytes
Microglia
Schwann cells
Ependymal cells
All MCAT Biology Resources
Changes to the MCAT (Medical College Admissions Test) exam will make it more challenging for prospective medical students. At 230 questions, the test is almost double the length as the previous version. Its format was updated in 2015 to make it a better match to what patients expect from their doctors by adding sections on basic neuroscience, sociology, and psychology. A section on social sciences and the humanities has been added, and the essay question has been eliminated.
Biology, as one of the “hard sciences” is still covered in the MCAT. When studying for the new test, it’s still important to have a good base of knowledge in this area. The new test will be measuring your critical thinking and problem solving abilities, too.
Since you would never want to walk into the MCAT without having gone through plenty of sample questions, you’ll want to make a point of checking out the Varsity Tutors’ Learning Tools. The MCAT biology flashcards are a valuable Learning Tool that you can use on your mobile phone, tablet, or computer.
The flashcards are a free resource that can be used in conjunction with your other study methods to help you prepare for the MCAT biology section. When you visit this section of the Varsity Tutors’ Learning Tools, you will see that there a great many flashcards available to you. Challenge yourself by having a card come up at random with a question for you to answer.
You also have the option of focusing on different biology categories and subcategories if you wish. Some examples of categories include: cell biology, cellular structures, genetics, respiratory system, immune and lymphatic systems, reproductive system and development, and reactions.
In each category, there are subcategories to drill down your subject even further. You will find the number of flashcards for each category and subcategory noted on the web page. For example, the excretory system category has subcategories for excretory regulation mechanisms, kidney and nephron physiology, and other excretory physiology.
When you click on a particular category or subcategory, you will see a multiple-choice question. Select your answer, and you will immediately see whether you were correct or incorrect. If you were incorrect, you will see the correct response displayed, along with a detailed explanation providing more information about the correct answer. You have the option of moving back to the question to review it, along with the original choices, if you wish, or moving forward to the next question.
The Learning Tools Flashcards for MCAT biology can be used for a quick study session when you have a few minutes between classes. Use them on your phone or tablet if you are studying with a friend and want to test each other. This method is flexible enough for a longer session if you want to go over more than one section at a time; you decide how you want to use this resource.
Varsity Tutors’ Learning Tools are something that you can add to your list of study resources. Use them to help you prepare for the rigorous MCAT exam.
Medical school admissions committees are faced with a major challenge as they try to select the best and brightest to become our physicians of tomorrow. Students with aspirations to medical school generally post the best grades, complete the most impressive extracurricular activities, and excel on exams. Unfortunately, there are many more qualified students than there are seats in American medical schools. As a result of this discrepancy, admissions committees rely on a variety of measures to ensure that they are selecting the strongest students. Undergraduate grades, teacher recommendations, and extracurricular activities are all subjective measures to varying degrees. You may have attended a top college and posted a 3.9 GPA, while another student may have gone to a far less rigorous program and finished with the same grades. Whether you need top MCAT tutors in New York, MCAT tutors in Chicago, or top MCAT tutors in Los Angeles, working with a pro may take your studies to the next level.
The Medical College Admissions Test (MCAT) offers medical schools a means to judge students using a standardized, uniform metric. While long a fixture for pre-medical students, the MCAT is evolving. In light of the changing role of physicians, the MCAT is adapting its demands. The new MCAT, first administered in the spring of 2015, promises to test the same capacities as before, but with some new dimensions as well.
The Biological and Biochemical Foundations of Living Systems section of the new MCAT is especially noteworthy because of how it differs from previous versions of the test. This part of the exam contains fifty-nine questions, and includes both discrete and passage-based questions. You are allotted ninety-five minutes to work on this section, and it is designed to gauge your ability to apply biological and biochemical concepts to new ideas introduced in passages and question stems. 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.
In comparison to years past, you will now be expected to have mastered basic concepts in biochemistry and statistics to a significant degree. The new focus on these two core competencies reflects the changes in medical practice. As medical technology proliferates, more and more physicians are being asked to evaluate competing interventions. Consider that on the United States Medical Licensure Examination Step 3, taken at the end of your first year of residency, you are asked to statistically evaluate pharmaceutical advertisements included on the test. A strong foundation in evidence evaluation is critical even at the level of the MCAT!
Despite the shift, the new MCAT Biological and Biochemical Foundations of Living Systems section does what its predecessors have done for years. Its major goal is to ascertain your ability to think critically and rationally. Memorizing reams of equations will be of little help for the reasoning demanded in passages based on biochemistry and statistics, but they will also do you little good in facing passage that concern genetics, developmental biology, and human pathology. Instead of rote memorization, collaborative efforts with tutors, peers, and faculty can be your best path to success on this standardized exam. In addition to the MCAT Biology flashcards and MCAT Biology tutoring, you may also want to consider using some of our MCAT Biology Diagnostic Tests.
Practicing model MCAT problems is another tactic that you will likely want to incorporate into your review. You can do so by making use of Varsity Tutors’ Learning Tools website and its free MCAT Biology resources. If you want to review MCAT content on the go or focus on one practice question at a time, our MCAT Biology Flashcards can help. Answers are provided for each MCAT Biology problem that you answer, as well as a full explanation walking you through the steps of how that problem can be correctly solved. Instruction is thus available instantly as soon as you miss a problem, allowing you to adjust your approach while the question and your method of solving it are each still fresh in your mind. Our free MCAT Biology flashcards are available not only on the Learning Tools website, but also on Varsity Tutors’ free app, so you can take them with you and incorporate them into even the most hectic schedule.
The skills of critical thinking tested on the MCAT are enormously valuable in medical school. Developing strong reasoning skills will therefore not only serve you well on test day, but will be a major investment in your future success as a medical student and a physician. Try out Varsity Tutors’ free MCAT Biology flashcards and get started today on your preparation plan for the MCAT Biological and Biochemical Foundations of Living Systems exam!
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