Biology

We found 57 articles

Adaptive vs innate immunity—a bird’s eye view
Our immune systems are comprised of dozens of different types of cells, antibodies, cascades, and more. This is often why immunology is such a daunting subject for so many students.
The sympathetic and parasympathetic nervous systems on the MCAT
The autonomic nervous system is a division of the peripheral nervous system that mediates non-voluntary control of many of the basic functions of the body, such as heart rate, breathing, and digestion. It is made up of the sympathetic and parasympathetic nervous systems, which have opposing functions that help to regulate the body depending on the ...
What is structural biology (and why should you care)?
Within all of our cells, we have millions of proteins, nucleic acids, lipids, and carbohydrates serving various biological functions. Many of these molecules have structure which play key roles in understanding how the mechanisms of those biological functions work. Scientists who study structural biology seek to determine the structure of these ...
Breaking down the brachial plexus
These three words are enough to strike fear into the heart of even the most intrepid anatomy, pre-clinical, or clinical student. There’s so many nerves, some in front and some behind, some looping around – it’s easy to get tripped up trying to make sense of this complex structure.
To biologists – why we should love math
The mention of mathematics often evokes mixed emotions among biologists. While some embrace it as a powerful tool, most merely view it as a black box for their collaborators to navigate for them or as intimidating and unrelated to their study. However, as a Biology PhD student, I firmly believe that math is not scary and an essential and ...
Evolution is mostly random
Competition in nature is relentless. Predation, famine, disease, and disaster all threaten to prevent individuals from reproducing. In this competitive environment, mutations that make survival more likely are more likely to appear in future generations, and mutations that make survival less likely probably won’t stick around in the population for ...
How to approach biology and biomedical graduate school interviews
The graduate school application process is exhausting. Tailoring multiple applications for each school is a daunting task. A sigh of relief finally arrives when invitations to interview for graduate programs arrive. However, as part of the application process, interviews carry a lot of weight, and most students don’t get a blueprint for what to ...
An introduction to action potentials
Have you ever wondered how our brains work? Our every thought, every emotion, and every movement are generated by our brain through a vast network of cells called neurons. Neurons make connections and talk to each other through electrical signals called action potentials.
The next-generation of DNA sequencing: understanding modern genomics technologies
On October 21st, 2004, the International Human Genome Sequencing Consortium published a near-complete draft of the human genome, a 100 million dollar initiative to understand the genetics of our species. By 2022, the cost to sequence the human genome neared $1000. This drastic price reduction has led to new advancements in understanding cellular ...
How algorithms changed my perspective on biology
When I first started studying biology, I thought the discipline was mostly about memorizing facts and figures about different organisms and their characteristics. In high school, I was more interested in physics and chemistry, which seemed to involve learning general principles and laws that could be applied to many problems. In other words, I ...
Breaking down glycolytic regulation
You can stare at or redraw the pathway for glycolysis to memorize it, but obtaining a deeper understanding of cellular and tissue metabolism requires an understanding of the regulatory mechanisms governing glycolysis. Below you can find a figure of the steps for glycolysis as a reference as we discuss the regulation.
How to conquer the biology/biochemistry MCAT section
Long paragraphs. Confusing graphs. Convoluted protein names. If this all sounds a bit too familiar, you’re probably thinking of the Biology/Biochemistry section on the MCAT. Even as a Biochemistry major, I still found this as one of the more difficult sections on the MCAT, so do not panic if you feel like you’re not making any progress – you are ...
Linkage and association mapping in genetic analysis
When geneticists want to see how closely related two genes are, they have two main ways of doing so: linkage analysis and association mapping.
How to tell the difference between mitosis and meiosis
If you’ve ever taken a biology class, you’ve most likely come across the concept of the cell cycle. Put simply, the cell cycle is the growth of cells, the replication of DNA, and the subsequent division of DNA, organelles, and cytoplasm that creates new cells. For eukaryotes, cell division is an essential part of both growth and reproduction. ...
A brief primer on the secretory pathway
The secretory pathway is arguably one of the most important pathways in the body. It deemed ‘Secretory’ primarily because it’s the pathway that controls how the cell secretes proteins int extracellular environment.
Tips for studying biology
I am often asked the question, “Brooke how do you study for biology?” We know to use practice problems to study for physics, or pathway diagrams for chemistry, but biology is different: it is a lot of memorizations!
Fetal circulation: three shunts, one rule
Hearts are pretty cool, and so are developing fetuses. Unfortunately for the student preparing for the MCAT, they’re also both pretty complicated, and fetal circulation differs from adult circulation in three main structures. In the next couple paragraphs, I’m going to break down these structures with one rule. If you’re not familiar with adult ...
The Immune System
The immune system has many different components that can be difficult to keep track of at times. How do we distinguish between innate and adaptive immunity? Why are there so many types of T cells? And what are these MHC molecules that people keep talking about?
Cells and Burning Stones: Robert Hooke’s Contribution to Science
The discovery of cells, and the naming of them, is most often credited to Robert Hooke, an enigmatic genius from England in the mid 1600s. Robert Hooke was born in July of 1635 on the Isle of Wight and was, by many accounts, brilliant when it came to science, architecture, and engineering, but a little rough around the edges socially.
Hormones of the female reproductive system
The female reproductive system can at times feel like a difficult jumble of hormones that all seem to be related, but fluctuate in unpredictable ways. To make sense of the particularities of the female reproductive system, especially for exams like the MCAT, it is important to not only know what hormones are involved, but also to understand what ...
Gametogenesis and spermatogenesis and oogenesis, oh my!
Meiosis is one of those processes that we all learned about in high school biology as a deceptively simple concept. You take the diploid cell, divide it twice, and it becomes four haploid gametes that are each capable of participating in fertilization. Easy, right?
Start by learning how you learn…and then tackle the sciences
When I was an undergraduate, I had a wonderful research mentor in a neuroendocrinology lab, and it was this research experience that led me to pursue a Ph.D. in neuroscience. My research mentor was deeply interested in the process of learning. In my time as his advisee, he taught me how to study efficiently, how to really remember something in the ...
Pituitary gland hormones made simple
What is the pituitary gland? Even though the pituitary gland is about the size of a pea, it plays a very important role in regulating a lot of our body’s endocrine functions. Located in an area known as the sella turcica at the base of the brain and suspended from the hypothalamus by a stalk, the pituitary gland consists of two parts: the ...
How Does the Brain Work Anyway? A Look Back on the Study of Neuroscience
The brain continues to fascinate scientists and non-scientists alike because it takes up so much real estate in our body and controls virtually everything we do from talking to breathing, thinking and moving. It is probably not surprising that reports about the nervous system (made up of our brain, spinal cord, and nerves spanning our whole body) ...
A Brief History of Neuroscience and the Field Today
The discoveries about the brain over the past hundred years have only spurred more questions about how the brain works. These questions have captivated scientists, the public and policymakers alike. In the past 30 years, two Presidents of the United States have introduced large scale initiatives to study the brain. In 1990, President Bush declared ...
How does the brain work anyway? A short overview on the future of neuroscience
If the ultimate goal of neuroscience is to understand how the brain works, how will scientists know when that goal has been reached? Is it by our ability to build artificial intelligence matching human capabilities? Our ability to treat or completely prevent neurodegenerative diseases like Parkinson’s, or mental disorders like schizophrenia? ...
Ants go marching: ant navigation and vector addition
Desert ants don’t need to emulate Hansel and Gretel’s breadcrumbs to get out of the forest; they can just count their steps! Ants who live in dense forests create scented trails home by squeezing glands covering their bodies on the floor. But the intense heat of the Sahara destroys these scents and there are few environmental markers to help the ...
What are lymphocytes? A guide to your immune system
The immune system is designed to prevent disease and fight infection and is critical for human survival. It specializes in the ability to attack foreign microorganisms, but what stops your immune system from eating you alive? Given that cells of the immune system can essentially eat microorganisms, you may be wondering what mechanisms are in place ...
What to expect during interview weekend for PhD Biomedical programs
Congratulations! If you have been selected to interview at a Biomedical PhD program (e.g. Biology, Neuroscience, Biophysics) that means you were selected from a pile of hundreds of applicants. The program is willing to fly you in for interview weekend and take the time to show off its program and city. Let that act as a confidence booster, but you ...
How do enzymes work? Catalytic strategies and models of substrate fit
In this post, we are going to do a brief Q and A to review what enzymes do and how they work. This post will be slightly beyond a basic introduction so it is probably most appropriate for a student who already has a sense of what enzymes are.
What is CRISPR-Cas9?
In this blog post, we will be covering one of the most important developments in the field of biology in my lifetime, CRISPR-Cas9. You may or may not cover CRISPR in an intro biology course, but you likely will cover it in upper level courses. Regardless, this topic is important enough that any new biologist should understand the very basics even ...
What is the phospholipid bilayer and what determines its fluidity?
All cells are surrounded by a cell membrane that forms a barrier between the cell and its surroundings. This membrane is often referred to as the phospholipid bilayer. As you can probably tell from the name, a phospholipid bilayer is made up of two layers of lipids. The fluidity of this membrane must be maintained within a certain range for the ...
An introduction to blood types: genotype, phenotype, inheritance, transfusion, and more!
What determines blood type? Contained within their cell membranes, some red blood cells have special glycolipids called A and B glycolipids. People with blood type A have the A glycolipid in their cell membranes, people with blood type B have the B glycolipid in their cell membranes, and people with blood type AB, have both glycolipids in their ...
How do we classify mutations in biology?
In the previous post, we discussed some of the built in mechanisms that help to prevent mutations. Sometimes, however, mutations occur in spite of these systems. There are a few different ways that mutations are typically classified in an intro biology course and there are often overlaps between these categories. Here is a brief review of some of ...
Preventing and repairing DNA mistakes during the cell cycle
If you are currently studying biology, you have probably learned that mistakes in DNA can create very big problems, including cancer. These DNA errors often (but not always) occur during replication. Whenever they occur, it is very important for the cell to have a set of systems in place to both prevent and repair these errors. In this blog post, ...
Tips for interpreting pedigree charts and understanding inheritance patterns!
Different traits are inherited in different ways. Many intro biology classes will expect you to be able to identify different patterns of inheritance and parental genotypes based on either a pedigree or the rates of a given phenotype in the offspring. It is helpful to be familiar with the phenotype ratios, pedigree charts, and the specifics of the ...
Essential tips for learning the anterior pituitary hormones
Learning the anterior pituitary hormones for your biology class or the MCAT can be a little overwhelming. It is easy to get lost in the weeds and struggle to see how it all connects. One thing that helped me when I was learning the anterior pituitary hormones was to visualize the connections between the most important structures. This both helped ...
Breaking down nephron functioning into six easy steps!
The nephron is the kidney’s smallest functional unit. It works to ensure that the urine you excrete leaves your body in the correct volume and concentration. This is a complicated process, but once you master it, it is exciting to understand this important function of the human body!
Cracking an AP Bio biotechnology question
The AP Biology exam for 2017 is set for the morning of Monday May 8th. So it’s that time of the year again to begin reviewing past concepts and doing practice exams.
Tips and mnemonics for memorizing amino acid structures
Learning amino acid structures is a challenging part of biology and biochemistry coursework. Many students feel totally overwhelmed by the task. The best way to master this skill is lots of repetition (here is a link to a Sporcle quiz that may help you with the repetition part) but it can be helpful to have tricks and mnemonics to get you started. ...
How to solve a 6 grid-in question on the AP Biology exam
On the AP Bio exam, there will be 6 grid-in questions that will require you to do some math. Yes, math. These questions will require you to do some simple calculations and thus you are only allowed a four-function calculator to do addition, subtraction, division, and multiplication. That being said I’ll break down an example grid-in question to ...
Real AP Biology exam solutions
The AP Biology Exam date has been set for Monday, May 8, 2017. Beginning at 8 am that morning, everything you learned over the course of the year will be tested with 63 multiple choice, 6 grid-in, and 8 free-response questions. Although the AP exam seems far off, it’s a good idea to master the basics now and set a good foundation off which to ...
Odor perception on the AP Biology exam
Last year, AP Biology students did a great job applying their math skills to the test. On average, 55% of math related question were answered correctly compared to 35% in 2013! That’s great news but there were still many questions that students struggled with such as free response Question 7 about odor perception. This question gave students a ...
How to study for AP Biology
When I was in high school, it was actually my AP Calculus teacher who gave me this AP Bio study tip. I used it with great success that year in AP Bio, and it continued to serve me well throughout college as I majored in molecular biology.
Enzyme inhibition and Lineweaver-Burk plots: MCAT test prep
We’ve already covered a little bit about the basics of enzyme kinetics, so now let’s move on to discuss an important application of enzyme kinetics in the body (and in medicine)...
How to study for biology: 10 failsafe tips
Here’s how to keep all the bio you learn in your brain Many students find biology courses difficult because there is just so much content covered! Though biology isn’t easy, any student can succeed in a biology course with a little organization and a commitment to reviewing the course material for about 10-45 minutes almost every day. After years ...
What is the Warburg Effect?
The Warburg Effect We know that although cancer cells are derived from our own healthy cells, they undergo many changes that render them distinctive from normal cells. In the 1950s, a scientist named Otto Warburg discovered quite a startling difference in the metabolism between tumor cells and normal cells. This difference, now called the Warburg ...
How to make scientific writing intelligible
Many students struggle with scientific or technical writing, unsure how to present complicated and number-heavy information in readable prose. Commonly, students fall into the trap of vomiting data onto the page without very much connecting prose to help the reader understand the material. This forces the reader to shoulder the burden of figuring ...
The basics of amino acids
I have met two groups of people who are VERY excited about amino acids. The first group is bodybuilders. Bodybuilders are OBSESSED with amino acids, because amino acids make up protein, and protein make up muscles and muscles are what bodybuilders want. Since you are reading this blog looking for an MCAT tutor, I feel it is relatively unlikely ...
How to remember the steps of photosynthesis
Over the years, I have tutored many students studying for the AP biology exam and I have noticed that the majority of them find photosynthesis and cellular respiration very difficult and confusing. These are very important processes that frequently appear on the AP exam. However, there is so much information, so much detail, and so many terms, ...
Biology and chemistry tutor: acidity, pH and pKa
When it comes to the advanced science classes you will take in college, there is usually a clear distinction between the kinds of material covered in each of them. For example, the material you cover in biology classes is quite different than that covered in chemistry classes. However, there are some topics that know no boundaries––for example, ...
Transcription, translation, and the Central Dogma of Biology
Anyone studying biology, I mean anyone, will have to learn about the Central Dogma of Biology. The name itself, Central Dogma, clearly portrays how important this is. So what is it? The Central Dogma describes how information flows in a biological system, from DNA to RNA to Protein. If you stop for a second and think about it, this is quite ...
Biology Tutor: Mitosis and Meiosis-what’s the big deal?
If you have decided to study biology, at some point (probably sooner rather than later), you will have to learn about meiosis and mitosis. Some concepts in biology, you can learn about in an introductory course and you may never, ever have to face them again. Meiosis and mitosis are not these kinds of concepts. Whatever you decide to do, as long ...
Tips from a Biology Tutor in Cambridge: Taking science tests
We all know that science tests can be challenging. Not only is the content broad and sometimes difficult to master, but the tests themselves can be tricky and confusing. How many of you have run out of time because you got stuck on one confusing question that was probably low yield? Science tests are also notorious for having poorly articulated ...
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