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Preparation for the IELTS Test
2008-05-10 23:32:00
You are a student planning to sit for the IELTS test. Naturally, you want to get the best core you possibly can. What is the most effective preparation for the IELTS test? First of all, you must be realistic. How good is your English now? A student who currently has a band score of 5 will ...
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Mitosis and Meiosis
2008-04-10 10:11:00
Interphase precedes both mitosis and meiosis and is the period between cell divisions during which time the chromosomes replicate and the chromosomes are not visible (loosely packed). During interphase, two pairs of centrioles lie next to each other, just outside the nucleus. Mitosis is a process where in, one parent cell gives rise to two identical daughter cells. Mitosis can be divided into four stages: Prophase, Metaphase, Anaphase and Telophase. Prophase: Chromosomes (two identical copies) condense, each chromosome has two arms and each copy of chromosome is called Chromatid. Spindle fibers form at centriole and centriole begin to separate. In addition, nuclear membrane disappears. A short period just before metaphase, called prometaphase, comprises movement of centrioles to opposite ends of the cell and attachment of spindle fibers to each of the chromatids. Metaphase: Chromosomes line up along an imaginary line, called the metaphase plate that divides the cell into two. The s...

short spiel on immunity and immune response
2008-04-09 10:11:00
Cells of the Immune System: derived from the hematopoietic stem cell 1. Lymphoid Lineage T lymphocytes (T cells, made in the thymus) B lymphocytes (B cells, made directly from the bone marrow) Natural Killer cells (NK cells) 2. Myeloid lineage Monocytes that give rise to macrophages Langerhans cells and Dendritic cells Megakaryocytes that give ...
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Enzyme Inhibition: Competitive and Uncompetitive
2008-04-07 10:10:00
Note: this explanation is best understood if you have a Lineweaver-Burke plot and a velocity vs. concentration graph available while reading it. When you look at an enzyme reaction, you’re really looking at two reactions: E+S <–> ES –> E + P So in those rxns, E is the enzyme, S is the substrate, and P ...
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Eukaryotic Translation
2008-04-06 10:10:00
Please feel free to add if I may have missed anything or correct if I’m even partially wrong. tRNA molecule • Single chain, contains 73-93 ribonucleotides • Contains many unusual bases such as inosine, pseudouridine • tRNA is L shaped • 5’ end is phosphorylated • 3’ end ends in CCA and contains the amino acid attachment, it is at one end of the L • The other ...
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Eukaryotic Transcription
2008-04-05 10:09:00
Please excuse me if the material is slightly long or beyond the scope of MCAT. But, I think, this should summarize most of eukaryotic transcription. For the purposes of this post, I’m only going to summarize RNA pol II (mRNA synthesis) mediated transcription. RNA pol I regulates rRNA synthesis and Pol III regulates 5s RNA ...

Operons in Prokaryotes
2008-04-04 10:09:00
Operons in prokaryotes consist of groups of genes that typically work together and are all controlled by one promoter, which is in turn controlled by an operator region. This means that all of the genes in the operon are turned on and off together. As far as inducible operons go, the first example that comes to ...

Memorizing Cell and Molecular Biology Details
2008-04-03 10:08:00
Flash cards can work for memorization, but I consider them a waste of time. The amount of time you spend making them could be better used working to understand the big picture of what’s going on with metabolism. The MCAT is not about memorization. The MCAT is about critical thinking. You must UNDERSTAND the equations and ...
More About: Biology , Cell , Details , Molecular Biology

Eukaryotic Cell Organelles
2008-04-02 10:06:00
I will post further details about them at a later time, but for MCAT, DAT, OAT, and PCAT biology, you should know the structure and function of the following organelles: nucleus cell membrane cytosol (cytoplasm) cytoskeleton (microtubules, microfilaments, and intermediate filaments) endoplasmic reticulum Golgi apparatus vesicles vacuoles ribosomes lysosomes microbodies mitochondria chloroplasts cell wall centrioles You should also know that prokaryotes do NOT have any membrane-bound organelles, such as a nucleus, ...
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Cellular Metabolism Overview
2008-04-01 10:00:00
For all of the pre-health tests (MCAT, PCAT, DAT, and OAT), you should be able to follow the generation of ATP in each step, and also the energy carrier reduction (NAD and FAD) in each stage. You do NOT need to memorize any enzymes or pathway intermediates; they will make you do that in your ...
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Development of Ova (Female Gametes)
2008-03-30 10:00:00
The primary oocytes formed at birth (no more will be made, ever), and start meiosis I and are arrested in Prophase I until puberty, during which time many of the primary oocytes regress. Once puberty starts, ONE primary oocyte, every month, will complete meiosis I, resulting in the formation of a secondary oocyte and a ...
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Blood pH and How It Is Controlled
2008-03-29 08:59:00
Important things to know about acid/base balance in the human body FOR THE MCAT: The buffer system you need to know: HCO3-/CO2 (think HCO3- = base and CO2 = acid) Chemical equation: H+ + HCO3- = H2CO3 = CO2 + H2O (imagine the equilibria arrows) The lungs independently control CO2 (fast response – minutes to hours) while the ...
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How to Read Biology Passages
2008-03-28 08:59:00
There is no perfect answer to the question about how to attack a bio passage, but what I advise is very similar to my approach to physics passages. Possible differences: It may be acceptable to skim the entire passage, or skim until you get to obviously detailed information, because biology passages resemble verbal reasoning more ...
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PV Work
2008-02-16 07:58:00
When energy is transferred between a system and its surroundings it can be transferred in the form of work or heat. To understand how work is involved a derivation may help. Consider a gas which is confined to a cylinder with a movable piston. Furthermore, consider a lead shot of some weight on top of ...
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Applications of Thermodynamics
2008-02-14 07:58:00
Thermodynamics is generally a tricky subject, so maybe an real world application of the material may help. (These are also the types of questions the MCAT might ask). How do refrigerators work? This can be answered using the concepts of thermodynamics. The first law of thermodynamics states that the change in internal energy of ...
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Galvanic vs. Electrolytic Cells
2008-02-13 07:57:00
Electrons always go from the anode to the cathode. ALWAYS, no matter what kind of cell you have. This is because the cathode is defined as the reducing electrode, while the anode is being oxidized. Again, this is always the case, regardless of what kind of cell it is. What changes for galvanic vs. electrolytic ...

Vapor Pressure and Boiling
2008-02-12 07:57:00
Vapor pressure is the part of the total pressure that is accounted for by the vapor. Ideally, this means that if the total pressure is 12 atm, and the air is 25% vapor, then the vapor pressure is 25% of 12 atm = 3 atm. In a closed system, the amount of vapor in the ...
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Intermolecular Interactions (Molecular Associations)
2008-02-11 07:56:00
Interactions that are inTERmolecular are among more than one molecule of a substance. These are the forces that attract the molecules of a liquid or solid to each other. Intermolecular interactions occur among nonpolar molecules as well as among polar ones, but polar interactions are much stronger than nonpolar ones are. Polar Molecules: Polar molecules contain one ...
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Calculating EMF for Electrolytic and Galvanic Cells
2008-02-10 07:56:00
Question: Is it ok to calculate the emf just as if the cell were galvanic, and then simply switch to a negative value? Yes, that will work as long as you write one half-reaction as a reduction and the other as an oxidation. Many times both half-reactions will be written as reductions, so check where the ...

Deviations from Ideal Gas Law Behavior
2008-02-09 07:55:00
Deviations Due to Raising Pressure: Ideal gas behavior is most closely approximated at low pressure. There are two factors that cause real gas behavior to deviate from ideal gas behavior as pressure is increased. One is the attraction that exists among gas particles, which becomes significant at medium pressure; and the other is the volume ...
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Logs: How to Derive Henderson-Hasselbalch and Calculate pH Without a Calcul
2008-02-08 07:55:00
Calculating logs without a calculator is not as difficult as you might expect it to be. First, you should be familiar with the following log rules: log (xy) = log x + log y log (x/y) = log x - log y log (x)^y = y(log x) You can use these rules to derive the Henderson -Hasselbalch equation from the ...
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Mnemonic for Remembering Salt Solubility Rules
2008-02-07 07:54:00
extremely clever mnemonic to remember salt solubility rules. C A S H n Gia Read it as "Cashin’ Gia"…how to remember that? well the story is…im a pimp…and gia is my hoe, and i need to get my cash from her. hence…Cashing from gia. C is clorates, A is acetates, S is sulfates, H is halogens, n ...
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List of Strong Acids and Strong Bases
2008-02-06 07:54:00
All pre-health test students should memorize this list of strong acids and strong bases. Any acid not on this list should be considered to be a weak acid. Most other bases are also weak bases, but realize that there are also some strong organic bases. I have listed some examples. Strong Acids : -H2SO4 -HNO3 -HCl -HBr -HI -HClO3 -HClO4 *note that HF is ...
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Intramolecular Interactions (Bonds)
2008-02-04 07:52:00
Students commonly confuse intramolecular interactions (bonds) with intermolecular interactions (molecular attractions). This post will explain the types of bonds that hold an individual molecule or crystal together, as well as the molecular attractions that bind molecules to their neighbors. Intramolecular Interact ions (Bonds ) Interactions that are inTRAmolecular are within a single molecule or ion pair. We normally ...

Periodic Trends: Part II
2008-02-03 07:51:00
If you have read and understood the previous post about Z, you will now find that the other four trends we mentioned are all quite intuitive. Let’s consider them one at a time. Atomic Radius: Remember that the size of the nucleus of an atom is extremely small relative to the size of the entire atom. ...
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Periodic Trends: Effective Nuclear Charge (Z or Zeff)
2008-02-02 07:51:00
The worst way to learn periodic trends (or anything else in the PS portion of the MCAT) is to memorize them. This is because memorization without understanding will only allow you to solve problems that are asked in the same format that you have memorized. However, the MCAT is infamous for forcing you to take ...
More About: Nuclear , Trends , Charge , Effective , Period

Example questions dealing with capacitors
2008-01-16 22:11:00
Q: What would happen to the capacitance value, C, for a capacitor if the charge, q, were doubled? A: The MCAT loves proportions, but this is a trick question. Possible answer choices could be: a. double b. triple c. no change d. cannot be determined Without a good understanding of capacitance, many might choose a, but that is the incorrect ...
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Capacitors - MCAT
2008-01-15 22:09:00
There are many different ways to store potential energy. You can stretch a spring, compress a gas or lift an object over your head. You can also use an electric field to store potential energy and a capacitor does just that. Capacitors have many uses in electronic devices. Examples include computers and the defibrillator. Capacitors ...

Electric Potential and Work (Electrostatics) - MCAT
2008-01-14 22:06:00
What is electric potential? By definition, electric potential is the potential energy per unit charge. The unit for electric potential is the volt (V). According to the definition of electric potential, the unit can also be expressed as (J/C). This is very important because the MCAT may use both interchangeably. So, what exactly does electric ...
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Electric Fields - Physics- MCAT
2008-01-13 21:56:00
I think I will tackle the question on electric fields, electric potential and work done in an electric field in parts. First, I will discuss electric fields. What is an electric field? Imagine you have a positive point charge and place a test positive charge in its vicinity. Coulomb’s law tells us that there is repulsion ...
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