MCAT Organic Chemistry
Table of Contents
Stereochemistry governs the arrangement of atoms on a molecule and has many influences on physical properties and molecule structure itself. Understanding the different ways that molecules can arrange themselves in nature is essential in becoming a successful doctor as even the same atoms with differed configuration have completely different effects.
Being able to understand how some configurations are more stable and thus more common in nature is key to performing well on the MCAT and stereochemistry is another of the basic skills that can be applied to all of the different compounds and functional groups discussed throughout the rest of organic chemistry.
Spectroscopy is helpful to know what and how much of something makes up a compound, but it is vastly important to know the molecular structure. The molecular structure is simply the way the atoms that make up the compound are arranged in space, and in relation to each other.
The arrangement of these atoms effects how a molecule will behave both in physical properties and during reactions. This section will explain the what, why, and how of absorption spectroscopy, mass spectrometry, and 1H NMR spectroscopy.
See Lab Procedures
Lab Procedures are very important in chemistry. Purification and Separation are topics of great importance in organic chemistry. Organic chemists, when applying theory in the lab to create compounds, use various techniques to perform tasks such as the separation of an organic solution from its impurities contained in an aqueous solution.
These include the removal of excess water in the organic solution using a drying agent, the recrystallization of a crude product to obtain a purer sample, and many other tasks. Specifically, extractions, distillation, chromatography, and recrystallization will be examined in detail in this section.
Hydrocarbons are compounds that are entirely composed of carbon and hydrogen atoms. The majority of hydrocarbons are found naturally on earth in crude oil. It appears possible to form seemingly endless hydrocarbon chains.
Hydrocarbons are further classified into multiple groups, which are alkanes, alkenes, alkynes, unsaturated hydrocarbons, cycloalkanes, andaromatic hydrocarbons. In this section, we will be examining only alkanes in detail, including their naming scheme, properties, and reactions important to alkanes.
Alcohols are organic compounds that contain a hydroxyl functional group, -OH, which is bonded to one of its carbon atoms. A popular and widely known alcohol is ethanol, which is found in all alcoholic beverages. However, this is merely one of numerous alcohols, which are a diverse set of compounds used in various applications such as antifreeze, solvents, and fuel. This section will examine the properties of alcohol and its related reactions in detail.
Aldehydes and Ketones are both functional groups that contain carbonyls (a carbon double bonded to an oxygen). The only thing that separates the two is what is attached to the carbonyl carbon. An aldehyde has one alkyl or aryl group and one hydrogen attached to the carbonyl carbon, and a ketone has two alkyl or aryl groups attached to the carbonyl carbon. Since an aldehyde has a hydrogen atom on the carbonyl, it then follows that an aldehyde will always appear at the end of a carbon chain. This section will examine their properties and related reactions.
See Carboxylic Acids
The Carboxylic Acids group of compounds takes on one of the most important roles in organic chemistry. This class of compounds are included in the active ingredients of numerous products including soaps, skin care products (e.g. salicylic acid in facial cleansing pads), preservatives, and food ingredients (acetic acid in vinegar) to name a few. These compounds are so important because for one, they are acids, and thus can donate protons.
It’s resonance structure is stabilized between two oxygens, known as the carboxyl group, on the molecule, which makes this group so acidic. Another property that makes this class of compounds special is the fact that both hydrogen donating and accepting groups are found in this group of molecules, giving them higher boiling points.
The carbonyl carbon in carboxylic acids makes this group a great electrophile, and since this group is a terminal functional group, it is assigned highest priority in nomenclature. Since these compounds are synthesized widely throughout nature, and even the human body, they are an important topic that the MCAT will cover. The properties of carboxylic acids and the important reactions involved in its chemistry will be discussed in this section.
See Acid Derivatives
Acid Derivatives are compounds that are derived from carboxylic acids. The most important ones, that can be found on the MCAT, are acyl halides, anhydrides, amides, and esters. These compounds and their chemistry are discussed in this section.
Keto Acids and Esters are compounds that contain both a ketone and either a carboxylic acid or ester group. The alpha-keto acids are especially important in biology as they are involved in the Krebs citric acid cycle and in glycolysis. These compounds and their chemistry are discussed in this section.
Amines are organic compounds and functional groups that contain a basic nitrogen atom with a lone pair. Amines are derivatives of ammonia, wherein one or more hydrogen atoms have been replaced by a substituent such as an alkyl or aryl group. These compounds are highly important in biology because they are both a component of amino acids and neurotransmitters among other compounds, which are highly important to the proper functioning of the human body. Amines and their chemistry are discussed in this section.
Carbohydrates are compounds containing carbon, oxygen, and hydrogen in the form of polyhydroxylated aldehydes or ketones. These compounds are important to biology, as they serve as a method of energy storage as well as a source of energy for organisms, and serve as part of the building blocks of DNA, RNA, and coenzymes such as ATP, which transports chemical energy for use in metabolic processes. This group of compounds and their chemistry will be discussed in this section.
Amino Acids & Proteins are biologically important organic compounds made from amine (-NH2) and carboxylic acid (-COOH) functional groups, along with a side-chain specific to each amino acid. They serve as the building block of proteins, and also serve as neurotransmitter transports and biosynthesis, which is the conversion of one or more substrates (think starting materials) to form more complex products, which serve higher roles in bodily functions.
Proteins are large biological molecules consisting of one or more chains of amino acids. They are highly versatile molecules that are critically important in biology, and are involved in processes including the replication of DNA, cell repair, the catalyzing of metabolic processes, and lead the response to certain stimuli, such as muscle hypertrophy, among many other functions. The properties of amino acids and proteins and their chemistry are discussed in this section.
Lipids, which constitute compounds such as mono-, di-, and triglycerides, cholesterols, free fatty acids, and steroids, among many others. Lipids serve as a method of energy storage, signaling for certain biological responses (for example the sex hormone estrogen, a tpe of lipid, signals certain bodily processes such as breast and ovarian development in women at the onset of puberty), and serve as structural components of cell membranes. Various lipids, their properties, and their chemistry will be discussed in this section.
Phosphorus Compounds, in relation to organic chemistry, are compounds containing phosphorous bonded to a carbon containing structure. In relation to biology, its most important function is to hold together DNA through phosphorous bridges, making these compounds essential to all known life. Phosphorous compounds, their properties and their chemistry will be discussed in this section.