Amino Acids and Proteins

Amino Acid  -  A class of 20 organic compounds that combine to form proteins.

Deoxyribonucleic acid (DNA)  -  A long polymer of nucleotides joined by phosphate groups, DNA is the genetic material that provides the blueprint for the proteins that each different cell will produce in its lifetime. It consists of a double stranded helix consisting of a five-sided sugar (deoxyribose) without a free hydroxyl group, a phosphate group linking the two nucleotides, and a nitrogenous base. If you are so inclined, you can see a of DNA.

Ribonucleic acid (RNA)  -  RNA is a long polymer of ribose (a five-sided sugar with a free hydroxyl group) and nitrogenous bases linked via phosphate groups. It is complementary to one of the DNA strands and forms the proteins that are specified by the cell.

pKA  -  The pKa is an intrinsic property of a compound defined as the ability to release protons into solution.

Primary Structure  -  The first level of protein structure that is simply the linear sequence of its constituent amino acids.

Secondary Structure  -  The second level of protein structure where the linear sequence of proteins begins to fold into regular repeating patterns.

Tertiary Structure  -  The third level of protein structure where side chain interactions dictate the direction of the folding.

Quaternary Structure  -  The fourth level of protein structure that refers to the spatial arrangement of the subunits within the protein.

Hydrophobic Collapse  -  The process whereby water-fearing protein side chains interact more favorably with themselves than with water to create a hydrophilic exterior.

Levinthal's Paradox  -  The difference between the actual and theoretical times of protein folding.

Zwitterions  -  Amino acids in a form of neutrality where the carboxyl group and amino group are ready to donate and accept protons, respectively.

Polar  -  As opposed to non-polar, referring to the hydrophilic or "water loving" qualities of amino acids.

Non-polar  -  As opposed to polar, Referring to the hydrophobic or "water fearing" qualities of amino acids.

Polypeptides  -  Multiple amino acids joined by peptide bonds.

Alpha Helix  -  The secondary structure of proteins that is a rod-like, tightly coiled polypeptide chain wound in a clockwise or counterclockwise direction.

Beta Sheet  -  The secondary structure of proteins where the polypeptide chains are almost completely extended during the process of folding.

Transamination  -  The synthesis of amino acids in the liver.

Alpha keto acid  -  A precursor molecule for amino acid synthesis.

Aminotransferases  -  Enzymes, derived from vitamin B6, that are important in amino acid synthesis.

Ketogenic  -  The process whereby fatty acids are broken down to produce ketones.

Gluconeogenesis  -  The process of synthesizing glucose from non- glucose precursors such as amino acids.

Pyruvate  -  Pyruvate is a three-carbon compound formed through the degradation of glucose via glycolysis. Two pyruvate molecules are formed per molecule of glucose that enters glycolysis.

Epinephrine  -  A hormone secreted from the adrenal medulla in response to sympathetic nervous system stimulation and low blood glucose. Its effects include causing the liver to degrade glycogen into glucose and decreasing the utilization of glucose by skeletal muscle.

Neurotransmitter  -  Proteins responsible for transmission of the electrical potential across a synapse between nerves.

Substrates  -  A molecule that an enzyme binds to preferentially with high affinity.

Activation Energy  -  The amount of energy required to bring the substrate to a transitional state.

Allosteric  -  Regulatory sites, other than the active site of the enzyme that serve to regulate enzymatic activity.

Active Transport  -  The process whereby ions are forced up their concentration gradient across a membrane.

Fatty acids  -  Fatty acids are long hydrocarbon chains that contain a carboxylic acid group at one end of the molecule. Three fatty acid units and one glycerol unit form a triglyceride.

Oxaloacetate  -  A four-carbon molecule found in mitochondria that condenses with acetyl CoA to form citrate in the first reaction of the Krebs Cycle. Oxaloacetate must be constantly regenerated in order for the Krebs Cycle and the electron transport chain to continue.

Krebs Cycle  -  Also known as the Citric Acid Cycle, the Krebs Cycle consists of a series of reactions that produce high-energy electron carriers to be used in the electron transport chain in the production of adenosine triphosphate (ATP).

Acetyl CoA  -  A molecule produced in the mitochondria upon the oxidation of pyruvate and the reduction of nicotinamide adenine dinucleotide (NAD+) to be used in the Krebs Cycle. Acetyl CoA can also be formed via the degradation of fatty acids.

Phenylketonuria  -  The disease state in which an individual has a defect in phenylalanine metabolism.

Ketosis  -  The incomplete breakdown of fats.