Biochemistry Flashcards
An element of secondary structure, marked by peptide chains lying alongside one another, forming rows or strands.
β-Pleated Sheet
A sphingolipid containing a carbohydrate as a head group.
Cerebroside
Transport of materials through the cell; requires interaction with the cytoplasm and may require transport proteins.
Transcellular Transport
The strand of DNA that is transcribed to form mRNA; also called the antisense strand.
Template Strand
Specialized structural proteins that are involved in cell-to-cell junctions as well as transient cellular interactions; common cell adhesion molecules include cadherins, integrins, and selectins.
Cell Adhesion Molecules
Regaining the correct tertiary structure after denaturation of a protein.
Renaturation
Production of an mRNA molecule from a strand of DNA.
Transcription
A lipid containing a phosphate and an alcohol (glycerol or sphingosine) joined to hydrophobic fatty acid tails.
Phospholipid
Energy-producing metabolic processes that do not require oxygen, including glycolysis and fermentation.
Anaerobic Respiration
The primary energy molecule of the body; it releases energy by breaking the bond with the terminal phosphate to form ADP and an inorganic phosphate.
Adenosine Triphosphate (ATP)
The movement of a molecule against its concentration gradient with energy investment; primary active transport uses ATP, whereas secondary active transport uses a favorable transport gradient of a different molecule.
Active Transport
The first codon in an mRNA molecule that codes for an amino acid (AUG for methionine or N-formylmethionine).
Start Codon
Proteins that are involved in the cytoskeleton and extracellular matrix; they are generally fibrous in nature and include collagen, elastin, keratin, actin, and tubulin.
Structural Proteins
A three-nucleotide sequence on a tRNA molecule that pairs with a corresponding mRNA codon during translation.
Anticodon
A long chain of monosaccharides linked by glycosidic bonds; can be divided into homopolysaccharides (only one type of monosaccharide is used) and heteropolysaccharides (more than one type of monosaccharide is used).
Polysaccharide
The representation of the plasma membrane as a dynamic phospholipid bilayer that interacts with cholesterol and proteins.
Fluid Mosaic Model
Proteins that are involved in cell motility through interactions with structural proteins; motor proteins have ATPase activity and include myosin, kinesin, and dynein.
Motor Proteins
A structural protein around which DNA is coiled in eukaryotic cells.
Histone
The last codon of translation (UAA, UGA, or UAG); release factor binds here, terminating translation.
Stop Codon
Refers to the presence or absence of double bonds in a fatty acid; saturated fatty acids have only single bonds, whereas unsaturated fatty acids have at least one double bond.
Saturation
The conversion of pyruvate to either at the mall and carbon dioxide (yeast) or lactic acid (animal cells); does not require oxygen.
Fermentation
A decrease in enzyme activity that results from the interaction of an inhibitor with an allosteric site; mixed inhibitors bind to the free enzyme and to the substrate-bound enzyme with different affinities. They cannot be overcome by addition of substrate and impact both K{m} and v{max}.
Mixed Inhibition
The synthesis of ketone bodies from the metabolic products of β-oxidation or amino acid metabolism; occurs under conditions of starvation.
Ketogenesis
The primary monosaccharide used for fuel by all cells of the body; has the formula C6H12O6.
Glucose
The simple diffusion of water.
Osmosis
A solution that has a lower concentration than the one to which it is being compared.
Hypotonic
A three-nucleotide sequence in an mRNA molecule that pairs with an appropriate tRNA anticodon during translation.
Codon
The concentration of substrate at which an enzyme runs at half its maximum velocity; a measure of enzyme affinity (the higher the K{m}, the lower the affinity).
K{m}
Being repelled by water; describes nonpolar, uncharged compounds (usually lipids or certain R groups of amino acids).
Hydrophobic
An enzyme that unwinds the double helix of a DNA molecule, allowing replication to take place.
Helicase
The strand of DNA that is synthesized in small fragments, called Okazaki fragments, and then ligated together. The Okazaki fragments are synthesized in the 5’ to 3’ direction, but the overall synthesis is in the 3’ to 5’ direction.
Lagging Stand
The best-supported of the most prominent theories of enzyme specificity; states that the enzyme and the substrate experience a change in conformation during binding to increase complementarity. Usually contrasted with the lock and key theory.
Induced Fit Model
Being attracted to water; describes polar and charged compounds and those that can participate in hydrogen bonding.
Hydrophilic
A molecule composed of more than one amino acid; can be subdivided into dipeptides (two amino acids), tripeptides (three), oligopeptides (up to 20) and polypeptides (more than 20).
Peptide
The major steps in the transfer of genetic information, from transcription of DNA to RNA and translation of that RNA to protein.
Central Dogma of Molecular Biology
Infoldings of the inner mitochondrial membrane that increase the surface area available for electron transport chain complexes.
Cristae
A solution that has a greater concentration than the one to which it is being compared.
Hypertonic
Describes amino acids that can be converted into intermediates that feed into ketogenesis.
Ketogenic
The loss of tertiary structure in a protein, leading to loss of function.
Denaturation
A decrease in enzyme activity that results from the interaction of an inhibitor that binds permanently at either the active site or an allosteric site; in laboratory settings, irreversible inhibitors are sometimes called suicide substrates.
Irreversible Inhibition
A nucleic acid found exclusively in the nucleus that codes for all of the genes necessary for life; transcribed to mRNA and always read 5’ to 3’.
Deoxyribonucleic Acid (DNA)
A decrease in enzyme activity that results from the interaction with an inhibitor at the allosteric site; uncompetitive inhibitors bind only to the substrate-bound enzyme and cannot be overcome by addition of substrate.
Uncompetitive Inhibition
The transport of molecules into a cell through invagination of the cell membrane and the formation of a vesicle; phagocytosis is the endocytosis of solids, pinocytosis is the endocytosis of liquids.
Endocytosis
An inorganic molecule or ion that helps an enzyme carry out its function.
Cofactor
One of the two most prominent theories of enzyme specificity; states that the enzyme and the substrate have a static but complimentary state. Less well-supported than the induced fit model.
Lock and Key Theory
A solution that has the same concentration as the one to which it is being compared.
Isotonic
The lasso-shaped structure formed during the removal of introns in mRNA processing.
Lariat
A special class of membrane receptors with an associated GTP binding protein; activation of a G protein-coupled receptor involves dissociation and GTP hydrolysis.
G Protein-Coupled Receptors
An essential organic coenzyme that assists an enzyme in carrying out its action.
Vitamin
A branched polymer of glucose that represents a storage form of glucose.
Glycogen
A decrease in enzyme activity that results from the interaction of an inhibitor with the active site of an enzyme; competitive inhibition can be overcome by addition of excess substrate.
Competitive Inhibition
An organic molecule that helps an enzyme out its function.
Coenzyme
The process of separating molecules on the basis of size and charge using a porous gel and an electric field; protein electrophoresis generally uses polyacrylamide, while nucleic acid electrophoresis generally uses agarose.
Electrophoresis
A compound that lowers surface tension by acting as a detergent or emulsifier.
Surfactant
The electric potential that results from the unequal distribution of charge around the cell membrane; resting membrane potential which characterizes a cell that has not been stimulated.
Resting Membrane Potential
Dense, tightly coiled DNA that appears dark-colored under the microscope; transcriptionally inactive.
Heterochromatin
Looser, less dense collections of DNA that appear light-colored under the microscope; transcriptionally active.
Euchromatin
A biological molecule with catalytic activity; includes many proteins and some RNA molecules.
Enzyme
The three-dimensional shape of a polypeptide, stabilized by numerous interactions between R groups.
Tertiary Structure
The movement of a molecule down its concentration gradient without energy investment; includes simple and facilitated diffusion and osmosis.
Passive Transport
Transport of materials through the interstitial space without interactions with the cytoplasm or cell membrane.
Paracellular Transport
The transfer of a phosphate group, generally to ATP, which is powered by a gradient formed by oxidation-reduction reactions; occurs in the mitochondria.
Oxidative Phosphorylation
Cell-to-cell junctions that allow for the passage of small molecules between adjacent cells.
Gap Junctions
Metabolic processes that result in the release of energy and the breakdown of molecules.
Catabolism
A decrease in enzyme activity that results from the interaction of an inhibitor with an allosteric site; noncompetitive inhibitors bind equally well to free enzymes and to substrate-bound enzymes. They cannot be overcome by addition of substrate.
Noncompetitive Inhibition
A five-membered ring sugar.
Furanose
An element of secondary structure, marked by clockwise coiling of amino acids around a central axis.
α-Helix
The linear sequence of amino acids in a polypeptide.
Primary Structure
The process of separating components on the basis of their density and resistance to flow by spinning a sample at very high speeds; the most dense components form a solid pellet and the least dense components remain in the supernatant (liquid portion).
Centrifugation
A numerical representation that can be used to determine the prevalent type of biomolecule being used in metabolism; the ratio of carbon dioxide produced to oxygen consumed.
Respiratory Quotient
A method of drawing organic molecules in which horizontal lines are coming out of the page (wedges) and vertical lines are going into the page (dashes).
Fischer Projection
Metabolic processes that result in the consumption of energy and the synthesis of molecules.
Anabolism
A cofactor or coenzyme that is covalently bonded to a protein to permit its function.
Prosthetic Group
The local structure of neighboring amino acids; most common are α-helices and β-pleated sheets.
Secondary Structure