[3] Vocabulary Flashcards
enzyme
(en’-zīm) A macromolecule serving as a catalyst, a chemical agent that increases the rate of a reaction without being consumed by the reaction. Most enzymes are proteins.
quaternary structure
The particular shape of a complex, aggregate protein, defined by the characteristic three-dimensional arrangement of its constituent subunits, each a polypeptide.
shape of protein, 3D arrangement of polypeptides
evolutionary lineage
The sequence of ancestral organisms leading to a particular taxon; represented by a branch (line) in a phylogenetic tree.
sequence of organisms, new taxon, line on phylogenetic tree
polynucleotide
A polymer consisting of many nucleotide monomers in a chain. The nucleotides can be those of DNA or RNA.
structural isomer
One of two or more compounds that have the same molecular formula but differ in the covalent arrangements of their atoms.
enantiomer
One of two compounds that are mirror images of each other and that differ in shape due to the presence of an asymmetric carbon.
mirror-image compounds, differ in shape due to asymmetric carbon
x-ray crystallography
A technique used to study the three-dimensional structure of molecules. It depends on the diffraction of an X-ray beam by the individual atoms of a crystallized molecule.
ribonucleic acid
A type of nucleic acid consisting of a polynucleotide made up of nucleotide monomers with a ribose sugar and the nitrogenous bases adenine (A), cytosine (C), guanine (G), and uracil (U); usually single-stranded; functions in protein synthesis, gene regulation, and as the genome of some viruses.
catalyst
A chemical agent that selectively increases the rate of a reaction without being consumed by the reaction.
saturated fatty acid
A fatty acid in which all carbons in the hydrocarbon tail are connected by single bonds, thus maximizing the number of hydrogen atoms attached to the carbon skeleton.
fatty acid, carbons connected by single bonds, maximizes hydrogen atoms attached
deoxyribonucleic acid
A nucleic acid molecule, usually a double-stranded helix, in which each polynucleotide strand consists of nucleotide monomers with a deoxyribose sugar and the nitrogenous bases adenine (A), cytosine (C), guanine (G), and thymine (T); capable of being replicated and determining the inherited structure of a cell’s proteins.
dehydration reaction
A chemical reaction in which two molecules become covalently bonded to each other with the removal of a water molecule
covalent bonding due to loss of H2O
isomer
One of two or more compounds that have the same numbers of atoms of the same elements but different structures and hence different properties.
compound, same # of atoms of same element, different shape and properties
amino acid
An organic molecule possessing both a carboxyl and an amino group. Amino acids serve as the monomers of polypeptides.
carboxyl and amino group, monomer of polypeptides
disaccharide
A double sugar, consisting of two monosaccharides joined by a glycosidic linkage formed by a dehydration reaction.
glycogen
An extensively branched glucose storage polysaccharide found in the liver and muscle of animals; the animal equivalent of starch.
genomics
the study of whole sets of genes and their interactions within a species, as well as genome comparisons between species.
cellulose
a structural polysaccharide of plant cell walls, consisting of glucose monomers joined by β glycosidic linkages.
nucleic acid
A polymer (polynucleotide) consisting of many nucleotide monomers; serves as a blueprint for proteins and, through the actions of proteins, for all cellular activities. The two types are DNA and RNA.
cholesterol
a steroid that forms an essential component of animal cell membranes and acts as a precursor molecule for the synthesis of other biologically important steroids, such as many hormones.
macromolecule
a giant molecule formed by the joining of smaller molecules, usually by a dehydration reaction. Polysaccharides, proteins, and nucleic acids are macromolecules.
gene expression
The process by which information encoded in DNA directs the synthesis of proteins or, in some cases, RNAs that are not translated into proteins and instead function as RNAs.
disulfide bridges
A strong covalent bond formed when the sulfur of one cysteine monomer bonds to the sulfur of another cysteine monomer.
fatty acid
A carboxylic acid with a long carbon chain. Fatty acids vary in length and in the number and location of double bonds; three fatty acids linked to a glycerol molecule form a fat molecule, also known as a triacylglycerol or triglyceride.
glycosidic linkage
A covalent bond formed between two monosaccharides by a dehydration reaction.
cis-trans isomer
One of two or more compounds that have the same molecular formula and covalent bonds between atoms but differ in the spatial arrangements of their atoms owing to the inflexibility of double bonds; formerly called a geometric isomer.