[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.
hydrocarbon
An organic molecule consisting of only carbon and hydrogen.
triacylglycerol
A lipid consisting of three fatty acids linked to one glycerol molecule; also called a triacylglycerol or triglyceride.
secondary structure
Regions of repetitive coiling or folding of the polypeptide backbone of a protein due to hydrogen bonding between constituents of the backbone (not the side chains).
ribose
the sugar component of RNA nucleotides
denaturation
In proteins, a process in which a protein loses its native shape due to the disruption of weak chemical bonds and interactions, thereby becoming biologically inactive; in DNA, the separation of the two strands of the double helix. Denaturation occurs under extreme (noncellular) conditions of pH, salt concentration, or temperature.
hydrolysis
A chemical reaction that breaks bonds between two molecules by the addition of water; functions in disassembly of polymers to monomers.
adenosine triphosphate
primary carrier of energy in cells
unsaturated fatty acid
A fatty acid that has one or more double bonds between carbons in the hydrocarbon tail. Such bonding reduces the number of hydrogen atoms attached to the carbon skeleton.
monomer
The subunit that serves as the building block of a polymer.
deoxyribose
The sugar component of DNA nucleotides, having one fewer hydroxyl group than ribose, the sugar component of RNA nucleotides.
chitin
A structural polysaccharide, consisting of amino sugar monomers, found in many fungal cell walls and in the exoskeletons of all arthropods.
polymer
A long molecule consisting of many similar or identical monomers linked together by covalent bonds.
starch
A storage polysaccharide in plants, consisting entirely of glucose monomers joined by glycosidic linkages.
bioinformatics
The use of computers, software, and mathematical models to process and integrate biological information from large data sets.
polypeptide
A polymer of many amino acids linked together by peptide bonds.
pyrimidine
One of two types of nitrogenous bases found in nucleotides, characterized by a six-membered ring. Cytosine (C), thymine (T), and uracil (U) are pyrimidines.
polysaccharide
A polymer of many monosaccharides, formed by dehydration reactions.
gene
A discrete unit of hereditary information consisting of a specific nucleotide sequence in DNA (or RNA, in some viruses).
antiparallel
Referring to the arrangement of the sugar-phosphate backbones in a DNA double helix (they run in opposite 5’ S 3’ directions).
peptide bond
The covalent bond between the carboxyl group on one amino acid and the amino group on another, formed by a dehydration reaction.
proteomics
The systematic study of the full protein sets (proteomes) encoded by genomes.
organic compound
A chemical compound containing carbon.
hydrophobic interaction
A type of weak chemical interaction caused when molecules that do not mix with water coalesce to exclude water.
monosaccharide
The simplest carbohydrate, active alone or serving as a monomer for disaccharides and polysaccharides. Also known as simple sugars, monosaccharides have molecular formulas that are generally some multiple of CH2O.
β pleated sheet
One form of the secondary structure of proteins in which the polypeptide chain folds back and forth. Two regions of the chain lie parallel to each other and are held together by hydrogen bonds between atoms of the polypeptide backbone (not the side chains).
purine
One of two types of nitrogenous bases found in nucleotides, characterized by a six-membered ring fused to a five-membered ring. Adenine (A) and guanine (G) are purines.
sickle-cell disease
A recessively inherited human blood disorder in which a single nucleotide change in the β-globin gene causes hemoglobin to aggregate, changing red blood cell shape and causing multiple symptoms in afflicted individuals.
trans fat
An unsaturated fat, formed artificially during hydrogenation of oils, containing one or more trans double bonds.
phospholipid
A lipid made up of glycerol joined to two fatty acids and a phosphate group. The hydrocarbon chains of the fatty acids act as nonpolar, hydrophobic tails, while the rest of the molecule acts as a polar, hydrophilic head. Phospholipids form bilayers that function as biological membranes.
nucleotide
The building block of a nucleic acid, consisting of a five-carbon sugar covalently bonded to a nitrogenous base and one to three phosphate groups.
α helix
A coiled region constituting one form of the secondary structure of proteins, arising from a specific pattern of hydrogen bonding between atoms of the polypeptide backbone (not the side chains).
tertiary structure
The overall shape of a protein molecule due to interactions of amino acid side chains, including hydrophobic interactions, ionic bonds, hydrogen bonds, and disulfide bridges.
valence
The bonding capacity of a given atom; the number of covalent bonds an atom can form, which usually equals the number of unpaired electrons in its outermost (valence) shell.
protein
A biologically functional molecule consisting of one or more polypeptides folded and coiled into a specific three-dimensional structure.
steroid
A type of lipid characterized by a carbon skeleton consisting of four fused rings with various chemical groups attached.
double helix
The form of native DNA, referring to its two adjacent antiparallel polynucleotide strands wound around an imaginary axis into a spiral shape.
lipid
Any of a group of large biological molecules, including fats, phospholipids, and steroids, that mix poorly, if at all, with water.
functional group
a specific configuration of atoms commonly attached to the carbon skeletons of organic molecules and involved in chemical reactions.
primary structure
the level of protein structure referring to the specific linear sequence of amino acids.
