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| 37803936 | macromolecules | giant molecules formed by the joining of smaller molecules, usually by a condensation reaction; polysaccharides, proteins, and nucleic acids are considered these | |
| 37803937 | polymer | a long molecule consisting of many similar or identical building blocks linked by covalent bonds, much as a train consists of a train of cars; carbohydrates, nucleic acids, and proteins are examples of these | |
| 37803938 | monomers | repeating units that serve as building blocks of a polymer; smaller molecules; some also have functions on their own | |
| 37803939 | condensation reaction | when two monomers connect to each other by a reaction in which two molecules are covalently bonded to each other through a loss of a molecule | |
| 37803940 | dehydration reaction | when two monomers connect to each other by a reaction in which a hydroxyl group covalently bonds to a hydrogen atom, which causes the loss of a water molecule in the process | |
| 37803941 | enzymes | specialized macromolecules that speed up chemical reactions in cells; considered proteins | |
| 37803942 | hydrolysis | a process that occurs when the bonds between two monomers are broken by the addition of water molecules, with a hydrogen from the water attaching to one monomer and a hydroxyl group attaching to the adjacent monomer | |
| 37803943 | carbohydrates | a sugar (monosaccharide) or one of its dimers (disaccharides) or polymers (polysaccharides) | |
| 37803944 | monosaccharides | molecules with a general formula of some multiple of the unit CH2O; these are major nutrients as carbon skeletons serve as raw material for synthesis of other organic molecules | |
| 37803945 | disaccharide | molecule that consists of two monosaccharides joined by a glycosidic linkage | |
| 37803946 | glycosidic linkage | a covalent bond formed between two monosaccharides by a dehydration reaction; the most common type of this in nature is a "1-4" | |
| 37803947 | polysaccharides | macromolecules; polymers with a few hundred to a few thousand monosaccharides joined by glycosidic linkages; serve as storage material, hydrolyzed as needed to provide sugar for cells; building material for structures that protect a cell or an organism; architecture and function are determined by sugar monomers and by positions of glycosidic linkages | |
| 37803948 | starch | a polymer of glucose monomers; synthesizing this allows for the storage of glucose, and thus, stored energy; this molecule is helical in shapeq | |
| 37803949 | glycogen | a polymer of glucose that is like amylopectin (a complex starch that is a branched polymer with 1-6 linkages at branch points) but more extensively branched; animals store this | |
| 37803950 | cellulose | a polysaccharide that is a major component of the tough walls that enclose plant cells; most abundant organic compound on Earth; polymer of glucose | |
| 37803951 | chitin | an important structural polysaccharide used by arthropods to build their exoskeletons; pure forms of this are leathery and flexible, but they harden when encased within calcium carbonate | |
| 37803952 | lipid | one of a group of compounds, including fats, phospholipids, and steroids, that mix poorly, if at all, with water; they are not composed of true polymers, so they are generally not large enough to be considered macromolecules; they are hydrophobic because they contain few polar bonds and many hydrocarbon regions; they vary in form and function | |
| 37803953 | fat | a large molecule constructed by two smaller molecules, glycerol and a fatty acid, through dehydration reaction; major function is energy storage | |
| 37803954 | glycerol | an alcohol with three carbons, each having a hydroxyl group | |
| 37803955 | fatty acid | a molecule with a long carbon skeleton (usually 16 or 18 in length) and a carboxyl group at the end of the molecule (hence the acid); these are hydrophobic | |
| 37803956 | triacylglycerol | a fat that consists of three fatty acids linked to one glycerol molecule; linkages that bond hydroxyl to carboxyl are called ester linkages | |
| 37803957 | saturated fatty acid | a fatty acid that has no double-bonded carbon atoms so that as many hydrogen atoms as possible are bonded to the carbon skeleton | |
| 37803958 | unsaturated fatty acid | a fatty acid that has one or more double-bonded carbon atoms formed by the removal of hydrogen atoms from the carbon skeleton; there will be a kink in the hydrocarbon chain wherever a -cis double-bond occurs (causes bending) | |
| 37803959 | saturated fat | a fat made from saturated fatty acid; animal fats are solid at room temperature because they lack double-bonds, thus flexibility enables molecules to pack together tightly | |
| 37803960 | unsaturated fat | a fat made from unsaturated fatty acids; they are liquid at room temperature (oils) because kinks in -cis bonding prevent molecules from packing together to solidify | |
| 37803961 | trans fat | the fat that results when unsaturated fats are synthetically converted to saturated fats to prevent the separation of lipids (margarine and peanut butter are examples); this process produces saturated fats and unsaturated fats with trans double bonds | |
| 37803962 | phospholipids | cells need these in order to exist because they make up cell membranes; has 2 fatty acids attached to glycerol instead of traditional 3 (triacylglycerol); always assemble into a double-layer aggregate because of hydrophilic head and hydrophobic tail | |
| 37803963 | steroids | lipids characterized by a carbon skeleton consisting of four fused rings | |
| 37803964 | cholesterol | a common component of animal cell membranes, and a foundation from which other steroids are synthesized; crucial molecule in animals, but can be dangerous when in high amounts | |
| 37803965 | catalysts | chemical agents that selectively speed up chemical reactions without being consumed by the reaction; can be seen as workhorses that keep cells running by carrying out processes of life | |
| 37803966 | polypeptides | polymers of all amino acids | |
| 37803967 | proteins | macromolecules that are constructed from one or more polypeptides, each folded and coiled into a specific three-dimensional structure; all made from same 20 amino acids; most structurally sophisticated molecule known | |
| 37803968 | amino acids | organic molecules possessing both carboxyl and amino groups | |
| 37803969 | peptide bond | a covalent bond that results when two amino acids join through dehydration reaction | |
| 37803970 | enzymatic | the type of protein that selectively accelerates chemical reactions; example: digestive enzymes release polymers in food | |
| 37803971 | structural | the type of protein that supports an organism; example: insects and spiders use silk fibers for cocoons and webs, collagen and elastin provide fibrous framework in animal connective tissues; keratin is protein of hair, horns, feathers, etc. | |
| 37803972 | storage | the type of protein that stores amino acids; example: ovalbumin is the protein of egg white, used as an amino acid source for developing embryos | |
| 37803973 | transport | the type of protein that transports other substances; example: hemoglobin, the iron-containing protein of vertebrate blood, transports oxygen from lungs to other parts of the body | |
| 37803974 | hormonal | the type of protein that coordinates an organism's activities; example: insulin, a hormone secreted by the pancreas, helps regulate the concentration of sugar in the blood of vertebrates | |
| 37803975 | receptor | the type of protein that helps a cell respond to chemical stimuli; example: receptors built into the membrane of a nerve cell detect chemical signals released by other nerve cells | |
| 37803976 | contractile and motor | the type of protein that controls movement; example: actin and myosin are responsible for the contraction of muscles; other proteins are responsible for the undulations of cilia and flagella | |
| 37803977 | defensive | the type of protein that protects against disease; example: antibodies combat bacteria and viruses | |
| 38719356 | globular | the shape of proteins that are roughly spherical | |
| 38719357 | fibrous | the shape of proteins that are long and fiber-like | |
| 38719358 | primary structure | the unique structure of amino acids; example: a polypeptide composed of 127 amino acids has 20^127 different ways it can be organized | |
| 38719359 | secondary structure | the collection of coils and folds that result from hydrogen bonds between repeating constituents of the polypeptide backbone (not the amino acid sides) | |
| 38719360 | alpha helix | a secondary structure that is a delicate coil held together by hydrogen bonding between every fourth amino acid | |
| 38719361 | beta pleated sheet | a secondary structure in which two or more regions of the polypeptide chain lying side by side are connected by hydrogen bonds between parts of two parallel polypeptide backbones; it makes up the core of globular proteins | |
| 38719362 | tertiary structure | the overall shape of a polypeptide that results from interactions between side chains of various amino acids | |
| 38719363 | hydrophobic interaction | an interaction that contributes to tertiary structure; as a polypeptide folds into functional shape, amino acids with hydrophobic side chains usually end up in clusters at the core of the protein, away from water | |
| 38719364 | disulfide bridges | links that form where two cysteine monomers are brought together by folding of protein; covalent bonds reinforce structure | |
| 38719365 | quaternary structure | the overall protein structure that results from the gathering of polypeptide subunits; some proteins consist of 2 or more polypeptide chains combined into one macromolecule | |
| 38719366 | sickle-cell disease | an inherited blood disorder that is caused by a substitution of one amino acid (valine) for the normal amino acid (glutamic acid) at a particular position in the primary structure of hemoglobin, the protein that carries oxygen in red blood cells | |
| 38719367 | denaturation | the unraveling and loss of a protein's native shape due to alterations of its environment, such as pH, salt concentration, and temperature; this causes a protein to become biologically inactive | |
| 38719368 | chaperonins | protein molecules that assist in the proper folding of other proteins; they do not specify the final structure of a protein, instead they keep the new polypeptide separated from "bad influences" in the cytoplasmic environment while it folds | |
| 38719369 | x-ray crystallography | the method used to determine 3-D structures of proteins; developed in 1959 | |
| 38719370 | gene | a discrete unit of hereditary information consisting of a specific nucleotide sequence in DNA (or RNA, in some viruses) | |
| 38719371 | 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; two types are DNA and RNA | |
| 38719372 | deoxyribonucleic acid | a double-stranded, helical nucleic acid molecule consisting of nucleotide monomers with a deoxyribose sugar and the nitrogenous bases adenine, guanine, cytosine, and thymine; it is capable of replicating and determining the inherited structure of a cell's proteins | |
| 38719373 | ribonucleic acid | a type of nucleic acid consisting of nucleotide monomers with a ribose sugar and nitrogenous bases adenine, cytosine, guanine, and uracil; usually single-stranded; functions in protein synthesis, gene regulation, and as the genome of some viruses | |
| 38719374 | messenger RNA | a nucleic acid that directs the production of polypeptides; this is found in the cells' ribosomes | |
| 38719375 | nucleotide | the monomer of nucleic acids that has three parts: 1) a nitrogenous base (A, C, G, T, U); 2) a give-carbon sugar (a pentose); 3) a phosphate group | |
| 38719376 | pyrimidines | the family of smaller nitrogenous bases in which its members have six-membered rings of carbon and nitrogen atoms; members include cytosine (C), thymine (T), and uracil (U) | |
| 38719377 | purines | the family of larger nitrogenous bases in which its members have a six-membered ring fused to a five-membered ring; members are adenine (A) and guanine (G) | |
| 38719378 | ribose | the sugar connected to RNA; has one more oxygen atom than the other sugar associated with nucleicacids | |
| 38719379 | deoxyribose | the sugar connected to DNA; has one less oxygen atom than the other sugar associated with nucleic acids | |
| 38719380 | double helix | the shape that cellular DNA molecules take as a result of spiraling around an imaginary axis; this was proposed by James Watson and Francis Crick in 1953 at Cambridge University | |
| 38719381 | antiparallel | the pattern that describes the formation of DNA; the two sugar-phosphate backbones run in opposite 5' >> 3' directions from each other, somewhat like a divided highway |
