BIO103 - B03 VOCAB - chemical building blocks of life

carbohydrate

A sugar (monosaccharide) or one of its dimers (disaccharide) or polymers (polysaccharide). This molecule contains hydrogen and oxygen in the same ratio as water (2:1) and, in our bodies, different types can be broken down to release energy, serve as surface markers on cells (ABO blood groups), and/or have a structural function.

lipid

Any of a group of large biological molecules, including fats, phospholipids, and steroids, that mix poorly, if at all, with water (=hydrophobic).

protein

A biologically functional molecule containing one or more polypeptides (=polypeptide chains) folded and coiled into a specific three-dimensional structure.

valence electron

An electron in the outermost electron shell.

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.

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.

functional group

A specific configuration of atoms commonly attached to the carbon skeletons of organic molecules and involved in chemical reactions. Examples include carboxyl group and phosphate group.

macromolecule

A giant molecule formed by the joining of smaller molecules. Polysaccharides, proteins, and nucleic acids are types of these giant molecules (NOTE: lipids are not considered as being these type of molecules).

monomer

The subunit that serves as the building block of a polymer.

polymer

A long molecule consisting of many similar or identical monomers linked together with covalent bonds.

enzyme

A macromolcule serving as a catalyst, a chemical agent that increases the rate of a reaction without being consumed by the reaction; most catalysts in biological systems are proteins.

dehydration

The ________________ reaction involves the removal of a water molecule to covalently bond two molecules together; functions in the assembly of monomers to polymers (...and polymers with polymers to make bigger polymers).

hydrolysis

The ________________ reaction involves the addition of water to break bonds between two molecules; functions in the disassembly of polymers to monomers.

monosaccharide

The simplest carbohydrate, active alone or serving as a monomer for disaccharides & polysaccharides. Also called simple sugars, they have molecular formulas that are generally some multiple of CH2O.

disaccharide

A "double" sugar, consisting of two monosaccharides joined by a glycosidic linkage formed by a dehydration reaction.

polysaccharide

A polymer of many monosaccharides, formed by dehydration reactions.

starch

A storage polysaccharide in plants, consisting entirely of glucose monomers joined by glycosidic linkages.

glycogen

An extensively branched storage polysaccharide in the liver and muscle of animals, consisting entirely of glucose monomers joined by glycosidic linkages. The animal equivalent of starch found in plants.

cellulose

A structural polysaccharide of plant cell walls, consisting of glucose monomers joined by beta glycosidic linkages.

chitin

A structural polysaccharide, consisting of amino sugar monomers, found in many fungal cell walls and in the exoskeletons of all arthropods.

fat

A less "fancy" term for triglyceride; it is a lipid consisting of three fatty acids linked to one glycerol molecule.

triglyceride

A "fancy" term for fat; it is a lipid consisting of three fatty acids linked to one glycerol molecule.

fatty acid

A carboxylic acid with a long carbon chain; they can vary in length as well as number & location of double bonds (unsaturated vs saturated); major component of triglycerides.

saturated fatty acid

This fatty acid has all carbons in the hydrocarbon tail connected to one another by single covalent bonds, thus maximizing the number of hydrogen atoms that are attached to the carbon skeleton.

unsaturated fatty acid

This fatty acid has one or more double covalent bonds between carbons in the hydrocarbon tail. Such bonding reduces the number of hydrogen atoms attached to the carbon skeleton.

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. They form bilayers that function as biological membranes.

steroid

A type of lipid characterized by a carbon skeleton consisting of four fused rings with various chemical groups attached.

catalyst

A chemical agent that selectively increases the rate of a reaction without being consumed by the reaction. In general, chemical reactions occur faster in the presence of a __________ because it provides an alternative reaction pathway (or mechanism) with a lower activation energy (... we'll cover this soon!) than the non-catalyzed mechanism.

amino acid

An organic molecule possessing amine (-NH2) and carboxyl (-COOH) functional groups, along with a side chain (R group) specific to each __________; they serve as the monomers of polypeptides.

polypeptide

A polymer of many amino acids linked together by peptide bonds; also called a __________ chain.

primary structure of protein

The level of protein structure referring to the specific linear sequence of amino acids; the __________ structure.

secondary structure of protein

The level of protein structure involving 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); the __________ structure.

tertiary structure of protein

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; the __________ structure.

quaternary structure of protein

The particular shape of a complex, aggregate (=multiple polypeptide chains involved) protein, defined by the characteristic three-dimensional arrangement of its constituent subunits, each a polypeptide; the __________ structure.

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.) This occurs under extreme (noncellular) conditions of pH, salt concentration (salinity), and/or temperature.

chaperone protein

A protein complex that assists in the proper folding of other proteins; also called a chaperonin.

nucleic acid

A polymer consisting of many nucleotide monomers (hence, also called a polynucleotide); serves as a blueprint for proteins and, through the actions of proteins, for all cellular activities. The two types are DNA and RNA.

gene

A discrete unit of hereditary information consisting of a specific nucleotide sequence in DNA (or RNA, in some viruses).

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.

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 (and RNAs).

ribonucleic acid

A nucleic acid molecule consisting of a polynucleotide strand 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, in gene regulation, and as the genome of some viruses.

nucleotide

The building blocks (monomers) of a nucleic acid, consisting of a five-carbon sugar (deoxyribose

or ribose) covalently bonded to a nitrogenous base (adenine, cytosine, guanine, thymine, or uracil) and

one to three phosphate groups.

double helix

The form of native DNA, referring to its adjacent antiparallel (=strands "go" in opposite directions to one another) polynucleotide strands wound around an imaginary axis into a spiral shape.

genome

The genetic material of an organism or virus; the complete compliment of an organism's or virus's genes along with its noncoding nucleic acid sequences.

proteome

The entire set of proteins expressed by a given cell, tissue, or organism.

adenosine triphosphate (ATP)

An adenine-containing nucleoside triphosphate that releases free energy when its phosphate bonds are hydrolyzed. This energy is used to drive endergonic (=a non-spontaneous chemical reaction in which free energy is absorbed from the surrounding... more soon!) reactions in cells.