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42 terms

Chapter 3: The Molecules of Life

Vocabulary
STUDY
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Organic compounds
Compounds that contain carbon
Organic chemistry
Study of organic compounds
Hydrocarbons
Organic molecules that contain only carbon and hydrogen
Functional groups
Atoms that form the chemically reactive part of a molecule
Macromolecules
Very large molecule in a living organism: protein, polysaccharide, lipid, nucleic acid
Polymer
A large molecule consisting of many identical or similar molecular units (monomers) covalently joined together in a chain
Monomer
A chemical subunit that serves as a building block of a polymer
Dehydration synthesis(condensation)
Chemical process in which a polymer forms as monomers are linked together by the removal of water molecules
Hydrolysis
Chemical process in which macromolecules are broken down by the chemical addition of water molecules to the bonds linking their monomers; an essential part of digestion
Carbohydrates
Biological molecule consisting of simple single-monomer sugars (monosaccharides), two-monomer sugars (disacchsride) and other multi-unit sugars (polysaccharides)
Monosaccharides
Smallest kind of sugar molecule; single sugar unit
Isomers
Organic compounds with the same molecular formula but different structures and thus different properties
Disaccharides
Sugar molecule consisting of two monosacccharides linked by a dehydration (condensation) reaction
Polysaccharides
Carbohydrate polymer consisting of hundreds to thousands of monosaccharides linked by covalent bonds
Starch
A storage polysaccharide found in the roots of plants and certain other cells; glucose polymer
Glycogen
A complex, extensively branched polysaccharide made up of glucose monomers; serves as as energy-storage molecule in liver and muscle cells
Cellulose
A large polysaccharide composed of many glucose monomers linked into cable-like fibrils that provide structural support in plant cell walls
Hydrophilic
"water-loving"; pertaining to polar or charged molecules (or parts of molecules) that are soluble in water
Hydrophobic
"water-fearing"; pertaining to nonpolar molecules (or parts of molecules) that do not dissolve in water
Fat
A large lipid molecule made from an alcohol called glycerol and three fatty acids; a trigyceride; Most fats function as energy-storage
Triglyceride
A fat that consists of a molecule of glycerol linked to three fatty acid molecules
Unsaturated
Refers to fats and fatty acids whose hydrocarbon chains lack the maximum number of hydrogen atoms and therefore have one or more double covalent bonds. Unsaturated fats and fatty acids do not solidify at room temperature
Saturated
Pertaining to fats and fatty acids whose hydrocarbon chains contain the maximum number of hydrogens and therefore have no double covalent bonds. Saturates fats and fatty acids solidify at room temperature
Atherosclerosis
A cardiovascular disease where growths called plaques develop on inner artery walls narrowing their diameter
hydrogenation
The process of converting unsaturated fats to saturated fats by the addition of hydrogen
Trans fat
An unsaturated fatty cid produced by the partial hydrogenation of vegetable oils and present in hardened vegetable oils, most margarines, commercial baked foods and many fried foods
Steroids
Type of lipid whose carbon skeleton is in the form of four fused rings; three 6-sided rings and on 5-sided ring; examples include cholesterol, testosterone, estrogen
Anabolic steroids
Synthetic variant of the male hormone testosterone that mimics some of its side effects
Protein
A biological polymer constructed from amino acids monomers
Amino acid
An organic molecule containing a carboxyl group and an amino group; protein monomers
Enzyme
Protein that serves as a biological catalyst, changing the rate of a chemical reaction without being changed itself in the process
Peptide bond
Covalent linkage between two amino acid molecules in a polypeptide; formed by dehydration reaction
Polypeptide
A chain of amino acids linked by peptide bonds
Primary structure
First level of protein structure; specific sequence of amino acids making up a polypeptide
Denaturation
Process where a protein loses its specific conformation and thus its function; separation of strands in the DNA double helix; can be caused by changes in pH, salt concentration, high temperature
Nucleic acids
Polymer consisting of many nucleotide monomers
DNA
Double-stranded helical macromolecule consisting of nucleotide monomers with the sugar deoxyribose and nitrogen bases A,T,G,C
RNA
Nucleic acid consisting of nucleotide monomers with a ribose sugar and nitrogenous bases adenine, cytosine, guanine and uracil
Nucleotide
Organic monomer consisting of a five-carbon sugar covalently bonded to a nitrogenous base and a phosphate group; building blocks of nucleic acids
Nitrogenous base
A molecule that contains nitrogen and has the chemical properties of a base
Sugar-phosphate backbone
Alternating chain of sugar and phosphate attached to nitrogenous bases
Double helix
Native form of DNA; two polynucleotide chains held together with hydrogen bonds and wound into a spiral shape