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Campbell Biology Chapter 5

The Structure and Function of Large Biological Molecules
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macromolecules
A giant molecule in a living organism formed by the joining of smaller molecules: a protein, carbohydrate, or nucleic acid.
polymer
a long molecule consisting of many similar or identical building blocks linked by covalent bonds
monomers
repeating units that serve as the building blocks of a polymer
enzymes
specialized macromolecules that speed up chemical reactions in cells
dehydration reaction
A chemical reaction in which two molecules covalently bond to each other with the removal of a water molecule.
hydrolysis
A chemical reaction that breaks bonds between two molecules by the addition of water; functions in disassembly of polymers to monomers.
carbohydrates
Organic compounds composed of carbon, hydrogen, and oxygen in a ratio of one carbon atom to two hydrogen atoms to one oxygen atom. They exist as monosaccharides, disaccharides, and polysaccharides.
monosaccharides
The simplest carbohydrate, active alone or serving as a monomer for disaccharides and polysaccharides. Also known as simple sugars, the molecular formulas of are generally some multiple of CH2O.
aldose
a monosaccharide sugar that contains the aldehyde group or is hemiacetal
ketose
any monosaccharide sugar that contains a ketone group or its hemiacetal
disaccharide
any of a variety of carbohydrates that yield two monosaccharide molecules on complete hydrolysis
glycosidic linkage
A covalent bond formed between two monosaccharides by a dehydration reaction. - sucrose, glucose
polysaccharides
macromolecules, polymers with a few hundred to a few thousand monosaccharides joined by glycosidic linkages - starch, cellulose
starch
A storage polysaccharide in plants consisting entirely of glucose.
glycogen
an extensively branched glucose storage polysaccharide found in the liver and muscle of animals; the animal equivalent of starch
cellulose
a structural polysaccharide of plant cell walls, consisting of glucose monomers joined by β glycosidic linkages.
chitin
complex carbohydrate that makes up the cell walls of fungi; also found in the external skeletons of arthropods
lipids
Large, non-polar organic molecules which do not dissolve in water. - fats, phospholipids, steroids, waxes.
fat
organic compound consisting of a three-carbon backbone (glycerol) attached to three fatty acids
fatty acids
A long carbon chain carboxylic acid. Fatty acids vary in length and in the number and location of double bonds; three fatty acids linked to a glycerol molecule form fat.
triacylglycerol
three fatty acids linked to one glycerol molecule; also called a fat or a triglyceride.
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 that can attach to the carbon skeleton.
unsaturated fatty acid
a fatty acid whose carbon chain can absorb additional hydrogen atoms
trans fats
made by hydrogenating unsaturated fats, considered "bad fats"; can lead to clogged arteries
phospholipids
A molecule that is a constituent of the inner bilayer of biological membranes, having a polar, hydrophilic head and a nonpolar, hydrophobic tail.
steroids
lipids characterized by a carbon skeleton consisting of four fused rings
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.
catalyst
substance that speeds up the rate of a chemical reaction
polypeptide
hundreds of amino acids bonded together in a long chain, sequence of amino acids determines protein
protein
A functional biological molecule consisting of one or more polypeptides folded and coiled into a specific three-dimensional structure.
enzymatic proteins
selective acceleration of chemical reactions
ex. digestive enzymes
storage proteins
Function: storage of amino acids (ex - casein in milk, ovalbumin in egg whites)
defensive proteins
protection against disease
ex. antibodies
transport proteins
Proteins that combine with other substances and acts as a mode of transport through the body (e.g. albumin, hemoglobin, transferrin, and vitamin d-binding protein).
hormonal proteins
Function: coordination of an organism's activities.
(ex - insulin causes other tissues to take up glucose)
receptor proteins
Function: response of cell to chemical stimuli (ex - nerve cell receptors detect signaling molecules)
motor proteins
protein that interacts with cytoskeletal elements and other cell components, producing movement of the whole cell or parts of the cell - cilia, flagella, actin and myosin proteins
structural proteins
very important in binding structures together and providing strength in certain body tissues, Keratins, collagens, and cytoskeleton, Proteins that are important for holding cells and organisms together, such as the proteins that make up the cell membrane, muscles, tendons, and blood
amino acid
monomer that makes up proteins; contains carboxyl and amino functional groups - 20
peptide bond
the covalent bond between two amino acid units in a polypeptide, formed by a dehydration reaction
primary structure
The first level of protein structure; the specific sequence of amino acids making up a polypeptide chain.
secondary structure
Alpha helix and beta pleated sheet formed through formation of hydrogen bonds., The second level of protein structure; the regular local patterns of coils or folds of a polypeptide chain.
tertiary structure
the third level of protein structure; the overall, three-dimensional shape of a polypeptide due to interactions of the R groups of the amino acids making up the chain
quaternary structure
The fourth level of protein structure; the shape resulting from the association of two or more polypeptide subunits
sickle-cell disease
A human genetic disease caused by a recessive allele that results in the substitution of a single amino acid in a globin polypeptide that is part of the hemoglobin protein; characterized by deformed red blood cells (due to protein aggregation) that can
denaturation
For proteins, a process in which a protein unravels and loses its native conformation, thereby becoming biologically inactive. For DNA, the separation of the two strands of the double helix. Denaturation occurs under extreme conditions of pH, salt concentration, and temperature.
chaperonins
Protein molecules that assist the proper folding of other proteins; they work by keeping the new polypeptide segregated from bad influences in the cytoplasmic environment while it folds spontaneously
X-ray crystallography
a laboratory technique that is used to determine the three-dimensional structure of biological molecules such as proteins and DNA
nuclear magnetic resonance spectroscopy
Technique used for determining the three-dimensional structure of a protein. It is performed in solution without requiring a protein crystal.
gene
sequence of DNA that codes for a protein and thus determines a trait
nucleic acids
Polymers assembled from individual nucleotides; used to store and transmit hereditary, or genetic, information; the two kinds of nucleic acids are ribonucleic acid (RNA) and deoxyribonucleic acid (DNA)
deoxyribonucleic acid
A nucleic acid found in all living cells which carries the organism's hereditary information
ribonucleic acid
A type of nucleic acid consisting 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 and as the genome of some viruses.
polynucleotides
A polymer 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
nucleotides
monomer of nucleic acids made up of a 5-carbon sugar, a phosphate group, and a nitrogenous base
nucleoside
portion of nucleotide without phosphate group
pyramidine
Six-membered ring of carbon and nitrogen; includes cytosine (C), thymine (T), and uracil (U)
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)
deoxyribose
a five carbon sugar that is a component of DNA nucleotides
ribose
a pentose sugar important as a component of ribonucleic acid
double helix
a pair of parallel helices intertwined about a common axis, esp. that in the structure of the DNA molecule
antiparallel
The opposite arrangement of the sugar-phosphate backbones in a DNA double helix.