The Structure and Function of Large Biological Mol

Gene

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

Nucleic Acids

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.

Deoxyribonucleic Acid (DNA)

A double-stranded, helical nucleic acid molecule consisting of nucleotide monomers with a deoxyribose sugar and the nitrogenous bases adenine (A), cytosine (C), guanine (G), and thymine (T); capable o

Ribonucleic Acid (RNA)

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 pro

Polynucleotides

A polymer consisting of many nucleotide monomers in a chain; nucleotides can be those of DNA or RNA.

Nucleotides

The building block of a nucleic acid, consisting of a five-carbon sugar covalently bonded to a nitrogenous base and a phosphate group.

Pyrimidine

One of two types of nitrogenous bases found in nucleotides, charaterized by a six-membered ring. Cytosine (C), Uracil (U), and Thymine (T)

Purines

One of two types of nitrogenous bases found in necleotide, characterized by a six-membered ring fused to a five-membered ring. Adenine (A) and Guanine (G)

Ribose

The sugar component of RNA necleotides.

Deoxyribose

The sugar component of DNA necleotides, having one fewer hydroxyl group than ribose, the sugar component of RNA nucleotides.

Double Helix

The form of native DNA, referring to its two adjacent antiparallel polynucleotide strands wound around an imaginary axis ito a spiral shape.

Antiparallel

The opposite arrangement of the sugar-phosphate backbones in a DNA double helix.

Enzymatic Proteins

Function: selective acceleration of chemical reactions. Digestive enzymes catalyze the hydrolysis of the polymers in food.

Structural Proteins

Function: support. Insects and spiders use silk fibers to make their cocoons and webs, respectively. Collagen and elastin provide a fibrous framework in animal connective tissues. Keratin is the prote

Storage Proteins

Function: storage of amino acids. Ovalumin is the protein of egg white, used as an amino acid source for the developing embryo. Casein, the protein of milk, is the major source of amino acids for baby

Transport Proteins

Function: transport of other substances. Hemoglobin, the iron-containing protein of vertebrate blood, transports oxygen from the lungs to other parts of the body. Other proteins transport molecules ac

Hormonal Proteins

Function: coordination of an organism's activities. Insulin, a hormone secreted by the pancreas, helps regulate the concentration of sugar in teh blood of vertebrates.

Receptor Proteins

Function: response of cell to chemical stimuli. Receptors build into the membrane of a nerve cell detect chemical signals released by other nerve cells.

Contractile and Motor Proteins

Function: movement. Actin and myosin are responsible for the contraction of muscles. Other proteins are responsible for the undulations of organelles called cilia and flagella.

Defensive Proteins

Function: protection against disease. Antibodies combat bacteria and viruses.

How to Make an Amino Acid Polymer

When two amino acids are positioned so that the carboxyl group of one is adjacent to the amino group of the other, they can become joined by a dehydration reaction, with the removal of a water molecule

Frederick Sanger

The pioneer in determining the amino acid sequence of proteins.

Roger Kornberg

Awarded the Nobel Prize in Chemistry for using X-ray crystallography to determine the 3-D shape of RNA polymerase II, which binds to the DNA double helix and synthesizes RNA.