Glossary of General Biological Terms from Chapter 26 Campbell Reece Biology Seventh Edition

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A long molecule consisting of many similar or identical monomers linked together.
The subunit that serves as the building block of a polymer.
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 protein synthesis and as the genome of some viruses.
A giant molecule formed by the joining of smaller molecules, usually by a condensation reaction. Polysaccharides, proteins, and nucleic acids are macromolecules.
A three-dimensional biological polymer constructed from a set of 20 different monomers called amino acids.
amino acid
An organic molecule possessing both carboxyl and amino groups. Amino acids serve as the monomers of proteins.
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.
The building block of a nucleic acid, consisting of a five-carbon sugar covalently bonded to a nitrogenous base and a phosphate group.
A protein serving as a catalyst, a chemical agent that changes the rate of a reaction without being consumed by the reaction.
A cell organelle constructed in the nucleolus and functioning as the site of protein synthesis in the cytoplasm; consists of rRNA and protein molecules, which make up two subunits.
natural selection
Differential success in the reproduction of different phenotypes resulting from the interaction of organisms with their environment. Evolution occurs when natural selection causes changes in relative frequencies of alleles in the gene pool.
The production of chemical compounds by reaction from simpler materials.
Two or more atoms held together by covalent bonds.
Having to do with compounds containing carbon and chiefly or ultimately of biological origin.
An aggregate of abiotically produced molecules surrounded by a membrane or membrane-like structure.
A whole formed by combining several different elements.
A skin-like structure that lines, connects, or covers a cell or part of the body.
An amino acid that functions as a CNS neurotransmitter.
amino group
A functional group that consists of a nitrogen atom bonded to two hydrogen atoms; can act as a base in solution, accepting a hydrogen ion and acquiring a charge of 1+.
An organic molecule consisting only of carbon and hydrogen.
carboxyl group
A functional group present in organic acids and consisting of a single carbon atom double-bonded to an oxygen atom and also bonded to a hydroxyl group.
hydroxl group
A functional group consisting of a hydrogen atom joined to an oxygen atom by a polar covalent bond. Molecules possessing this group are soluble in water and are called alcohols.
condensation reaction
A reaction in which two molecules become covalently bonded to each other through the loss of a small molecule, usually water; also called a dehydration reaction.
covalent bond
A type of strong chemical bond in which two atoms share one or more pairs of valence electrons.
A liquid that is a homogeneous mixture of two or more substances.
One of several formed bodies with specialized functions, suspended in the cytoplasm of eukaryotic cells.
(plural, nucleoli) A specialized structure in the nucleus, formed from various chromosomes and active in the synthesis of ribosomes.
(1) An atom’s central core, containing protons and neutrons. (2) The chromosome-containing organelle of a eukaryotic cell. (3) A cluster of neurons.
A threadlike, gene-carrying structure found in the nucleus. Each chromosome consists of one very long DNA molecule and associated proteins. See chromatin.
The complex of DNA and proteins that makes up a eukaryotic chromosome. When the cell is not dividing, chromatin exists as a mass of very long, thin fibers that are not visible with a light microscope.
The entire contents of the cell, exclusive of the nucleus, and bounded by the plasma membrane.
ribosomal RNA (rRNA)
The most abundant type of RNA, which together with proteins forms the structure of ribosomes. Ribosomes coordinate the sequential coupling of tRNA molecules to mRNA codons.
transfer RNA (tRNA)
An RNA molecule that functions as an interpreter between nucleic acid and protein language by picking up specific amino acids and recognizing the appropriate codons in the mRNA.
messenger RNA (mRNA)
A type of RNA, synthesized from DNA, that attaches to ribosomes in the cytoplasm and specifies the primary structure of a protein.
deoxyribonucleic acid (DNA)
A double-stranded, helical nucleic acid molecule capable of replicating and determining the inherited structure of a cell’s proteins.
A substance that increases the hydrogen ion concentration of a solution.
eukaryotic cell
A type of cell with a membrane-enclosed nucleus and membrane-enclosed organelles. Organisms with eukaryotic cells (protists, plants, fungi, and animals) are called eukaryotes.
The totality of an organism’s chemical reactions, consisting of catabolic and anabolic pathways.
A metabolic pathway that releases energy by breaking down complex molecules to simpler compounds.
A series of chemical reactions that either builds a complex molecule (anabolic pathway) or breaks down a complex molecule into simpler compounds (catabolic pathway).
A metabolic pathway that synthesizes a complex molecule from simpler compounds.
The scientific study of heredity and hereditary variation.
The transmission of traits from one generation to the next.
Differences between members of the same species.
Small membrane-bounded droplets that can form when lipids or other organic molecules are added to water.
One of a family of compounds, including fats, phospholipids, and steroids, that are insoluble in water.
Having an aversion to water; tending to coalesce and form droplets in water.
plasma membrane
The membrane at the boundary of every cell that acts as a selective barrier, thereby regulating the cell’s chemical composition.
selective permeability
A property of biological membranes that allows some substances to cross more easily than others.
The diffusion of water across a selectively permeable membrane.
A substance that is dissolved in a solution.
membrane potential
The charge difference between a cell’s cytoplasm and the extracellular fluid, due to the differential distribution of ions. Membrane potential affects the activity of excitable cells and the transmembrane movement of all charged substances.
A chemical agent that changes the rate of a reaction without being consumed by the reaction.
An enzyme-like RNA molecule that catalyzes reactions during RNA splicing.
RNA splicing
The removal of noncoding portions (introns) of the RNA molecule after initial synthesis.
A noncoding, intervening sequence within a eukaryotic gene.
The physical and physiological traits of an organism, which are determined by its genetic makeup.
The genetic makeup, or set of alleles, of an organism.
A change in the DNA of a gene, ultimately creating genetic diversity.
A discrete unit of hereditary information consisting of a specific nucleotide sequence in DNA (or RNA, in some viruses).
peptide bond
The covalent bond between two amino acid units, formed by a dehydration reaction.
The complete complement of an organism’s genes; an organism’s genetic material.
A polymer (chain) of many amino acids linked together by peptide bonds.

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