Chapter 5; Part 2 Vocab

Alpha Helix

a coiled region constituting one form of the secondary structure of proteins, arising from a specific pattern of hydrogen bonding between atoms of the polypeptide backbone (not the side chains).

Amino Acid

an organic molecule possessing both a carboxyl and an amino group. Amino acids serve as the monomers of polypeptides.

Beta Pleated Sheet

one form of the secondary structure of proteins in which the polypeptide chain folds back and forth. Two regions of the chain lie parallel to each other and are held together by hydrogen bonds between atoms of the polypeptide backbone (not the side chains).

Catalyst

a chemical agent that selectively increases the rate of a reaction without being consumed by the reaction

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. Denaturation occurs under extreme (noncellular) conditions of pH, salt concentration, or temperature

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.

Deoxyribose

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

Disulfide Bridge

a strong covalent bond formed when the sulfur of one cysteine monomer bonds to the sulfur of another cysteine monomer

Double Helix

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

Enzyme

a macromolecule serving as a catalyst, a chemical agent that increases the rate of a reaction without being consumed by the reaction. most enzymes are proteins.

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

Genomics

the systematic study of whole sets of genes (or other DNA) and their interactions within a species, as well as genome comparisons between species

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

Nucleotide

the building block of a nucleic acid, consisting of a five carbon sugar covalently bonded to a nitrogenous base and one to three phosphate groups

Peptide Bond

the covalent bond between the carboxyl group on one amino acid and the amino group of another, formed by a dehydration reaction

Polynucleotide

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

Polypeptide

a polymer of many amino acids linked together by peptide bonds

Primary Structure

the level of protein structure referring to the specific linear sequence of amino acids

Protein

a biologically functional molecule consisting of one or more polypeptides folded and coiled into a specific three-dimensional structure.

Quaternary Structure

the particular shape of a complex, aggregate protein, defined by the characteristic three-dimensional arrangement of its constituent subunits, each a polypeptide

Ribonucleic Acid

a type of nucleic acid consisting of a polynucleotide 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.

Ribose

the sugar component of RNA nucleotides

Secondary Structure

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).

Sickle-Cell Disease

a recessively inherited human blood disorder in which a single nucleotide change in the a-globin gene causes hemoglobin to aggregate, changing red blood cell shape and causing multiple symptoms in afflicted individuals

Tertiary Structure

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.

Transcription Factor

a regulatory proteins that binds to DNA and affects transcription of specific genes