Bio Chapter 3 Vocab

Alpha helix

A spiral shape constituting one form of the secondary structure of proteins, arising from a specific pattern of hydrogen bonding.

Amino acid

An organic molecule possessing both carboxyl and amino groups. Amino acids serve as the monomers of polypeptides.

Amino group

A chemical group consisting 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+.

Antiparallel

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

ATP

An adenine-containing nucleoside triphosphate that releases free energy when its phosphate bonds are hydrolyzed. This energy is used to drive endergonic reactions in cells.

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.

Carbohydrate

A sugar (monosaccharide) or one of its dimers (disaccharides) or polymers (polysaccharides).

Carboxyl group

A chemical 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.

Cellulose

A structural polysaccharide of plant cell walls, consisting of glucose monomers joined by β glycosidic linkages.

Chitin

A structural polysaccharide, consisting of amino sugar monomers, found in many fungal cell walls and in the exoskeletons of all arthropods.

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, such as hormones.

Dehydration Reaction

A chemical reaction in which two molecules covalently bond to each other with the removal of a water molecule.

Denaturation

In proteins, a process in which a protein unravels and loses its native shape, thereby becoming biologically inactive; in DNA, the separation of the two strands of the double helix; occurs under extreme (noncellular) conditions of pH, salt concentration, and temperature.

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 of replicating and determining the inherited structure of a cell's proteins.

Disaccharide

A double sugar, consisting of two monosaccharides joined by a glycosidic linkage formed during dehydration synthesis.

Disulfide Bridge

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

Enzyme

A macromolecule serving as a catalyst, a chemical agent that changes the rate of a reaction without being consumed by the reaction.

Fatty Acid

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 a fat molecule, also known as a triacylglycerol or triglyceride.

Functional Group

A specific configuration of atoms commonly attached to the carbon skeletons of organic molecules and usually involved in chemical reactions.

Glycogen

An extensively branded glucose storage polysaccharide found in the liver and muscle of animals: The animal equivalent of starch

Hydrocarbon

An organic molecule consisting only of carbon and hydrogen

Hydrolysis

A chemical processes that lyses or splits molecules by the addition of water, functioning in disassembly of polymers to monomers.

Hydrophobic Interaction

A type of weak chemical bond formed when molecules that do not mix with water coalesce to exclude water.

Hydroxyl group

A chemical group consisting of an oxygen atom joined to a hydrogen atom. Molecules possessing this group are soluble in water and are called alcohols.

Isomer

One of several compounds with the same molecular formula but different structures and therefore different properties

Lipid

One of a group compounds, including fats, phospholipids, and steroids, that mix poorly if at all with water.

Macromolecule

A giant molecule formed by the joining of smaller molecules, usually by a condensation reaction. Polysaccharides, proteins, and nucleic acids are examples.

Monomer

The subunit that serves as the building block of polymer

Monosaccharide

The simplest carbohydrate, active alone or serving as a monomer for disaccharides and polysaccharides.

Nucleic Acid

A polymer (polynucleotide) consisting of many nucleotide monomers; serves as a blueprint for proteins and through the actions of portends for all cellular activities. The 2 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 a phosphate group.

Organic Chemistry

The study of carbon compounds (organic compounds).

Peptide bond

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

Phosphate Group

A chemical group consisting of a phosphorus atom bonded to four oxygen atoms; important in energy transfer.

Polymer

A long molecule consisting of many similar or identical monomers linked together.

Polynucleotide

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

Polysaccharide

A polymer of many monosaccharides, formed by dehydration reactions.

Primary Structure

The level of protein structure referring to the specific sequence of amino acids.

Protein

A functional biological 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.

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, gene regulation, and as the genome of some viruses.

Saturate Fatty Acids

A fatty acid in which all carbons in the hydrocarbon tail are connected by single bonds, thus maximizing the number of hydrogen atoms that are attached to the carbon skeleton.

Secondary Structure

The localized, repetitive coiling or folding of the polypeptide backbone of a protein due to hydrogen bond formation between constituents of the backbone.

Starch

A storage polysaccharide in plants, consisting entirely of glucose monomers joined by glycosidic linkages.

Steroid

a type of lipid characterized by a carbon skeleton consisting of four rings with various chemical groups attached.

Tertiary Structure

Irregular contortions of a protein molecule due to interactions of side chains involved in hydrophobic interactions, ionic bonds, hydrogen bonds, and disulfide bridges.

Trans Fat

An unsaturated fat containing one or more trans double bonds.

Triacylglycerol

Three fatty acids linked to one glycerol molecule; also called a fat or a triglyceride.

Unsaturated fatty acid

A fatty acid possessing one or more double bonds between the carbons in the hydrocarbon tail. Such bonding reduces the number of hydrogen atoms attached to the carbon skeleton.