Biology vocab chapter 3

Deoxyribonucleic Acid (DNA)

A molecule composed of deoxyribose nucleotides; contains the genetic information of all living cells.

Adenosine Triphosphate (ATP)

A molecule composed of the sugar ribose, the base adenine, and three phosphate groups.

Polysaccharide

A polymer of many monosaccharides.

Starch

A polysaccharide that is composed of branched or unbranched chains or glucose molecules; used by plants as a carbohydrate-storage molecule

Enzyme

A protein catalyst that speeds up the rate of specific biological reactions.

Secondary Structure

A repeated, regular structure assembled by protein chains held together by hydrogen bonds; for example, a helix.

Sugar

A simple carbohydrate molecule, either a monosaccharide or a disaccharide.

Monomer

A small organic molecule, several of which may be bonded together to form a chain called a polymer.

Nucleotide

A subunit of which nucleic acids are composed of; a phosphate group bonded to a sugar, which in turn is bonded to a nitrogen-containing base.

Glycerol

A three-carbon alcohol to which fatty acids are covalently bonded to make fats and oils.

Cellulose

An insoluble carbohydrate composed of glucose subunits.

Fatty Acid

An organic molecule composed of a long change of carbon atoms, with a carboxyl acid group at one end; may be saturated (all single bonds between C) or unsaturated (one or more double bonds).

Nucleic Acid

An organic molecule composed of nucleotide subunits. EX: DNA or RNA.

Chitin

Compound composed of chains of nitrogen-containing modified glucose molecules.

Organic

Describing a molecule that contains both C and H.

Inorganic

Describing any molecule that does not contain both carbon and hydrogen.

Polymer

Long chains of monomers.

Ribonucleic Acids (RNA)

Molecules composed of ribose nucleotides, each of which consists of a phosphate group, a sugar ribose, and one of the bases adenine, cytosine, guanine, uracil; involved in converting the information in DNA into protein.

Function Group

One of several groups of atoms commonly found in an organic molecule, including hydrogen, hydroxyl, amino, carboxyl, and phosphate groups, that determine the characteristics and chemical reactivity of the molecule.

Lipid

Organic molecule that contains large nonpolar regions composed solely of C and H, which make lipids hydrophobic and insoluble in water; includes oils, fats, waxes, phospholipids, and steroids.

Denatured

To disrupt the secondary and/or tertiary structure of a protein while leaving its amino acid sequence intact. Denatured proteins can no longer perform their biological functions.

Protein

Polymer of amino acids joined by peptide bonds.

Unsaturated

Referring to a fatty acid with fewer than the maximum number of hydrogen atoms bonded to a carbon backbone; a fatty acid with one or more double bonds in its carbon backbone.

Saturated

Referring to fatty acids with as many hydrogen atoms as possible bonded to a carbon backbone; a fatty acid with no double bonds in its carbon backbone.

Primary Structure

The amino acid sequence of a protein structure.

Monosaccharide

The basic molecular unit of all carbohydrates, normaly composed of a chain of C atoms bonded to hydrogen and hydroxyl groups.

Hydrolysis

The chemical reaction that breaks a covalent bond by adding water.

Teritary Structure

The complex 3-dimensional structure of a single peptide chain; held in place by disulfide bonds between cysteines.

Quaternary Structure

The complex 3-dimensional structure of protein composed of more than one peptide chain.

Peptide Bond

The covalent bond between two amino acids, joining them into a peptide or protein.

Disulfide Bridge

The covalent bond formed between the sulfur atoms of two cysteines in a protein; typically causes the protein to fold by brining otherwise distant parts of the protein closer together.

Amino Acid

The individual subunit of which proteins are made, composed of a carbon atom bonded to an amina group, a carboxyl group, a hydrogen atom, and a variable group of atoms denoted by the letter R.

Glucose

The most common monosaccharide; most polysaccharides, including cellulose, starch, and glycogen, are made of glucose subunits covalently bonded together

Disaccharide

A carbohydrate formed by the covalent bonding of two monosaccharides.

Peptide

A chain composed of two or amino acids linked together by a peptide bond.

Dehydration Synthesis

A chemical reaction in which two moleculess are joined by a covalent bond with the simultaneous removal of a hydrogen from one molecule and a hydroxyl from the other, forming water.

Helix

A coil, springlike secondary structure of a protein.

Carbohydrates

A compound composed of carbon, hydrogen, oxygen, with the appropriate chemical formula (CH2O); includes sugars and starches.

Sucrose

A disaccharide composed of glucose and fructose.

Lactose

A disaccharide composed of glucose and galactose.

Maltose

A disaccharide composed of two glucose molecules.

Pleated Sheet

A form of primary structure in which protein chains live side-by side, with hydrogen bonds holding adjacent chains together.

Wax

A lipid composed of fatty acids covalently bonded to long-chain alcohols.

Oil

A lipid composed of three fatty acids, some of which are unsaturated, covalently bonded to a glycerol; liquid at room temperature.

Triglyceride

A lipid composed of three fatty-acid molecules bonded to a single glycerol molecule.

Fat

A lipid composed of three saturated fatty acids covalent bonded to glycerol; solid at room temperature.

Steroid

A lipid consisting of four fused carbon rings, with various function groups attached.

Phospholipids

A lipid consisting of glycerol bonded to two fatty acids and one phosphate group.