CHAPTER 2.5 ORGANIC MOLECULES Flashcards
PROTEINS
The key structural and functional molecules that do the work of the cell, providing structural support and catalyzing chemical reactions. Often referred to as “Polypeptides”.
NUCLEIC ACIDS
A polymer of nucleotides that encodes and transmits genetic information.
CARBOHYDRATES
An organic molecule containing C, H, and O atoms that provides a source of energy for metabolism and that forms the starting point for the synthesis of all other organic molecules.
LIPIDS
An organic molecule that stores energy, acts as a signaling molecule, and is a component of cell membranes.
POLYMERS
A complex organic molecule made up of repeated simpler units connected by covalent bonds.
AMINO ACIDS
An organic molecule containing a central carbon atom attached to a carboxyl group, an amino group, a hydrogen atom, and a side chain. Amino acids are the building blocks of proteins.
NUCLEOTIDES
A constituent of nucleic acids, consisting of a 5-carbon sugar, a nitrogen-containing base, and one or more phosphate groups.
SUGARS
The simplest carbohydrate molecule; also called a saccharide
FATTY ACIDS
A long chain of carbons attached to a carboxyl group; three fatty acid chains attached to glycerol form a triacylglycerol, a lipid used for energy storage.
FUNCTIONAL GROUPS
Groups of one or more atoms that have particular chemical properties of their own, regardless of what they are attached to.
ENZYMES
A protein that functions as a catalyst to accelerate the rate of a chemical reaction; enzymes are critical in determining which chemical reactions take place in a cell.
a (ALPHA) CARBON
The central carbon atom of each amino acid.
AMINO GROUP
NH2; a nitrogen atom bonded to two hydrogen atoms. An amino group is present covalently linked to the central carbon atom of an amino acid.
CARBOXYL GROUP
COOH; a carbon atom with a double bond to oxygen and a single bond to a hydroxyl group.
R GROUP/SIDE CHAIN
A chemical group attached to the central carbon atom of an amino acid, whose structure and composition determine the identity of the amino acid; also known as a side chain.
PEPTIDE BOND
A covalent bond that links the carbon atom in the carboxyl group of one amino acid to the nitrogen group in the amino group of another amino acid.
DEOXYRIBONUCLEIC ACID (DNA)
A linear polymer of four subunits; the information archive in all organisms.
RIBONUCLEIC ACID (RNA)
A molecule chemically related to DNA that is synthesized by proteins from a DNA template.
BASE
A nitrogen-containing compound that makes up part of a nucleotide.
PYRIMIDINE
In nucleic acids, any of the bases, thymine, cytosine, and uracil, which have a single-ring structure.
CYTOSINE (C)
A pyrimidine base.
THYMINE (T)
A pyrimidine base.
URACIL (U)
A pyrimidine base in RNA, where it replaces the thymine found in DNA.
PURINE
In nucleic acids, either of the bases adenine and guanine, which have a double-ring structure.
GUANINE (G)
A purine base.
ADENINE (A)
A purine base.
PHOSPHODIESTER BOND
A bond that forms when a phosphate group in one nucleotide is covalently joined to the sugar unit in another nucleotide. Phosphodiester bonds are relatively stable and form the backbone of a DNA strand.
DOUBLE HELIX
The structure formed by two strands of complementary nucleotides that coil around each other.
COMPLEMENTARY
Describes the relationship of purine and pyrimidine bases, in which the base A only pairs with T, and G pairs only with C.
SACCHARIDES
The simplest carbohydrate molecule, also called a sugar.
MONOSACCHARIDE
A simple sugar.
POLYSACCHARIDES
A polymer of simple sugars. Polysaccharides provide long-term energy storage or structural support.
COMPLEX CARBOHYDRATES
A long, branched chain of monosaccharides.
GLYOSIDIC BONDS
A covalent bon that attaches one monosaccharide to another.
TRIACYLGLYCEROL
a lipid composed of a glycerol backbone and three fatty acids.
GLYCEROL
A 3-carbon molecule with OH groups attached to each carbon.
SATURATED
Describes fatty acids that do not contain double bonds; the maximum number of hydrogen atoms is attached to each carbon atom, “saturating” the carbons with hydrogen atoms.
UNSATURATED
Describes fatty acids that contain carbon-carbon double bonds.
VAN DER WAALS FORCE
The binding of temporarily polarized molecules because of the attraction of opposite charges.
STEROIDS
A type of lipid.
PHOSPHOLIPIDS
A type of lipid and a major component of the cell membrane.
How is glucose different from galactose?
What are essential functions of proteins, nucleic acids, carbohydrates, and lipids?
How is diversity achieved in polymers? Use proteins as an example.
