Chapter 3: The Chemistry of Life: Organic Compounds

Enantiomers

________ are isomers that are mirror images of each other.

NAD

________* is also involved in energy metabolism through its role as an electron (hydrogen) acceptor in biological oxidation and reduction reactions.

Monoacylglycerols

________ and diacylglycerols contain one and two fatty acids, respectively.

Proteins

________ are complex macromolecules made of simpler sub- units, called amino acids, joined by peptide bonds.

ATP

________ (adenosine triphosphate) is a nucleotide of special significance in energy metabolism.

Carbohydrates

________ contain carbon, hydrogen, and oxygen in a ratio of approximately one carbon to two hydrogens to one oxygen.

Hydroxyl

________ and carbonyl groups are polar.

Monosaccharides

________ are simple sugars such as glucose, fructose and ribose.

RNA

________ contains the sugar ribose and the bases guanine, cytosine, adenine, and uracil.

DNA

________ contains the sugar deoxyribose and the bases guanine, cytosine, adenine, and thymine.

fatty acids

A phospholipid consists of a glycerol molecule attached at one end to two ________ and at the other end to a phosphate group linked to an organic compound such as choline.

Lipids

________ have a greasy or oily consistency and are relatively insoluble in water.

molecular subunit

Each ________, called a nucleotide, consists of a pentose, a phosphate, and a nitrogenous base.

Phospholipids

________ are structural components of cell membranes.

Partial charges

________ on atoms at opposite ends of a bond are responsible for the polar property of a functional group.

Carboxyl

________ and phosphate groups are acidic, becoming negatively charged when they release hydrogen ions.

simple sugar

Most carbohydrates are polysaccharides, long chains of repeating units of a(n) ________.

nucleic acids DNA

The ________ and RNA, composed of long chains of nucleotide subunits, store and transfer information that specifies the sequence of amino acids in proteins and ultimately the structure and function of the organism.

main storage

Triacylglycerol, the ________ form of fat in organisms, consists of a molecule of glycerol combined with three fatty acids.

Nucleic Acids

________ (C, H, O, N, P): Backbone composed of alternating pentose and phosphate groups, from which nitrogenous bases project.

Large polymers

________ such as polysaccharides, proteins, and DNA are referred to as macromolecules.

two ring

Nucleotides are composed of a(n) ________ purine or one- ring pyrimidine nitrogenous base, a five- carbon sugar (ribose or deoxyribose), and one or more phosphate groups.

Hydrogen bonds

________, ionic bonds, hydrophobic interactions, and disulfide bridges contribute to tertiary structure.

Steroid molecules

________ contain carbon atoms arranged in four attached rings.

Tertiary structure

________ is the overall shape of the polypeptide chains, as dictated by chemical properties and interactions of the side chains of specific amino acids.

Isomers

________ are compounds with the same molecular formula but different structures.

Amino group

The ________ is basic, becoming positively charged when it accepts a hydrogen ion.

carbon atom

Each ________ forms four covalent bonds with up to four other atoms; these bonds are single, double, or triple bonds.

cell walls of plants

The ________ are composed mainly of the structural polysaccharide cellulose.

longer chain of amino acids

A(n) ________ is a polypeptide.

Monoacylglycerol

________ contains one fatty acid; diacylglycerol contains two fatty acids; triacylglycerol contains three fatty acids If fatty acids contain double carbon- to- carbon linkages (C== C), they are unsaturated; otherwise, they are saturated.

Fatty acid

A(n) ________ can be either saturated with hydrogen or unsaturated.

Carbohydrates

________ (C, H, O): Contain approximately 1 C: 2 H: 1 O (but make allowance for loss of oxygen when sugar units as nucleic acids and glycoproteins are linked)

Proteins

________ are the most versatile class of biological molecules, serving a variety of functions, such as enzymes, structural components, and cell regulators.

DNA

________ forms a double helix.

Lipids

________ are composed mainly of hydrocarbon- containing regions, with few oxygen- containing (polar or ionic) functional groups.

Carbon atoms

________ form straight or branched chains, or join into rings.

Proteins

________ are composed of various linear sequences of 20 different amino acids.

Carbohydrates

________ are typically stored in plants as the polysaccharide starch and in animals as the polysaccharide glycogen.

Amino acids vary in their side chains, which dictate their chemical properties

nonpolar, polar, acidic, or basic

Proteins (C, H, O, N, usually S)

 One or more polypeptides (chains of amino acids) coiled pr folded in characteristic shapes

Nucleic Acids (C, H, O, N, P)

 Backbone composed of alternating pentose and phosphate groups, from which nitrogenous bases project