CHAPTER 2.5 ORGANIC MOLECULES

Question 1

PROTEINS

Answer 1

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”.

Question 2

NUCLEIC ACIDS

Answer 2

A polymer of nucleotides that encodes and transmits genetic information.

Question 3

CARBOHYDRATES

Answer 3

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.

Question 4

LIPIDS

Answer 4

An organic molecule that stores energy, acts as a signaling molecule, and is a component of cell membranes.

Question 5

POLYMERS

Answer 5

A complex organic molecule made up of repeated simpler units connected by covalent bonds.

Question 6

AMINO ACIDS

Answer 6

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.

Question 7

NUCLEOTIDES

Answer 7

A constituent of nucleic acids, consisting of a 5-carbon sugar, a nitrogen-containing base, and one or more phosphate groups.

Question 8

SUGARS

Answer 8

The simplest carbohydrate molecule; also called a saccharide

Question 9

FATTY ACIDS

Answer 9

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.

Question 10

FUNCTIONAL GROUPS

Answer 10

Groups of one or more atoms that have particular chemical properties of their own, regardless of what they are attached to.

Question 11

ENZYMES

Answer 11

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.

Question 12

a (ALPHA) CARBON

Answer 12

The central carbon atom of each amino acid.

Question 13

AMINO GROUP

Answer 13

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.

Question 14

CARBOXYL GROUP

Answer 14

COOH; a carbon atom with a double bond to oxygen and a single bond to a hydroxyl group.

Question 15

R GROUP/SIDE CHAIN

Answer 15

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.

Question 16

PEPTIDE BOND

Answer 16

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.

Question 17

DEOXYRIBONUCLEIC ACID (DNA)

Answer 17

A linear polymer of four subunits; the information archive in all organisms.

Question 18

RIBONUCLEIC ACID (RNA)

Answer 18

A molecule chemically related to DNA that is synthesized by proteins from a DNA template.

Question 19

BASE

Answer 19

A nitrogen-containing compound that makes up part of a nucleotide.

Question 20

PYRIMIDINE

Answer 20

In nucleic acids, any of the bases, thymine, cytosine, and uracil, which have a single-ring structure.

Question 21

CYTOSINE (C)

Answer 21

A pyrimidine base.

Question 22

THYMINE (T)

Answer 22

A pyrimidine base.

Question 23

URACIL (U)

Answer 23

A pyrimidine base in RNA, where it replaces the thymine found in DNA.

Question 24

PURINE

Answer 24

In nucleic acids, either of the bases adenine and guanine, which have a double-ring structure.

Question 25

GUANINE (G)

Answer 25

A purine base.

Question 26

ADENINE (A)

Answer 26

A purine base.

Question 27

PHOSPHODIESTER BOND

Answer 27

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.

Question 28

DOUBLE HELIX

Answer 28

The structure formed by two strands of complementary nucleotides that coil around each other.

Question 29

COMPLEMENTARY

Answer 29

Describes the relationship of purine and pyrimidine bases, in which the base A only pairs with T, and G pairs only with C.

Question 30

SACCHARIDES

Answer 30

The simplest carbohydrate molecule, also called a *sugar*.

Question 31

MONOSACCHARIDE

Answer 31

A simple sugar.

Question 32

POLYSACCHARIDES

Answer 32

A polymer of simple sugars. Polysaccharides provide long-term energy storage or structural support.

Question 33

COMPLEX CARBOHYDRATES

Answer 33

A long, branched chain of monosaccharides.

Question 34

GLYOSIDIC BONDS

Answer 34

A covalent bon that attaches one monosaccharide to another.

Question 35

TRIACYLGLYCEROL

Answer 35

a lipid composed of a glycerol backbone and three fatty acids.

Question 36

GLYCEROL

Answer 36

A 3-carbon molecule with OH groups attached to each carbon.

Question 37

SATURATED

Answer 37

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.

Question 38

UNSATURATED

Answer 38

Describes fatty acids that contain carbon-carbon double bonds.

Question 39

VAN DER WAALS FORCE

Answer 39

The binding of temporarily polarized molecules because of the attraction of opposite charges.

Question 40

STEROIDS

Answer 40

A type of lipid.

Question 41

PHOSPHOLIPIDS

Answer 41

A type of lipid and a major component of the cell membrane.

Question 42

How is glucose different from galactose?

Question 43

What are essential functions of proteins, nucleic acids, carbohydrates, and lipids?

Question 44

How is diversity achieved in polymers? Use proteins as an example.