Chapter 3

Question 1

What is an alpha-helix structure?

Answer 1

A type of secondary protein structure formed by folding the polypeptide into a helix shape with hydrogen bonds stabilizing the structure.

Question 2

What is an amino acid?

Answer 2

A protein’s monomer; has a central carbon or alpha carbon to which an amino group, a carboxyl group, a hydrogen, and an R group or side chain is attached. The R group is different for all 20 common amino acids.

Question 3

What is a beta-pleated sheet?

Answer 3

A secondary structure in proteins in which hydrogen bonding forms ‘pleats’ between atoms on the polypeptide chain’s backbone.

Question 4

What is a biological macromolecule?

Answer 4

A large molecule necessary for life that is built from smaller organic molecules.

Question 5

What is a carbohydrate?

Answer 5

A biological macromolecule in which the ratio of carbon to hydrogen and to oxygen is 1:2:1; carbohydrates serve as energy sources and structural support in cells and form arthropods’ cellular exoskeleton.

Question 6

What is cellulose?

Answer 6

A polysaccharide that comprises the plants’ cell wall; provides structural support to the cell.

Question 7

What is a chaperone?

Answer 7

A protein that helps nascent protein in the folding process.

Question 8

What is chitin?

Answer 8

A type of carbohydrate that forms the outer skeleton of all arthropods, including crustaceans and insects; it also forms fungi cell walls.

Question 9

What is dehydration synthesis?

Answer 9

A reaction that links monomer molecules, releasing a water molecule for each bond formed.

Question 10

What is denaturation?

Answer 10

Loss of shape in a protein as a result of changes in temperature, pH, or chemical exposure.

Question 11

What is deoxyribonucleic acid (DNA)?

Answer 11

A double-helical molecule that carries the cell’s hereditary information.

Question 12

What is a disaccharide?

Answer 12

Two sugar monomers that a glycosidic bond links.

Question 13

What is an enzyme?

Answer 13

A catalyst in a biochemical reaction that is usually a complex or conjugated protein.

Question 14

What is glycogen?

Answer 14

Storage carbohydrate in animals.

Question 15

What is a glycosidic bond?

Answer 15

A bond formed by a dehydration reaction between two monosaccharides with the elimination of a water molecule.

Question 16

What is a hormone?

Answer 16

A chemical signaling molecule, usually protein or steroid, secreted by endocrine cells that act to control or regulate specific physiological processes.

Question 17

What is hydrolysis?

Answer 17

A reaction that causes the breakdown of larger molecules into smaller molecules by utilizing water.

Question 18

What is a lipid?

Answer 18

A macromolecule that is nonpolar and insoluble in water.

Question 19

What is messenger RNA (mRNA)?

Answer 19

RNA that carries information from DNA to ribosomes during protein synthesis.

Question 20

What is a monomer?

Answer 20

The smallest unit of larger molecules that are polymers.

Question 21

What is a monosaccharide?

Answer 21

A single unit or monomer of carbohydrates.

Question 22

What is a nucleic acid?

Answer 22

A biological macromolecule that carries the cell’s genetic blueprint and carries instructions for the cell’s functioning.

Question 23

What is a nucleotide?

Answer 23

A monomer of nucleic acids; contains a pentose sugar, one or more phosphate groups, and a nitrogenous base.

Question 24

What is an omega fat?

Answer 24

A type of polyunsaturated fat that the body requires; numbering the carbon omega starts from the methyl end or the end that is farthest from the carboxylic end.

Question 25

What is a peptide bond?

Answer 25

A bond formed between two amino acids by a dehydration reaction.

Question 26

What is a phosphodiester bond?

Answer 26

A covalent chemical bond that holds together the polynucleotide chains with a phosphate group linking neighboring nucleotides' two pentose sugars.

Question 27

What is a phospholipid?

Answer 27

Membranes' major constituent; comprised of two fatty acids and a phosphate-containing group attached to a glycerol backbone.

Question 28

What is a polymer?

Answer 28

A chain of monomer residues that covalent bonds link; polymerization is the process of polymer formation from monomers by condensation.

Question 29

What is a polynucleotide?

Answer 29

A long chain of nucleotides.

Question 30

What is a polypeptide?

Answer 30

A long chain of amino acids that peptide bonds link.

Question 31

What is a polysaccharide?

Answer 31

A long chain of monosaccharides; may be branched or unbranched.

Question 32

What is primary structure?

Answer 32

The linear sequence of amino acids in a protein.

Question 33

What is a protein?

Answer 33

A biological macromolecule comprised of one or more amino acid chains.

Question 34

What is a purine?

Answer 34

A type of nitrogenous base in DNA and RNA; adenine and guanine are purines.

Question 35

What is a pyrimidine?

Answer 35

A type of nitrogenous base in DNA and RNA; cytosine, thymine, and uracil are pyrimidines.

Question 36

What is quaternary structure?

Answer 36

The association of discrete polypeptide subunits in a protein.

Question 37

What is ribonucleic acid (RNA)?

Answer 37

A single-stranded, often internally base paired, molecule that is involved in protein synthesis.

Question 38

What is ribosomal RNA (rRNA)?

Answer 38

RNA that ensures the proper alignment of the mRNA and the ribosomes during protein synthesis and catalyzes forming the peptide linkage.

Question 39

What is a saturated fatty acid?

Answer 39

A long-chain hydrocarbon with single covalent bonds in the carbon chain; the number of hydrogen atoms attached to the carbon skeleton is maximized.

Question 40

What is secondary structure?

Answer 40

The regular structure that proteins form by intramolecular hydrogen bonding between the oxygen atom of one amino acid residue and the hydrogen attached to the nitrogen atom of another amino acid residue.

Question 41

What is starch?

Answer 41

Storage carbohydrate in plants.

Question 42

What is a steroid?

Answer 42

A type of lipid comprised of four fused hydrocarbon rings forming a planar structure.

Question 43

What is tertiary structure?

Answer 43

A protein's three-dimensional conformation, including interactions between secondary structural elements; formed from interactions between amino acid side chains.

Question 44

What is trans fat?

Answer 44

Fat formed artificially by hydrogenating oils, leading to a different arrangement of double bond(s) than those in naturally occurring lipids.

Question 45

What is transcription?

Answer 45

The process through which messenger RNA forms on a template of DNA.

Question 46

What is transfer RNA (tRNA)?

Answer 46

RNA that carries activated amino acids to the site of protein synthesis on the ribosome.

Question 47

What is translation?

Answer 47

The process through which RNA directs the protein's formation.

Question 48

What is triacylglycerol (also, triglyceride)?

Answer 48

A fat molecule; consists of three fatty acids linked to a glycerol molecule.

Question 49

What is an unsaturated fatty acid?

Answer 49

A long-chain hydrocarbon that has one or more double bonds in the hydrocarbon chain.

Question 50

What is wax?

Answer 50

A lipid comprised of a long-chain fatty acid that is esterified to a long-chain alcohol; serves as a protective coating on some feathers, aquatic mammal fur, and leaves.