Chapter 3.4: Proteins: Molecules with Diverse Structures and Functions

Question 1

What are the seven functions of proteins?

Answer 1

1. Enzyme catalysis
2. Defense
3. Transport
4. Support
5. Motion
6. Regulation
7. Storage

Question 2

Define amino acid

Answer 2

the subunit structure from which proteins are produced, consisting of a central carbon atom with a carboxyl group (-COOH), an amino group (-NH2), a hydrogen, and a side group (R group); only the side group differs from one amino acid to another

Question 3

What is the subunit structure from which proteins are produced, consisting of a central carbon atom with a carboxyl group (-COOH), an amino group (-NH2), a hydrogen, and a side group (R group); only the side group differs from one amino acid to another?

Answer 3

amino acid

Question 4

Define peptide bond

Answer 4

the type of bond that links amino acids together in proteins through a dehydration reaction

Question 5

What is the type of bond that links amino acids together in proteins through a dehydration reaction?

Answer 5

peptide bond

Question 6

Define polypeptide

Answer 6

a molecule consisting of many joined amino acids; not usually as complex as a protein

Question 7

What is a molecule consisting of many joined amino acids; not usually as complex as a protein?

Answer 7

polypeptide

Question 8

Define primary structure

Answer 8

the specific amino acid sequence of a protein

Question 9

What is the specific amino acid sequence of a protein?

Answer 9

primary structure

Question 10

Define secondary structure

Answer 10

the bonding interactions between -CO and -NH groups of the primary structure

Question 11

What is the bonding interactions between -CO and -NH groups of the primary structure?

Answer 11

secondary structure

Question 12

Define alpha helix

Answer 12

a form of secondary structure in proteins where the polypeptide chain is wound into a spiral due to interactions between amino and carboxyl groups in the peptide backbone

Question 13

What is a form of secondary structure in proteins where the polypeptide chain is wound into a spiral due to interactions between amino and carboxyl groups in the peptide backbone?

Answer 13

alpha helix

Question 14

Define beta sheet

Answer 14

a form of secondary structure in proteins where the polypeptide folds back on itself one or more times to form a planar structure stabilized by hydrogen bonding between amino and carboxyl groups in the peptide backbone

Question 15

What is a form of secondary structure in proteins where the polypeptide folds back on itself one or more times to form a planar structure stabilized by hydrogen bonding between amino and carboxyl groups in the peptide backbone?

Answer 15

beta sheet

Question 16

Define tertiary structure

Answer 16

the folded shape of a protein, produced by hydrophobic interactions with water, ionic and covalent bonding between side chains of different amino acids, and van der Waal’s forces; may be changed by denaturation so that the protein becomes inactive

Question 17

What is the folded shape of a protein, produced by hydrophobic interactions with water, ionic and covalent bonding between side chains of different amino acids, and van der Waal’s forces; may be changed by denaturation so that the protein becomes inactive?

Answer 17

tertiary structre

Question 18

Define quaternary structure

Answer 18

the structural level of a protein composed of more than one polypeptide chain, each of which has its own tertiary structure

Question 19

What is the structural level of a protein composed of more than one polypeptide chain, each of which has its own tertiary structure?

Answer 19

quaternary structure

Question 20

Define motif

Answer 20

a substructure in proteins that confers function and can be found in multiple proteins

Question 21

What is a substructure in proteins that confers function and can be found in multiple proteins?

Answer 21

motif

Question 22

Define domain (protein_

Answer 22

a distinct modular region of a protein that serves a particular function in the action of the protein

Question 23

What is a distinct modular region of a protein that serves a particular function in the action of the protein?

Answer 23

domain

Question 24

Define chaperone protein

Answer 24

a class of enzymes that help proteins fold into the correct configuration and can refold proteins that have been misfolded or denatured

Question 25

What is a class of enzymes that help proteins fold into the correct configuration and can refold proteins that have been misfolded or denatured?

Answer 25

chaperone protein

Question 26

Define denaturation

Answer 26

the loss of the native configuration of a protein or nucleic acid as a result of excessive heat, extremes of pH, chemical modification, or changes in solvent ionic strength or polarity that disrupt hydrophobic interactions; usually accompanied by loss of biological activity

Question 27

What is the loss of the native configuration of a protein or nucleic acid as a result of excessive heat, extremes of pH, chemical modification, or changes in solvent ionic strength or polarity that disrupt hydrophobic interactions; usually accompanied by loss of biological activity?

Answer 27

denaturation

Question 28

Define dissaciation

Answer 28

in proteins, the reversible separation of protein subunits from a quaternary structure without altering their tertiary structure

Question 29

What is in proteins, the reversible separation of protein subunits from a quaternary structure without altering their tertiary structure?

Answer 29

dissociation