Module 5: 3D Structure of Proteins

Question 1

What function of proteins is the following: proteins that direct and
accelerate thousands of
biochemical reactions in such
processes as digestion, energy
capture, and biosynthesis

Answer 1

Catalysis

Question 2

What function of proteins is the following: provide protection and support

Answer 2

Structure

Question 3

What function of proteins is the following: involved in all cell movement

Answer 3

Movement

Question 4

What function of proteins is the following: proteins are protective

Answer 4

Defense

Question 5

What function of proteins is the following: binding a hormone to its target cell changes cellular function

Answer 5

Regulation

Question 6

What function of proteins is the following: carrier of molecules or ions across membranes or between cells

Answer 6

Transport

Question 7

At least how many amino peptide residues are present in a protein

Answer 7

40

Question 8

a protein in which only one peptide chain is present.

Answer 8

Monomeric protein

Question 9

a protein in which more than one peptide chain is present- The peptide chains present are called protein subunits

Answer 9

A multimeric protein

Question 10

•Only amino acid residues are present
•More than one protein subunit may be present, but all subunits contain only amino acids

Answer 10

Simple protein

Question 11

•Has one or more nonamino-acid entities present in its structure in addition to one or more peptide chains

Answer 11

Conjugated protein

Question 12

The non-amino acid components present in a conjugated protein are called

Answer 12

Prosthetic group

Question 13

The spatial arrangement of atoms in a protein or any part of a protein is called its

Answer 13

Conformation

Question 14

The functional conformation of the protein is called its

Answer 14

Native state

Question 15

The native state is usually the conformation that is

Answer 15

The most thermodynamically stable

Question 16

A protein’s conformation is stabilized largely by multiple contributing weak non-covalent interactions. What are those interactions?

Answer 16

Hydrogen Bonds, Ionic Interactions, Van der Waals interactions, and the Hydrophobic Effect

Question 17

Primary protein structure always involves more than just the numbers and kinds of amino acid present. It also involves _______

Answer 17

The order of attachment of the amino acids to each other through peptide bonds

Question 18

What is the preferred orientation of proteins

Answer 18

Trans isomer orientation

Question 19

What is the preferred orientation of proteins

Answer 19

Trans isomer orientation

Question 20

The O atom of the C=O group and the H atom of the N-H group are positioned _____ to each other

Answer 20

Trans

Question 21

the hormone that regulates blood-glucose levels, was the first protein for which primary structure was determined

Answer 21

Insulin

Question 22

Sequencing of insulin’s 51 amino acids was completed in

Answer 22

1953 by British biochemist Frederick Sanger

Question 23

There are ________ sequences possible for the 51 amino acid found in insulin.

Answer 23

1.55 x 10^66

Question 24

How many amino acids are found in insulin

Answer 24

51

Question 25

What secrets insulin and where is it secreted

Answer 25

Secreted by the β-cells in the Islets of Langerhans

Question 26

What are the two chains found in insulin and how many amino acids does each chain contain?

Answer 26

The chains are chain A with 21 amino acids and chain B with 30 amino acids.

Question 27

What are the kinds of bridges formed in insulin?

Answer 27

Two disulfide bridges between A and B and an internal disulfide bridge in A

Question 28

Name 3 functions of Insulin in the body

Answer 28

• Functions in the regulation of blood glucose levels. • It assists the entry of blood glucose into cells by interacting with receptors on cell membranes. • It also helps facilitate the conversion of glucose to the storage polysaccharide glycogen

Question 29

The amino acids present in a protein, whose order is the primary structure of the protein, are linked to each other by

Answer 29

Peptide linkages

Question 30

Attached to the backbone, at the CH locations are various

Answer 30

amino acid R groups

Question 31

The ______ and ______ atoms of a protein backbone are arranged in a “zigzag” manner.

Answer 31

carbon and nitrogen

Question 32

The carbons of adjacent amino acid residues are separated by three covalent bonds, arranged as

Answer 32

Cα – C – N – Cα.

Question 33

the six atoms that are part of the peptide group of a peptide bond are ________

Answer 33

coplanar

Question 34

The arrangement in space by the backbone portion of a protein

Answer 34

Secondary structure

Question 35

the two most common types of secondary structure

Answer 35

alpha helix and beta pleated sheet

Question 36

type of interaction responsible for both types of secondary structure

Answer 36

hydrogen bonding between a carbonyl oxygen atom and the hydrogen atom of an amino group of another peptide linkage

Question 37

were aware of the importance of hydrogen bonds in orienting polar chemical groups

Answer 37

Pauling and Corey

Question 38

A protein secondary structure in which a single protein chain adopts a shape that resembles a coiled spring (helix), with the coil configuration maintained by hydrogen bonds

Answer 38

the alpha helix

Question 39

The twist of the helix forms a _______ spiral.

Answer 39

right handed or clockwise

Question 40

How many amino acids per turn does an alpha helix have

Answer 40

3.6 residues

Question 41

What is the pitch of a alpha helix

Answer 41

5.4 A

Question 42

why haven't extended left handed alpha helices been observed in proteins

Answer 42

they are theoretically less stable

Question 43

Which of the following will not form a helix: a.) a polypeptide chain has a long block of glutamic acid b.) Many adjacent Lys and/or Arg residues c.) The bulk and shape of asparagine (Asn), serine (Ser), Theonine (Thr), and cysteine (Cys) residues d.) all of the above

Answer 43

All of the above