In the α helix the hydrogen bonds: a. are roughly parallel to the axis of the helix. b. are roughly perpendicular to the axis of the helix. c. occur mainly between electronegative atoms of the R groups. d. occur only between some of the amino acids of the helix. e. occur only near the amino and carboxyl termini of the helix.

The following is a segment of the primary structure of an α-helix:N terminus.......– amino acid 1 – amino acid 2 – amino acid 3 – amino acid 4 – amino acid 5 – amino acid 6 – amino acid 7 – ......Which amino acid residue forms a hydrogen bond with the backbone of amino acid 3 to stabilize the helix?   a. Amino Acid 1   b. Amino Acid 3   c. Amino Acid 5   d. Amino Acid 7

A structural difference between uracil and cystosine is: A. At C-4 cytosine has an amino group, while uracil as an oxo group B. At C-6 cytosine has an amino group, while uracil as an oxo group C. At C-4 cytosine has an amino group, while uracil as an oxo group D. Both have an oxo group at C-2 E. At C-2 cytosine has an amino group, while uracil as an oxo group

If the polypeptide chain CVNIKFDS were in an alpha helix, then the alpha amino group of amino acid D would be in a hydrogen bond with the C=O of Please write letter of amino acid as answer.

In a new protein structure you just solved by X-ray crystallography, you found a very long a-helix composed of 36 amino acids. What is the length of this helix? O A. 5.4 nm O B. 0.54 nm O C. 0.36 nm D. 36 nm E. 54 nm

If the polypeptide chain GHREAQNF were in an alpha helix, then the alpha amino group of amino acid N would be in a hydrogen bond with the C=O of Please write letter of amino acid as answer.

Which of the following does not contribute to the tertiary structure of protein? a. ionic interaction     b. H-bond   c. peptide bond          d. hydrophobic interaction

In the alpha-helices, which of the following statement is NOT true?   a.   Backbone carbonyl oxygen of residue (i) hydrogen bonds to backbone NH of the fourth residue of chain of residue (i + 4).   b.   Side chains project out from an α-helix.   c.   Hydrogen bonds are almost straight and parallel to the helix axis.   d.   Helix has a macrodipole.   e.   The rise or advance per amino acid residue is 0.54 nm.

Beta-sheets are roughly planar structures, in which the backbone hydrogen bonding pattern defines the plane. Where are the side chains in a sheet? Select one: a. The side-chains are on the outside of the sheet. O b. The side-chains are in the plane of the sheet, with residues from one chain on one side of the sheet, and residues from the other chain being on the other side. The side-chains do not have a consistent pattern. d. The side-chains are perpendicular to the plane of the sheet, with residues from one chain being above and residues from the other being below the plane of the sheet. C. e. The side-chains are perpendicular to the plane of the sheet, with residues from each chain alternating between above and below the plane of the sheet. O f. The side-chains are in the plane of the sheet, with residues from each chain alternating being on one side or the other of the sheet. g. Beta-sheets are rarely observed in proteins.

The bases represented by X are... Select one: OA. Uracil O B. Guanine OC. Adenine OD. Cytosine X X