Question

1. hydrogen bonds can occur between molecules (intermolecularly), or within different parts of a single molecule (intramolecularly). hydrogen bonds are a crucial component of biomolecular structures. in the following drawings, draw in any hydrogen bonds that are possible between atoms within the same molecule or between different molecules:

a: protein structure
b: enzyme/substrate interaction
c: dna base pairing
d: plant cell wall (cellulose)

Explanation:

Step1: Recall hydrogen - bond conditions

Hydrogen bonds form between a hydrogen atom covalently bonded to a highly electronegative atom (N, O, or F) and another electronegative atom.

Step2: Analyze protein structure (A)

In the alpha - helix of a protein, hydrogen bonds form between the carbonyl oxygen of one amino - acid residue and the amide hydrogen of another residue, stabilizing the helical structure. These are shown as dotted lines between the C=O and N - H groups along the helix.

Step3: Analyze enzyme/substrate interaction (B)

The hydroxyl group (-OH) can form a hydrogen bond with a nitrogen atom in the substrate. The hydrogen of the -OH group is attracted to the electronegative nitrogen, shown as a dotted line.

Step4: Analyze DNA base - pairing (C)

In DNA base - pairing, adenine (A) forms two hydrogen bonds with thymine (T), and guanine (G) forms three hydrogen bonds with cytosine (C). The hydrogen bonds are shown as dotted lines between the complementary bases.

Step5: Analyze plant cell wall (cellulose) (D)

Cellulose is a polysaccharide. The hydroxyl groups on the glucose monomers in cellulose chains can form hydrogen bonds with each other, both intra - chain and inter - chain. Dotted lines are drawn between the appropriate oxygen and hydrogen atoms of the hydroxyl groups.

Answer:

Draw dotted lines to represent hydrogen bonds as described in each of the steps above for A, B, C, and D. For A, between C=O and N - H in the protein helix; for B, between -OH and N; for C, between complementary DNA bases; for D, between hydroxyl groups of cellulose glucose monomers.