Name two biologically important compounds that contain both oxygen and nitrogen.

Two biologically important compounds that contain both oxygen and nitrogen are 

Proteins (their basic units are amino acids which are made up of an amino group with nitrogen and a carboxylic acid with oxygen in them) Nucleic acids- both DNA and RNA are compounds with a ribose and phosphate groups with oxygen and the nitrogen bases with nitrogen

The biologically important compounds that contain both oxygen and nitrogen are nitrates ( NO₂⁻) and nitrates (NO₃⁻). These are important forms of nitrogen to be utilized by the plants to synthesize biomolecules like proteins.

1. Oxygen:

(i) Carbon dioxide

(ii) Phosphorus pentoxide.

2. Nitrogen:

(i) Amino acid

(ii) Protein.

DNA (Deoxyribonucleic acid) and RNA (Ribonucleic acid) are two biologically important compounds that contain both oxygen and nitrogen. Oxygen is present in pentose sugar (Ribose in case of RNA and Deoxyribose in case of DNA) and nitrogen is present in nitrogenous bases (purines and pyrimidine).

Two biologically important compounds that contain both oxygen and nitrogen are:
(i) Amino acids
(ii) Deoxyribonucleic acid (DNA) and Ribonucleic acid (RNA)