A scientist observes some cells under a compound microscope and needs to determine if they are bacteria or yeast. Aside from size, what chemical compounds (not organelles!) would positively identify the cell as either a bacterium or a yeast?

Peptidoglycan and chitin.

Explanation:

Bacteria and yeast differ from each due to the different chemical composition of their cell wall.

Chitin: chitin is a large structural polysaccharide that is derived from chains of modified glucose. It is the primary components of cell wall in fungi such as yeast. Chitin is a minor component in the yeast cell wall, it accounts for only 1-2% of the cell wall dry mass. Chitin contributes to the mechanical strength of the cell wall.

Peptidoglycan: Peptidoglycan also known as murein is a polymer that makes up a the cell wall of a bacterium. It is composed of sugars and amino acids. A bacteria is a unicellular organism, therefore Peptidoglycan gives strength to the outer structure of the organism.

chitin and murein

Explanation:

The chemical compounds that distinguish bacteria cell from yeast cell are

chitin and murein

Chitin is a polysaccharide present in the exoskeleton of fungi made up of chains of modified glucose known as N-acetylglucosamine. N-acetylglucosamine is derived from glucose

While murein is a mesh like structure made up of sugar and amino acids. Murein forms a layer outside the plasma membrane of bacterial cell.