Question

question 2
in the \identifying known and unknown biological substances\ lab, the test for which substance(s) require heating? select all correct answers.
o a nucleic acid
o b protein
o c starch
o d glucose
o e lipid

Explanation:

In biological substance identification labs, glucose (a reducing sugar) is tested using Benedict's reagent. Benedict's test requires heating the sample - reagent mixture. Heating accelerates the chemical reaction between the reducing sugar (glucose) and the copper ions in Benedict's reagent, resulting in a color change (from blue to green/yellow/orange/red depending on sugar concentration). Nucleic acid tests (like DNA extraction - based tests) don't typically involve heating as a core part of the substance - identification test in a basic lab (not in the context of a simple "identifying known and unknown biological substances" lab). Protein tests (e.g., Biuret test) don't require heating. Starch tests (using iodine - potassium iodide solution) are done at room temperature. Lipid tests (e.g., Sudan stain tests) are also conducted at room temperature.

Answer:

d. Glucose