1. What structurally defines a peptide?

A chain of amino acids linked by peptide bonds
A single ring-shaped carbon molecule
Any compound sold in a freeze-dried vial
A type of carbohydrate

2. Why are most research peptides shipped as a lyophilized (freeze-dried) powder?

It’s cheaper to manufacture
Peptides in solution are unstable over time and degrade faster
It’s required by FDA labeling law
Freeze-dried powder weighs less for shipping only

3. On a Certificate of Analysis, what does the purity percentage (e.g. ≥98%) come from?

A visual inspection of the powder’s color
The manufacturer’s marketing claim
HPLC chromatogram peak-area analysis
The vial’s expiration date

4. What is bacteriostatic water most commonly used for in a research context?

Cleaning lab glassware
Reconstituting a lyophilized peptide into solution
Diluting HPLC solvents
Calibrating a mass spectrometer

5. What does a “Research Use Only” label on a compound legally indicate?

It has been approved by the FDA for veterinary use
It is intended for laboratory/analytical use, not human or animal consumption
It is a dietary supplement
It has completed Phase 3 clinical trials