1. Proteins are biological molecules made of . A. amino acids
B. nucleotides
C. Sugars
D. glycerol

2. When a protein makes it easier for a biological reaction to happen, it is acting as a/an
A. structural protein
B. messenger
C. enzyme
D. transporter

3. What role(s) do proteins play?
A. enzymes
B. transporter molecule
C. immunity (antibodies)
D. messenger
E. locomotion (muscles)
F. structure
G. all of the above

4. Keratin and collagen are examples of what type of protein?
A. antibody
B. enzyme
C. structural
D. transporter

5. Enzymes play an important role for living things because
A. they reduce the energy required called the activation barrier.
B. they increase the energy required called the activation barrier.
C. they transport oxygen via hemoglobin to our cells. D. they (antibodies) protect us from viruses.