Question: A scientist uses a special chemical marker to label some amino acids. He follows the marker until it becomes part of a large molecule in a cell. Which molecule does he find the chemical marker on?

  Options: 
 A. a lipid in a membrane
 B. an enzyme in a lysosome
 C. a polysaccharide in a cell wall
 D. a DNA molecule in a mitochondrion 
Answer: B