Which of the following is a polysaccharide? A) cellulose, the primary component of plant cell walls B) fructose, one of the most important blood sugars C) glucose, the chief cellular energy source D) insulin, the chief blood sugar regulator E) All of the above are polysaccharides. Which of the following nucleotide bases are present in equal amount in DNA? A) adenine and guanine B) adenine and thymine C) thymine and guanine D) thymine and cytosine E) adenine and cytosine A partial sequence of a molecule is “AACTGCT.” The molecule is A) a polysaccharide. B) a protein. C) a nucleic acid. D) a polypeptide. E) a triglyceride. Enzymes: A) catalyze reactions that release energy, but not those that consume energy. B) reduce the energy released by a reaction by one four different mechanisms. C) are always consumed by catalyzing a reaction. D) sometimes increase the amount of energy necessary to initiate a reaction. E) increase the rate at which reaction occurs. What are the two distinct “faces” of the phospholipids that make up the surface membrane of a cell? A) a hydrophilic head and a hydrophobic tail B) a hydrophobic head and a hydrophilic tail C) a phosphate group head and two fatty acid tails D) Both a) and c) are correct. E) Both b) and c) are correct.