Macromolecules are built up from small repeating units called _______________? TRUE / FALSE 1. Ribonucleic acid is usually double stranded. 2. The sugar in DNA is 2-deoxyribose. 3. An enzyme can catalyze the reaction at any PH value. 4. Activators decrease the enzyme activity. 5. Lipids are an integral part of cell protoplasm and cell membranes.