How are purines distinguished from pyrimidines?
a. Purines are derived from a pair of fused C-N rings, while pyrimidines are derived from a single C-N ring.
b. Pyrimidines are derived from a pair of fused C-N rings, while purines are derived from a single C-N ring.
c. Purines have a carbon-containing ring, while pyrimidines have a nitrogenous ring.
d. Pyrimidines have a carbon-containing ring, while purines have a nitrogenous ring.
e. Purines are found only in DNA, while pyrimidines are found only in RNA.
ANSWER: a
You might also like to view...
The formation of amino acids under abiotic
conditions was important because they serve as a. a supply of structural units for proteins. b. enzymes to catalyze reactions. c. subunits in the formation of DNA. d. subunits in the formation of RNA. e. subunits for the formation of lipids
After energy flows into a food web, it leaves mainly by
a. losses of metabolic heat. b. evaporation. c. conversion to chemical energy. d. waste production. e. convection.
Which statement about bioremediation is FALSE?
a. Methogens are used in sewage treatment. b. When bacteria break down toxins, they leave behind harmless byproducts. c. Very few species of bacteria are used to clean up various forms of pollution. d. Bacteria and other microorganisms are used to break down oil from oil spills. e. The byproducts of microorganisms breaking down toxins are often carbon dioxide and chlorides.
rough ER
What will be an ideal response?