The combustion of glucose ultimately involves the transfer of electrons to oxygen (o2). in biological systems, this takes place without a large increase in temperature. which of the following statements about this process in biological systems is true? 1) coupled oxidation-reduction reactions occur with electrons being passed to intermediate electron carriers. 2) the process involves the transfer of 12 pairs of electrons to oxygen. 3) the transfer of electrons from intermediate electron carriers to molecular oxygen is catalyzed by the electron transport chain. 4) though the process is a controlled oxidation, some energy is lost.

Juan and carol were studying invertebrates in biology. they knew that segmented or earth worms preferred a dark, moist habitat. during this lab, they would be investigating the responses of organisms called planaria or dugesia tigrina. these were simple flatworms that still had a one-way digestive system and a very simple nervous system. juan and carol placed the planaria in a petri dish containing cool, distilled water that was partially covered with black paper. they shined a light on the dish. next, they removed the paper and placed a small amount of chicken liver at one end of the dish. they added a few large salt crystals to the water. finally, they added drops of hot water to the cool water in the petri dish. their results can be seen in the data table. according to their experiment, all but one conclusion is valid.

If a checkpoint detects damaged dna, the checkpoint may

The smallest parts of these that retain their original properties are called