Final answer:
A respiring mitochondrion typically has more cristae to increase the surface area for ATP synthesis, not less. Cristae are essential for the electron transport chain and ATP production by chemiosmosis. The presence of DNA and ribosomes within mitochondria resembles that of prokaryotic organisms.
Step-by-step explanation:
The question 'Why does a respiring mitochondrion have less cristae?' suggests a misunderstanding, as typically a respiring mitochondrion would be expected to have more, not less, cristae. Cristae are infoldings of the mitochondrial inner membrane and serve to increase the surface area for oxidative phosphorylation, where ATP synthesis takes place. Within the mitochondrial matrix, the Krebs Cycle occurs, while the electron transport chain is embedded in the inner membrane and utilizes the space of both the matrix and the cristae to generate ATP through chemiosmosis. Mitochondria are unique as they contain their own DNA and ribosomes, similar to prokaryotic organisms, and each of their membranes is a phospholipid bilayer with embedded proteins. The question may originate from a scenario where the cell lacks genes encoding an appropriate cytochrome oxidase, which could potentially affect the electron transport system and thus the structure and function of the mitochondria, but more context is necessary for a precise answer.