Question

6. You are wandering in the wilderness, naked, hungry, and cold. You find two caves of the same dimensions. In one cave there is 600 kg moose and in the other cave are 100,000 6-gram mice. Both species are very friendly and they have an unlimited supply of food.

a. Which cave would you enter to warm up quickly? (you cannot eat the animals!!). Why?

b. If you were to isolate mitochondria from the liver of the moose and livers of the mice, how would the State 4 respiration rates differ? How does this relate to your answer in question 6a? It is to your advantage to give as detailed an answer as possible because it will help you integrate the material from the subcellular to the whole-animal level.

Answer 1

6.a) The cave with the 600 kg moose is the one a person should enter to warm up quickly. The moose is a large mammal (the largest member of the deer family), and has long, thick fur on its body. Moreover, in winter mice prefer to hole up in quieter indoor areas where there is no human interference, like corners, spaces behind walls and ceilings, whereas the moose prefers cooler temperatures. Also, the availability of ample food resources is a factor here. The mice prefers to stay close to food sources during winter, since it is unable to venture out for gathering food. Therefore the mice would require all the food that it has stored for the winter months. The moose on the other hand, due to its preference of cold temperatures, can easily venture out into the winderness looking for food. Additionally, during winters the moose eats lower quality food than it does in summer, and mostly survives on willows, birch and twigs. In the extreme cold temperatures, the moose tends to expend energy than acquire it and some might even starve. The food they eat in winters provide much lesser energy and therefore they eat large quantities of twigs and branches. Therefore, the high calorie food is left unconsumed by the moose which can be consumed by the person venturing into the cave. Thus, since it has been stated in the question that both the moose and the mice in question are friendly, therefore it would be a better idea to choose the cave with the moose if one is looking for warmth.

b) The fourth stage of cellular respiration is the Electron transport chain (ETC), wherein the food is oxidised to produce ATP which is the energy currency of biological systems. As stated above, during winter the moose eats low calorie food or food which generate lower energy since (or even starve), unlike mice which keep themselves sufficiently fed during winter. The calories that are consumed by an organism help in providing energy required for the high energy bonds of ATP, that in turn provides energy to the muscles for musculoskeletal activities and the brain for carrying out electrochemical repsosnes. The shortage of calories leads to poorer generation of energy, which leads to lower ATP generation. As a result, the cellular respiration rates in the moose and the mice would differ when it comes to energy production via the ETC, as the rate would be lower in moose as compared to the mice due to differences in dietary consumption in winter.