Two phases of proton translocation
Article Abstract:
The molecular mechanism of oxygen reduction coupled to proton translocation remains in question. Several redox linkage models have been proposed but they lack a quantitative temporal relationship between chemical steps and proton translocation. Marten Wikstrom and colleagues have proposed a time frame for this relationship. PH change of liposomes with cytochrome c oxidase embedded in their membranes was measured, and the time resolved potential over a membrane containing cytochrome c oxidase was also measured. The translocation of charge was found to be incomplete at the end of the oxidative phase.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1999
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Scaling of elastic strain energy in kangaroos and the benefits of being big
Article Abstract:
The ability for elastic strain energy storage in kangaroo tendons is proportional to their body mass. The pattern of structural growth in these animals is different from that of eutherian animals. The maximum achievable speed by kangaroos is proportional to their body mass indicating that the ground reaction force for small animals is restricted to reduced multiples of body mass, which is necessary for strain energy storage and tendon safety factor. Energy storage is proportional to the amount of stress in tendons during ground-contact phase and appears to have a 50-60 kg body mass upper limit.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1995
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One price to run, swim or fly?
Article Abstract:
It is accepted that it is metabolically cheaper for animals to fly than to run, and even cheaper for them to swim. However a recent paper by Williams concludes that the three types of locomotion are equally priced. Williams compared total costs of transport for marine mammals having differing degrees of aquatic specialization, and found that swimming is expensive for semi-aquatic mammals. The research shows that enothermic submerged swimmers have transport costs similar to those of running mammals.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1999
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