Recent scientific findings suggest that consuming beetroot juice as a dietary su
ID: 254117 • Letter: R
Question
Recent scientific findings suggest that consuming beetroot juice as a dietary supplement can reduce oxygen demand during moderate exercise and increase endurance during strenuous exercise. Beetroot juice is converted to nitric oxide, NO, in the body, and scientists hypothesize that the NO may increase the number of protons pumped into the intermembrane space per molecule of oxygen and may also reduce proton leakage across the inner membrane. Using your knowledge of the mitochondrial ETC, explain how this could result in increased endurance and reduced demand for oxygen. R Paragraph ? B 1 EExplanation / Answer
Nitric oxide (NO) is an important signalling molecule. It has been implicated in the regulation of many biological processes including blood flow,skeletal muscle excitation-contraction coupling and mitochondrial bioenergetics.Dietary inorganic nitrate is a popular sports nutrition supplement and has possible therapeutic applications.
Nitrate is abundant in certain foods such as beetroot and some leafy vegetables.however beyond the limit, any substance may produce adverse effects and some times severe effects and even fatal.
Beetroot juice in which nitrate is the main active ingredient. One remarkable effect of inorganic nitrate supplementation is a decrease in the oxygen cost of submaximal exercise, with consequent improvements in exercise tolerance and performance. The effect is robust, at least in young healthy subjects, but its physiology is by no means well understood.
Explanation :
In general terms there are two possible explanations of a decreased oxygen cost of muscular work.
first, a decrease in the oxygen cost of ATP synthesis i.e. an increase in its reciprocal, the mitochondrial P:O ratio, which can be thought of as ‘mitochondrial efficiency.
second, a decrease in the ATP cost of contraction i.e. an increase in its reciprocal, ‘contractile efficiency’.
This leaves decreased ATP cost of work as the only remaining explanation of the decreased oxygen cost of work.
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