<P> Red blood cells can also produce hydrogen sulfide, a signalling gas that acts to relax vessel walls . It is believed that the cardioprotective effects of garlic are due to red blood cells converting its sulfur compounds into hydrogen sulfide . </P> <P> Red blood cells also play a part in the body's immune response: when lysed by pathogens such as bacteria, their hemoglobin releases free radicals, which break down the pathogen's cell wall and membrane, killing it . </P> <P> As a result of not containing mitochondria, red blood cells use none of the oxygen they transport; instead they produce the energy carrier ATP by the glycolysis of glucose and lactic acid fermentation on the resulting pyruvate . Furthermore the pentose phosphate pathway plays an important role in red blood cells; see glucose - 6 - phosphate dehydrogenase deficiency for more . </P> <P> As red blood cells contain no nucleus, protein biosynthesis is currently assumed to be absent in these cells . </P>

Where do red blood cells get their energy