biochemistry Please type answers instead of hand writing for me to be able to re
ID: 201845 • Letter: B
Question
biochemistry
Please type answers instead of hand writing for me to be able to read. Thanks!
Eastern skunk cabbage has the ability to maintain the temperature of the plant 15-35 °C higher than ambient temperatures during the months of February and March where ambient temperatures range from -15 to +15 °C. Thermogenesis in the skunk cabbage is critical to the survival of the plant since the spadix tissue is not frost-resistant. The skunk cabbage may be unique in its ability to carry out thermogenesis for longer than just a few hours. Explain how uncoupling agents work and how an uncoupling agent acts to bring about an increase in temperature. a) b) In the skunk cabbage, the site of thermogenesis is the spadix. However, the spadix tissue does not store starch in its tissues. Instead, the spadix relies on the massive root system in the skunk cabbage which stores appreciable quantities of starch. The large quantity of starch available may explain why the skunk cabbage is able to carry out thermogenesis in weeks rather than hours. Why is starch required for thermogenesis?Explanation / Answer
a) An uncoupling agents are found in inner membrane of mitochondria and it is regulated by proton channel or transporter. An uncoupling protein is thus capable of dissipating the proton gradient generated by NADH-powered pumping of protons from the mitochondrial matrix to the mitochondrial intermembrane space. The energy lost in dissipating the proton gradient via uncouplers is not used to do biochemical work. Instead, heat is generated. That is how uncouplers bring about an increase in temperature.
b) Energy from sunlight is used to make glucose in the leaves via photosynthesis during the summer. This sugar is then transported to the thick underground rhizome and stored as starch where it sits until flowering time; then, starch is broken down to yield sugar that is transported to the flower cluster (spadix), where it is burned, in large part, to produce heat. Therefore starch conversion to sugars is required for thermogenesis.
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