PART II – BONUS QUESTIONS The following are bonus ques…
PART II – BONUS QUESTIONS The following are bonus questions. (Points WILL NOT be deducted, even if you answer the questions wrong.) Read the following news article and answer the questions. How liver responds so quickly to food The finding could help better understand metabolism and some forms of diabetes Source: Salk Institute Summary: Researchers have uncovered how the liver can have a speedy response to food; liver cells store up pre-RNA molecules involved in glucose and fat metabolism. Salk researchers discover how liver responds so quickly to food. Image shows NONO protein immunostained green in liver cells after a meal. Blue indicates cell nuclei. Credit: Salk Institute Minutes after you eat a meal, as nutrients rush into your bloodstream, your body makes massive shifts in how it breaks down and stores fats and sugars. Within half an hour, your liver has made a complete switch, going from burning fat for energy to storing as much glucose, or sugar, as possible. But the speed at which this happens has puzzled scientists — it’s too short a time span for the liver’s cells to activate genes and produce the RNA blueprints needed to assemble new proteins to guide metabolism. Now, Salk researchers have uncovered how the liver can have such a speedy response to food; liver cells store up pre-RNA molecules involved in glucose and fat metabolism. “The switch from fasting to feeding is a very quick switch and our physiology has to adapt to it in the right time frame,” says Satchidananda Panda, a professor in the Salk Institute’s Regulatory Biology Laboratory. Their paper “Now we know how our body quickly handles that extra rush of sugar” was published in the journal Cell Metabolism. It was known that a RNA-binding protein “NONO” was associated in regulating daily rhythms in the body. But Panda’s group wondered whether NONO had a specific role in the liver. They analyzed levels of NONO in response to feeding and fasting in mice. After the animals ate, speckled clumps of NONO suddenly appeared in their liver cells, newly attached to RNA molecules. Within half an hour, the levels of corresponding proteins — those encoded by the NONO-bound RNA — increased. “After mice eat, it looks as if NONO brings all these RNAs together and processes them so they can be used to make proteins,” says Panda. When mice lacked NONO, it took more than three hours for levels of the same proteins, involved in processing glucose, to increase. During that time lag, blood glucose levels shot up to unhealthy levels. Since blood glucose levels are also heightened in diabetes, the researchers think that the mice without NONO may act as a model to study some forms of the disease. “Understanding how glucose storage and fat burning are regulated at the molecular level will be important for the development of new therapies against obesity and diabetes,” says Benegiamo. (… truncated below) According to the article, the liver responds quickly to food after a meal is to ___________.