Question

Uncoupling Proteins in Plants Background In mammals, body temperature can be regulated by uncoupling proteins which act by uncoupling electron transport and oxidative phosphorylation. Two such uncoupling proteins have been identified which have been named UCP1 and UCP2. UCP1 is believed to be involved in heat production, whereas UCP2 might be involved in obesity in humans. The mechanism of thermogenesis in plants is not as well understood. Several studies have been carried out which indicate that thermogenesis is an important process in the developing plant. For example, the 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. Thermoregulation has also been studied in lotus flowers. Investigators in Australia noted that the temperature of the lotus flower receptacle rises one or two days before the flower opens. Temperatures fall only after the flower is completely opened. The investigators speculated that heat production in the lotus flower serves to enhance evaporation of the floral scent that attracts pollinating insects. Noting that many pollinating insects require a thoracic temperature of 30°C or higher to initiate flight, the investigators hypothesized that heat production in the lotus flower would assist the departure of the insects from the flower. Although observations of temperature and oxygen utilization in the skunk cabbage and lotus flower implicated an uncoupler, an uncoupling protein was not isolated until fairly recently. A research team in France recently reported that they had identified an uncoupling protein in potatoes (Solanum tuberosum) that is involved in thermoregulation in plants in a manner similar to the brown fat uncoupling proteins in mammals. The uncoupling protein is named StUCP and its synthesis is induced by cold temperatures. The authors note that heat production concomitant with a "burst of respiration" occurs during plant flowering and fruit ripening. Questions 1. Explain how uncoupling agents work and how an uncoupling agent acts to bring about an increase in temperature. (Don't overthink this – just describe the overall process) 2. 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. How is starch used for thermogenesis? (As above, this is not a "complex/trick" question – just describe the overall process).

Name: uncoupling proteins in plants background in mammals body temperature can be regulated by uncoupling proteins which act by uncoupling electron transport and oxidative phosphorylation two such 12642
Uploaded: 2023-05-05T06:40:15-08:00
Duration: 1 min 53 s
Channel: Adi S
Description: uncoupling proteins in plants background in mammals body temperature can be regulated by uncoupling proteins which act by uncoupling electron transport and oxidative phosphorylation two such 12642

Uncoupling Proteins in Plants Background
In mammals, body temperature can be regulated by uncoupling proteins which act by uncoupling electron transport and oxidative phosphorylation. Two such uncoupling proteins have been identified which have been named UCP1 and UCP2. UCP1 is believed to be involved in heat production, whereas UCP2 might be involved in obesity in humans. The mechanism of thermogenesis in plants is not as well understood. Several studies have been carried out which indicate that thermogenesis is an important process in the developing plant. For example, the 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.
Thermoregulation has also been studied in lotus flowers. Investigators in Australia noted that the temperature of the lotus flower receptacle rises one or two days before the flower opens. Temperatures fall only after the flower is completely opened. The investigators speculated that heat production in the lotus flower serves to enhance evaporation of the floral scent that attracts pollinating insects. Noting that many pollinating insects require a thoracic temperature of 30°C or higher to initiate flight, the investigators hypothesized that heat production in the lotus flower would assist the departure of the insects from the flower.
Although observations of temperature and oxygen utilization in the skunk cabbage and lotus flower implicated an uncoupler, an uncoupling protein was not isolated until fairly recently. A research team in France recently reported that they had identified an uncoupling protein in potatoes (Solanum tuberosum) that is involved in thermoregulation in plants in a manner similar to the brown fat uncoupling proteins in mammals. The uncoupling protein is named StUCP and its synthesis is induced by cold temperatures. The authors note that heat production concomitant with a "burst of respiration" occurs during plant flowering and fruit ripening.

Questions
1. Explain how uncoupling agents work and how an uncoupling agent acts to bring about an increase in temperature. (Don't overthink this – just describe the overall process)
2. 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. How is starch used for thermogenesis? (As above, this is not a "complex/trick" question – just describe the overall process).

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Biology for AP Courses

Julianne Zedalis, John Eggebrecht

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Solved by Expert Adi S

05/05/2023

Step 1

Uncoupling agents work by disrupting the coupling between electron transport and oxidative phosphorylation in the mitochondria. This process usually generates ATP, but when an uncoupling agent is present, the energy from the electron transport chain is released as Show more…

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Uncoupling Proteins in Plants Background In mammals, body temperature can be regulated by uncoupling proteins which act by uncoupling electron transport and oxidative phosphorylation. Two such uncoupling proteins have been identified which have been named UCP1 and UCP2. UCP1 is believed to be involved in heat production, whereas UCP2 might be involved in obesity in humans. The mechanism of thermogenesis in plants is not as well understood. Several studies have been carried out which indicate that thermogenesis is an important process in the developing plant. For example, the 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. Thermoregulation has also been studied in lotus flowers. Investigators in Australia noted that the temperature of the lotus flower receptacle rises one or two days before the flower opens. Temperatures fall only after the flower is completely opened. The investigators speculated that heat production in the lotus flower serves to enhance evaporation of the floral scent that attracts pollinating insects. Noting that many pollinating insects require a thoracic temperature of 30°C or higher to initiate flight, the investigators hypothesized that heat production in the lotus flower would assist the departure of the insects from the flower. Although observations of temperature and oxygen utilization in the skunk cabbage and lotus flower implicated an uncoupler, an uncoupling protein was not isolated until fairly recently. A research team in France recently reported that they had identified an uncoupling protein in potatoes (Solanum tuberosum) that is involved in thermoregulation in plants in a manner similar to the brown fat uncoupling proteins in mammals. The uncoupling protein is named StUCP and its synthesis is induced by cold temperatures. The authors note that heat production concomitant with a "burst of respiration" occurs during plant flowering and fruit ripening. Questions 1. Explain how uncoupling agents work and how an uncoupling agent acts to bring about an increase in temperature. (Don't overthink this – just describe the overall process) 2. 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. How is starch used for thermogenesis? (As above, this is not a "complex/trick" question – just describe the overall process).