The University of North Carolina at Pembroke
Robeson Community College
Microgravity Research Team site
The proposal for the 2012-13 year will be investigating
The Effects of Gravity on the Cori Cycle
With the increased duration of space flights and the continual habitation of the International Space Station, the human body is put under new and unexplored stresses. Although there has been significant research conducted to investigate the effects of microgravity on human biological mechanisms (Stein, 2005 and references within), there has been very little research conducted to better understand the effects of microgravity on the Cori cycle (Woodman, 2009; Inobe, 2002). The Cori cycle is important because it is responsible for producing the energy needed to allow muscular activity. Muscle activity requires energy, which means that glycogen is broken down to glucose via glycogenesis (Wickman). After glycogenesis, the resulting glucose is fed into glycolysis, which is the process that actually makes energy, or Adenosine Triphosphate (ATP), for your skeletal muscles to use. During muscular activity, glycolysis occurs constantly and ATP is constantly replenished (Elmhurst, 2003). Glycolysis can occur aerobically or anaerobically. When oxygen is not present, such as during intense muscular activity, ATP is formed through the conversion of pyruvate to lactate. The lactate produced by anaerobic glycolysis is taken to the liver where it is converted back to glucose and the process starts again (Romano, 1996). This process is shown schematically in figure 1a. Part of this critical process is lactic fermentation, figure 1b. In lactic fermentation pyruvate is converted to lactate, which consumes Nicotinamide Adenine Dinucleotide (NADH) and NAD+ is released. It should be noted that the NAD+ is essential for glycolysis to continue to occur, thereby to obtain energy through the consumption of sugars. To summarize, the process serves to regenerate NAD+ so that glycolysis can continue to occur in the absence of O2, as glycolysis is the process that will produce ATP (Nelson, 2004).
The majority of a human’s life is lived in a gravitational pull of 1-g whereas an astronaut, in orbit around the Earth, can experience extended periods of reduced gravitational pull. Does the change in gravity experienced by the human body affect some of its most basic functions, such as the Cori cycle? The main focus of our research is to understand the effects that a reduced gravitational field (0-g) has on the reaction rate of pyruvate to lactate during anaerobic glycolysis. We believe that in a reduced gravitational field the conversion rate of pyruvate to lactate will be lowered in comparison to the rate measured in 1-g. In the human body, a reduction in this reaction rate results in a decrease in the energy available for skeletal muscular activity and could adversely affect an astronaut’s productivity.
The 2012-13 Weightless Lumbees
From left to right: Tiffany Scott (UNCP-Chemistry), Molly Musselwhite (UNCP-Biology), Alex Mitchell (UNCP-Chemistry), Candace Langston (UNCP-Sports Science)
Crystal Oxendine-Jerald (not shown, RCC-Electronics)
Past Outreach Activities
Clint Haywood discussing some of the Weightless Lumbees
outreach experiments NC Museum of Natural Science
Tamra Henderson and Lindsay Willis working with children as
part of National Chemistry day at the NC Museum of Natural Science
Tamra Henderson and Lindsay Willis working with children as part of National Chemistry day at the
NC Museum of Natural Science
Branyun Bullard educates the crowd as part of National
Chemistry day at the NC Museum of Natural Science
Branyun Bullard educates the crowd as part of National Chemistry day at the NC Museum of Natural Science
Branyun Bullard explaining the concept of density to some future Weightless Lumbees
NC Museum of Natural Science
Lane Guyton explains microgravity at the kids level while Tamra Henderson and Lindsay Willis
help the children make some of their own density demonstrators
NC Museum of Natural Science
UNCP Team Advisor, Dr. Tim Ritter,
presenting at Cherokee High School
NASA’s Reduced Gravity Student Flight Opportunities Program is designed to inspire students’ interest in science, engineering and technology. The program provides select undergraduate student teams, from around the country, the opportunity to successfully propose, design, fabricate, fly and evaluate a reduced gravity experiment of their choice on board the famous reduced gravity aircraft. The overall experience includes scientific research, hands-on experimental design, test operations and educational/public outreach activities. The reduced gravity aircraft generally flies 30 parabolic maneuvers over the Gulf of Mexico. This parabolic pattern provides about 30 seconds of hypergravity (1.8g) as the plane climbs to the top of the parabola. Once the plane starts to “nose over” the top of the parabola to descend toward Earth, the plane experiences about 25 seconds of microgravity (0g).
Video clip showing a candle flame in zero gravity.
clip showing the effects of gravity on mixing fluids. The clear fluid is water and the yellow fluid
is cooking oil.
Fluid Mixing experiment
Movie clip from on board the C-9. This clip shows a steel ball falling (actually NOT falling!) through a viscous fluid in 0-g
And the same experiment performed during the 2-g portion of the flight
The outreach presentation that we use when visiting schools and community groups (large file, please be patient).
Check out our infomational brochure (requires acrobat reader).
A complete overview of the Reduced Gravity Student Opportunities Program can be found at the following site: RGSFOP
The counties across
The states across the
The countries in which The Weightless Lumbees have presented their outreach message
Please revisit our site for regular updates to include pictures from the latest trip to Houston, more outreach program details, and general program information. Until then, if you require additional information, please feel free to contact one the students or the faculty advisor, Dr. Tim Ritter at firstname.lastname@example.org