MEGA
Energy in Biology
Cellular respiration is a chemical process in which the bonds between atoms of food molecules and oxygen molecul…
Item EB032003: When scientists fed laboratory rats food with labeled carbon atoms, they found the labeled carbon atoms in both the rats’ waste products and body structures.
Scientists were testing a new food for laboratory rats. They were trying to find out what happens to the food after it is eaten by the rats. To help them conduct their research, they fed the rats food that contained amino acids that had radioactively “labeled” carbon atoms. The radioactive label allowed the scientists to track where the carbon atoms ended up after the rat ate the food.
The scientists collected the rats’ waste products over three days and analyzed them to see how many of the labeled carbon atoms were in the rats' waste products. The scientist then analyzed the rats’ bodies to see how many of the labeled carbon atoms were in the rats' body structures. Where did the scientist find labeled carbon atoms?
- The scientists found labeled carbon atoms in both the body structures and the waste products.
- The scientists found labeled carbon atoms in the body structures but not the waste products.
- The scientists found labeled carbon atoms in the waste products but not the body structures.
- The scientists did not find labeled carbon atoms in either the waste products or the body structures.
- Distribution of Responses
- Points Earned
| Group | Correct | Total | Percent |
|---|---|---|---|
| Overall | 40 | 124 | 32% |
| Grades | |||
| 6–8 | N/A | N/A | N/A |
| 9–12 | 34 | 106 | 32% |
| Gender | |||
| Male | 16 | 61 | 26% |
| Female | 20 | 49 | 41% |
| Primary Language | |||
| English | 31 | 96 | 32% |
| Other | 0 | 6 | 0% |
- Distribution of Responses
- Points Earned
| Group | Correct | Total | Percent |
|---|---|---|---|
| Overall | 56 | 146 | 38% |
| Grades | |||
| 6–8 | N/A | N/A | N/A |
| 9–12 | 51 | 134 | 38% |
| Gender | |||
| Male | 30 | 73 | 41% |
| Female | 21 | 59 | 36% |
| Primary Language | |||
| English | 46 | 122 | 38% |
| Other | 4 | 10 | 40% |
- Disciplinary Core Ideas
- PS3.D Cellular respiration in plants and animals involve chemical reactions with oxygen that release stored energy. In these processes, complex molecules containing carbon react with oxygen to produce carbon dioxide and other materials.
LS1.C Within individual organisms, food moves through a series of chemical reactions in which it is broken down and rearranged to form new molecules, to support growth, or to release energy.
LS1.C The sugar molecules thus formed contain carbon, hydrogen, and oxygen: their hydrocarbon backbones are used to make amino acids and other carbon-based molecules that can be assembled into larger molecules (such as proteins or DNA), used for example to form new cells.
LS1.C As a result of these chemical reactions, energy is transferred from one system of interacting molecules to another. Cellular respiration is a chemical process in which the bonds of food molecules and oxygen molecules are broken and new compounds are formed that can transport energy to muscles. Cellular respiration also releases the energy needed to maintain body temperature despite ongoing energy transfer to the surrounding environment.