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.
Pre-Test
Answer Choice |
Overall |
Grades |
Gender |
Primary Language |
||||
|---|---|---|---|---|---|---|---|---|
| n = 124 |
6–8 n = 0 |
9–12 n = 106 |
Male n = 61 |
Female n = 49 |
English n = 96 |
Other n = 6 |
||
| A. | The scientists found labeled carbon atoms in both the body structures and the waste products. | 32% | NAN% | 32% | 26% | 41% | 32% | 0% |
| B. | The scientists found labeled carbon atoms in the body structures but not the waste products. | 28% | NAN% | 27% | 30% | 22% | 28% | 33% |
| C. | The scientists found labeled carbon atoms in the waste products but not the body structures. | 28% | NAN% | 30% | 34% | 24% | 30% | 50% |
| D. | The scientists did not find labeled carbon atoms in either the waste products or the body structures. | 11% | NAN% | 10% | 10% | 12% | 9% | 17% |
Post-Test
Answer Choice |
Overall |
Grades |
Gender |
Primary Language |
||||
|---|---|---|---|---|---|---|---|---|
| n = 146 |
6–8 n = 0 |
9–12 n = 134 |
Male n = 73 |
Female n = 59 |
English n = 122 |
Other n = 10 |
||
| A. | The scientists found labeled carbon atoms in both the body structures and the waste products. | 38% | NAN% | 38% | 41% | 36% | 38% | 40% |
| B. | The scientists found labeled carbon atoms in the body structures but not the waste products. | 30% | NAN% | 31% | 29% | 32% | 31% | 20% |
| C. | The scientists found labeled carbon atoms in the waste products but not the body structures. | 20% | NAN% | 19% | 18% | 20% | 18% | 40% |
| D. | The scientists did not find labeled carbon atoms in either the waste products or the body structures. | 12% | NAN% | 12% | 12% | 12% | 13% | 0% |