A researcher performed an experiment in which he exposed young potato plants to a radioactive form of carbon dioxide gas containing
carbon-14 instead of carbon-12. After several weeks, the researcher took tissue samples from the plants and isolated several different
types of organic molecules from them.
In which of the following types of molecules might the researcher find carbon-14?
A.
lipids
B.
nucleic acids
C. amino acids
D. all of these

In addition to seeds, which of the following characteristics are unique to the seed-producing plants? a) sporopollenin b) lignin present in cell walls c) pollen d) use of air currents as a dispersal agent e) megaphylls

Which of the following would be an important part of a multi-step plan to restore the stability of the red-cockaded woodpecker's ecosystem?

The empty trna moves off and picks up another matching amino acid from the cytoplasm in the cell. the anticodon of the trna, with its attached amino acid, pairs to the codon of the mrna, which is attached to a ribosome. this sequence is repeated until the ribosome reaches a stop codon on the mrna, which signals the end of protein synthesis. the ribosome forms a peptide bond between the amino acids, and an amino acid chain begins to form. when a second trna with its specific amino acid pairs to the next codon in sequence, the attached amino acid breaks from the first trna and is bonded to the amino acid of the second trna.