Which of the following are common features of expression vectors?
a. small segments of dna that encode tags for protein purification
b. transcriptional start and stop sites
c. a tightly controlled promoter than can only be induced under certain circumstances
d. antibiotic resistance gene
e. all of the above are common features of expression vectors

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.

Why is the statement not a hypothesis? sunflowers require soil and plenty of sunlight and water to grow and thrive.

Which of these correctly describes the difference between processes that take place in prokaryotic and eukaryotic cells?