Which of the following is true of a codon? (A) It never codes for the same amino acid as another codon. (B) It can code for more than one amino acid. (C) It can be either in DNA or in RNA (D) It is the basic unit of protein structure

The efficiency of cloning, and the ability to generate healthy cloned animals, has been largely hampered by the difficulty of __________.

In genetic engineering, the highly active plasmid from Agrobacterium tumefaciens is used to __________.

A molecular biologist used a retroviral vector to introduce a gene coding for a certain human enzyme into mouse cells. One cell line was isolated that was able to make the human enzyme, but it had lost the ability to express an endogenous, normally expressed gene in the process. What is the best explanation for these results?

In DNA technology, the term vector can refer toa. the enzyme that cuts DNA into restriction fragments.b. the sticky end of a DNA fragment.c. a SNP marker.d. a plasmid used to transfer DNA into a living cell.

Which of the following would be considered a transgenic organism?a. a bacterium that has received genes via conjugationb. a human given a corrected human blood-clotting genec. a fern grown in cell culture from a single fern root celld. a rat with rabbit hemoglobin genes

Which of the following is true of cDNA produced using human brain tissue as the starting material? (A) The procedure to make it requires amplification by the polymerase chain reaction. (B) It is produced from pre-mRNA using reverse transcriptase. (C) It can be labeled and used as a probe to detect genes expressed in the brain. (D) It includes the introns of the pre-mRNA.

Which of the following is not true of cDNA produced using human brain tissue as the starting material?a. It can be amplified by the polymerase chain reaction.b. It was produced from pre-mRNA using reverse transcriptase.c. It can be labeled and used as a probe to detect genes expressed in the brain.d. It lacks the introns of the pre-mRNA.

Recombinant DNA techniques are used to custom-build bacteria for two main purposes: to obtain multiple copies of certain genes and to obtain useful proteins produced by certain genes. Give an example of each of these applications in medicine and agriculture.