- What is the most logical sequence of steps for splicing foreign DNA into a plasmid and inserting the plasmid into a bacterium?A: Extract plasmid DNA from bacterial cells. Cut the plasmid DNA using restriction enzymes. Hydrogen-bond the plasmid DNA to nonplasmid DNA fragments. Use ligase to seal plasmid DNA to nonplasmid DNA. Transform bacteria with a recombinant DNA molecule.B: Extract plasmid DNA from bacterial cells. Hydrogen-bond the plasmid DNA to nonplasmid DNA fragments. Use ligase to seal plasmid DNA to nonplasmid DNA. Transform bacteria with a recombinant DNA molecule. Cut the plasmid DNA using restriction enzymes.C: Transform bacteria with a recombinant DNA molecule. Cut the plasmid DNA using restriction enzymes. Hydrogen-bond the plasmid DNA to nonplasmid DNA fragments. Extract plasmid DNA from bacterial cells. Use ligase to seal plasmid DNA to nonplasmid DNA.D: Cut the plasmid DNA using restriction enzymes. Hydrogen-bond the plasmid DNA to nonplasmid DNA fragments. Use ligase to seal plasmid DNA to nonplasmid DNA. Extract plasmid DNA from bacterial cells. Transform bacteria with a recombinant DNA molecule.
- In E. coli, which of the following enzymes removes the RNA primer from the 5' end of the DNA fragment?A: DNA polymerase IIIB: DNA polymerase IC: helicaseD: ligase
- Which of the following statements accurately describes why Taq polymerase is used in PCR?A: It has regions that are complementary to the primers.B: It is heat stable and can withstand the heating step of PCR.C: It binds more readily than other polymerases to the primers.D: Only minute amounts are needed for each cycle of PCR.
- Which of the following changes are most likely to occur in a male songbird that has a mutation in the cells in its anterior pituitary gland such that FSH and LH are produced at 1% of normal levels?A) decreased frequency of "singing" to attract females B) increased testosterone productionC) increased courtship displays to attract females D) decreased GnRH production
- Which cells are most likely to have the gene for making telomerase switched on?A: The cells in a developing embryo.B: The muscle cells of a woman who is 80 years old.C: The skin cells of a 28 year old person.D: The nerve cells of a 55 year old man.
- The elongation of the leading strand during DNA synthesis __________.A: depends on the action of DNA polymeraseB: occurs in the 3' → 5' directionC: produces Okazaki fragmentsD: progresses away from the replication fork
- Which of the following has the greatest potential as a cancer treatment?A: Find a way to turn on the gene for making telomerase in normal cells, so that the normal cells would soon outnumber the cancer cells.B: Find a way to turn off the gene for making telomerase in cancer cells, since the cells would stop dividing when the telomeres were gone.C: Find a way to turn off the gene for making telomerase in all cells in embryos, so that they never develop cancer.D: Find a way to turn on the gene for making telomerase in cancer cells, since they will be unable to divide if their telomeres are too long.
- Which of the following statements describes one difference between DNA replication in prokaryotes and DNA replication in eukaryotes?A: Prokaryotic chromosomes have a single origin of replication, whereas eukaryotic chromosomes have many.B: The rate of elongation during DNA replication is slower in prokaryotes than in eukaryotes.C: Prokaryotes produce Okazaki fragments during DNA replication, but eukaryotes do not.D: Prokaryotic chromosomes have histones, whereas eukaryotic chromosomes do not.
- Which of the following is NOT true about naked mole rats?A: They can survive in burrows with high levels of carbon dioxide.B: They seem to be resistant to getting cancer.C: They often live for 30 years.D: Their cells do not produce telomerase.
- In the figure, which letter identifies a paired structure that transports sperm during an ejaculation?A) IB) IIC) IIID) IV
- Once uterine contractions have begun in labor, the female body releases several hormones that act in a positive feedback loop. The purpose of this feedback loop ________.A) promotes the development of a new follicleB) ensured continued contractions until labor is completeC) inhibits the release of prostaglandins D) decreases the number of oxytocin receptors in the uterus
- Which enzyme in E. coli catalyzes the elongation of a DNA strand in the 5'→→3' direction?A: topoisomeraseB: DNA ligaseC: primaseD: DNA polymerase III
- A pregnant woman comes into the hospital past her due date. The doctor decides it is time for the baby to be delivered. Which hormone could the doctor use to induce labor?A) progesteroneB) luteinizing hormoneC) follicle stimulating hormoneD) oxytocin
- Which of the following statements correctly describes how the leading and the lagging strands of DNA formed during DNA replication differ?A: The leading strand is synthesized at twice the rate of the lagging strand.B: The lagging strand is synthesized continuously, whereas the leading strand is synthesized in short fragments that are ultimately stitched together.C: The leading strand is synthesized by adding nucleotides to the 3' end of the growing strand, and the lagging strand is synthesized by adding nucleotides to the 5' end.D: The leading strand is synthesized in the same direction as the movement of the replication fork, and the lagging strand is synthesized in the opposite direction.
- Many enzymes are named for the substrate on which they work, either to build or disassemble molecules. Also, enzyme names often end in "-ase." For example, lactase is the enzyme that breaks down lactose. With a name like "telomerase," we can deduce that telomerase is probably:A: some type of a nucleotide that codes for protein, perhaps DNA or RNAB: a protein that tells the cell when to divide and produce new cellsC: an enzyme that chains sugars together to make starches, to provide food for the cellD: an enzyme that regulates the assembly of DNA at the ends of chromosomes
- Which of the following characteristics of the structure of DNA was determined directly from X-ray diffraction photographs of crystallized DNA?A: the double helical structureB: the length of a given DNA moleculeC: the frequency of A versus T nucleotidesD: the sequence of nucleotides
- Cytosine makes up 42% of the nucleotides in a sample of DNA from an organism. Approximately what percentage of the nucleotides in this sample will be thymine?A: 16%B: 8%C: 42%D: 31%
- A student isolates, purifies, and combines in a test tube a variety of molecules needed for DNA replication. After adding some DNA to the mixture, replication occurs, but each DNA molecule consists of a normal strand paired with numerous segments of DNA a few hundred nucleotides long. What has the student probably LEFT OUT of the mixture?A: DNA polymeraseB: primaseC: Okazaki fragmentsD: DNA ligase
- In trying to determine whether DNA or protein was the genetic material, Hershey and Chase made use of which of the following facts about these two types of molecules?A: DNA contains phosphorus, whereas protein does not.B: DNA contains nitrogen, whereas protein does not.C: DNA contains sulfur, whereas protein does not.D: DNA contains purines, whereas protein includes pyrimidines.
- What are telomeres?A: regions of DNA at the end of chromosomes which do not code for making proteinsB: "junk DNA" present throughout the length of our chromosomesC: protein caps found on the ends of chromosomesD: DNA sequences which code for making proteins that regulate cell division