4. Why is it so important to be able to amplify DNA fragments when studying genes?
(A) DNA fragments are too small to use individually.
(B) A gene may represent only a millionth of the cell's DNA.
(C) Restriction enzymes cut DNA into fragments that are too small.
(D) A clone requires multiple copies of each gene per clone.
(E) It is important to have multiple copies of DNA in the case of laboratory error.

50. Which of the following best expresses the author’s overall view of modern consumerism? (A) It was deliberately constructed to sustain economic growth. (B) It arose unintentionally from technological progress. (C) It was a beneficial development due to labor shortages. (D) It primarily reflected individual consumer choices.

1. The host range of a virus is determined by (A) the enzymes carried by the virus. (B) whether its nucleic acid is DNA or RNA. (C) the proteins in the host's cytoplasm. (D) the enzymes produced by the virus before it infects the cell. (E) the proteins on its surface and that of the host.

2. Most molecular biologists think that viruses originated from fragments of cellular nucleic acid. Which of the following observations supports this theory? (A) Viruses contain either DNA or RNA. (B) Viruses are enclosed in protein capsids rather than plasma membranes. (C) Viruses can reproduce only inside host cells. (D) Viruses can infect both prokaryotic and eukaryotic cells. (E) Viral genomes are usually similar to the genome of the host cell.

3. Why are yeast cells frequently used as hosts for cloning? (A) They easily form colonies. (B) They can remove exons from mRNA. (C) They do not have plasmids. (D) They are eukaryotic cells. (E) Only yeast cells allow the gene to be cloned.

5. Carl Woese and collaborators identified two major branches of prokaryotic evolution. What was the basis for dividing prokaryotes into two domains? (A) microscopic examination of staining characteristics of the cell wall (B) metabolic characteristics such as the production of methane gas (C) metabolic characteristics such as chemoautotrophy and photosynthesis (D) genetic characteristics such as ribosomal RNA sequences (E) ecological characteristics such as the ability to survive in extreme environments

6. Mitochondrial DNA is primarily involved in coding for proteins needed for electron transport. Therefore, in which body systems would you expect most mitochondrial gene mutations to be exhibited? (A) the immune system and the blood (B) the excretory and respiratory systems (C) the skin and senses (D) the nervous and muscular systems (E) the circulation system

7. What is a syndrome? (A) a characteristic facial appearance (B) a group of traits, all of which must be present if an aneuploidy is to be diagnosed (C) a group of traits typically found in conjunction with a particular chromosomal aberration or gene mutation (D) a characteristic trait usually given the discoverer's name (E) a characteristic that only appears in conjunction with one specific aneuploidy

8. In the formation of biofilms, such as those forming on unbrushed teeth, cell signaling serves which function? (A) formation of mating complexes (B) secretion of apoptotic signals (C) aggregation of bacteria that can cause cavities (D) secretion of substances that inhibit foreign bacteria (E) digestion of unwanted parasite populations

9. Which of the following is true of transcription factors? (A) They control gene expression. (B) They transcribe ATP into cAMP. (C) They initiate the epinephrine response in animal cells. (D) They regulate the synthesis of DNA in response to a signal. (E) They regulate the synthesis of lipids in the cytoplasm.

10. The toxin of Vibrio cholerae causes profuse diarrhea because it (A) modifies a G protein involved in regulating salt and water secretion. (B) decreases the cytosolic concentration of calcium ions, making the cells hypotonic. (C) binds with adenylyl cyclase and triggers the formation of cAMP. (D) signals IP3 to act as a second messenger for the release of calcium. (E) modifies calmodulin and activates a cascade of protein kinases.