7. Why do histones bind tightly to DNA?
(A) Histones are highly hydrophobic, and DNA is hydrophilic.
(B) Both histones and DNA are strongly hydrophobic.
(C) Histones are covalently linked to the DNA.
(D) Histones are positively charged, and DNA is negatively charged.

3. Consider an experiment in which nucleic acids are separated using agarose gel electrophoresis. In the gel you load the following samples: Lane 1: a population of linearized 3000-bp double-stranded DNA (dsDNA) molecules. Lane 2: a population of circular 3000-bp double-stranded DNA (dsDNA) molecules Which population of nucleic acids would most likely migrate through the gel fastest, and in which direction through the gel will these molecules migrate? (A) The linearized dsDNA would most likely migrate faster than the circular dsDNA. AlI DNA molecules would migrate toward the positive end of the gel. (B) The linearized dsDNA would most likely migrate faster than the circular dsDNA. AIl DNA molecules would migrate towards the negative end of the gel. (C) The circular dsDNA would most likely migrate faster than the linearized dsDNA. All DNA molecules would migrate toward the positive end of the gel. (D) The circular dsDNA would most likely migrate faster than the linearized dsDNA. All DNA molecules would migrate toward the negative end of the gel

4. Which of the following bioinformatics analyses involves scanning sequences in the genomes of related organisms to identify conserved non-coding regions, which may represent unknown regulatory elements? (A) BLAST (B) VISTA (C) genome annotation (D) genome editing

5. In a linear eukaryotic chromatin sample, which of the following strands is looped into domains by scaffolding? (A) the 30-nm chromatin fiber (B) the metaphase chromosome (C) DNA with H1 only (D) the 10-nm chromatin fiber

複選題6. Which of the following statements is true about histones? (A) The mass of histone in chromatin is approximately nine times the mass of DNA. (B) The carboxyl end of each histone extends outward from the nucleosome and is called a "histone tail." (C) Histones are found in mammals, but not in other animals or in plants or fungi. (D) Histone H1 is not present in the nucleosome bead； instead, it draws the nucleosomes together.

8. Why might they be conducting such an experiment? (A) to find the location of this gene in the human genome (B) to collect population data that can be used to assess natural selection (C) to collect population data that can be used to study genetic drift (D) to find which of the students has which alleles

9. Their next two steps, in order, should be (A) electrophoresis of the fragments, followed by Southern blotting using a probe. (B) electrophoresis of the fragments followed by autoradiography. (C) use of a ligase that will anneal the pieces, followed by Southern blotting. (D) use of a fluorescent probe for the gene sequence, then electrophoresis.

10. In recombinant DNA methods, the term vector can refer to (A) a DNA probe used to identify a particular gene. (B) a Single nucleotide polymorhism marker. (C) a plasmid used to transfer DNA into a living cell. (D) the sticky end of a DNA fragment.

11. Double-stranded DNA absorbs less UV light than single-stranded DNA because: (A) base stacking in double-stranded DNA increases the absorbance of white light and causes a decrease in the amount of UV light it can absorb. This decrease in UV absorbance is called the hyperchromic effect. (B) the bases are on the inside of the helix, inaccessible to the UV light in double-stranded DNA. (C) in single-stranded DNA the bases are not interacting, which adds to the light already absorbed by the pentose rings. (D) of the hypochromic effect that results when hydrogen bonding and base stacking in double- stranded DNA limits resonance in the aromatic rings of the bases.

12. A genome is … (A) All of the DNA in a cell. (B) A haploid set of chromosomes plus one copy of any organelle DNA present. (C) A haploid set of chromosomes. (D) A diploid set of chromosomes.

13. DNA microarrays have made a huge impact on genomic studies because they (A) dramatically enhance the efficiency of restriction enzymes. (B) can be used to introduce entire genomes into bacterial cells. (C) allow the expression of many or even all of the genes in the genome to be compared at once. (D) allow physical maps of the genome to be assembled in a very short time.