Reference no: EM133334031

1. A replicon is:

A. The segment of DNA that after replication is segregated during cell division.
B. The segment of DNA to be replicated and the enzymes and proteins needed in the process.
C. Any autonomously replicated DNA sequence that is not separated in cis from an origin by a terminus.
D. The product of any given replication mechanisms (e.g. single circle).
E. The segment of DNA between the origin and the replication fork.

2. The following features are common to all (prokaryotic, eukaryotic, viral) replication origins:

A. Origins are unique DNA segments that contain multiple short repeated sequences.
B. Origins are palindromic sequences that form stable secondary structures.
C. Multimeric DNA-binding proteins specifically recognize these short repeat sequences.
D. The origin-flanking sequences are A-T-rich to allow melting of the DNA duplex.
E. The origin flanking sequences are G-C rich to stabilize the initiation complex.

3. Rolling circle replication:

A. is the dominant mechanism of replication in bacteria.
B. allows for amplification of the original replicon.
C. always generates double-stranded circular copies of the original replicon.
D. is a common mechanism of bacteriophage DNA replication in bacteria.
E. is autoregulatory in that the gene for the nicking protein resides in the replicon.

4. When DNA is coiled around a histone octamer:

A. it follows a smooth, circular path.
B. The DNA enters and exits on opposite sides of the nucleosome.
C. NA sequences 40 nucleotides apart are brought into proximity.
D. All of the above are true.
E. None of the above are true.

5. All histones undergo post-translational modification of specific amino acids. These modifications:

A. alter the charge of the histone molecule.
B. are permanent.
C. occur (in part) on the N-terminal arms of the histones, which are thought to extend out from the core.
D. occur at specific times during the cell cycle.

6. DNAse I hypersensitive sites:

A. are approximately 100-fold more sensitive to digestion than normal chromatin.
B. Are regions where the DNA is free of nucleosomes.
C. Are regions where the DNA is free of proteins.
D. usually occur only when a gene is being expressed.
E. Can be found at promoters, origins of DNA replication, and centromeres.
F. Can be maintained through DNA replication.

7. When a gene is active:

A. the promoter is generally free of nucleosomes.
B. The entire gene is generally free of nucleosomes.
C. The gene is covered by nucleosomes but the chromatin structure is altered in such a way that the entire gene is more sensitive to nuclease degradation.

8. Which of the following statements about heterochromatin are true?

A. It is transcriptionally inactive.
B. It remains condensed during interphase, when active chromatin decondenses.
C. Constitutive heterochromatin is found in specialized parts of the chromosome that are never expressed, such as centromeres and telomeres.
D. Facultative heterochromatin can control gene expression by placing genes in an inaccessible chromatin structure.