Question 1

Why is there a need for a specialized structure at the ends of eukaryotic chromosomes and for the enzyme telomerase?

Accepted Answer

Because all known DNA polymerases elongate DNA in the 5´ to 3´ direction,all require a RNA or DNA primer to initiate synthesis.As the replication fork approaches the end of the chromosome,DNA synthesis on the leading strand continues to the end of the chromosome without a problem.However,because the lagging strand is synthesized discontinuously,it cannot be replicated in its entirety.When the RNA primer is removed,a short segment of DNA remains single-stranded with no way to make this region double-stranded.If there were no specialized mechanism for replicating DNA at the ends,then the chromosome would shorten with each round of replication.Telomerase is the enzyme that completes DNA synthesis at the telomeres.

Question 2

All the following statements are true about a nucleosome except:

Accepted Answer

A) It contains an octamer core of histones. 
B)  It is about 10 nm in diameter. 
C) It is the "string" of the "beads-on-a-string" appearance. 
D) It contains approximately 150 base pairs of DNA. 
A) It contains an octamer core of histones. 
B)  It is about 10 nm in diameter. 
C) It is the "string" of the "beads-on-a-string" appearance. 
D) It contains approximately 150 base pairs of DNA. C

Question 3

Which of the following terms describes when a chromosome is replicated everywhere except the telomeres and centromere,but the daughter chromosomes do not separate?

Accepted Answer

A) hybridization 
B) polytenization 
C) polymerization 
D) heterochromatization 
A) hybridization 
B) polytenization 
C) polymerization 
D) heterochromatization B

Question 4

Histone modifications play integral roles in chromatin condensation and function.Which of the following is NOT considered to be a histone modification?

Accepted Answer

A) acetylation 
B) methylation 
C) phosphorylation 
D) prenylation 
A) acetylation 
B) methylation 
C) phosphorylation 
D) prenylation

Question 5

Short micro RNAs (miRNAs)

Accepted Answer

A) code for proteins. 
B) are common in bacteria but not eukaryotes. 
C) are involved in regulation of gene expression. 
D) have no known function. 
A) code for proteins. 
B) are common in bacteria but not eukaryotes. 
C) are involved in regulation of gene expression. 
D) have no known function.

Question 6

Which of the following is an algorithm designed to compare the sequence of a newly identified protein with sequences already stored in the GenBank database?

Accepted Answer

A) LINES 
B) BLAST 
C) HATs 
D) 3C 
A) LINES 
B) BLAST 
C) HATs 
D) 3C

Question 7

Telomeres

Accepted Answer

A) consist of repetitive sequences with high G content. 
B) are a few hundred base-pairs long in vertebrates. 
C) have specific proteins bound at the DNA ends. 
D) a and c 
A) consist of repetitive sequences with high G content. 
B) are a few hundred base-pairs long in vertebrates. 
C) have specific proteins bound at the DNA ends. 
D) a and c

Question 8

Which of the following is a typical feature of prokaryotic genes?

Accepted Answer

A) polycistronic messenger RNAs 
B) complex transcription units 
C) introns 
D) a and c 
A) polycistronic messenger RNAs 
B) complex transcription units 
C) introns 
D) a and c

Question 9

The chicken lysozyme gene is considered to be a solitary gene because

Accepted Answer

A) it contains no introns. 
B) it is not present on a chromosome. 
C) it is represented only once in the haploid genome. 
D) none of the above 
A) it contains no introns. 
B) it is not present on a chromosome. 
C) it is represented only once in the haploid genome. 
D) none of the above

Question 10

All the following steps are performed by the enzyme transposase during transposition of bacterial insertion sequences except

Accepted Answer

A) excision of the IS element from the donor DNA molecule. 
B) introduction of staggered cuts into the target DNA molecule. 
C) ligation of the IS element to the target DNA. 
D) synthesis of DNA to fill in the single-stranded gaps. 
A) excision of the IS element from the donor DNA molecule. 
B) introduction of staggered cuts into the target DNA molecule. 
C) ligation of the IS element to the target DNA. 
D) synthesis of DNA to fill in the single-stranded gaps.

Question 11

Open reading frame (ORF)analysis is not effective in identifying genes in higher eukaryotes because of the presence of

Accepted Answer

A) promoters. 
B) enhancers. 
C) introns. 
D) repetitious DNA. 
A) promoters. 
B) enhancers. 
C) introns. 
D) repetitious DNA.

Question 12

Describe how modification of histone tails can control chromatin condensation.

Accepted Answer

The amino termini of histones,which are

Question 13

To examine the folding and compaction of chromatin during mitosis,you will need to isolate and stain chromosomes at a particular stage using a special spreading preparation technique.For the best analysis,the chromosomes must be at which one of the following stages?

Accepted Answer

A) metaphase 
B) interphase 
C) telophase 
D) anaphase 
A) metaphase 
B) interphase 
C) telophase 
D) anaphase

Question 14

Which of the following is not a mobile DNA element?

Accepted Answer

A) transposon 
B) long terminal repeats (LTR) 
C) long interspersed elements (LINES) 
D) insertion sequence (IS)elements 
A) transposon 
B) long terminal repeats (LTR) 
C) long interspersed elements (LINES) 
D) insertion sequence (IS)elements

Question 15

All of the following can be found in chromatin except

Accepted Answer

A) DNA. 
B) histones. 
C) RNA. 
D) transcription factors. 
A) DNA. 
B) histones. 
C) RNA. 
D) transcription factors.

Question 16

SINES (short interspersed elements)

Accepted Answer

A) are approximately 300 base pairs long. 
B) are LTRs containing retrotransposons. 
C) are present in over 1 million copies in the human genome. 
D) a and c 
A) are approximately 300 base pairs long. 
B) are LTRs containing retrotransposons. 
C) are present in over 1 million copies in the human genome. 
D) a and c

Question 17

Which of the following pairs of proteins are considered to be paralogous?

Accepted Answer

A) yeast α-tubulin and yeast β-tubulin 
B) yeast α-tubulin and worm α-tubulin 
C) fly β-tubulin and human β-tubulin 
D) worm β-tubulin and human α-tubulin 
A) yeast α-tubulin and yeast β-tubulin 
B) yeast α-tubulin and worm α-tubulin 
C) fly β-tubulin and human β-tubulin 
D) worm β-tubulin and human α-tubulin

Question 18

All the following statements about microsatellite DNA are true except:

Accepted Answer

A) It consists of a repeat length of 1-13 base pairs. 
B) It can cause neurological diseases such as myotonic dystrophy. 
C) It can occur within transcription units. 
D) all of the above 
A) It consists of a repeat length of 1-13 base pairs. 
B) It can cause neurological diseases such as myotonic dystrophy. 
C) It can occur within transcription units. 
D) all of the above

Question 19

"3C" or chromosome conformation capture methods,used to determine the three-dimensional spatial organization of chromatin within nuclei of interphase cells,rely on a series of steps where the end result is the sequence analysis of purified DNA fragments.Which one of the following presents the correct order of steps you as an investigator need to follow in a 3C method strategy?

Accepted Answer

A) shear DNA to 200-600 bp;cross-link proteins and DNA with formaldehyde 
B) ligate linkers marked with biotin onto DNA fragments;dilute and ligate the fragments 
C) cross-link streptavidin to DNA;purify and shear biotin-labeled fragments 
D) none of the above 
A) shear DNA to 200-600 bp;cross-link proteins and DNA with formaldehyde 
B) ligate linkers marked with biotin onto DNA fragments;dilute and ligate the fragments 
C) cross-link streptavidin to DNA;purify and shear biotin-labeled fragments 
D) none of the above

Question 20

How many genes are estimated to be in the human genome?

Accepted Answer

A) 21,000 
B) 35,000 
C) 75,000 
D) 100,000 
A) 21,000 
B) 35,000 
C) 75,000 
D) 100,000

Exam 7: Genes Genomics and Chromosomes

Why is there a need for a specialized structure at the ends of eukaryotic chromosomes and for the enzyme telomerase?

All the following statements are true about a nucleosome except:

Which of the following terms describes when a chromosome is replicated everywhere except the telomeres and centromere,but the daughter chromosomes do not separate?

Histone modifications play integral roles in chromatin condensation and function.Which of the following is NOT considered to be a histone modification?

Short micro RNAs (miRNAs)

Which of the following is an algorithm designed to compare the sequence of a newly identified protein with sequences already stored in the GenBank database?

Telomeres

Which of the following is a typical feature of prokaryotic genes?

The chicken lysozyme gene is considered to be a solitary gene because

All the following steps are performed by the enzyme transposase during transposition of bacterial insertion sequences except

Open reading frame (ORF)analysis is not effective in identifying genes in higher eukaryotes because of the presence of

Describe how modification of histone tails can control chromatin condensation.

To examine the folding and compaction of chromatin during mitosis,you will need to isolate and stain chromosomes at a particular stage using a special spreading preparation technique.For the best analysis,the chromosomes must be at which one of the following stages?

Which of the following is not a mobile DNA element?

All of the following can be found in chromatin except

SINES (short interspersed elements)

Which of the following pairs of proteins are considered to be paralogous?

All the following statements about microsatellite DNA are true except:

How many genes are estimated to be in the human genome?

Chemical Foundations

Molecular Genetic Techniques

Protein Structure and Function

Culturing and Visualizing Cells

Fundamental Molecular Genetic Mechanisms

Bio-membrane Structure

Transcriptional Control of Gene Expression

Post-Transcriptional Gene Control

Transmembrane Transport of Ions and Small Molecules

Cellular Energetics

Moving Proteins Into Membranes and Organelles

Vesicular Traffic, Secretion, and Endocytosis

Signal Transduction and G-Protein Coupled Receptors

Signaling Pathways That Control Gene Activity

Cell Organization and Movement I: Microfilaments

Cell Organization and Movement II: Microtubules and Intermediate Filaments

Regulating the Eukaryotic Cell Cycle

Integrating Cells Into Tissues

Cell Birth, Lineage, and Death

Nerve Cells

Immunology

Cancer

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