Question 1

Plectonemic supercoils in a negatively supercoiled DNA molecule:

Accepted Answer

A)  are always left-handed.
B)  are always right-handed.
C)  are balanced by solenoidal supercoils
D)  can be either right- or left-handed.
E)  never occur.F) B) and C)
G) A) and E)

Question 2

The SMC proteins (for structural maintenance of chromosomes) include cohesins and condensins,and are known to have all of the following properties except:

Accepted Answer

A)  a complete ATP binding site.
B)  a hinge region.
C)  topoisomerase activity to produce positive supercoils.
D)  the ability to condense DNA.
E)  two coiled-coil domains.F) A) and C)
G) A) and E)

Question 3

Briefly describe the changes in eukaryotic chromosome structure during the cell cycle.

Accepted Answer

Starting with prophase,the DNA undergoes...

Question 4

The most precise modern definition of a gene is a segment of genetic material that:

Accepted Answer

A)  codes for one polypeptide.
B)  codes for one polypeptide or RNA product.
C)  determines one phenotype.
D)  determines one trait.
E)  that codes for one protein.F) B) and E)
G) D) and E)

Question 5

Functional DNA is not found in:

Accepted Answer

A)  bacterial nucleoids.
B)  chloroplasts.
C)  lysosomes.
D)  mitochondria.
E)  nuclei.F) B) and C)
G) D) and E)

Question 6

It is correct to say that DNA supercoiling cannot:

Accepted Answer

A)  be induced by strand separation.
B)  be induced by underwinding of the double helix.
C)  form if there is Z-DNA structure present.
D)  occur if a closed circular double-stranded DNA molecule has a nick.
E)  result in compaction of the DNA structure.F) A) and E)
G) A) and C)

Question 7

Explain the difference between plectonemic and solenoidal supercoiling of DNA;use diagrams to help in your explanation.

Accepted Answer

In plectonemic supercoiling,the double h...

Question 8

Topoisomerases:

Accepted Answer

A)  can change the linking number in increments of 1 or 2.
B)  can act on single-stranded DNA circles.
C)  change the degree of supercoiling of a DNA molecule but not its linking number of DNA.
D)  occur in bacteria,but not in eukaryotes.
E)  always require energy from ATP.F) A) and B)
G) None of the above

Question 9

Approximately what fraction of the human genome is tranaposable elements?

Accepted Answer

A)  1) 5%
B)  5%
C)  10%
D)  45%
E)  80%F) B) and D)
G) A) and C)

Question 10

Bacterial plasmids:

Accepted Answer

A)  are always covalently joined to the bacterial chromosome.
B)  are composed of RNA.
C)  are never circular.
D)  cannot replicate when cells divide.
E)  often encode proteins not normally essential to the bacterium's survival.F) None of the above
G) C) and D)

Question 11

Topoisomerases can:

Accepted Answer

A)  change the linking number (Lk) of a DNA molecule.
B)  change the number of base pairs in a DNA molecule.
C)  change the number of nucleotides in a DNA molecule.
D)  convert D isomers of nucleotides to L isomers.
E)  interconvert DNA and RNA.F) All of the above
G) A) and E)

Question 12

Define,in the context of DNA structure,"topoisomers."

Accepted Answer

Topoisomers are different form...

Question 13

Which of the following does not contribute to the octameric histone core?

Accepted Answer

A)  H1
B)  H2A
C)  H2B
D)  H3
E)  H4F) C) and D)
G) A) and C)

Question 14

Which of these statements about nucleic acids is false?

Accepted Answer

A)  Mitochondria and chloroplasts contain DNA.
B)  Plasmids are genes that encode plasma proteins in mammals.
C)  The chromosome of E.coli is a closed-circular,double-helical DNA.
D)  The DNA of viruses is usually much longer than the viral particle itself.
E)  The genome of many plant viruses is RNA.F) A) and E)
G) D) and E)

Question 15

The overall compaction of a eukaryotic chromosome is greater than ____________ -fold.The first level is nucleosome formation,which compacts about _________ -fold.Next is the 30 nm fiber,which compacts about ________ -fold overall.Higher order folding involves association of the DNA with a nuclear ______________________,which contains large amounts of ________________ and ___________________.

Accepted Answer

10,000
7
100
scaffol...

Question 16

Histones are _______ that are usually associated with _________.

Accepted Answer

A)  acidic proteins;DNA
B)  acidic proteins;RNA
C)  basic proteins;DNA
D)  basic proteins;RNA
E)  coenzymes derived from histidine;enzymesF) A) and B)
G) A) and C)

Question 17

A condensed eukaryotic chromosome is known to be associated with all of the following proteins,except for:

Accepted Answer

A)  core histones H2A,H2B,H3,and H4.
B)  histone H1.
C)  SMC proteins.
D)  topoisomerase I.
E)  topoisomerase II.F) A) and E)
G) None of the above

Question 18

For a closed-circular DNA molecule of 10,000 base pairs in the fully relaxed form,the linking number (Lk) is about:

Accepted Answer

A)  10,000.
B)  950.
C)  100.
D)  9) 5.
E)  2) F) B) and D)
G) C) and D)

Question 19

Nucleosomes:

Accepted Answer

A)  are important features of chromosome organization in eukaryotes and bacteria.
B)  are composed of proteins rich in acidic amino acids,such as Asp and Glu.
C)  are composed of protein and RNA.
D)  bind DNA and alter its supercoiling.
E)  occur in chromatin at irregular intervals along the DNA molecule.F) B) and C)
G) A) and E)

Question 20

Explain how inhibitors of topoisomerase would inhibit the growth of tumors.Would these drugs be expected to inhibit the growth of normal cells as well?

Accepted Answer

Dividing cells must replicate their DNA;...

Exam 24: Genes and Chromosomes

Explain how inhibitors of topoisomerase would inhibit the growth of tumors.Would these drugs be expected to inhibit the growth of normal cells as well?

Correct Answer
verified
Dividing cells must replicate their DNA;...
View Answer

Plectonemic supercoils in a negatively supercoiled DNA molecule:

Correct Answer
verified

Nucleosomes:

Correct Answer
verified

Correct Answer
verified
10,000
7
100
scaffol...
View Answer

The SMC proteins (for structural maintenance of chromosomes) include cohesins and condensins,and are known to have all of the following properties except:

Correct Answer
verified

Topoisomerases can:

Correct Answer
verified

Define,in the context of DNA structure,"topoisomers."

Correct Answer
verified
Topoisomers are different form...
View Answer

Which of the following does not contribute to the octameric histone core?

Correct Answer
verified

Which of these statements about nucleic acids is false?

Correct Answer
verified

Explain the difference between plectonemic and solenoidal supercoiling of DNA;use diagrams to help in your explanation.

Correct Answer
verified
In plectonemic supercoiling,the double h...
View Answer

It is correct to say that DNA supercoiling cannot:

Correct Answer
verified

A condensed eukaryotic chromosome is known to be associated with all of the following proteins,except for:

Correct Answer
verified

Briefly describe the changes in eukaryotic chromosome structure during the cell cycle.

Correct Answer
verified
Starting with prophase,the DNA undergoes...
View Answer

Histones are _ that are usually associated with ___.

Correct Answer
verified

Approximately what fraction of the human genome is tranaposable elements?

Correct Answer
verified

For a closed-circular DNA molecule of 10,000 base pairs in the fully relaxed form,the linking number (Lk) is about:

Correct Answer
verified

Bacterial plasmids:

Correct Answer
verified

The most precise modern definition of a gene is a segment of genetic material that:

Correct Answer
verified

Functional DNA is not found in:

Correct Answer
verified

Topoisomerases:

Correct Answer
verified

Exam 24: Genes and Chromosomes

Explain how inhibitors of topoisomerase would inhibit the growth of tumors.Would these drugs be expected to inhibit the growth of normal cells as well?

Correct AnswerverifiedDividing cells must replicate their DNA;...View AnswerShow Answer

Plectonemic supercoils in a negatively supercoiled DNA molecule:

Correct AnswerverifiedShow Answer

Nucleosomes:

Correct AnswerverifiedShow Answer

Correct Answerverified10,0007100scaffol...View AnswerShow Answer

The SMC proteins (for structural maintenance of chromosomes) include cohesins and condensins,and are known to have all of the following properties except:

Correct AnswerverifiedShow Answer

Topoisomerases can:

Correct AnswerverifiedShow Answer

Define,in the context of DNA structure,"topoisomers."

Correct AnswerverifiedTopoisomers are different form...View AnswerShow Answer

Which of the following does not contribute to the octameric histone core?

Correct AnswerverifiedShow Answer

Which of these statements about nucleic acids is false?

Correct AnswerverifiedShow Answer

Explain the difference between plectonemic and solenoidal supercoiling of DNA;use diagrams to help in your explanation.

Correct AnswerverifiedIn plectonemic supercoiling,the double h...View AnswerShow Answer

It is correct to say that DNA supercoiling cannot:

Correct AnswerverifiedShow Answer

A condensed eukaryotic chromosome is known to be associated with all of the following proteins,except for:

Correct AnswerverifiedShow Answer

Briefly describe the changes in eukaryotic chromosome structure during the cell cycle.

Correct AnswerverifiedStarting with prophase,the DNA undergoes...View AnswerShow Answer

Histones are _______ that are usually associated with _________.

Correct AnswerverifiedShow Answer

Approximately what fraction of the human genome is tranaposable elements?

Correct AnswerverifiedShow Answer

For a closed-circular DNA molecule of 10,000 base pairs in the fully relaxed form,the linking number (Lk) is about:

Correct AnswerverifiedShow Answer

Bacterial plasmids:

Correct AnswerverifiedShow Answer

The most precise modern definition of a gene is a segment of genetic material that:

Correct AnswerverifiedShow Answer

Functional DNA is not found in:

Correct AnswerverifiedShow Answer

Topoisomerases:

Correct AnswerverifiedShow Answer

Correct Answer
verified
Dividing cells must replicate their DNA;...
View Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
10,000
7
100
scaffol...
View Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
Topoisomers are different form...
View Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
In plectonemic supercoiling,the double h...
View Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
Starting with prophase,the DNA undergoes...
View Answer

Histones are _ that are usually associated with ___.

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified