Question 1

The 30 nm fibers of a chromosome are attached to a/an scaffold that holds the fibers in large loops.

Accepted Answer

A)  RNA-protein 
B)  glycoprotein 
C)  actin filament 
D)  histone 
A)  RNA-protein 
B)  glycoprotein 
C)  actin filament 
D)  histone

Question 2

Supercoiling of pure circular DNA is a result of .

Accepted Answer

A)  underwinding or overwinding of the helix 
B)  entanglements because of the long length of the strands 
C)  the lack of associated histones 
D)  the activity of exonucleases 
A)  underwinding or overwinding of the helix 
B)  entanglements because of the long length of the strands 
C)  the lack of associated histones 
D)  the activity of exonucleases

Question 3

Which type of RNA is the most abundant in living cells by percent)?

Accepted Answer

A)  ribosomal 
B)  messenger 
C)  small 
D)  transfer 
A)  ribosomal 
B)  messenger 
C)  small 
D)  transfer

Question 4

Topoisomerases cut one or both coiled DNA strands, wind the ends by rotation, and then rejoin the cut ends.

Accepted Answer

A) True 
 B)False

Question 5

Histone is not part of the histone octamer, but binds to linker DNA and is responsible for higher-order chromatin structure.

Accepted Answer

A)  H1 
B)  H2 
C)  H3 
D)  H4 
E)  None of the above 
A)  H1 
B)  H2 
C)  H3 
D)  H4 
E)  None of the above

Question 6

RNAs are single-stranded molecules with little complex secondary structure.

Accepted Answer

A) True 
 B)False

Question 7

Purines and pyrimidines exist in two tautomeric forms lactam and lactim); nucleosides exist in two conformations syn and anti). The most common forms found in cells are

Accepted Answer

A)  lactam and anti. 
B)  lactam and syn. 
C)  lactim and anti. 
D)  lactim and syn. 
A)  lactam and anti. 
B)  lactam and syn. 
C)  lactim and anti. 
D)  lactim and syn.

Question 8

Regions of DNA that are most easily unwound have

Accepted Answer

A)  about half G and half C. 
B)  alternating A and G. 
C)  greater G:C content. 
D)  greater A:T content. 
A)  about half G and half C. 
B)  alternating A and G. 
C)  greater G:C content. 
D)  greater A:T content.

Question 9

Adenylate and AMP each contain phosphate groups.

Accepted Answer

A)  0 
B)  1 
C)  2 
D)  3 
E)  None of the above 
A)  0 
B)  1 
C)  2 
D)  3 
E)  None of the above

Question 10

The two strands of double-stranded DNA have the same content of each of the bases A, T, G and C.

Accepted Answer

A) True 
 B)False

Question 11

The genome of a species does not include the DNA in mitochondrial and chlorplast DNA.

Accepted Answer

A) True 
 B)False

Question 12

The major and minor grooves are the same in B-DNA, A-DNA, and Z-DNA.

Accepted Answer

A) True 
 B)False

Question 13

Uracil is found in most RNA, while 5-methyluracil is found in most DNA.

Accepted Answer

A) True 
 B)False

Question 14

Which does not occur during the hydrolysis of RNA by RNase A?

Accepted Answer

A)  Covalent catalysis involving a bond between a pyrimidine and a lysine of RNase A. 
B)  Acid-base catalysis to cleave the phosphodiester bond. 
C)  Abstraction of a proton from the 2ʹ-hydroxyl group by histidine. 
D)  Transition-state stabilization of a pentavalent phosphorous atom. 
A)  Covalent catalysis involving a bond between a pyrimidine and a lysine of RNase A. 
B)  Acid-base catalysis to cleave the phosphodiester bond. 
C)  Abstraction of a proton from the 2ʹ-hydroxyl group by histidine. 
D)  Transition-state stabilization of a pentavalent phosphorous atom.

Question 15

Stem-loop structures in RNA resemble the form of double-helical DNA.

Accepted Answer

A)  A 
B)  B 
C)  Z 
D)  supercoiled circular 
A)  A 
B)  B 
C)  Z 
D)  supercoiled circular

Question 16

About 150 bp of DNA wrap around the histone octamer to form a bead-like structure. The
ʺbeadsʺ are separated by about 50 bp of linker DNA.

Accepted Answer

A) True 
 B)False

Question 17

The difference between dGMP and GMP is

Accepted Answer

A)  the type of phosphodiester linkage. 
B)  one hydroxyl group. 
C)  syn versus anti conformation. 
D)  the presence of DNA or RNA. 
A)  the type of phosphodiester linkage. 
B)  one hydroxyl group. 
C)  syn versus anti conformation. 
D)  the presence of DNA or RNA.

Question 18

Cells fed5-methyl uracil radioactive in the methy group) will form radioactive .

Accepted Answer

A)  RNA 
B)  DNA 
C)  ribosomes 
D)  tRNA 
E)  A, C and D 
A)  RNA 
B)  DNA 
C)  ribosomes 
D)  tRNA 
E)  A, C and D

Question 19

Which recognition sequence is not a palindrome? DNA sequences are shown in the standard 5ʹ →3ʹ direction)

Accepted Answer

A)  GGGCCC 
B)  TCTAGA 
C)  AAGCTT 
D)  Both B and C 
E)  None of the above. All of the sequences shown are palindromes. 
A)  GGGCCC 
B)  TCTAGA 
C)  AAGCTT 
D)  Both B and C 
E)  None of the above. All of the sequences shown are palindromes.

Question 20

The supercoiling of double-stranded circular DNA can be removed by cleaving a single phosphodiester bond on only one strand nicking).

Accepted Answer

A) True 
 B)False

Exam 19: Nucleic Acids

The 30 nm fibers of a chromosome are attached to a/an scaffold that holds the fibers in large loops.

Supercoiling of pure circular DNA is a result of .

Which type of RNA is the most abundant in living cells by percent)?

Topoisomerases cut one or both coiled DNA strands, wind the ends by rotation, and then rejoin the cut ends.

Histone is not part of the histone octamer, but binds to linker DNA and is responsible for higher-order chromatin structure.

RNAs are single-stranded molecules with little complex secondary structure.

Purines and pyrimidines exist in two tautomeric forms lactam and lactim); nucleosides exist in two conformations syn and anti). The most common forms found in cells are

Regions of DNA that are most easily unwound have

Adenylate and AMP each contain phosphate groups.

The two strands of double-stranded DNA have the same content of each of the bases A, T, G and C.

The genome of a species does not include the DNA in mitochondrial and chlorplast DNA.

The major and minor grooves are the same in B-DNA, A-DNA, and Z-DNA.

Uracil is found in most RNA, while 5-methyluracil is found in most DNA.

Which does not occur during the hydrolysis of RNA by RNase A?

Stem-loop structures in RNA resemble the form of double-helical DNA.

About 150 bp of DNA wrap around the histone octamer to form a bead-like structure. The ʺbeadsʺ are separated by about 50 bp of linker DNA.

The difference between dGMP and GMP is

Cells fed5-methyl uracil radioactive in the methy group) will form radioactive .

Which recognition sequence is not a palindrome? DNA sequences are shown in the standard 5ʹ →3ʹ direction)

The supercoiling of double-stranded circular DNA can be removed by cleaving a single phosphodiester bond on only one strand nicking).

Introduction to Biochemistry

Water

Amino Acids and the Primary Structures of Proteins

Proteins: Three-Dimensional Structure and Function

Properties of Enzymes

Mechanisms of Enzymes

Coenzymes and Vitamins

Carbohydrates

Lipids and Membranes

Introduction to Metabolism

Glycolysis

Gluconeogenesis, the Pentose Phosphate Pathway, and Glycogen Metabolism

The Citric Acid Cycle

Electron Transport and Oxidative Phosphorylation

Photosynthesis

Lipid Metabolism

Amino Acid Metabolism

Nucleotide Metabolism

Dna Replication, Repair, and Recombination

Transcription and Rna Processing

Protein Synthesis

Recombinant Dna Technology

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