Question 1

Explain how inheriting mutations in genes encoding DNA repair enzymes could lead to increased cancer risk.

Accepted Answer

Inheriting mutations in genes encoding D

Question 2

Why is the drug acyclovir effective against the herpes simplex virus?

Accepted Answer

Acyclovir is an antiviral medication tha

Question 3

In E. coli oriC, the following portion of the sequence corresponds to one strand of the DUE-containing region.   Which nucleotides in this sequence can be methylated by Dam methylase?

Accepted Answer

The answer of In E. coli oriC, the following portion...

Question 4

The Meselson-Stahl experiment established that:

Accepted Answer

A)  DNA polymerase has a crucial role in DNA synthesis. 
B)  DNA synthesis in E. coli proceeds by a conservative mechanism. 
C)  DNA synthesis in E. coli proceeds by a semiconservative mechanism. 
D)  DNA synthesis requires dATP, dCTP, dGTP, and dTTP. 
E)  newly synthesized DNA in E. coli has a different base composition than the preexisting DNA. 
A)  DNA polymerase has a crucial role in DNA synthesis. 
B)  DNA synthesis in E. coli proceeds by a conservative mechanism. 
C)  DNA synthesis in E. coli proceeds by a semiconservative mechanism. 
D)  DNA synthesis requires dATP, dCTP, dGTP, and dTTP. 
E)  newly synthesized DNA in E. coli has a different base composition than the preexisting DNA.

Question 5

In homologous recombination in E. coli, the protein that assembles into long, helical filaments that coat a region of DNA is:

Accepted Answer

A)  DNA methylase. 
B)  DNA polymerase. 
C)  histone. 
D)  RecA protein. 
E)  RecBCD enzyme. 
A)  DNA methylase. 
B)  DNA polymerase. 
C)  histone. 
D)  RecA protein. 
E)  RecBCD enzyme.

Question 6

At replication forks in E. coli:

Accepted Answer

A)  DNA helicases make endonucleolytic cuts in DNA. 
B)  DNA primers are degraded by exonucleases. 
C)  DNA topoisomerases make endonucleolytic cuts in DNA. 
D)  RNA primers are removed by primase. 
E)  RNA primers are synthesized by primase. 
A)  DNA helicases make endonucleolytic cuts in DNA. 
B)  DNA primers are degraded by exonucleases. 
C)  DNA topoisomerases make endonucleolytic cuts in DNA. 
D)  RNA primers are removed by primase. 
E)  RNA primers are synthesized by primase.

Question 7

Which factor is NOT required for elongation during DNA replication in E. coli?

Accepted Answer

A)  DnaB (helicase) 
B)  DnaG (primase) 
C)  DnaC 
D)  a $\beta$-sliding clamp 
E)  a clamp loader 
A)  DnaB (helicase) 
B)  DnaG (primase) 
C)  DnaC 
D)  a $\beta$-sliding clamp 
E)  a clamp loader

Question 8

All known DNA polymerases can only elongate a preexisting DNA chain (i.e., require a primer) but cannot initiate a new DNA chain. Nevertheless, during semiconservative DNA replication in the cell, entirely new daughter DNA chains are synthesized. Explain the process that occurs in the cell that allows for the synthesis of daughter chains by DNA polymerase.

Accepted Answer

During semiconservative DNA replication,

Question 9

Which statement is FALSE about transposition of DNA?

Accepted Answer

A)  The diversity of immunoglobins is in part due to DNA recombination by transposition. 
B)  Transposition occurs in both prokaryotes and eukaryotes. 
C)  Enzymes are not required for transposition. 
D)  The first step of transposition can be single- or double-stranded DNA cleavage. 
E)  Transposition can lead to simple movement of a DNA region or duplication of that region in a new location. 
A)  The diversity of immunoglobins is in part due to DNA recombination by transposition. 
B)  Transposition occurs in both prokaryotes and eukaryotes. 
C)  Enzymes are not required for transposition. 
D)  The first step of transposition can be single- or double-stranded DNA cleavage. 
E)  Transposition can lead to simple movement of a DNA region or duplication of that region in a new location.

Question 10

Which statement does NOT accurately describe a difference between E. coli DNA polymerases Pol I and Pol III?

Accepted Answer

A)  Pol I has a 3' to 5'exonuclease, and DNA Pol III does not. 
B)  Pol I has a slower polymerization rate than Pol III. 
C)  Pol I is less processive than Pol III. 
D)  Pol I is a single subunit, while Pol III is a multisubunit protein. 
E)  All of these statements accurately describe differences between Pol I and Pol III. 
A)  Pol I has a 3' to 5'exonuclease, and DNA Pol III does not. 
B)  Pol I has a slower polymerization rate than Pol III. 
C)  Pol I is less processive than Pol III. 
D)  Pol I is a single subunit, while Pol III is a multisubunit protein. 
E)  All of these statements accurately describe differences between Pol I and Pol III.

Question 11

Which of the following is/are NOT made out of DNA?

Accepted Answer

A)  Ter 
B)  telomeres 
C)  DNA unwinding elements 
D)  TUS 
E)  All of these are made out of DNA. 
A)  Ter 
B)  telomeres 
C)  DNA unwinding elements 
D)  TUS 
E)  All of these are made out of DNA.

Question 12

DNA replication in E. coli begins at a site in the DNA called the (a) _____. At the replication fork the (b) _____ strand is synthesized continuously while the (c) _____ strand is synthesized discontinuously. On the strand synthesized discontinuously, the short pieces are called (d) _____ fragments. An RNA primer for each of the fragments is synthesized by an enzyme called (e) _____, and this RNA primer is removed after the fragment is synthesized by the enzyme (f) _____, using its (g) _____ activity. The nicks left behind in this process are sealed by the enzyme (h) _____.

Accepted Answer

DNA replication in E. coli begins at a s

Question 13

Which protein is NOT required for E. coli Pol III elongation?

Accepted Answer

A)  SSBP 
B)  DnaB 
C)  DnaG 
D)  DNA gyrase 
E)  All of these are required for elongation. 
A)  SSBP 
B)  DnaB 
C)  DnaG 
D)  DNA gyrase 
E)  All of these are required for elongation.

Question 14

Which process or proteins is/are NOT generally required in homologous recombination to occur?

Accepted Answer

A)  helicase activity 
B)  DNA-dependent DNA polymerases 
C)  primases 
D)  ligases 
E)  nucleases 
A)  helicase activity 
B)  DNA-dependent DNA polymerases 
C)  primases 
D)  ligases 
E)  nucleases

Question 15

Which factor is NOT responsible for the variations in IgG light-chain variations?

Accepted Answer

A)  variations in the V segment sequence 
B)  variations in the J segment sequence 
C)  variations in the C-segment sequence 
D)  variations in the V-J junction 
E)  All of these contribute to the variation in light-chain variations. 
A)  variations in the V segment sequence 
B)  variations in the J segment sequence 
C)  variations in the C-segment sequence 
D)  variations in the V-J junction 
E)  All of these contribute to the variation in light-chain variations.

Question 16

Phage $\lambda$integrates into the E. coli genome using site-specific recombination between a phage sequence, identified as attP, and a bacterial sequence, identified as attB. The attP and attB sequences are different sizes: The attP site is approximately 240-bp long, while attB is significantly shorter at approximately 25 bp. Why does it make sense that the attB site is smaller than the attP site?

Accepted Answer

The attB site being significantly smalle

Question 17

An Okazaki fragment is a:

Accepted Answer

A)  fragment of DNA resulting from endonuclease action. 
B)  fragment of RNA that is a subunit of the 30S ribosome. 
C)  piece of DNA that is synthesized in the 3' $\rightarrow$5' direction. 
D)  segment of DNA that is an intermediate in the synthesis of the lagging strand. 
E)  segment of mRNA synthesized by RNA polymerase. 
A)  fragment of DNA resulting from endonuclease action. 
B)  fragment of RNA that is a subunit of the 30S ribosome. 
C)  piece of DNA that is synthesized in the 3' $\rightarrow$5' direction. 
D)  segment of DNA that is an intermediate in the synthesis of the lagging strand. 
E)  segment of mRNA synthesized by RNA polymerase.

Question 18

Outline the key steps that occur during meiosis in animal germ-line cells.

Accepted Answer

During meiosis in animal germ-line cells

Question 19

E. coli cells exposed to visible light following exposure to ultraviolet light have higher survivability rates than cells that are kept in the dark after exposure to ultraviolet light. Briefly explain this observation, indicating both the type of damage and any significant enzymes that may be involved.

Accepted Answer

When E. coli cells are exposed to ultrav

Question 20

Why does DNA damage that causes alkylation of nucleotides sometimes lead to transition mutations?

Accepted Answer

DNA damage that causes alkylation of nuc

Exam 25: DNA Metabolism

Explain how inheriting mutations in genes encoding DNA repair enzymes could lead to increased cancer risk.

Why is the drug acyclovir effective against the herpes simplex virus?

In E. coli oriC, the following portion of the sequence corresponds to one strand of the DUE-containing region. Which nucleotides in this sequence can be methylated by Dam methylase?

The Meselson-Stahl experiment established that:

In homologous recombination in E. coli, the protein that assembles into long, helical filaments that coat a region of DNA is:

At replication forks in E. coli:

Which factor is NOT required for elongation during DNA replication in E. coli?

Which statement is FALSE about transposition of DNA?

Which statement does NOT accurately describe a difference between E. coli DNA polymerases Pol I and Pol III?

Which of the following is/are NOT made out of DNA?

Which protein is NOT required for E. coli Pol III elongation?

Which process or proteins is/are NOT generally required in homologous recombination to occur?

Which factor is NOT responsible for the variations in IgG light-chain variations?

An Okazaki fragment is a:

Outline the key steps that occur during meiosis in animal germ-line cells.

Why does DNA damage that causes alkylation of nucleotides sometimes lead to transition mutations?

The Foundations of Biochemistry

Water

Amino Acids, Peptides, and Proteins

The Three-Dimensional Structure of Proteins

Protein Function

Enzymes

Carbohydrates and Glycobiology

Nucleotides and Nucleic Acids

DNA-Based Information Technologies

Lipids

Biological Membranes and Transport

Biosignaling

Bioenergetics and Biochemical Reaction Types

Glycolysis, Gluconeogenesis, and the Pentose Phosphate Pathway

Principles of Metabolic Regulation

The Citric Acid Cycle

Fatty Acid Catabolism

Amino Acid Oxidation and the Production of Urea

Oxidative Phosphorylation and Photophosphorylation

Carbohydrate Biosynthesis in Plants and Bacteria

Lipid Biosynthesis

Biosynthesis of Amino Acids, Nucleotides, and Related Molecules

Hormonal Regulation and Integration of Mammalian Metabolism

Genes and Chromosomes

RNA Metabolism

Protein Metabolism

Regulation of Gene Expression

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