The effect on lac operon on deleting the gene encoding the lac repressor is to be determined. Concept Introduction : E. Coli contains of lac operon, which is involved in lactose metabolism . It can be expressed in the presence of lactose and absence of glucose. The two regulators of lac operons are the lac repressor and the CAP. The function of these two regulators is to turn ‘on’ and ‘off’ the operon in response to glucose and lactose.

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Answer 1

Question

Chapter 32, Problem 1P

a)

Interpretation Introduction

Interpretation: The effect on lac operon on deleting the gene encoding the lac repressor is to be determined.

Concept Introduction: E. Coli contains of lac operon, which is involved in lactose metabolism. It can be expressed in the presence of lactose and absence of glucose. The two regulators of lac operons are the lac repressor and the CAP. The function of these two regulators is to turn ‘on’ and ‘off’ the operon in response to glucose and lactose.

a)

Expert Solution

Answer to Problem 1P

In the absence of lac repressor gene, beta-galactosidase, lac permease, and thiogalactosidase transacetylase will be expressed by the cell.

Explanation of Solution

The function of lac repressor is to sense the lactose. It blocks the operon transcription in the absence of lactose. Lac operon consists of a promoter, lac repressor, terminator, lac promoter, lac operator, lac Z, lac Y, and lac A. The function of lac Z is to express beta-galactosidase, lac Y is to express beta-galactosidase permease, and lac A is to express galactosidase acetyltransferase. So, when lac repressor in gene is absent, then even in the absence of lactose, all the above proteins are expressed.

b)

Interpretation Introduction

Interpretation: The effect on lac operon on deleting the gene encoding the lac operator.

Concept Introduction: E. Coli contains lac operon, which is involved in lactose metabolism. It can be expressed in the presence of lactose and absence of glucose. The two regulators of lac operons are the lac repressor and the CAP. The function of these two regulators is to turn ‘on’ and ‘off’ the operon in response to glucose and lactose.

b)

Expert Solution

Answer to Problem 1P

In the absence of lac operator gene, beta-galactosidase, beta-galactosidasepermease, and thiogalactosidase transacetylase will be expressed by the cell.

Explanation of Solution

The function of the lac operator is to express lac operon in the presence of lactose. Lac operon consists of a promoter, lac repressor, terminator, lac promoter, lac operator, lac Z, lac Y, and lac A. The function of lac Z is to express beta-galactosidase, lac Y is to express beta-galactosidase permease, and lac A is to express galactosidase acetyltransferase. So, when the lac operator gene is absent, then even in the absence of lactose, all the above proteins are expressed.

c)

Interpretation Introduction

Interpretation: The effect on lac operon on deleting the gene encoding the CAP.

Concept Introduction:E. Coli contains lac operon, which is involved in lactose metabolism. It can be expressed in the presence of lactose and absence of glucose. The two regulators of lac operons are the lac repressor and the CAP. The function of these two regulators is to turn ‘on’ and ‘off’ the operon in response to glucose and lactose.

c)

Expert Solution

Answer to Problem 1P

If gene encoding CAP is absent, then even in the low glucose levels, the levels of beta-galactosidase and arabinose isomerase will remain low.

Explanation of Solution

Catabolite activator protein (CAP) senses the presence or absence of glucose. When glucose levels are low, then the operon transcription gets activated. At low glucose concentrations, cAMP is produced, which gets bind to CAP. After this, CAP binds to DNA and helps RNA pol bin to the lac operator, leading to the transcription process.

So, when the CAP gene is absent, then it cannot bind to RNA pol, and transcription of lac operator will not occur.

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Students have asked these similar questions

The beta-lactamase hydrolyzes the lactam-ring in penicillin. Describe the mechanism of hydrolysis, insuring to include the involvement of S, D, & K in the reaction sequence. Please help

To map the active site of beta-lactamase, the enzyme was hydrolyzed with trypsin to yield a hexapeptide (P1) with the following amino acids. Glu, Lys, Leu, Phe, Met, and Ser. Treatment of P1 with phenyl isothiocyanate yielded a PTH derivative of phenylalanine and a peptide (P2). Treatment of P1 with cyanogenbromide gave an acidic tetrapeptide (P3) and a dipeptide (P4).Treatment of P2 with 1-fluoro-2,4-dinitrobenzene, followed by complete hydrolysis, yields N-2,4-dinitrophenyl-Glu. P1, P2, and P3 contain the active site serine. Why doesn't D in this hexapeptide not participate in the hydrolysis of the beta-lactam ring even though S, K, and D are involved in the catalyst?

To map the active site of -lactamase, the enzyme was hydrolyzed with trypsin to yield a hexapeptide (P1) with the following amino acids. Glu, Lys, Leu, Phe, Met, and Ser. Treatment of P1 with phenyl isothiocyanate yielded a PTH derivative of phenylalanine and a peptide (P2). Treatment of P1 with cyanogenbromide gave an acidic tetrapeptide (P3) and a dipeptide (P4).Treatment of P2 with 1-fluoro-2,4-dinitrobenzene, followed by complete hydrolysis, yields N-2,4-dinitrophenyl-Glu. P1, P2, and P3 contain the active site serine. Using the experimental results described above derive the primary sequence of the active site hexapeptide. Please help!

Answer 2

Question

Chapter 32, Problem 1P

a)

Interpretation Introduction

Interpretation: The effect on lac operon on deleting the gene encoding the lac repressor is to be determined.

Concept Introduction: E. Coli contains of lac operon, which is involved in lactose metabolism. It can be expressed in the presence of lactose and absence of glucose. The two regulators of lac operons are the lac repressor and the CAP. The function of these two regulators is to turn ‘on’ and ‘off’ the operon in response to glucose and lactose.

a)

Expert Solution

Answer to Problem 1P

In the absence of lac repressor gene, beta-galactosidase, lac permease, and thiogalactosidase transacetylase will be expressed by the cell.

Explanation of Solution

The function of lac repressor is to sense the lactose. It blocks the operon transcription in the absence of lactose. Lac operon consists of a promoter, lac repressor, terminator, lac promoter, lac operator, lac Z, lac Y, and lac A. The function of lac Z is to express beta-galactosidase, lac Y is to express beta-galactosidase permease, and lac A is to express galactosidase acetyltransferase. So, when lac repressor in gene is absent, then even in the absence of lactose, all the above proteins are expressed.

b)

Interpretation Introduction

Interpretation: The effect on lac operon on deleting the gene encoding the lac operator.

Concept Introduction: E. Coli contains lac operon, which is involved in lactose metabolism. It can be expressed in the presence of lactose and absence of glucose. The two regulators of lac operons are the lac repressor and the CAP. The function of these two regulators is to turn ‘on’ and ‘off’ the operon in response to glucose and lactose.

b)

Expert Solution

Answer to Problem 1P

In the absence of lac operator gene, beta-galactosidase, beta-galactosidasepermease, and thiogalactosidase transacetylase will be expressed by the cell.

Explanation of Solution

The function of the lac operator is to express lac operon in the presence of lactose. Lac operon consists of a promoter, lac repressor, terminator, lac promoter, lac operator, lac Z, lac Y, and lac A. The function of lac Z is to express beta-galactosidase, lac Y is to express beta-galactosidase permease, and lac A is to express galactosidase acetyltransferase. So, when the lac operator gene is absent, then even in the absence of lactose, all the above proteins are expressed.

c)

Interpretation Introduction

Interpretation: The effect on lac operon on deleting the gene encoding the CAP.

Concept Introduction:E. Coli contains lac operon, which is involved in lactose metabolism. It can be expressed in the presence of lactose and absence of glucose. The two regulators of lac operons are the lac repressor and the CAP. The function of these two regulators is to turn ‘on’ and ‘off’ the operon in response to glucose and lactose.

c)

Expert Solution

Answer to Problem 1P

If gene encoding CAP is absent, then even in the low glucose levels, the levels of beta-galactosidase and arabinose isomerase will remain low.

Explanation of Solution

Catabolite activator protein (CAP) senses the presence or absence of glucose. When glucose levels are low, then the operon transcription gets activated. At low glucose concentrations, cAMP is produced, which gets bind to CAP. After this, CAP binds to DNA and helps RNA pol bin to the lac operator, leading to the transcription process.

So, when the CAP gene is absent, then it cannot bind to RNA pol, and transcription of lac operator will not occur.

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Answer 3

Question

Chapter 32, Problem 1P

a)

Interpretation Introduction

Interpretation: The effect on lac operon on deleting the gene encoding the lac repressor is to be determined.

Concept Introduction: E. Coli contains of lac operon, which is involved in lactose metabolism. It can be expressed in the presence of lactose and absence of glucose. The two regulators of lac operons are the lac repressor and the CAP. The function of these two regulators is to turn ‘on’ and ‘off’ the operon in response to glucose and lactose.

a)

Expert Solution

Answer to Problem 1P

In the absence of lac repressor gene, beta-galactosidase, lac permease, and thiogalactosidase transacetylase will be expressed by the cell.

Explanation of Solution

The function of lac repressor is to sense the lactose. It blocks the operon transcription in the absence of lactose. Lac operon consists of a promoter, lac repressor, terminator, lac promoter, lac operator, lac Z, lac Y, and lac A. The function of lac Z is to express beta-galactosidase, lac Y is to express beta-galactosidase permease, and lac A is to express galactosidase acetyltransferase. So, when lac repressor in gene is absent, then even in the absence of lactose, all the above proteins are expressed.

b)

Interpretation Introduction

Interpretation: The effect on lac operon on deleting the gene encoding the lac operator.

Concept Introduction: E. Coli contains lac operon, which is involved in lactose metabolism. It can be expressed in the presence of lactose and absence of glucose. The two regulators of lac operons are the lac repressor and the CAP. The function of these two regulators is to turn ‘on’ and ‘off’ the operon in response to glucose and lactose.

b)

Expert Solution

Answer to Problem 1P

In the absence of lac operator gene, beta-galactosidase, beta-galactosidasepermease, and thiogalactosidase transacetylase will be expressed by the cell.

Explanation of Solution

The function of the lac operator is to express lac operon in the presence of lactose. Lac operon consists of a promoter, lac repressor, terminator, lac promoter, lac operator, lac Z, lac Y, and lac A. The function of lac Z is to express beta-galactosidase, lac Y is to express beta-galactosidase permease, and lac A is to express galactosidase acetyltransferase. So, when the lac operator gene is absent, then even in the absence of lactose, all the above proteins are expressed.

c)

Interpretation Introduction

Interpretation: The effect on lac operon on deleting the gene encoding the CAP.

Concept Introduction:E. Coli contains lac operon, which is involved in lactose metabolism. It can be expressed in the presence of lactose and absence of glucose. The two regulators of lac operons are the lac repressor and the CAP. The function of these two regulators is to turn ‘on’ and ‘off’ the operon in response to glucose and lactose.

c)

Expert Solution

Answer to Problem 1P

If gene encoding CAP is absent, then even in the low glucose levels, the levels of beta-galactosidase and arabinose isomerase will remain low.

Explanation of Solution

Catabolite activator protein (CAP) senses the presence or absence of glucose. When glucose levels are low, then the operon transcription gets activated. At low glucose concentrations, cAMP is produced, which gets bind to CAP. After this, CAP binds to DNA and helps RNA pol bin to the lac operator, leading to the transcription process.

So, when the CAP gene is absent, then it cannot bind to RNA pol, and transcription of lac operator will not occur.

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Answer 4

Question

Chapter 32, Problem 1P

a)

Interpretation Introduction

Interpretation: The effect on lac operon on deleting the gene encoding the lac repressor is to be determined.

Concept Introduction: E. Coli contains of lac operon, which is involved in lactose metabolism. It can be expressed in the presence of lactose and absence of glucose. The two regulators of lac operons are the lac repressor and the CAP. The function of these two regulators is to turn ‘on’ and ‘off’ the operon in response to glucose and lactose.

a)

Expert Solution

Answer to Problem 1P

In the absence of lac repressor gene, beta-galactosidase, lac permease, and thiogalactosidase transacetylase will be expressed by the cell.

Explanation of Solution

The function of lac repressor is to sense the lactose. It blocks the operon transcription in the absence of lactose. Lac operon consists of a promoter, lac repressor, terminator, lac promoter, lac operator, lac Z, lac Y, and lac A. The function of lac Z is to express beta-galactosidase, lac Y is to express beta-galactosidase permease, and lac A is to express galactosidase acetyltransferase. So, when lac repressor in gene is absent, then even in the absence of lactose, all the above proteins are expressed.

b)

Interpretation Introduction

Interpretation: The effect on lac operon on deleting the gene encoding the lac operator.

Concept Introduction: E. Coli contains lac operon, which is involved in lactose metabolism. It can be expressed in the presence of lactose and absence of glucose. The two regulators of lac operons are the lac repressor and the CAP. The function of these two regulators is to turn ‘on’ and ‘off’ the operon in response to glucose and lactose.

b)

Expert Solution

Answer to Problem 1P

In the absence of lac operator gene, beta-galactosidase, beta-galactosidasepermease, and thiogalactosidase transacetylase will be expressed by the cell.

Explanation of Solution

The function of the lac operator is to express lac operon in the presence of lactose. Lac operon consists of a promoter, lac repressor, terminator, lac promoter, lac operator, lac Z, lac Y, and lac A. The function of lac Z is to express beta-galactosidase, lac Y is to express beta-galactosidase permease, and lac A is to express galactosidase acetyltransferase. So, when the lac operator gene is absent, then even in the absence of lactose, all the above proteins are expressed.

c)

Interpretation Introduction

Interpretation: The effect on lac operon on deleting the gene encoding the CAP.

Concept Introduction:E. Coli contains lac operon, which is involved in lactose metabolism. It can be expressed in the presence of lactose and absence of glucose. The two regulators of lac operons are the lac repressor and the CAP. The function of these two regulators is to turn ‘on’ and ‘off’ the operon in response to glucose and lactose.

c)

Expert Solution

Answer to Problem 1P

If gene encoding CAP is absent, then even in the low glucose levels, the levels of beta-galactosidase and arabinose isomerase will remain low.

Explanation of Solution

Catabolite activator protein (CAP) senses the presence or absence of glucose. When glucose levels are low, then the operon transcription gets activated. At low glucose concentrations, cAMP is produced, which gets bind to CAP. After this, CAP binds to DNA and helps RNA pol bin to the lac operator, leading to the transcription process.

So, when the CAP gene is absent, then it cannot bind to RNA pol, and transcription of lac operator will not occur.

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Subscribe now to access step-by-step solutions to millions of textbook problems written by subject matter experts!

Answer 5

Chapter 32, Problem 1P

a)

Interpretation Introduction

Interpretation: The effect on lac operon on deleting the gene encoding the lac repressor is to be determined.

Concept Introduction: E. Coli contains of lac operon, which is involved in lactose metabolism. It can be expressed in the presence of lactose and absence of glucose. The two regulators of lac operons are the lac repressor and the CAP. The function of these two regulators is to turn ‘on’ and ‘off’ the operon in response to glucose and lactose.

a)

Expert Solution

Answer to Problem 1P

In the absence of lac repressor gene, beta-galactosidase, lac permease, and thiogalactosidase transacetylase will be expressed by the cell.

Explanation of Solution

The function of lac repressor is to sense the lactose. It blocks the operon transcription in the absence of lactose. Lac operon consists of a promoter, lac repressor, terminator, lac promoter, lac operator, lac Z, lac Y, and lac A. The function of lac Z is to express beta-galactosidase, lac Y is to express beta-galactosidase permease, and lac A is to express galactosidase acetyltransferase. So, when lac repressor in gene is absent, then even in the absence of lactose, all the above proteins are expressed.

b)

Interpretation Introduction

Interpretation: The effect on lac operon on deleting the gene encoding the lac operator.

Concept Introduction: E. Coli contains lac operon, which is involved in lactose metabolism. It can be expressed in the presence of lactose and absence of glucose. The two regulators of lac operons are the lac repressor and the CAP. The function of these two regulators is to turn ‘on’ and ‘off’ the operon in response to glucose and lactose.

b)

Expert Solution

Answer to Problem 1P

In the absence of lac operator gene, beta-galactosidase, beta-galactosidasepermease, and thiogalactosidase transacetylase will be expressed by the cell.

Explanation of Solution

The function of the lac operator is to express lac operon in the presence of lactose. Lac operon consists of a promoter, lac repressor, terminator, lac promoter, lac operator, lac Z, lac Y, and lac A. The function of lac Z is to express beta-galactosidase, lac Y is to express beta-galactosidase permease, and lac A is to express galactosidase acetyltransferase. So, when the lac operator gene is absent, then even in the absence of lactose, all the above proteins are expressed.

c)

Interpretation Introduction

Interpretation: The effect on lac operon on deleting the gene encoding the CAP.

Concept Introduction:E. Coli contains lac operon, which is involved in lactose metabolism. It can be expressed in the presence of lactose and absence of glucose. The two regulators of lac operons are the lac repressor and the CAP. The function of these two regulators is to turn ‘on’ and ‘off’ the operon in response to glucose and lactose.

c)

Expert Solution

Answer to Problem 1P

If gene encoding CAP is absent, then even in the low glucose levels, the levels of beta-galactosidase and arabinose isomerase will remain low.

Explanation of Solution

Catabolite activator protein (CAP) senses the presence or absence of glucose. When glucose levels are low, then the operon transcription gets activated. At low glucose concentrations, cAMP is produced, which gets bind to CAP. After this, CAP binds to DNA and helps RNA pol bin to the lac operator, leading to the transcription process.

So, when the CAP gene is absent, then it cannot bind to RNA pol, and transcription of lac operator will not occur.

Answer 6

Chapter 32, Problem 1P

a)

Interpretation Introduction

Interpretation: The effect on lac operon on deleting the gene encoding the lac repressor is to be determined.

Concept Introduction: E. Coli contains of lac operon, which is involved in lactose metabolism. It can be expressed in the presence of lactose and absence of glucose. The two regulators of lac operons are the lac repressor and the CAP. The function of these two regulators is to turn ‘on’ and ‘off’ the operon in response to glucose and lactose.

a)

Expert Solution

Answer to Problem 1P

In the absence of lac repressor gene, beta-galactosidase, lac permease, and thiogalactosidase transacetylase will be expressed by the cell.

Explanation of Solution

The function of lac repressor is to sense the lactose. It blocks the operon transcription in the absence of lactose. Lac operon consists of a promoter, lac repressor, terminator, lac promoter, lac operator, lac Z, lac Y, and lac A. The function of lac Z is to express beta-galactosidase, lac Y is to express beta-galactosidase permease, and lac A is to express galactosidase acetyltransferase. So, when lac repressor in gene is absent, then even in the absence of lactose, all the above proteins are expressed.

Answer 7

Chapter 32, Problem 1P

a)

Interpretation Introduction

Interpretation: The effect on lac operon on deleting the gene encoding the lac repressor is to be determined.

Concept Introduction: E. Coli contains of lac operon, which is involved in lactose metabolism. It can be expressed in the presence of lactose and absence of glucose. The two regulators of lac operons are the lac repressor and the CAP. The function of these two regulators is to turn ‘on’ and ‘off’ the operon in response to glucose and lactose.

Answer 8

a)

Expert Solution

Answer to Problem 1P

In the absence of lac repressor gene, beta-galactosidase, lac permease, and thiogalactosidase transacetylase will be expressed by the cell.

Answer 9

a)

Expert Solution

Answer 10

a)

Expert Solution

Answer 11

Expert Solution

Answer 12

Explanation of Solution

The function of lac repressor is to sense the lactose. It blocks the operon transcription in the absence of lactose. Lac operon consists of a promoter, lac repressor, terminator, lac promoter, lac operator, lac Z, lac Y, and lac A. The function of lac Z is to express beta-galactosidase, lac Y is to express beta-galactosidase permease, and lac A is to express galactosidase acetyltransferase. So, when lac repressor in gene is absent, then even in the absence of lactose, all the above proteins are expressed.

Answer 13

b)

Interpretation Introduction

Interpretation: The effect on lac operon on deleting the gene encoding the lac operator.

Concept Introduction: E. Coli contains lac operon, which is involved in lactose metabolism. It can be expressed in the presence of lactose and absence of glucose. The two regulators of lac operons are the lac repressor and the CAP. The function of these two regulators is to turn ‘on’ and ‘off’ the operon in response to glucose and lactose.

b)

Expert Solution

Answer to Problem 1P

In the absence of lac operator gene, beta-galactosidase, beta-galactosidasepermease, and thiogalactosidase transacetylase will be expressed by the cell.

Explanation of Solution

The function of the lac operator is to express lac operon in the presence of lactose. Lac operon consists of a promoter, lac repressor, terminator, lac promoter, lac operator, lac Z, lac Y, and lac A. The function of lac Z is to express beta-galactosidase, lac Y is to express beta-galactosidase permease, and lac A is to express galactosidase acetyltransferase. So, when the lac operator gene is absent, then even in the absence of lactose, all the above proteins are expressed.

Answer 14

b)

Interpretation Introduction

Interpretation: The effect on lac operon on deleting the gene encoding the lac operator.

Concept Introduction: E. Coli contains lac operon, which is involved in lactose metabolism. It can be expressed in the presence of lactose and absence of glucose. The two regulators of lac operons are the lac repressor and the CAP. The function of these two regulators is to turn ‘on’ and ‘off’ the operon in response to glucose and lactose.

Answer 15

b)

Expert Solution

Answer to Problem 1P

In the absence of lac operator gene, beta-galactosidase, beta-galactosidasepermease, and thiogalactosidase transacetylase will be expressed by the cell.

Answer 16

b)

Expert Solution

Answer 17

b)

Expert Solution

Answer 18

Expert Solution

Answer 19

Explanation of Solution

The function of the lac operator is to express lac operon in the presence of lactose. Lac operon consists of a promoter, lac repressor, terminator, lac promoter, lac operator, lac Z, lac Y, and lac A. The function of lac Z is to express beta-galactosidase, lac Y is to express beta-galactosidase permease, and lac A is to express galactosidase acetyltransferase. So, when the lac operator gene is absent, then even in the absence of lactose, all the above proteins are expressed.

Answer 20

c)

Interpretation Introduction

Interpretation: The effect on lac operon on deleting the gene encoding the CAP.

Concept Introduction:E. Coli contains lac operon, which is involved in lactose metabolism. It can be expressed in the presence of lactose and absence of glucose. The two regulators of lac operons are the lac repressor and the CAP. The function of these two regulators is to turn ‘on’ and ‘off’ the operon in response to glucose and lactose.

c)

Expert Solution

Answer to Problem 1P

If gene encoding CAP is absent, then even in the low glucose levels, the levels of beta-galactosidase and arabinose isomerase will remain low.

Explanation of Solution

Catabolite activator protein (CAP) senses the presence or absence of glucose. When glucose levels are low, then the operon transcription gets activated. At low glucose concentrations, cAMP is produced, which gets bind to CAP. After this, CAP binds to DNA and helps RNA pol bin to the lac operator, leading to the transcription process.

So, when the CAP gene is absent, then it cannot bind to RNA pol, and transcription of lac operator will not occur.

Answer 21

c)

Interpretation Introduction

Interpretation: The effect on lac operon on deleting the gene encoding the CAP.

Concept Introduction:E. Coli contains lac operon, which is involved in lactose metabolism. It can be expressed in the presence of lactose and absence of glucose. The two regulators of lac operons are the lac repressor and the CAP. The function of these two regulators is to turn ‘on’ and ‘off’ the operon in response to glucose and lactose.

Answer 22

c)

Expert Solution

Answer to Problem 1P

If gene encoding CAP is absent, then even in the low glucose levels, the levels of beta-galactosidase and arabinose isomerase will remain low.

Answer 23

c)

Expert Solution

Answer 24

c)

Expert Solution

Answer 25

Expert Solution

Answer 26

Explanation of Solution

Catabolite activator protein (CAP) senses the presence or absence of glucose. When glucose levels are low, then the operon transcription gets activated. At low glucose concentrations, cAMP is produced, which gets bind to CAP. After this, CAP binds to DNA and helps RNA pol bin to the lac operator, leading to the transcription process.

So, when the CAP gene is absent, then it cannot bind to RNA pol, and transcription of lac operator will not occur.