Concept explainers
For each of the terms in the left column, choose the best matching phrase in the right column.
a. induction | 1. glucose prevents expression of catabolic operons |
b. repressor | 2. protein or RNA undergoes a reversible conformational change |
c. operator | 3. regulates translation of mRNAs in trans |
d. allostery | 4. RNA leader that regulates gene expression in response to a small molecule or ion |
e. operon | 5. site to which repressor binds |
f. catabolite repression | 6. termination of transcription elongation in repression response to translation |
g. reporter gene | 7. group of genes transcribed into one mRNA |
h. attenuation | 8. negative regulator |
i. sRNA | 9. a fusion of the regulatory regions of genes whose expression is being monitored |
j. riboswitch | 10. stimulation of protein synthesis by a specific molecule |
a.
To determine:
The phrase that describes “induction” among the options given below.
1. glucose prevents expression of catabolic operons |
2. protein or RNA undergoes a reversible conformational change |
3. regulates translation of mRNAs in trans |
4. RNA leader that regulates gene expression in response to a small molecule or ion |
5. site to which repressor binds |
6. termination of transcription elongation in repression response to translation |
7. group of genes transcribed into one mRNA |
8. negative regulator |
9. a fusion of the regulatory region of one gene to the coding region of another gene whose product is assayed readily |
10. stimulation of protein synthesis by a specific molecule |
Introduction:
When a specific molecule is used for the synthesis of protein, it is called induction.
Answer to Problem 1P
Correct answer:
Induction: Stimulation of protein synthesis by a specific molecule
Explanation of Solution
Induction is associated with the stimulation of protein synthesis by the process of transcription, where specific factor initiates the process of transcription.
b.
To determine:
The phrase that describes “repressor” among the options given below.
1. glucose prevents expression of catabolic operons |
2. protein or RNA undergoes a reversible conformational change |
3. regulates translation of mRNAs in trans |
4. RNA leader that regulates gene expression in response to a small molecule or ion |
5. site to which repressor binds |
6. termination of transcription elongation in repression response to translation |
7. group of genes transcribed into one mRNA |
8. negative regulator |
9. a fusion of the regulatory region of one gene to the coding region of another gene whose product is assayed readily |
10. stimulation of protein synthesis by a specific molecule |
Introduction:
A molecule which is responsible for the blockage of tanscription process is called repressor.
Answer to Problem 1P
Correct answer:
Repressor: Negative regulator
Explanation of Solution
Repressor is a type of protein molecule which prevents the transcription of the particular gene associated with the regulatory parts of the gene.
c.
To determine:
The phrase that describes “operator” among the options given below.
1. glucose prevents expression of catabolic operons |
2. protein or RNA undergoes a reversible conformational change |
3. regulates translation of mRNAs in trans |
4. RNA leader that regulates gene expression in response to a small molecule or ion |
5. site to which repressor binds |
6. termination of transcription elongation in repression response to translation |
7. group of genes transcribed into one mRNA |
8. negative regulator |
9. a fusion of the regulatory region of one gene to the coding region of another gene whose product is assayed readily |
10. stimulation of protein synthesis by a specific molecule |
Introduction:
An operator can be defined as the site at which attachment of repressor takes place.
Answer to Problem 1P
Correct answer:
Operator: Site to which repressor binds
Explanation of Solution
Operator is considered as the important part of the regulatory sequence of the gene. The repressor binds to the operator region of the regulatory gene and suppresses the process of transcription.
d.
To determine:
The phrase that describes “allostery” among the options given below.
1. glucose prevents expression of catabolic operons |
2. protein or RNA undergoes a reversible conformational change |
3. regulates translation of mRNAs in trans |
4. RNA leader that regulates gene expression in response to a small molecule or ion |
5. site to which repressor binds |
6. termination of transcription elongation in repression response to translation |
7. group of genes transcribed into one mRNA |
8. negative regulator |
9. a fusion of the regulatory region of one gene to the coding region of another gene whose product is assayed readily |
10. stimulation of protein synthesis by a specific molecule |
Introduction:
When a specific RNA or the protein undergoes the process of reversible conformation change, it is referred to as allostery.
Answer to Problem 1P
Correct answer:
Allostery: Protein or RNA undergoes a reversible conformational change
Explanation of Solution
Allostery means change in the conformation that is associated with the proteins involved in the regulation of a particular gene. The repressor molecule undergoes conformational change, which enables it to be relieved from the operator region and then promotes transcription.
e.
To determine:
The phrase that describes “operon” among the options given below.
1. glucose prevents expression of catabolic operons |
2. protein or RNA undergoes a reversible conformational change |
3. regulates translation of mRNAs in trans |
4. RNA leader that regulates gene expression in response to a small molecule or ion |
5. site to which repressor binds |
6. termination of transcription elongation in repression response to translation |
7. group of genes transcribed into one mRNA |
8. negative regulator |
9. a fusion of the regulatory region of one gene to the coding region of another gene whose product is assayed readily |
10. stimulation of protein synthesis by a specific molecule |
Introduction:
When group of genes results into the transcription of one messenger RNA, it is called operon.
Answer to Problem 1P
Correct answer:
Operon: Group of genes transcribed into one mRNA
Explanation of Solution
An operon is the set region found in the genome that consists of regulatory, structural, and functional portion. The structural region contains the promoter and operator whereas the functional region codes for the actual protein.
f.
To determine:
The phrase that describes “catabolite” among the options given below.
1. glucose prevents expression of catabolic operons |
2. protein or RNA undergoes a reversible conformational change |
3. regulates translation of mRNAs in trans |
4. RNA leader that regulates gene expression in response to a small molecule or ion |
5. site to which repressor binds |
6. termination of transcription elongation in repression response to translation |
7. group of genes transcribed into one mRNA |
8. negative regulator |
9. a fusion of the regulatory region of one gene to the coding region of another gene whose product is assayed readily |
10. stimulation of protein synthesis by a specific molecule |
Introduction:
Catabolite repression can be seen as a normal process in the microbes.
Answer to Problem 1P
Correct answer:
Catabolite repression: glucose prevents expression of catabolic operons
Explanation of Solution
Catabolite repression is seen among microbes when both glucose and lactose are supplied in their growing environment. The presence of glucose suppresses the utilization of lactose.
g.
To determine:
The phrase that describes “reporter gene” among the options given below.
1. glucose prevents expression of catabolic operons |
2. protein or RNA undergoes a reversible conformational change |
3. regulates translation of mRNAs in trans |
4. RNA leader that regulates gene expression in response to a small molecule or ion |
5. site to which repressor binds |
6. termination of transcription elongation in repression response to translation |
7. group of genes transcribed into one mRNA |
8. negative regulator |
9. a fusion of the regulatory region of one gene to the coding region of another gene whose product is assayed readily |
10. stimulation of protein synthesis by a specific molecule |
Introduction:
The activity of monitoring the regulatory genes is carried out with the help of reporter gene.
Answer to Problem 1P
Correct answer:
Reporter gene: A fusion of the regulatory region of one gene to the coding region of another gene whose product is assayed readily.
Explanation of Solution
The function of reporter genes is monitored through the regulatory regions of other well-studied genes. Due to this reason, the regulatory region of the lactose operon is used in the expression system for analyzing and studying the expression of unknown genes.
h.
To determine:
The phrase that describes “attenuation” among the options given below.
1. glucose prevents expression of catabolic operons |
2. protein or RNA undergoes a reversible conformational change |
3. regulates translation of mRNAs in trans |
4. RNA leader that regulates gene expression in response to a small molecule or ion |
5. site to which repressor binds |
6. termination of transcription elongation in repression response to translation |
7. group of genes transcribed into one mRNA |
8. negative regulator |
9. a fusion of the regulatory region of one gene to the coding region of another gene whose product is assayed readily |
10. stimulation of protein synthesis by a specific molecule |
Introduction:
Various types of anabolic pathways are regulated by the process of attenuation.
Answer to Problem 1P
Correct answer:
Attenuation: Termination of transcription elongation in repression response to translation
Explanation of Solution
Attenuation is a process that controls the regulation of anabolic pathways. When the substrate is available, the transcription continues further and transcribes the functional regions or shrugs off the mRNA completely.
i.
To determine:
The phrase that describes “sRNA” among the options given below.
1. glucose prevents expression of catabolic operons |
2. protein or RNA undergoes a reversible conformational change |
3. regulates translation of mRNAs in trans |
4. RNA leader that regulates gene expression in response to a small molecule or ion |
5. site to which repressor binds |
6. termination of transcription elongation in repression response to translation |
7. group of genes transcribed into one mRNA |
8. negative regulator |
9. a fusion of the regulatory region of one gene to the coding region of another gene whose product is assayed readily |
10. stimulation of protein synthesis by a specific molecule |
Introduction:
Short ribonucleic acid RNA is actually the trans-acting molecules that are useful for the expression of specific genes.
Answer to Problem 1P
Correct answer:
sRNA: Regulates translation of mRNA in trans
Explanation of Solution
sRNA, known as short ribonucleic acid sequence are trans-acting molecules that regulate the expression of specific genes. When a sRNA molecule binds to the mRNA, it leads to the breakdown of transcribed mRNA molecule by the action of ribonuclease enzyme. The binding of sRNA to the mRNA molecule prevents the formation of stem and loops in the mRNA.
j.
To determine:
The phrase that describes “riboswitch” among the options given below.
1. glucose prevents expression of catabolic operons |
2. protein or RNA undergoes a reversible conformational change |
3. regulates translation of mRNAs in trans |
4. RNA leader that regulates gene expression in response to a small molecule or ion |
5. site to which repressor binds |
6. termination of transcription elongation in repression response to translation |
7. group of genes transcribed into one mRNA |
8. negative regulator |
9. a fusion of the regulatory region of one gene to the coding region of another gene whose product is assayed readily |
10. stimulation of protein synthesis by a specific molecule |
Introduction:
The riboswitch are important type of RNA leader sequences that is used for regulating expressions of gene.
Answer to Problem 1P
Correct answer:
Riboswitch: RNA leader that regulates gene expression in response to a small molecule or ion
Explanation of Solution
Riboswitch is an important part of RNA leader sequence that binds to specific molecules called effectors. The formation of stem and loop in the transcript of mRNA molecule plays an important role in the continuation and attenuation of transcription through the riboswitches.
Want to see more full solutions like this?
Chapter 15 Solutions
Genetics: From Genes to Genomes, 5th edition
- Define the following in the context of operons: a. positive control b. give an example of an operon that is under positive control c. negative control d. give an example of an operon that is under negative control e. repressor f. give an example of a repressor molecule g. activator h. give an example of an activatorarrow_forwardAnswer this 3 part question: (MC) What is the function of lactose in regulation of the lac operon? 1. activates a repressor protein 2. activates an activator protein 3. inactivates a repressor protein 4. inactivates an activator protein Consider a bacterial strain with a lac operon Р. О Y A a) Mention which parts of the DNA region shown in the diagram encode for • Enzyme proteins? • Operator • Promoter • Repressor gene b) Where would the lac repressor be bound in a E. coli cell that is growing in ( • high lactose? No lactosearrow_forwardYou are growing E. coli in a laboratory in order to study their operons. The growth media you are using contains lactose, no glucose and no tryptophan. Using your knowledge of operons and their regulation, answer the following questions Which operons would be functional under these conditions? 2. What repressors would be made? (NOTE: name the repressors using their gene names) 3.Which repressor(s) would be made in the inactive form? 4.Which repressor(s) would be made in the active form? 5.Which repressor(s) under these conditions can bind the operator sequence? 6.Which repressor(s)under these conditions cannot bind the operator sequence?arrow_forward
- Study the depiction of the lac operon in Figure 11.2. Normally, the genes are turned off when lactose is not present. Lactose activates the genes, which code for enzymes that enable the cell to use lactose. Mutations can alter the function of this operon. Predict how the following mutations would affect the function of the operon in the presence and absence of lactose: a. mutation of regulatory gene; repressor will not bind to lactose b. mutation of operator; repressor will not bind to operator c. mutation of regulatory gene; repressor will not bind to operator d. mutation of promoter; RNA polymerase will not attach to promoterarrow_forwardYou are growing E. coli in a laboratory in order to study their operons. The growth media you are using contains lactose, no glucose and no tryptophan. Using your knowledge of operons and their regulation a.Which operons would be functional under these conditions? b.What repressors would be made? (NOTE: name the repressors using their gene names) c.Which repressor(s) would be made in the inactive form? d.Which repressor(s) would be made in the active form? e.Which repressor(s) under these conditions can bind the operator sequence? f.Which repressor(s)under these conditions cannot bind the operator sequence?arrow_forwardE. coli are grown on a medium containing lactose. Once glucose is added to the medium, the bacteria stop fermenting lactose. Which of the following BEST explains the observed effect? A. Cellular levels of cAMP are lowB.Glucose is bound to the promoter C. Repressor protein is bound to the operator D. Repressor protein is bound to the promoterarrow_forward
- a. What is the function of operons in bacterial gene regulation? b. Describe how a bacterial operon can be regulated by repressible proteins (such as the tryptophan operon). Include in your description both the “on” and “off” states of the operon. Key elements of your diagram should include: Co-repressor, Genes, mRNA, Operator, Operon, Promoter, Repressor, RNA polymerase.arrow_forwardDefine the following terms: a. promoter b. consensus sequence c. operon d. chromatin-remodeling complex e. general transcription factorsarrow_forwardWhich statement about the transcription attenuation mechanism is TRUE? 1.In some operons (e.g., the his operon), attenuation may be the only regulatory mechanism. 2. Sequences of the trp operon leader RNA resemble an operator. 3. The leader peptide acts by a mechanism that is similar to that of a repressor protein. 4.The leader peptide gene of the trp operon includes no Trp codons. 5. The leader peptide is an enzyme that catalyzes transcription attenuation.arrow_forward
- The lac operon of E. coli controls the expression of genes that code for enzymes involved in lactose metabolism. Mutations to various regions of the lac operon have been discovered which affect both the control of gene expression and the function of the gene products. These mutations include: I - = produces a repressor protein that cannot bind to the operator region IS = produces a repressor protein that cannot be removed from the operator region OC = cannot bind a repressor protein Z - = produces a defective (non-functioning) β-galactosidase enzyme + = wild type Detail the functionality of the lac operon under the following genetic and cellular conditions. You do not need to consider the role of CAP in your analysis. Genes Repressed (yes/no) Constitutive (yes/no) I+ OC Z+ I+ O+ Z+ (Lactose present) I- O+ Z+arrow_forwardThe lac operon of E. coli controls the expression of genes that code for enzymes involved in lactose metabolism. Mutations to various regions of the lac operon have been discovered which affect both the control of gene expression and the function of the gene products. These mutations include: I - = produces a repressor protein that cannot bind to the operator region IS = produces a repressor protein that cannot be removed from the operator region OC = cannot bind a repressor protein Z - = produces a defective (non-functioning) β-galactosidase enzyme + = wild type Detail the functionality of the lac operon under the following genetic and cellular conditions. You do not need to consider the role of CAP in your analysis. Genes Repressed (yes/no) Constitutive (yes/no) IS O+ Z+ IS OC Z+arrow_forwardDecide which operon each of the following characteristics applies to. Note: a description may apply to both. a. lac operon b. trp operon 68. repressible 69. Turned off when end product is present (feedback inhibition) 70. Promoter, activator region, and 3 genes 71. Repressible 72. contain operator and promoter regions as well as transcript units of at least two or more coding genes 73. Codes for catabolic enzymes that break down lactose 74. Inducible 75. Promoter, activator region, and 5 genes 76. Codes for anabolic enzymes that help manufacture tryptophan 77. Lactose is the co-inducer 78. Turned on when substrate is present 79. Tryptophan is the co-repressor 80. Regulatory gene segmentsarrow_forward
- Biology (MindTap Course List)BiologyISBN:9781337392938Author:Eldra Solomon, Charles Martin, Diana W. Martin, Linda R. BergPublisher:Cengage Learning