Genetics And Gene Mutation Trivia Quiz
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A lot of genetic disorders can be labeled as being caused by gene mutation, where a person’s DNA undergoes different changes. The mutations can either be deletions, insertions, or base substitutions. The quiz below is designed to test your understanding of gene and gene mutations, think that you are well informed to tackle it? Why don’t you give it a shot and get to find out!
- 1.An inducible gene is transcribed when a specific substance is present.
- A.
True
- B.
False
- 2.A gene is any DNA sequence that is transcribed into a mRNA molecule.
- A.
True
- B.
False
- 3.Regulatory genes are genes whose products are either RNA or proteins.
- A.
True
- B.
False
- 4.A repressible gene is controlled by a regulatory protein that inhibits transcription.
- A.
True
- B.
False
- 5.For a gene under negative repressible control, a small molecule is required to prevent the gene's repressor from binding to DNA.
- A.
True
- B.
False
- 6.For a gene under positive repressible control, the normal state is transcription of a gene, stimulated by a transcriptional activator.
- A.
True
- B.
False
- 7.When a structural gene is under positive inducible control, a mutation that eliminates the activator protein will cause the structural gene to be constitutively expressed.
- A.
True
- B.
False
- 8.When a structural gene is under negative inducible control, a mutation that eliminates the repressor protein will cause the structural gene to be constitutively expressed.
- A.
True
- B.
False
- 9.In the absence of allolactose, the lac operon is constitutively transcribed.
- A.
True
- B.
False
- 10.In the absence of tryptophan, the genes of the trp operon are not expressed.
- A.
True
- B.
False
- 11.Transcriptional control that acts by regulating the continuation of transcription is called
- 12.A promoter that affects only genes that are on the same piece of DNA is ____ -acting.
- 13.Since the binding of the inducer to the repressor prevents it from binding to DNA by causing a conformational change in its structure, it is called an __________ protein.
- 14.The repressor is a type of regulator protein that binds to a region of DNA in the promoter of a gene called the ________ and prevents transcription from taking place.
- 15.An example of a gene product encoded by a regulatory gene is
- A.
Beta-galactosidase enzyme.
- B.
Allolactose
- C.
Repressor protein.
- D.
Operator
- 16.It is possible for a repressor to negatively regulate the expression of an operon because
- A.
the repressor induces the expression of inducer.
- B.
One of the genes expressed in the operon negatively regulates the repressor.
- C.
The repressor binding site overlaps the promoter site of the operon allowing it to physically block the binding of RNA polymerase.
- D.
The repressor binding site on the DNA overlaps with the translation start site.
- 17.E. coli lac operon control by lac I
- A.
Negative inducible
- B.
Negative repressible
- C.
Positive inducible
- D.
Positive repressible
- 18.E. coli lac operon control by CAP
- A.
Negative inducible
- B.
Negative repressible
- C.
Positive inducible
- D.
Positive repressible
- 19.An operon is controlled by a repressor. When the repressor binds to a small molecule, it binds to DNA near the operon. The operon is constitutively expressed if a mutation prevents the repressor from binding to the small molecule.
- A.
Negative inducible
- B.
Negative repressible
- C.
Positive inducible
- D.
Positive repressible
- 20.An operon is controlled by a repressor. When the repressor binds to a small molecule, it is released from binding to DNA near the operon. The operon is never expressed if a mutation prevents the repressor from binding to the small molecule.
- A.
Negative inducible
- B.
Negative repressible
- C.
Positive inducible
- D.
Positive repressible
- 21.What is the function of allolactose in regulation of the lac operon?
- A.
Inducer
- B.
Repressor
- C.
Activator
- D.
Promoter
- E.
Regulatory protein
- 22.
- A.
It activates a repressor protein.
- B.
It activates a activator protein.
- C.
It inactivates a repressor protein.
- D.
It inactivates a activator protein.
- 23.If a mutation prevents the formation of the antiterminator 2 + 3 loop in the trp operon, what would be the effect?
- A.
Transcription only when tryptophan is absent
- B.
Transcription only when tryptophan is present
- C.
Constitutive attenuation of transcription
- D.
Constitutive transcription
- 24.
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Where would the lac repressor be bound in a (nonmutant) E. coli cell that is growing in low glucose and high lactose? Use the following diagram of the lac I gene and lac operon for questions 24-25. (I = lac repressor gene; Z, Y, A = lac operon structural genes; P = lac promoter; O = lac operator- A.
P
- B.
O
- C.
P and O
- D.
I, P, O
- E.
The repressor would not be bound.
- 25.
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Which parts of the DNA region shown in the diagram encode proteins? Use the following diagram of the lac I gene and lac operon for questions 24-25. (I = lac repressor gene; Z, Y, A = lac operon structural genes; P = lac promoter; O = lac operator- A.
P
- B.
P, O, Z, Y, A
- C.
I, Z, Y, A
- D.
I, P, O, Z, Y, A
- 26.
- A.
These are mutations that are, respectively, cis and trans acting on lac operon expression.
- B.
These are mutations that are, respectively, trans and cis acting on lac operon expression.
- C.
These will affect the expression of I only.
- D.
These will affect the expression of only Z, Y, and A.
- 27.
- A.
lacI+ lacP+ lacO+ lacZ– lacY+ lacA+
- B.
. lacI+ lacP+ lacOc lacZ+ lacY+ lacA+
- C.
LacI– lacP+ lacO+ lacZ– lacY+ lacA+
- D.
LacI+ lacP– lacO+ lacZ+ lacY+ lacA+
- 28.
- A.
LacI+ lacP+ lacO+ lacZ+ lacY– lacA+
- B.
LacI+ lacP+ lacOc lacZ+ lacY+ lacA+
- C.
Lacl+ lacP+ lacO+ lacZ+ lacY+ lacA+
- D.
LacI+ lacP– lacO+ lacZ+ lacY+ lacA+
- 29.
- A.
Phosphorylation
- B.
Demethylation
- C.
Acetylation
- D.
Polyadenylation
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