Genetic Regulation Prokaryotes

Q1: In the presence of tryptophan in the cell, the repressor is __________

A bound to tryptophan

B bound to DNA

C bound to both DNA and tryptophan

D bound to neither tryptophan nor DNA

ANS:C - bound to both DNA and tryptophan

No answer description is available.

Q2: Which of the following occur in the presence of glucose?

A lac Z gene expression is increased

B cAMP increases

C Binding of CAP-cAMP complex to the promoter area decreases

D none of the above

ANS:C - Binding of CAP-cAMP complex to the promoter area decreases

No answer description is available.

Q3: Why are several structural genes regulated as a unit in bacteria?

A An accident of evolution

B It allows coordinating regulation of genes with a common function

C The bacteria chromosome is so small; many different genes must be controlled by the same promoter

D none of the above

ANS:B - It allows coordinating regulation of genes with a common function

No answer description is available.

Q4: Catabolite activating protein exerts __________ control on transcription of the lac operon genes.

A positive

B negative

C may be positive or negative

D none of these

ANS:A - positive

No answer description is available.

Q5: Which of the following is not part of the lac operon?

A I

B O

C P

D none of these

ANS:A - I

LacI is a part of lac operon.

Q6: Sex lethal (sxl) in Drosophila is transcribed when

A the X autosome balance is less than 0.5

B the X autosome balance is 1 or greater

C the X autosome balance equals 0.5

D none of the above

ANS:B - the X autosome balance is 1 or greater

No answer description is available.

Q7: A mutation in the tip binding site of the repressor would result in

A constitutive trp operon expression

B inducible trp operon expression

C no operon expression

D none of the above

ANS:A - constitutive trp operon expression

No answer description is available.

Q8: Sex hormones activate transcription of specific genes by

A binding to a transcription factor

B binding to RNA polymerase

C binding to DNA enhancer region

D binding to DNA promoter region

ANS:A - binding to a transcription factor

No answer description is available.

Q9: The lac operon is translated into __________ proteins.

A 1

B 2

C 3

D 4

ANS:C - 3

No answer description is available.

Q10: Enhancers differ from promoters in that

A they initiate transcription

B they are adjacent to the start codon

C their orientation can be inverted without effect

D they are restricted to a specific gene

ANS:C - their orientation can be inverted without effect

No answer description is available.

Q11: Which of the following is not a transcription factor?

A Helix-turn-helix proteins

B Zinc finger proteins

C Leucine zipper proteins

D Steroid hormones

ANS:D - Steroid hormones

No answer description is available.

Q12: Genes which need to be coordinately regulated but are not in operons may be regulated by

A common transcription factor binding domains

B TATA boxes

C CAAT regions

D GC regions

ANS:A - common transcription factor binding domains

No answer description is available.

Q13: A frameshift mutation occurs in the sigma subunit gene transcribed as part of SPOl early genes. What will be the immediate result?

A Early genes will not be translated

B Middle genes will not be transcribed

C The bacterial host will lyse immediately

D Infection will proceed as usual

ANS:C - The bacterial host will lyse immediately

No answer description is available.

Q14: The lac operon is transcribed in which segments?

A 1

B 2

C 3

D 4

ANS:A - 1

No answer description is available.

Q15: DNA is methylated at

A AC sequences

B TATA sequences

C CAAT sequences

D CG sequences

ANS:D - CG sequences

No answer description is available.

Q16: In the presence of high levels of tryptophan

A attenuator allows transcription of trp structural genes

B attenuator propogates transcription

C attenuator terminates transcription

D none of the above

ANS:C - attenuator terminates transcription

No answer description is available.

Q17: Sex determination in Drosophila involves

A alternate splicing

B methylation

C gene amplification

D none of these

ANS:A - alternate splicing

No answer description is available.

Q18: Tubulin is regulated by

A binding of tubulin to tubulin mRNA

B splicing of the tubulin transcript

C binding of tubulin to the tubulin translational product

D binding of tubulin to DNA

ANS:C - binding of tubulin to the tubulin translational product

No answer description is available.

Q19: Alternate splicing of RNA transcripts is a mechanism to regulate

A tubulin

B tachykinins

C DNA methylation

D leucine zippers

ANS:B - tachykinins

No answer description is available.

Q20: The first protein complex to bind to the TATA box is

A transcription factor IIA

B transcription factor IIB

C transcription factor IID

D all of these

ANS:C - transcription factor IID

No answer description is available.

Q21: Methylated gene are

A active

B silent

C dynamic

D either (a) or (b)

ANS:B - silent

No answer description is available.

Q22: What are genes?

A The functional unit of inheritance

B A fragment of DNA

C A portion of a chromosome

D All of the above

ANS:D - All of the above

No answer description is available.

Q23: Transcription factors are

A regions of DNA in the promoter area

B regions of DNA in the enhancer area

C any protein which binds to DNA

D proteins which bind DNAand initiate transcription

ANS:D - proteins which bind DNAand initiate transcription

No answer description is available.



img not found
img

For help Students Orientation
Mcqs Questions

One stop destination for examination, preparation, recruitment, and more. Specially designed online test to solve all your preparation worries. Go wherever you want to and practice whenever you want, using the online test platform.