Genetic Regulation Prokaryotes MCQs : This section focuses on the "Genetic Regulation Prokaryotes". These Multiple Choice Questions (MCQs) should be practiced to improve the Genetic Regulation Prokaryotes skills required for various interviews (campus interview, walk-in interview, company interview), placement, entrance exam and other competitive examinations.
Question 1
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
Question 2
The lac operon is translated into __________ proteins.
A. 1
B. 2
C. 3
D. 4
Question 3
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
Question 4
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
Question 5
DNA is methylated at
A. AC sequences
B. TATA sequences
C. CAAT sequences
D. CG sequences
Question 6
Alternate splicing of RNA transcripts is a mechanism to regulate
A. tubulin
B. tachykinins
C. DNA methylation
D. leucine zippers
Question 7
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
Question 8
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
Question 9
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
Question 10
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
Question 11
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
Question 12
Methylated gene are
A. active
B. silent
C. dynamic
D. either (a) or (b)
Question 13
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
Question 14
Which of the following is not part of the lac operon?
A. I
B. O
C. P
D. none of these
Question 15
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
Question 16
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
Question 17
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
Question 18
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
Question 19
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
Question 20
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
Question 21
Sex determination in Drosophila involves
A. alternate splicing
B. methylation
C. gene amplification
D. none of these
Question 22
The lac operon is transcribed in which segments?
A. 1
B. 2
C. 3
D. 4