MCQOPTIONS
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MCQOPTIONS
This section includes 242 Mcqs, each offering curated multiple-choice questions to sharpen your Biochemistry knowledge and support exam preparation. Choose a topic below to get started.
| 101. |
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 |
| Answer» B. TATA boxes | |
| 102. |
The work ‘Hybridization’ in DNA finger printing means ____________ |
| A. | Pairing between the nucleotides of DNA sample with probe |
| B. | Pairing between the nucleotides of DNA and mRNA |
| C. | Pairing between the nucleotides of probe with mRNA |
| D. | Pairing between the nucleosides with mRNA |
| Answer» B. Pairing between the nucleotides of DNA and mRNA | |
| 103. |
Which of the following about mRNA stability is not correct? |
| A. | Regulation of mRNA stability is a way of regulating gene expression |
| B. | Prokaryotic mRNAs have a half-life of only a few minutes |
| C. | Histone mRNAs have especially long poly-A tails and are stable |
| D. | It is thought that poly-A tails stabilize eukaryotic mRNAs |
| Answer» D. It is thought that poly-A tails stabilize eukaryotic mRNAs | |
| 104. |
Which of the following is not an example of housekeeping genes? |
| A. | RNA polymerase |
| B. | r-RNA genes |
| C. | Beta galactosidase |
| D. | Enzymes required for basic metabolic pathways common to most cells |
| Answer» D. Enzymes required for basic metabolic pathways common to most cells | |
| 105. |
The RP13 gene of chromosome 17 codes for a protein __________ . |
| A. | involved in glucose transport |
| B. | that is a component of hair and nails |
| C. | involved in eye development |
| D. | involved in the determination of personality |
| Answer» D. involved in the determination of personality | |
| 106. |
Under which of the following conditions would population gene frequencies remain the same? |
| A. | Selection for homozygotes |
| B. | Small population size |
| C. | Active migration between groups |
| D. | Random mating |
| Answer» E. | |
| 107. |
The mechanism by which CBP activates transcription is |
| A. | CBP has DNA methyl transferase activity |
| B. | CBP has histone acetyl transferase activity |
| C. | CBP interacts with the basal transcription complex |
| D. | CBP interacts with the basal transcription complex and has histone acetyl transferase activity |
| Answer» D. CBP interacts with the basal transcription complex and has histone acetyl transferase activity | |
| 108. |
Which of the following is not required for the expression of genes in the lactose operon? |
| A. | lacl gene product |
| B. | cAMP |
| C. | Allolactose |
| D. | Adenylate cyclase |
| Answer» B. cAMP | |
| 109. |
To make the recombinant plasmid permeable to DNA molecules, which of the chemicals is added? |
| A. | MgCl₂ |
| B. | CaCl₂ |
| C. | NaCl |
| D. | HCl |
| Answer» C. NaCl | |
| 110. |
Which of the following does not act as a restriction enzyme? |
| A. | EcorI |
| B. | BamHI |
| C. | HindIII |
| D. | polydeoxyribonucleotide synthase |
| Answer» E. | |
| 111. |
Which of the following is helpful in distinguishing DNA of one individual from another? |
| A. | PCR |
| B. | Reverse transcriptase |
| C. | cDNA |
| D. | RFLP |
| Answer» E. | |
| 112. |
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 |
| Answer» C. The bacteria chromosome is so small; many different genes must be controlled by the same promoter | |
| 113. |
Whose interaction with Lex-A facilitates the repressor’s self-cleavage reaction? |
| A. | Rec-A |
| B. | Rec-B |
| C. | Rec-C |
| D. | Rec-D |
| Answer» B. Rec-B | |
| 114. |
Which of the following endonuclease removes a length of DNA between two telomere sequences? |
| A. | EcoR1 |
| B. | EcoR2 |
| C. | BamHI |
| D. | HindIII |
| Answer» D. HindIII | |
| 115. |
The lac operon is translated into __________ proteins. |
| A. | 1 |
| B. | 2 |
| C. | 3 |
| D. | 4 |
| Answer» D. 4 | |
| 116. |
Agar is extracted from ____________ |
| A. | Fungi |
| B. | Bacteria |
| C. | Algae |
| D. | Virus |
| Answer» D. Virus | |
| 117. |
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 |
| Answer» D. bound to neither tryptophan nor DNA | |
| 118. |
Generally, YAC contains how many elements? |
| A. | 1 |
| B. | 2 |
| C. | 3 |
| D. | 4 |
| Answer» E. | |
| 119. |
Explant can be a __________ |
| A. | Cut part of the plant used in tissue culture |
| B. | Plant extract used in tissue culture |
| C. | Source of growth regulators added to media |
| D. | Solidifying agent |
| Answer» B. Plant extract used in tissue culture | |
| 120. |
A segment of DNA that reads from the same forward and backward is called ____________ |
| A. | Palindromic DNA |
| B. | Complementary DNA |
| C. | Plasmid DNA |
| D. | Copy DNA |
| Answer» B. Complementary DNA | |
| 121. |
X-rays cause |
| A. | the formation of thymine dimers |
| B. | ionization of water in the cell |
| C. | heat |
| D. | none of the above |
| Answer» C. heat | |
| 122. |
Which of the following is not part of the lac operon? |
| A. | I |
| B. | O |
| C. | P |
| D. | none of these |
| Answer» B. O | |
| 123. |
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 |
| Answer» D. none of the above | |
| 124. |
Which of the following are the two methods of screening? |
| A. | Hybridization and PCR |
| B. | ELISA and blotting |
| C. | ELISA and PCR |
| D. | PCR and RFLP |
| Answer» B. ELISA and blotting | |
| 125. |
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 |
| Answer» B. negative | |
| 126. |
Formation of the attenuator stem-and-loop structure depends on the events that occur during translation of |
| A. | Regulatory sequence 1 |
| B. | Regulatory sequence 2 |
| C. | Regulatory sequence 3 |
| D. | Regulatory sequence 4 |
| Answer» B. Regulatory sequence 2 | |
| 127. |
When DNA segment is in one orientation |
| A. | The gene for FljB and gene encoding FljA are expressed |
| B. | The gene for FliC are expressed |
| C. | The gene for FljB and gene encoding FljA are not expressed |
| D. | The gene for FljB and gene encoding FljC are not expressed |
| Answer» B. The gene for FliC are expressed | |
| 128. |
Which of the following can be termed as a restriction modification system? |
| A. | Restriction endonuclease + methylase |
| B. | DNA ligase + methylase |
| C. | Restriction endonuclease + acetylase |
| D. | DNA ligase + acetylase |
| Answer» B. DNA ligase + methylase | |
| 129. |
When populations are small, gene frequencies can change from generation to generation and some alleles may become fixed in a population. This is called __________ . |
| A. | assortative mating |
| B. | inbreeding |
| C. | heterosis |
| D. | genetic drift |
| Answer» E. | |
| 130. |
Which of the following pair will produce complementary sticky ends? |
| A. | Eco RI & MspI |
| B. | Msp I & HPA II |
| C. | Sau 3A & Bam HI |
| D. | Mbo I & Sau 3A |
| Answer» D. Mbo I & Sau 3A | |
| 131. |
Which of the following enzyme is responsible for making a DNA copy from RNA? |
| A. | Reverse transcriptase |
| B. | DNA polymerase |
| C. | RNA polI |
| D. | RNA polII |
| Answer» B. DNA polymerase | |
| 132. |
Some genetic diseases cannot be diagnosed by changes in restriction sites. Some of these can be detected by allele-specific oligonucleotide probes. These are |
| A. | copies of the gene with an altered sequence so that a restriction site is inserted |
| B. | mutagenized copies of a gene |
| C. | short sequences that will hybridize only to a specific base sequence |
| D. | PCR-amplified variable numbers of tandem repeats (VNTRs) |
| Answer» D. PCR-amplified variable numbers of tandem repeats (VNTRs) | |
| 133. |
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 |
| Answer» D. they are restricted to a specific gene | |
| 134. |
Which of the following term is associated with DNA finger printing? |
| A. | Hybridoma |
| B. | Site specific mutagenesis |
| C. | Shotgun cloning |
| D. | RFLP |
| Answer» E. | |
| 135. |
Which of the following enzyme is required for end to end joining of DNA? |
| A. | DNA ligase |
| B. | Restriction endonuclease |
| C. | RNA polymerase |
| D. | DNA polymerase |
| Answer» B. Restriction endonuclease | |
| 136. |
Rho-dependent termination of transcription in E. coli |
| A. | requires ATP |
| B. | requires about 50 nucleotides of uncomplexed mRNA |
| C. | both (a) and (b) |
| D. | removes mRNA and holoenzyme from the DNA |
| Answer» D. removes mRNA and holoenzyme from the DNA | |
| 137. |
Enhancers are regions that |
| A. | bind RNA polymerase |
| B. | are adjacent to the TATA box |
| C. | are CAT box binding proteins |
| D. | modulate transcription |
| Answer» E. | |
| 138. |
Which of the following is necessary for transcription to occur? |
| A. | DNA molecule |
| B. | RNA polymerase |
| C. | DNA polymerase |
| D. | Both DNA & RNA polymerase |
| Answer» E. | |
| 139. |
The function of the sigma factor of RNA polymerase is to |
| A. | assure that transcription begins at the proper point |
| B. | assure that transcription ends at the proper point |
| C. | assure that translation begins at the proper point |
| D. | assure that translation ends at the proper point |
| Answer» B. assure that transcription ends at the proper point | |
| 140. |
What is a promoter? |
| A. | A specific sequence of DNA to which a catabolic repressor binds |
| B. | A specific sequence of DNA to which RNA polymerase binds |
| C. | A specific DNA sequence to which a restriction endonuclease binds |
| D. | None of the above |
| Answer» C. A specific DNA sequence to which a restriction endonuclease binds | |
| 141. |
In both eukaryotes and prokaryotes, a promoter region that is rich in AT bases is called as |
| A. | CATT |
| B. | Shine Dalgarno region |
| C. | TATA box |
| D. | SV40 region |
| Answer» D. SV40 region | |
| 142. |
Upstream regions which are essential for correct transcription are called |
| A. | enhancers |
| B. | start codons |
| C. | promoters |
| D. | transcription factors |
| Answer» D. transcription factors | |
| 143. |
Each tRNA molecule has a cloverleaf secondary structure consisting of |
| A. | three stem loops |
| B. | two stem loops |
| C. | four stem loops |
| D. | either (a) or (b) |
| Answer» B. two stem loops | |
| 144. |
The complex of RNA polymerase, DNA template and new RNA transcript is called |
| A. | transcription bubble |
| B. | replication bubble |
| C. | a translation bubble |
| D. | none of these |
| Answer» B. replication bubble | |
| 145. |
The nucleons of eukaryotic cell has |
| A. | RNA polymerase I |
| B. | RNA polymerase II |
| C. | RNA polymerase III |
| D. | all of these |
| Answer» E. | |
| 146. |
In eukaryotes, there are three different RNA polymerases. The RNA polymerase responsible for transcription of mRNA is |
| A. | RNA polymerase I |
| B. | RNA polymerase II |
| C. | RNA polymerase III |
| D. | none of these |
| Answer» C. RNA polymerase III | |
| 147. |
The closed complex at bacterial promoters is |
| A. | in equilibrium with free RNA polymerase and the promoter |
| B. | not affected by promoter mutations |
| C. | bound more tightly when repressors are present |
| D. | not affected by activator proteins |
| Answer» B. not affected by promoter mutations | |
| 148. |
Transcription of each set of rRNA genes by RNA polymerasel produces |
| A. | a single 45S rRNA precursor molecule |
| B. | a single 5S rRNA precursor molecule |
| C. | a single 18S rRNA precursor molecule |
| D. | a single 28S rRNA precursor molecule |
| Answer» B. a single 5S rRNA precursor molecule | |
| 149. |
The major function of RNA polymerase's sigma factor is |
| A. | recognition of the translational stop sequence |
| B. | recognition of the transcriptional start sequence |
| C. | recognition of the transcriptional stop sequence |
| D. | recognition of the translational start sequence |
| Answer» C. recognition of the transcriptional stop sequence | |
| 150. |
RNA polymerase holoenzyme initiates transcription which involves |
| A. | recognition of the -10 sequence and -35 sequence |
| B. | recognition of the -10 sequence only |
| C. | recognition of the -35 sequence only |
| D. | none of the above |
| Answer» B. recognition of the -10 sequence only | |