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.
| 151. |
Which of the following is true about restriction endonucleases? |
| A. | Type I and II requires ATP to move along DNA |
| B. | Type I, II and III requires ATP to move along DNA |
| C. | Type II requires no ATP and cleaves DNA within recognition sequence |
| D. | Type II requires ATP and cleaves DNA within recognition sequence |
| Answer» D. Type II requires ATP and cleaves DNA within recognition sequence | |
| 152. |
What is the main aim of human genome project? |
| A. | To identify and sequence of all the genes present in the human body |
| B. | To introduce new genes to human beings |
| C. | To remove disease causing genes from humans |
| D. | To improve techniques of finger printing |
| Answer» B. To introduce new genes to human beings | |
| 153. |
Which out of the following is not an example of inducible operon? |
| A. | Lactose operon |
| B. | Galactose operon |
| C. | Maltose operon |
| D. | Tryptophan operon |
| Answer» E. | |
| 154. |
Promoters for tRNAs are located |
| A. | upstream from the start codon |
| B. | downstream from the start codon |
| C. | both (a) and (b) |
| D. | none of these |
| Answer» C. both (a) and (b) | |
| 155. |
The unpaired nucleotides produced by the action of restriction enzymes are referred to have |
| A. | sticky ends |
| B. | single strands |
| C. | restriction fragments |
| D. | ligases |
| Answer» B. single strands | |
| 156. |
To which class of transcription factor do nuclear receptors belong? |
| A. | Zinc finger proteins |
| B. | Leucine zipper proteins |
| C. | Helix-turn-helix proteins |
| D. | Helix-loop-helix proteins |
| Answer» B. Leucine zipper proteins | |
| 157. |
Transcription by E. coli polymerase occurs in |
| A. | four phases known as initiation, propagation, elongation and termination |
| B. | three phases known as initiation, elongation and termination |
| C. | two phases known as initiation and termination |
| D. | none of the above |
| Answer» C. two phases known as initiation and termination | |
| 158. |
Meristem culture helps in developing which of the following? |
| A. | Tall plants |
| B. | Disease resistant plants |
| C. | Virus free plants |
| D. | Hybrid plants |
| Answer» D. Hybrid plants | |
| 159. |
Which of the following enzyme is used in PCR? |
| A. | Taq DNA polymerase |
| B. | HRP |
| C. | EcoRI |
| D. | EcoRII |
| Answer» B. HRP | |
| 160. |
The transcriptional regulatory proteins in eukaryotes which induce transcription usually have |
| A. | at least two distinct domains of protein structure, a DNA binding domain and an activation domain |
| B. | at least two distinct domains of protein structure and a DNA binding domain |
| C. | at least one distinct domains of protein structure, a DNA binding domain and an activation domain |
| D. | none of these |
| Answer» B. at least two distinct domains of protein structure and a DNA binding domain | |
| 161. |
Restriction enzymes are named for |
| A. | the person who discovered |
| B. | the bacterium they are derived from |
| C. | the viral DNA that they attack |
| D. | none of the above |
| Answer» C. the viral DNA that they attack | |
| 162. |
Immediately after transcription |
| A. | a methylated guanine cap is added to the 51 end of the transcript |
| B. | a methylated guanine cap is added to the 31 end of the transcript |
| C. | both (a) and (b) |
| D. | a poly adenylation signal is added |
| Answer» B. a methylated guanine cap is added to the 31 end of the transcript | |
| 163. |
The RNA polymerases that transcribe bacterial DNA are |
| A. | multisubunit enzymes |
| B. | only active inside the cell |
| C. | interchangable with DNA polymerases |
| D. | highly glycosylated in their active forms |
| Answer» B. only active inside the cell | |
| 164. |
Bacterial protein called catabolic activator protein (CAP) is an example of |
| A. | negative control of gene expression |
| B. | positive control of gene expression |
| C. | second type of positive control of gene expression |
| D. | none of the above |
| Answer» D. none of the above | |
| 165. |
Which of the following techniques was carried out by Nirenberg and Matthaei in 1961 to determine the first codon? |
| A. | In vitro synthesis of a polypeptide using UUUUU |
| B. | Labeled peptide binding to a ribosome |
| C. | Mixed co-polymer mRNA synthesis |
| D. | none of the above |
| Answer» B. Labeled peptide binding to a ribosome | |
| 166. |
How many different codons are possible? |
| A. | 3 |
| B. | 20 |
| C. | 64 |
| D. | An infinite number |
| Answer» D. An infinite number | |
| 167. |
Which of the following has been used as an evidence that primitive life forms lacked both DNA and enzymes? |
| A. | RNA can both code genetic information and act as a catalyst |
| B. | DNA and enzymes are only present in the most advanced cells |
| C. | Advanced cells lack RNA |
| D. | All of the above |
| Answer» B. DNA and enzymes are only present in the most advanced cells | |
| 168. |
A structure that has hydrogen bonds between polypeptide chains arranged side by side is |
| A. | Primary structure |
| B. | α-helix |
| C. | β-pleated sheets |
| D. | Tertiary structure |
| Answer» D. Tertiary structure | |
| 169. |
What enzyme forms covalent bonds between restriction fragments? |
| A. | DNA primase |
| B. | DNA helicase |
| C. | DNA polymerase |
| D. | DNA ligase |
| Answer» E. | |
| 170. |
Which of the following are important for white blood cell recognition? |
| A. | Glycosamineglycans |
| B. | Proteoglycans |
| C. | Gycoproteins |
| D. | Glycolipids |
| Answer» D. Glycolipids | |
| 171. |
AUG codes for methionine act as a |
| A. | initiation code |
| B. | elongation code |
| C. | termination code |
| D. | propagation code |
| Answer» B. elongation code | |
| 172. |
In prokaryotes, AUG encodes |
| A. | methionine |
| B. | N-formyl methionine |
| C. | a stop codon |
| D. | alanine |
| Answer» C. a stop codon | |
| 173. |
Both DNA gel electrophoresis and SDS-PAGE of proteins are similar because |
| A. | in both cases molecules migrate to the anode |
| B. | both techniques rely on a constant charge to mass ratio |
| C. | both techniques utilize the sieving properties of gels |
| D. | all of the above |
| Answer» E. | |
| 174. |
A human cDNA library |
| A. | contains DNA for specific human proteins |
| B. | contains DNA for virtually all of the human proteins in vectors |
| C. | cannot be used to obtain human genes because it would be radioactive |
| D. | none of the above |
| Answer» C. cannot be used to obtain human genes because it would be radioactive | |
| 175. |
The binding of lac repressor to DNA could be considered to be analogous to |
| A. | competitive inhibition of an enzyme |
| B. | mixed-type inhibition of an enzyme |
| C. | uncompetitive inhibition of an enzyme |
| D. | allosteric effects in enzyme regulation |
| Answer» B. mixed-type inhibition of an enzyme | |
| 176. |
The effects of protein on an entire organism is described in __________ |
| A. | Phenotypic function |
| B. | Cellular function |
| C. | Molecular function |
| D. | Structural genomics |
| Answer» B. Cellular function | |
| 177. |
The lac repressor has which of the following DNA-binding motif? |
| A. | Helix-turn-helix |
| B. | Zinc finger |
| C. | Homeodomain |
| D. | Leucine zipper |
| Answer» B. Zinc finger | |
| 178. |
Which of the following encodes recombinase? |
| A. | fliC |
| B. | fljB |
| C. | hin |
| D. | fljA |
| Answer» D. fljA | |
| 179. |
Trp repressor is a |
| A. | Homodimer |
| B. | Homotrimer |
| C. | Heterodimer |
| D. | Heterotrimer |
| Answer» B. Homotrimer | |
| 180. |
What is a DNA library? |
| A. | A DNA fragment inserted into a vector |
| B. | A general collection of all genes sequenced thus far |
| C. | All DNA fragments identified with a probe |
| D. | A collection of DNA fragments that make up the entire genome of a particular organism |
| Answer» E. | |
| 181. |
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 |
| Answer» D. all of these | |
| 182. |
The regions of a gene located at -10 and -35, with respect to the start of transcription, are termed |
| A. | start codons. |
| B. | oriC regions. |
| C. | Shine Dalgarno sequences. |
| D. | promoters. |
| Answer» E. | |
| 183. |
Electrophoresis helps to separate ____________ |
| A. | DNA segments |
| B. | Cells from DNA |
| C. | Tissues |
| D. | RNA from DNA |
| Answer» B. Cells from DNA | |
| 184. |
In order to insert a foreign gene into a plasmid, both must __________ |
| A. | have identical DNA sequences |
| B. | originate from the same type of cell |
| C. | be cut by the same restriction enzyme |
| D. | be of the same length |
| Answer» D. be of the same length | |
| 185. |
Genes of same species, similarly related to each other are __________ |
| A. | Ortholog |
| B. | Synteny |
| C. | Paralog |
| D. | Microarray |
| Answer» D. Microarray | |
| 186. |
DNA Ligase, used in recombinant DNA technology is obtained from _______________ |
| A. | E.coli only |
| B. | E.coli and also Ligase encoded by T4 phage |
| C. | Saccharomyces |
| D. | Retroviruses |
| Answer» C. Saccharomyces | |
| 187. |
Which of the following is correct in terms of determination of location of genetic traits? |
| A. | Known protein coding sequences are too far apart to allow linkage determination for most new genes |
| B. | Restriction sites allow DNAs to be digested |
| C. | Protein-coding genes are always associated with a restriction pattern |
| D. | None of the above |
| Answer» B. Restriction sites allow DNAs to be digested | |
| 188. |
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 |
| Answer» B. binding to RNA polymerase | |
| 189. |
Which type of restriction enzymes do not usually require ATP? |
| A. | Type I |
| B. | Type II |
| C. | Type III |
| D. | Type IV |
| Answer» C. Type III | |
| 190. |
Knockout mice are created by |
| A. | mutagenizing a mouse and selecting for mutant offspring |
| B. | creating a chimera by fusing cells from two different cell lines |
| C. | infecting the mouse with a retrovirus |
| D. | transfecting embryonic stem cells with an altered gene sequence |
| Answer» E. | |
| 191. |
Which of the following is not true of small inbreeding populations? |
| A. | They tend to loose genetic diversity |
| B. | There is an increased incidence of recessive diseases |
| C. | Alleles may become fixed |
| D. | Mutation is increased |
| Answer» E. | |
| 192. |
Which of the following statements regarding the regulation of trp operon expression by attenuation is correct? |
| A. | Rapid translation of the leader peptide prevents completion of mRNA transcript |
| B. | Rapid translation of the leader peptide allows completion of mRNA transcript |
| C. | The leader peptide sequence encodes enzymes required for tryptophan synthesis |
| D. | The leader peptide sequence contains no tryptophan residues |
| Answer» B. Rapid translation of the leader peptide allows completion of mRNA transcript | |
| 193. |
Generally a plasmid vector contains how many elements? |
| A. | 1 |
| B. | 2 |
| C. | 3 |
| D. | 4 |
| Answer» D. 4 | |
| 194. |
If lactose and glucose are provided in the growth medium of a culture of E. coli |
| A. | Lactose operon is not transcribed |
| B. | Lactose metabolism is favored |
| C. | Both lactose and glucose are metabolized at same rate |
| D. | Adenylate cyclase is activated |
| Answer» B. Lactose metabolism is favored | |
| 195. |
Which of the following enzymes’ combined action leads to the generation of sticky ends in the plasmid vector? |
| A. | Alkaline phosphatase and terminal transferase |
| B. | Exonuclease III and alkaline phosphatase |
| C. | Bacteriophage lambda exonuclease and terminal transferase |
| D. | Exonuclease III and terminal transferase |
| Answer» D. Exonuclease III and terminal transferase | |
| 196. |
The lac operon is transcribed in which segments? |
| A. | 1 |
| B. | 2 |
| C. | 3 |
| D. | 4 |
| Answer» B. 2 | |
| 197. |
Multiple copies of 5S genes, located at a chromosomal site distinct from the other rRNA genes |
| A. | are transcribed by rRNA polymerase III and the 5S rRNA |
| B. | are transcribed by rRNA polymerase II |
| C. | are transcribed by rRNA polymerase I and the 5S rRNA |
| D. | are transcribed by DNA polymerase I |
| Answer» B. are transcribed by rRNA polymerase II | |
| 198. |
Short sub-sequence of a cDNA sequence is ____________ |
| A. | Expressed sequence tag |
| B. | Sequence tagged site |
| C. | Contig |
| D. | YAC |
| Answer» B. Sequence tagged site | |
| 199. |
Translation begins |
| A. | at the replication fork |
| B. | on the lagging strand |
| C. | at the start codon |
| D. | in nucleus |
| Answer» D. in nucleus | |
| 200. |
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 |
| Answer» B. inducible trp operon expression | |