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.
| 201. |
A plasmid |
| A. | is a circular DNA molecule |
| B. | always contains an origin of replication |
| C. | usually contains one or more restriction sites |
| D. | all of the above |
| Answer» E. | |
| 202. |
Transgenic organisms are generally __________ |
| A. | Extinct organisms |
| B. | Naturally occurring and endemic |
| C. | Produced by traditional plant breeding technique |
| D. | Produced by gene transfer technology |
| Answer» E. | |
| 203. |
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 |
| Answer» E. | |
| 204. |
Transcription results in |
| A. | an amino acid chain |
| B. | messenger RNA |
| C. | complementary DNA |
| D. | Okazaki fragments |
| Answer» C. complementary DNA | |
| 205. |
Transcription begins |
| A. | at the start codon |
| B. | upstream from the start codon |
| C. | downstream from the start codon |
| D. | none of these |
| Answer» C. downstream from the start codon | |
| 206. |
Glucose is added to the tissue culture media as a/an __________ |
| A. | Carbon source |
| B. | Growth regulator |
| C. | Solidifying agent |
| D. | Antibiotic |
| Answer» B. Growth regulator | |
| 207. |
Which of the following statements regarding DNA fingerprinting is false? |
| A. | DNA fingerprinting cannot be used for paternity testing |
| B. | DNA profile using STR (short terminal repeats) is unique to an individual |
| C. | PCR is used for DNA profiling |
| D. | Forensic analysis makes use of SNPs (single nucleotide polymorphisms) in coding sequences to distinguish between individuals |
| Answer» B. DNA profile using STR (short terminal repeats) is unique to an individual | |
| 208. |
The lactose repressor is encoded by |
| A. | Lac-l |
| B. | Lac-A |
| C. | Lac-Y |
| D. | Lac-Z |
| Answer» B. Lac-A | |
| 209. |
Most transcripts of protein coding genes are cleaved |
| A. | at the 3' end just after a poly adenylation signal |
| B. | at the 3' end just before a poly adenylation signal |
| C. | at the 5' end immediately after a poly adenylation signal |
| D. | at the 5' end immediately before a poly adenylation signal |
| Answer» B. at the 3' end just before a poly adenylation signal | |
| 210. |
Gene therapy is a technique preferred to cure inherited diseases by __________ |
| A. | Repairing the faulty gene |
| B. | Introducing the correct copy of the gene |
| C. | Adding new cells to the body |
| D. | PCR |
| Answer» C. Adding new cells to the body | |
| 211. |
Lactose utilization by E. coli requires |
| A. | Lac-Z |
| B. | Lac-A |
| C. | Lac-Y |
| D. | Lac-l |
| Answer» D. Lac-l | |
| 212. |
Methylated gene are |
| A. | active |
| B. | silent |
| C. | dynamic |
| D. | either (a) or (b) |
| Answer» C. dynamic | |
| 213. |
The study of the full complement of proteins expressed by a genome is called __________ |
| A. | Proteome |
| B. | Proteomics |
| C. | Genomics |
| D. | Protein formation |
| Answer» C. Genomics | |
| 214. |
Which of these restriction enzymes produce blunt ends? |
| A. | SaII |
| B. | EcoRV |
| C. | XhoI |
| D. | HindIII |
| Answer» C. XhoI | |
| 215. |
Arrange the following steps involved in Gene cloning in the correct order.i) Isolation of desired geneii) Insertion of isolated gene to the vectoriii) Introduction of recombinant vector to the hostiv) Expression of recombinant gene in hostv) Extraction of recombinant gene product |
| A. | i, ii, iii, iv, v |
| B. | v, iv, iii, ii, i |
| C. | i, iii, ii, iv, v |
| D. | iv, v, ii, i, iii |
| Answer» B. v, iv, iii, ii, i | |
| 216. |
Rauolfia serpentine, to save this plant under the threat of extinction, which of the following techniques is useful? |
| A. | Genetic engineering |
| B. | In vitro culture |
| C. | DNA fingerprinting |
| D. | Hybridoma technology |
| Answer» C. DNA fingerprinting | |
| 217. |
Where does a repressor bind an operon? |
| A. | Operator |
| B. | Promoter |
| C. | Inducer |
| D. | Catabolite activator site |
| Answer» B. Promoter | |
| 218. |
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 |
| Answer» C. the X autosome balance equals 0.5 | |
| 219. |
Which of these genes codes for a protein that plays a role in white blood cell function? |
| A. | DCP1 |
| B. | MPO |
| C. | GLUT4 |
| D. | RP13 |
| Answer» C. GLUT4 | |
| 220. |
The sequence of one strand of DNA is: 5' ATTGCCA 3', what is the sequence of the other strand? |
| A. | 5' TAACGGT 3' |
| B. | 5' TGGCAAT 3' |
| C. | 5' ATTGCCA 3' |
| D. | 5' UAAGCCU3' |
| Answer» C. 5' ATTGCCA 3' | |
| 221. |
How many amino acids will be encoded by 5' GAU GGU UGA UGU 3' sequence? |
| A. | One |
| B. | Two |
| C. | Three |
| D. | Four |
| Answer» C. Three | |
| 222. |
Which of the following conditions would cause the release of the lac repressor protein from the lac operator site on DNA? |
| A. | Presence of glucose in the growth media |
| B. | Presence of lactose in the growth media |
| C. | Presence of IPTG (isopropyl thiogalactoside) in the growth media |
| D. | Both (b) and (c) |
| Answer» E. | |
| 223. |
Restriction enzymes |
| A. | protect bacteria from viral infection |
| B. | cut DNA in a staggered fashion |
| C. | cut DNAs producing a blunt end |
| D. | all of the above |
| Answer» E. | |
| 224. |
RNA polymerase in prokaryotes has a removable |
| A. | alpha subunit |
| B. | beta subunit |
| C. | both (a) and (b) |
| D. | sigma subunit |
| Answer» E. | |
| 225. |
An example of a restriction fragment length polymorphism is |
| A. | an Eco RI cuts DNA at a different sequence than Hind III |
| B. | different length fragments of DNA resulting from loss or gain of a restriction site |
| C. | cystic fibrosis results from a three base deletion in most cases but in other cases, other mutations are involved |
| D. | all of the above |
| Answer» C. cystic fibrosis results from a three base deletion in most cases but in other cases, other mutations are involved | |
| 226. |
Which of the following statements about lac operon in e.coli is true? |
| A. | Promoter is the binding site for the lac repressor |
| B. | Operon is only switched on in the absence of lactose in the growth medium |
| C. | β-galactosidase is only produced in large quantities when the lac repressor is bound to the operator |
| D. | Lac operon mRNA is a polycistronic mRNA |
| Answer» E. | |
| 227. |
In protein synthesis in prokaryotes |
| A. | the initiating amino acid is N- formyl methionine |
| B. | the initiating amino acid is methionine |
| C. | the initiating amino acid is phenyl alanine |
| D. | none of the above |
| Answer» B. the initiating amino acid is methionine | |
| 228. |
Which of the following takes place when tryptophan levels are high? |
| A. | Attenuation at the attenuator structure formed by sequences of 3 and 4 |
| B. | Ribosomes pauses at the Try codons in sequence 1 |
| C. | Formation of paired structure between 2 and 3 sequences prevents attenuation |
| D. | 2:3 structures, unlike the 3:4 attenuator, does not prevent transcription |
| Answer» B. Ribosomes pauses at the Try codons in sequence 1 | |
| 229. |
RNA is synthesized on a DNA template in a process called __________ , which utilizes the enzyme __________ |
| A. | translation, RNA polymerase |
| B. | transcription, DNA polymerase |
| C. | transcription, RNA polymerase |
| D. | replication, DNA polymerase |
| Answer» D. replication, DNA polymerase | |
| 230. |
Which of the following are the structural motifs that mediate protein-protein interactions? |
| A. | Leucine zipper and basic helix-loop-helix |
| B. | Homeodomain |
| C. | Zinc finger |
| D. | Helix-turn-helix |
| Answer» B. Homeodomain | |
| 231. |
Which of the following regulatory sequence allows transcription to continue? |
| A. | Sequence 1 |
| B. | Sequence 2 |
| C. | Sequence 3 |
| D. | Sequence 4 |
| Answer» C. Sequence 3 | |
| 232. |
Plant transformation can be obtained by |
| A. | combining plant and animal cells in culture |
| B. | shooting DNA into plant cells with a gun |
| C. | using the E. coli bacterium to infect plant roots |
| D. | infecting plants with a tobacco mosaic virus |
| Answer» C. using the E. coli bacterium to infect plant roots | |
| 233. |
Southern blotting technique is used in ____________ |
| A. | Monoclonal antibody production |
| B. | In vitro culture |
| C. | Genetic finger printing |
| D. | Polymerase chain reaction |
| Answer» D. Polymerase chain reaction | |
| 234. |
The genetic code is |
| A. | universal |
| B. | universal except for rare exceptions in mitochondria and some protozoa |
| C. | species-specific |
| D. | kingdom-specific |
| Answer» C. species-specific | |
| 235. |
Recombinant DNA construction involves ____________ |
| A. | Cleaving DNA with a restriction endonuclease and joining with ligase |
| B. | Cleaving DNA with ligase and joining with endonuclease |
| C. | Cleaving and joining DNA with restriction endonuclease |
| D. | Cleaving DNA with a restriction endonuclease and joining with polymerase |
| Answer» B. Cleaving DNA with ligase and joining with endonuclease | |
| 236. |
In prokaryotes, transcription is |
| A. | terminated by the stop codon |
| B. | terminated by a protein called rho |
| C. | terminated by a poly A sequence |
| D. | terminated by a start codon |
| Answer» C. terminated by a poly A sequence | |
| 237. |
Which of the following techniques can be used to determine the defective gene and for developing cancer? |
| A. | Western blot |
| B. | Southern blot |
| C. | Northern blot |
| D. | Eastern blot |
| Answer» C. Northern blot | |
| 238. |
The genetic code is degenerated. Which of the following codons represents the principle of degeneracy? |
| A. | UAA and UAC |
| B. | AUG and AUA |
| C. | CAU and CAC |
| D. | UUA and UUC |
| Answer» D. UUA and UUC | |
| 239. |
Crick demonstrated that the genetic code involved three bases and suggested that the code was degenerated. What experimental technique Crick conducted to suggest genetic code degeneration? |
| A. | Gel electrophoresis |
| B. | Density gradient centrifugation |
| C. | Frameshift mutagenesis |
| D. | Restriction digests of the rII gene |
| Answer» D. Restriction digests of the rII gene | |
| 240. |
In some organelles in eukaryotes, the genetic code for some codons |
| A. | differs from that used in prokaryotes |
| B. | are same |
| C. | are partially same |
| D. | none of the above |
| Answer» B. are same | |
| 241. |
Codon that specify the amino acids often differs in the |
| A. | first base |
| B. | second base |
| C. | third base |
| D. | none of these |
| Answer» D. none of these | |
| 242. |
The codons which do not specify an amino acid are called |
| A. | initiation code |
| B. | termination code |
| C. | propagation code |
| D. | none of these |
| Answer» C. propagation code | |