Biology

Molecular Genetics

917 Questions

Molecular genetics explores the mechanisms of genetic information transfer, including DNA replication, transcription, and translation. It is a core component of biology syllabi. These concepts frequently appear in general science sections of major competitive exams.

DNA replicationTranscription processTranslation processRNA typesCentral dogma

Molecular Genetics Questions

Multiple choice
  1. Each spliceosome is composed of five small nuclear RNAs.

  2. The RNA component of the small nuclear ribonucleic protein or snRNP is rich in adenine.

  3. Introns typically have a GU nucleotide sequence at the 5' end splice site, and an AG at the 3' end splice site.

  4. A spliceosome is a large and complex molecular machine found primarily within the nucleus of eukaryotes.

  5. The spliceosome removes introns from a transcribed pre-mRNA.

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The RNA component of the small nuclear ribonucleic protein or snRNP is rich in uridine (the nucleoside analog of the uracil nucleotide).

Multiple choice
  1. Mutually exclusive exons

  2. Intron retention

  3. Alternative acceptor site

  4. Exon skipping or cassette exon

  5. Alternative donor site

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A sequence may be spliced out as an intron or simply retained. This is distinguished from exon skipping because the retained sequence is not flanked by introns. If the retained intron is in the coding region, the intron must encode amino acids in frame with the neighboring exons, or a stop codon or a shift in the reading frame will cause the protein to be non-functional. This is the rarest mode in mammals.

Multiple choice
  1. The exons to be retained in the mRNA are determined during the splicing process.

  2. U3 is not involved in mRNA splicing.

  3. Each intron has GU at its 3' end.

  4. Splicing is regulated by trans-acting proteins.

  5. Splicing silencers are sites to which splicing repressor proteins bind.

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The typical eukaryotic nuclear intron has consensus sequences defining important regions. cc Near the 3' end there is a branch site.

Multiple choice
  1. A eukaryotic cell transcribes the DNA into RNA.

  2. The mixture of mature mRNA strands is extracted from the cell.

  3. A poly-T oligonucleotide primer is hybridized onto the poly-A tail of the mature mRNA template.

  4. DNA polymerase is added, along with deoxynucleotide triphosphates (A, T, G, C).

  5. It is likely that the ssDNA forms a hairpin loop at the 3' end.

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Reverse transcriptase is added, along with deoxynucleotide triphosphates (A, T, G, C). This synthesizes one complementary strand of DNA hybridized to the original mRNA strand.

Multiple choice
  1. 1

  2. 2

  3. 3

  4. 4

  5. 5

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Both Assertion (A) as well as Reason (R) are correct and R is the correct explanation of A. Pre messenger RNA (pre-m-RNA) must be modified before translation because pre-m-RNA contains the non-coding sequences (intron) within the coding region.

Multiple choice

Directions: Choose the correct answer for the following question on the basis of the given passage:

Which of the following statements would be most likely to come after the last sentences of the passage?

RC Passage 6:
Few areas of neuron behavioral research seemed more promising is the early sixties than that investigating the relationship between protein synthesis and learning. The conceptual framework for the research was derived directly from molecular biology, which had shown that genetic information is stored in nucleic acids and expressed in proteins why not acquired information as well.
The first step towards establishing a connection between protein synthesis and learning seemed to be to block memory (cause adhesion) by interrupting the production of proteins. We were fortunate in finding a non lethal dosage of puromycin that could, it first appealed, thoroughly inhibit brain protein synthesis as well as reliability produce amnesia. Before the actual connection between protein synthesis and learning could be established however we began to have douche about whether inhibition of protein synthesis was in fact the method by which puromycin produced amnesia. First, ocher drugs, glutavimides themselves potent protein synthesis inhibitors either failed to cause amnesia in some situations where it could easily be induced by puromycin or produced an amnesia with a different time course from that of puromycin. Second, puromycin was found to inhabit protein  synthesis by breaking certain amino acid chain, and the resulting fragments were suspected of being the actual cause of amnesia is some eases. Third, puromycin was reported to cause abnormalities in the train, including seizures. Thus, not only were decreased protein synthesis and amnesia dissociated, but alternative mechanism for the amnestic action of puromycin were readily suggested.

So, puromycin turned out to be a disappointment. It came to be regarded as a poor agent for amnesia studies, although, of course, it was poor only in the context of our original paradigm of protein synthesis inhibition. In our frustration, our initial response was simply to change dregs rather than our conceptual orientation. After many such disappointments, however, it now appears unlikely, that we will make a firm connection between protein synthesis and learning merely by pursuing the approaches of the past our experience with drugs has shown that all the amnestic agents, often interfere with memory in ways that seem unrelated to their inhibition of protein synthesis. More importantly, the notion that the interruption or intensification of protein production in the train can be related in cause and affect fashion to learning now seems simplistic and unproductive. Remove the battery from a car and the car will not go Drive the car a long distance at high speed and the battery will become more highly charged. Neither of these facts proves that the battery power the car, only knowledge of the overall automotive system will reveal its mechanism of locomotion and the role of the battery with in the system.
  1. It is important in the future, therefore for behavioral bio- chemist to focus on the several components of the total learning system.

  2. The ambivalent status of current research, however should not deter neuron behaviorists from exploring the deeper connection between protein production and learning.

  3. The failures of the past, however must not impede further research into the amnestic of protein-synthesis inhibitors.

  4. It is important in the future, therefore, for behavioral biochemist to emphasize more strongly place of their specific findings within the overall protein synthesis model of learning.

  5. It is a legacy of this research, therefore, that molecular biology's genetic models have led to disagreement among neuron behaviorists.

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

 The last line reads '  Neither of these facts proves that the battery power the car, only knowledge of the overall automotive system will reveal it mechanism of locomotion and the role of the battery with in the system.'  Therefore, the next line should talk about the importance of the learning process.

Multiple choice
  1. rRNA

  2. hnRNA

  3. tRNA

  4. mRNA

  5. None of these

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The basic structure of tRNA assumes the pattern of clover leaf that carry amino acids to the ribosome for polymerisation into a polypeptide.

Multiple choice
  1. frameshift mutation

  2. nonsense mutation

  3. missense mutations

  4. neutral mutation

  5. silent mutations

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A nonsense mutation is a point mutation in a sequence of DNA that results in a premature stop codon, or a nonsense codon in the transcribed mRNA, and possibly a truncated, and often nonfunctional protein product.

Multiple choice
  1. silent mutations

  2. neutral mutation

  3. missense mutations

  4. nonsense mutation

  5. frameshift mutation

Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

A frameshift mutation is a genetic mutation caused by indels (insertions or deletions) of a number of nucleotides in a DNA sequence that is not divisible by three. Due to the triplet nature of gene expression by codons, the insertion or deletion can change the reading frame.