Prepare for NEET Biology Molecular Basis of Inheritance with MCQs & PYQs on NEET.GUIDE. Access free practice, previous year questions, and expert explanations of DNA replication and genetics.
In eukaryotic DNA replication, which of the following is NOT a function of topoisomerase?
Relieving torsional stress
Preventing supercoiling
Untangling DNA strands
Synthesizing RNA primers
Which observation from Griffith's experiment with Streptococcus pneumoniae provided the strongest evidence for the existence of a 'transforming principle'?
Live non-virulent bacteria did not cause disease in mice.
Heat-killed virulent bacteria did not cause disease in mice.
Live virulent bacteria caused disease in mice.
Heat-killed virulent bacteria, when mixed with live non-virulent bacteria, caused the latter to become virulent.
In the Hershey-Chase experiment, what crucial observation confirmed that DNA, and not protein, was the genetic material injected into bacteria by bacteriophages?
Radioactive sulfur (35S) was found inside the bacterial cells, while radioactive phosphorus (32P) remained outside.
Both radioactive phosphorus (32P) and sulfur (35S) were found inside the bacterial cells.
Neither radioactive phosphorus (32P) nor sulfur (35S) were found inside the bacterial cells.
Radioactive phosphorus (32P) was found inside the bacterial cells, while radioactive sulfur (35S) remained outside.
Certain mutations in the DNA polymerase delta gene can lead to reduced fidelity of DNA replication. Which of the following would be the MOST LIKELY direct consequence of such a mutation?
Decreased rate of Okazaki fragment synthesis
Inhibition of DNA unwinding by helicase
Increased rate of DNA repair mechanisms
Increased mutation rate in the newly synthesized DNA
Imagine a prokaryotic organism with a mutated DNA polymerase III that lacks 3' to 5' exonuclease activity. What would be the MOST LIKELY consequence of this mutation?
Slower replication fork movement
Inability to initiate DNA replication
A higher rate of mutations in the replicated DNA
Increased formation of Okazaki fragments
Imagine a scenario where a novel amino acid is discovered. If the existing genetic code must accommodate this new amino acid without altering the existing amino acid assignments, what is the MOST likely mechanism for achieving this?
Expansion of the codon length from three to four bases
Overlapping reading frames
Reassignment of a rarely used codon
Modification of the ribosome structure
A researcher discovers a bacterial strain with an unusual genetic code. In this strain, the codon UAG, typically a stop codon, codes for tryptophan. Which of the following would be the MOST direct consequence of this altered genetic code?
Premature termination of protein synthesis
No effect on protein synthesis
Substitution of tryptophan with another amino acid
Elongation of proteins past the normal termination point
A mutation in a eukaryotic gene results in the production of a truncated protein lacking its C-terminal region. Analysis reveals a mutation within an intron of the gene. Which of the following is the MOST likely explanation?
The mutation disrupted a splicing enhancer sequence, leading to exon skipping.
The mutation created a new promoter within the intron.
The mutation disrupted the polyadenylation signal, preventing proper termination.
The mutation created a premature stop codon within the intron.
A researcher identifies a novel eukaryotic transcription factor. Experiments reveal that this factor binds to a DNA sequence downstream of the transcription start site. Which of the following is the MOST likely role of this factor?
Initiating transcription by recruiting RNA polymerase
Repressing transcription by blocking RNA polymerase binding
Enhancing transcription elongation or termination
Modifying the chromatin structure around the promoter
Which ethical concern regarding the Human Genome Project is MOST directly related to potential discrimination based on genetic information?
The cost of genetic testing and its accessibility
The potential for germline gene editing
Privacy and confidentiality of genetic data
The accuracy and reliability of genetic tests
