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.
A mutation changes a codon from UCG to UAG. This mutation is a:
Missense mutation
Silent mutation
Frameshift mutation
Nonsense mutation
During DNA replication, topoisomerases play a crucial role. Which statement BEST describes the function of topoisomerases?
They synthesize RNA primers for DNA polymerase.
They unwind the DNA double helix at the replication fork.
They relieve torsional stress in the DNA helix ahead of the replication fork.
They join Okazaki fragments on the lagging strand.
Which statement BEST describes the difference between rho-dependent and rho-independent transcription termination in prokaryotes?
Rho-dependent termination requires a helicase activity, while rho-independent termination relies on a hairpin structure and a poly-U sequence.
Rho-dependent termination occurs only in the presence of specific antibiotics, while rho-independent termination is the normal mechanism.
Rho-dependent termination utilizes sigma factor, while rho-independent termination utilizes rho factor.
Rho-dependent termination involves the formation of a G-quadruplex structure, while rho-independent termination involves a stem-loop structure.
In eukaryotes, the TATA box is a crucial promoter element. Which of the following statements about its function is INCORRECT?
It directly recruits RNA polymerase II to the promoter.
It is recognized by TATA-binding protein (TBP).
It helps determine the transcription start site.
It is typically located approximately 25-30 base pairs upstream of the transcription start site.
Which of the following is NOT a function of the Shine-Dalgarno sequence in prokaryotic translation?
Facilitating the binding of the ribosome to mRNA
Positioning the start codon correctly for initiation
Termination of translation
Aligning the mRNA on the small ribosomal subunit
A mutation in the 23S rRNA of the large ribosomal subunit affects peptidyl transferase activity. Which stage of translation is MOST directly impacted by this mutation?
Initiation
Elongation
Termination
mRNA binding
The Human Genome Project utilized a hierarchical approach to sequencing. Which of the following correctly describes the 'clone-by-clone' sequencing strategy?
Large DNA fragments were directly sequenced using high-throughput methods.
Small DNA fragments were randomly sequenced and assembled computationally.
The entire genome was amplified using PCR and then sequenced in segments.
Large DNA fragments were cloned into BACs, mapped, and then subcloned into smaller vectors for sequencing.
The “RNA world” hypothesis proposes that RNA preceded DNA and proteins as the primary genetic material. A major challenge to this hypothesis is the relative instability of RNA compared to DNA. Why is RNA less stable?
RNA utilizes uracil instead of thymine.
RNA is typically single-stranded.
The 2'-OH group on the ribose sugar makes RNA susceptible to hydrolysis.
RNA is shorter than DNA.
Which of the following enzymes is NOT directly involved in DNA replication?
DNA polymerase
Helicase
Primase
RNA polymerase
During DNA replication, Okazaki fragments are formed on the:
Leading strand
Lagging strand
Both leading and lagging strands
Neither strand
