Molecular Basis of Inheritance MCQs

Aminoacylation, or the charging of tRNA, is the process where a specific amino acid is chemically bonded to its corresponding tRNA. This process requires energy from ATP and is catalyzed by aminoacyl-tRNA synthetase.

The formation of the peptide bond during translation is catalyzed by the ribosome itself. In bacteria, the 23S rRNA component of the large ribosomal subunit acts as a ribozyme (an RNA enzyme) known as peptidyl transferase.

The Lac operon is an inducible operon. It is normally "off" because the repressor is bound to the operator. It is turned "on" (induced) only in the presence of an inducer (lactose), which inactivates the repressor.

The "i" gene in the Lac operon stands for "inhibitor." It is a constitutive gene that codes for the repressor protein. This repressor binds to the operator region to block transcription in the absence of lactose.

Beta-galactosidase, encoded by the lacZ gene, is responsible for hydrolyzing the disaccharide lactose into its monomeric units, glucose and galactose, which the bacteria can then use for energy.

The Human Genome Project was a 13-year mega-project that began in 1990 and was officially completed in 2003. However, the sequence of Chromosome 1 was completed slightly later in May 2006.

One of the striking findings of the Human Genome Project was that less than 2% of the entire human genome actually codes for proteins. The vast majority consists of non-coding sequences, including repetitive DNA.

DNA fingerprinting exploits differences in repetitive DNA sequences, specifically Satellite DNA. These sequences (like VNTRs) show high degrees of polymorphism (variation) between individuals, making them unique identifiers.

Gel electrophoresis is used to separate DNA fragments based on their size. Since DNA is negatively charged, it moves towards the positive electrode through a gel matrix, with smaller fragments moving faster than larger ones.

VNTR stands for Variable Number of Tandem Repeats. These are a class of satellite DNA (minisatellites) where a short sequence is repeated many times, and the number of repeats varies significantly among individuals.