Molecular Basis of Inheritance

An unknown organism that can utilise $\mathrm{NH}_4 \mathrm{Cl}$ as nitrogen source was grown for several generations under four different conditions as given below: (i) medium containing ${ }^{15} \mathrm{NH}_4…

Deoxyribonucleic acid (DNA) is a polymer composed of the nucleotides, deoxyadenosine triphosphate (dATP), deoxyguanosine triphosphate (dGTP), deoxythymidine triphosphate (dTTP) and deoxycytidine triphosphate (dCTP). Two…

The CENTN1 gene encodes the protein centrin that is localized to the centriolar apparatus. Mutation in this gene may give rise to dysfunctional cilia leading to respiratory disorders with different degrees of severity.…

DNA fingerprinting was performed on a human skeleton (S) to identify a missing person reported by four different families ($F_{1}$, $F_{2}$, $F_{3}$ and $F_{4}$). Four short tandem repeat (STR) loci were independently…

Escherichia coli strains (I-IV) with mutations in the lac operon were studied for $\beta$ galactosidase activity, followed by measuring its mRNA and protein levels (Graphs). The arrow indicates the time of addition of a…

An autosomal dominant muscular dystrophy is caused by a decrease in the repeat number of a VNTR present on chromosome 4 of humans. Each repeat is 2.5 kilo base pairs (kbp). If the repeat number is 1 to 15 , then an…

Proteins P1 and P2 bind to each other to form a complex. This complex has a high binding affinity to a specific element on the promoter sequence of a gene $\mathbf{X}$, thus transcribing it. The product of gene…

DNA $\mathrm{C}_o \mathrm{t}$ analysis is based upon the principles of DNA renaturation kinetics. The rate at which heat-denatured DNA sequences in solution will renature is dependent on DNA concentration,…

In biological systems, proteins (repressors and activators) control gene expression. Repressors bind to promoters and inhibit gene expression. Some promoters require activators for gene expression. These constitute a…

In a plant breeding experiment, scientists crossed two homozygous parental lines ($P_{1}$ and $P_{2}$) to produce $F^{1}$ hybrids, designated as $F^{1}$- $P_{1}$/$P_{2}$. Another group of researchers produced a…

The results obtained after following the experimental design of Meselson and Stahl to study DNA replication are shown in the adjacent figure. These results suggest that the mode of DNA replication is

In an experiment, bacteria were grown for $500$ generations in a medium containing $^{14}\text{N}$ (light isotope), then transferred to a medium with $^{15}\text{N}$ (heavy isotope) for one generation, and finally…