Molecular Genetics

This is the major structural protein and covers the RNA genome. It protects the genome from nucleases and holds it in a conformation that allows transcription.

During this stage the cellular proteolytic enzymes digest the capsid away from the nucleic acid. This always occurs in the cytoplasm of the host cell. The period of the replication cycle between the end of the uncoating stage and maturation of new viral particles is termed the eclipse. Thus, during the eclipse stage no complete viral particles can be viewed within the cell.

NSP1, the product of rotavirus gene 5, is a non-structural RNA-binding protein that contains a cysteine-rich region and is a component of early replication intermediates.

AUG is the universal start codon that codes for methionine and initiates protein synthesis in both prokaryotes and eukaryotes. UUU codes for phenylalanine, UAA is a stop codon, and AAA codes for lysine. The genetic code is nearly universal.

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 .

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

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

t-RNA molecule has a peculiar shape which acts as an adapter during translation.

A cistron is the functional unit of a gene that codes for a single polypeptide chain. A replicon is a DNA unit capable of replication, a muton is the smallest mutable unit, and a codon is a triplet coding for one amino acid. Cistron aligns with the 'one gene-one polypeptide' concept.

Kinetin (a cytokinin) is formed from the degradation products of DNA, specifically from the adenine base. It was discovered as a compound that promotes cell division. It is not derived from RNA, proteins, or carbohydrates.

Splicing is a modification of the nascent pre-messenger RNA (pre-mRNA) transcript in which introns are removed and exons are joined. In this process, snRNAs are used.

The signal recognition particle (SRP) is an abundant, cytosolic, universally conserved ribonucleoprotein (protein-RNA complex) that recognizes and targets specific proteins to the endoplasmic reticulum in eukaryotes and the plasma membrane in prokaryotes.

Viruses are classified as either RNA viruses or DNA viruses based on their genetic material. A virus contains either RNA or DNA, but never both simultaneously. This fundamental distinction is crucial for understanding viral replication mechanisms, classification, and the development of antiviral strategies. Option C correctly captures this binary characteristic of viral genomes.

Translation is the process of protein synthesis where mRNA is decoded by ribosomes to produce a polypeptide chain. This process requires mRNA (as the template), tRNA (as the adapter molecule bringing amino acids), and amino acids (as building blocks). DNA is involved in transcription (making mRNA) but not directly in translation, which occurs in the cytoplasm (or prokaryotic cytoplasm).