MCQs

RNA synthesis uses nucleoside triphosphates (ATP, CTP, GTP, UTP); the cleavage of pyrophosphate yields the energy needed for polymerization.

Eukaryotic structural genes are organized as split sequences where protein-coding regions (exons) are interrupted by non-coding regions (introns).

The anticodon loop exposes three nucleotide bases designed to form anti-parallel hydrogen bonds with the matching mRNA codon triplet.

Capping enzymes require the 5' triphosphate terminal structure of the nascent RNA transcript to successfully link the inverted guanosine cap.

The P (peptidyl) site retains the tRNA molecule attached to the evolving polypeptide chain before transferring it to the incoming A-site tRNA.

The A (aminoacyl) site welcomes the newly arrived, charged tRNA molecule carrying the next amino acid to be added to the growing peptide chain.

The physical stress of the hairpin combined with the weak hydrogen bonds of the U-rich stretch forces the transcript to detach from the DNA template.

Uncharged tRNAs lack attached amino acids; their buildup indicates that the cell is running low on amino acids to fuel protein translation.

RNA polymerases possess the unique biochemical capacity to initiate the synthesis of a new polynucleotide chain completely de novo.

Double-stranded RNA genomes rely on regular hydrogen bonds between complementary base pairs, specifically adenine-uracil and guanine-cytosine.

The signal recognition particle contains a specific small cytoplasmic RNA molecule known as 7SL RNA, which guides newly synthesizing proteins to the ER.

Specific identity elements scattered across the acceptor stem and variable loops allow the synthetase to accurately identify its matching tRNA.

Ribosomal RNA forms the dense, intricately folded catalytic and structural core of both the large and small ribosomal subunits.

Prokaryotes handle all transcription with a single multi-subunit core RNA polymerase that relies on changeable sigma factors for promoter recognition.

miRNAs are tiny, non-coding RNA molecules that associate with RISC complexes to pair with matching mRNAs and suppress translation.

The AAUAAA consensus sequence is recognized by specific endonucleases that cleave the nascent RNA transcript before poly-A polymerase adds the tail.

The coding (sense) DNA strand matches the mRNA transcript sequence exactly, with the sole exception that thymine (T) is replaced by uracil (U).

The T$psi$C loop contains ribothymidine and pseudouridine, which are critical for anchoring the tRNA molecule to the large ribosomal subunit.

Accurate translation relies entirely on the precise hydrogen-bond pairing between three consecutive mRNA bases and three complementary tRNA bases.