BIO NMDCAT

The wobble hypothesis states that non-standard base pairing can occur between the third base of a codon and the first base of an anticodon.

Ribonucleases (RNases) degrade mRNA molecules once their translational utility is exhausted, preventing overproduction of proteins.

The prokaryotic 30S small ribosomal subunit contains the 16S rRNA molecule, which plays a key role in identifying the Shine-Dalgarno sequence.

Polycistronic mRNA is characteristic of prokaryotes, where a single promoter controls an operon containing multiple related open reading frames.

Alternative splicing allows different combinations of exons to be joined, producing multiple distinct protein isoforms from a single gene.

A triplet code consisting of three consecutive nucleotides provides the minimum variations (43=64) needed to code for 20 amino acids.

RNA polymerase adds new nucleotides exclusively to the free 3'-OH group of the growing RNA polymer, moving in a 5' to 3' direction.

The 5' cap protects the transcript from exonuclease degradation and assists in ribosome binding during translation initiation.

Chargaff's rules apply only to double-stranded nucleic acids where base pairing forces a 1:1 ratio between complementary bases.

The cloverleaf pattern arises due to localized base pairing within a single tRNA strand, creating loops and stems.

In eukaryotes, RNA Polymerase I is specialized for transcribing the major ribosomal RNA genes within the nucleolus.

The large ribosomal subunit contains rRNA that acts as a ribozyme (peptidyl transferase) to catalyze peptide bond formation.

Introns are non-coding regions that must be excised, and exons are the coding sequences that are ligated together to form mature mRNA.

Written from the 3' to 5' direction (or 5'-CCA-3' read towards the 3' terminus), this terminal sequence attaches to the specific amino acid.

Aminoacyl-tRNA synthetase is the specific enzyme that catalyzes the esterification of a specific amino acid to its cognate tRNA.

The poly-A tail protects mRNA from 3' exonucleases, extending its operational lifespan within the cytoplasm.

Without a nuclear envelope separating DNA from ribosomes, prokaryotes can simultaneously transcribe and translate a genetic message.

AUG is the universal start codon that codes for methionine in eukaryotes and formyl-methionine in prokaryotes.

Complementary bases within the single-stranded tRNA bend back and form hydrogen bonds, creating its characteristic shapes.