BIO NMDCAT

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.

A nucleoside consists only of a sugar and a base; adding a phosphate group converts it into a nucleotide.

Ribose contains a hydroxyl group (-OH) at the 2' carbon position, distinguishing it from deoxyribose which has a hydrogen atom instead.

Uracil is a pyrimidine base specific to RNA that pairs with adenine, replacing the thymine found in DNA.

Phosphodiester bonds form the sugar-phosphate backbone by connecting the 3' carbon of one ribose to the 5' carbon of the next.