BIO NMDCAT

Placing the charged, polar groups on the outside allows DNA to interact favorably with the watery environment of the nucleoplasm.

The promoter is a specific upstream nucleotide sequence that signals the transcription machinery where to start making RNA.

A missense mutation alters a single nucleotide, changing a codon so that it incorporates a different amino acid into the protein.

Hydrogen bonds are weak non-covalent interactions, allowing the twin strands to unzip easily when driven by specialized enzymes.

Pleiotropy happens when a single gene codes for a protein used in multiple tissues, meaning a mutation can cause widespread symptoms.

An N-glycosidic bond connects the 1' carbon of the pentose sugar to the nitrogen atom at position 1 in pyrimidines or position 9 in purines.

Exons are the coding segments of a gene that remain in the mature mRNA transcript after splicing, carrying the blueprint for translation.

The B-DNA helix has a pitch of 3.4 nm and a base-pair step of 0.34 nm, accommodating roughly 10 base pairs per full turn.

By convention, the coding strand is written 5' to 3' because the ribosome reads mRNA 5' to 3' to build a protein from its N- to C-terminus.

Each phosphate group in the backbone retains a negative charge at physiological pH by releasing a hydrogen ion (H+), acting as an acid.

Inserting or deleting a base shifts the triplet reading frame downstream, completely altering the remaining amino acid sequence.

The nucleosome is the primary structural unit of chromatin, packing a 147-base-pair segment of DNA around a histone octamer core.

The non-template strand matches the mRNA transcript sequence exactly (except that DNA has T where RNA has U), earning it the name "coding strand."

Transcription generates an RNA transcript that is complementary and anti-parallel to the DNA template strand, swapping thymine for uracil.

Chargaff’s rules dictate that [A]=[T] and [G]=[C]; therefore, the sum of purines (A+G) must equal the sum of pyrimidines (T+C).

DNA polymerases require a free 3'-OH group to form a phosphodiester bond with the 5' phosphate group of an incoming dNTP.

One complete helical turn spans a longitudinal length of 3.4 nm (34 A˚) and contains approximately 10 base pairs.

Human genes contain introns, which bacteria cannot slice out because they lack spliceosomes, leading to a flawed, non-functional protein.

A codon is a triplet of bases that specifies a particular amino acid or a stop signal during protein translation.