2.1

In Week 2 of human genetics, the focus is on DNA sequences and chromosomes.

DNA is double-stranded; the strands are named based on their biological context.

During gene expression, one strand is copied into RNA, known as the template strand.

The coding strand is 5' to 3', while the template strand is the opposite (3' to 5').

RNA is an exact match of the coding strand except that T is replaced with U.

Terms used include sense (coding strand) and anti-sense (template strand).

Leading and lagging strands are concepts related to DNA replication.

DNA sequences are stored in public databases, allowing standardization and accessibility for research.

The coding strand in databases is presented in 5' to 3' direction and is inferred using base pairing rules.

Reference sequences are the agreed-upon versions of genes or genomes, and scientists often focus on specific DNA regions rather than entire sequences.

The importance of strand identity is highlighted, as it determines the strand used for RNA transcription, with coding strands written in the 5' to 3' direction, which RNA follows in structure for protein translation.

Understanding DNA strands sets the groundwork for exploring DNA packaging into chromosomes.