Copy DNA before cell division.
Polymerases synthesize new strands using complementary base pairing and proofreading.
Side 138
Molecular Biology
How cells store, copy, regulate and express biological information through molecular mechanisms built from nucleic acids and proteins.
DNA→RNA→protein→regulation→cellular function
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16working concepts
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SS-1.0standard
DNA stores sequence information inside organized chromosomes.
Genome function depends not just on sequence but on replication, packaging, accessibility and repair.
Package DNA with proteins.
Compaction and chemical modification influence which regions remain accessible.
Correct molecular damage and replication errors.
Multiple repair pathways recognize different lesion classes and preserve genome stability.
Exchange or rearrange DNA segments.
Recombination supports repair, meiosis and genetic diversity.
Gene expression converts sequence into functional products.
Transcription and translation are regulated processes rather than automatic readings of DNA.
Produce RNA from a DNA template.
Polymerase initiation and termination determine which sequences are copied.
Modify RNA before use.
Splicing, capping and polyadenylation can change stability and coding potential.
Build polypeptides from messenger RNA.
Ribosomes interpret codons through transfer RNAs and coordinated elongation.
Turn sequence into functional molecular structure.
Protein folding, modification and localization shape final function.
Cells control when, where and how strongly genes are expressed.
Regulatory systems act at DNA, RNA, translation and protein levels.
Recruit transcriptional machinery.
Regulatory DNA can integrate multiple signals across local and long-range interactions.
Bind sequence motifs and influence expression.
Combinations of regulators create context-dependent control.
Control stability, localization and translation.
Noncoding RNAs and RNA-binding proteins reshape expression after transcription.
Remove or modify existing proteins.
Degradation and post-translational control let cells change function without waiting for new transcription.
Molecular claims depend on techniques with different measurement limits.
Sequencing, amplification, perturbation and imaging reveal different levels of mechanism.
Amplify selected DNA sequences.
Amplification enables sensitive detection but can introduce bias and contamination.
Read nucleotide order at scale.
Platform choice affects read length, depth, error pattern and interpretation.
Perturb defined genomic sites.
Editing can test causal roles while off-target and compensatory effects require controls.
Measure many transcripts or proteins together.
High-dimensional assays expose system states but require careful normalization and validation.
Information in biology is implemented physically. Sequences matter because molecular machinery reads, copies, modifies and regulates them in particular cellular contexts.