Post-transcriptional modifications are processes that modify pre-mRNA into mature mRNA after transcription in eukaryotic cells. These modifications include the addition of a 5′ cap, splicing to remove introns, and the addition of a poly-A tail at the 3′ end. These changes protect mRNA from degradation, aid in its export from […]
Chargaff’s rule is a key principle in molecular biology, stating that in DNA, the proportion of adenine (A) always equals that of thymine (T), and guanine (G) always equals cytosine (C). This A=T and G=C ratio varies between species but remains constant within an organism. This discovery helped Watson and […]
DNA ligase is an essential enzyme that facilitates the joining of DNA strands by catalyzing the formation of phosphodiester bonds between adjacent nucleotides. It plays a critical role in DNA replication and repair by sealing breaks or “nicks” in the sugar-phosphate backbone, particularly on the lagging strand where Okazaki fragments […]
DNA polymerase is an enzyme responsible for synthesizing new DNA strands during replication by adding nucleotides to a pre-existing strand using the original DNA as a template. It works in the 5′ to 3′ direction, ensuring accurate base-pairing to maintain genetic fidelity. DNA polymerase also has proofreading capabilities, correcting errors […]
RNA polymerase is an enzyme that synthesizes RNA from a DNA template during transcription. It binds to specific regions of the DNA called promoters and unwinds the DNA strands to read the sequence. RNA polymerase then assembles complementary RNA nucleotides to form a single-stranded RNA molecule. This RNA serves as […]