AP Bio Gene Expression - Easy Visual Breakdown

Welcome to our exploration of DNA structure and transcription!DNA is often described as a twisted ladder, where the sides are made of sugar and phosphate molecules, and the rungs are made of paired nucleotide bases.The bases always pair in specific ways: Adenine pairs with Thymine using two hydrogen bonds, while Cytosine pairs with Guanine using three hydrogen bonds.During transcription, an enzyme called RNA polymerase approaches the DNA.The polymerase unzips the DNA double helix and begins reading one strand as a template.As it moves along the template strand, RNA polymerase builds a new RNA strand using complementary RNA nucleotides.In RNA, Uracil replaces Thymine, but the other bases remain the same. The RNA strand is built following specific base pairing rules.The process continues until the entire gene has been transcribed into messenger RNA.This newly created messenger RNA will now undergo processing before it can be used to make proteins.After transcription, the pre-messenger RNA needs to be processed before it can be used.The pre-messenger RNA contains both coding regions called exons, and non-coding regions called introns.First, a protective cap is added to the five prime end.And a poly-A tail is added to the three prime end for stability.Next, the spliceosome removes the introns and joins the exons together in a process called splicing.The mature messenger RNA, now ready for use, must leave the nucleus through nuclear pores.The mature messenger RNA passes through nuclear pores to reach the cytoplasm, where it will be used for protein synthesis.In the cytoplasm, protein synthesis occurs at the ribosome, a complex molecular machine.The messenger RNA, or mRNA, contains the genetic instructions in the form of codons - groups of three nucleotides.Once all amino acids are connected, the protein chain folds into its final three-dimensional shape, which is crucial for its function.Let's review the key points about protein synthesis.And that completes our journey from DNA to proteins!