What are the steps involved in transcription and translation?

Transcription and translation involve copying DNA into RNA and then translating that RNA into proteins.

Transcription is the first step in gene expression. It involves copying a gene's DNA sequence to make an RNA molecule. This process is carried out by an enzyme called RNA polymerase. Transcription occurs in three stages: initiation, elongation, and termination.

During initiation, the RNA polymerase binds to a specific region of the DNA called the promoter. This signals the start of the gene to be transcribed. The DNA strands then unwind, exposing the sequence to be copied.

In the elongation phase, the RNA polymerase moves along the DNA strand, adding complementary RNA nucleotides to the growing RNA chain. The RNA strand is created in the 5' to 3' direction.

Termination occurs when the RNA polymerase reaches a sequence of DNA called the terminator. This signals the end of the gene. The RNA molecule is then released, and the DNA molecule rewinds back into its original shape.

Translation is the process where the RNA molecule created during transcription is used to create a protein. This process occurs in the ribosome and also involves three stages: initiation, elongation, and termination.

During initiation, the ribosome binds to the start of the mRNA sequence. Then, a tRNA molecule carrying the appropriate amino acid binds to the start codon of the mRNA.

In the elongation phase, the ribosome moves along the mRNA, binding new tRNA molecules and their attached amino acids. The amino acids are joined together to form a polypeptide chain.

Finally, in the termination phase, the process continues until the ribosome reaches a stop codon on the mRNA. The newly formed polypeptide is then released, and the ribosome dissociates from the mRNA. The polypeptide will fold into a functional protein, completing the process of gene expression.