1. Describe the transcription and translation processes in the simulation. nswer.

The transcription and translation processes are fundamental steps in gene expression, where the information encoded in DNA is converted into functional proteins. Here’s a detailed description of each process: ### Transcription 1. **Initiation**: - The process begins when RNA polymerase binds to a specific region of the DNA called the promoter. This region is located at the start of a gene. - The DNA strands unwind and separate, exposing the coding sequence of the gene. 2. **Elongation**: - RNA polymerase moves along the template strand of the DNA, synthesizing a single strand of RNA. - The RNA is synthesized in the 5' to 3' direction, meaning that nucleotides are added to the 3' end of the growing RNA strand. - The RNA nucleotides are complementary to the DNA template strand (A pairs with U in RNA, and C pairs with G). 3. **Termination**: - Transcription continues until RNA polymerase reaches a termination signal in the DNA sequence. - Upon reaching this signal, RNA polymerase detaches from the DNA, and the newly synthesized RNA strand (pre-mRNA) is released. 4. **Post-Transcriptional Modifications** (in eukaryotes): - The pre-mRNA undergoes several modifications: - A 5' cap is added to the beginning of the RNA. - A poly-A tail is added to the 3' end. - Introns (non-coding regions) are removed, and exons (coding regions) are spliced together to form mature mRNA. ### Translation 1. **Initiation**: - The mature mRNA is transported from the nucleus to the cytoplasm, where it binds to a ribosome. - The ribosome scans the mRNA to find the start codon (AUG), which signals the beginning of translation. 2. **Elongation**: - Transfer RNA (tRNA) molecules, each carrying a specific amino acid, bind to the ribosome at the A site based on the codon sequence of the mRNA. - The ribosome facilitates the formation of peptide bonds between the amino acids, creating a growing polypeptide chain. - The ribosome moves along the mRNA, shifting the tRNA from the A site to the P site, and the empty tRNA exits from the E site. 3. **Termination**: - Translation continues until a stop codon (UAA, UAG, or UGA) is reached on the mRNA. - Release factors bind to the stop codon, prompting the ribosome to release the completed polypeptide chain. - The ribosomal subunits disassemble, and the mRNA is released. ### Summary In summary, transcription is the process of synthesizing RNA from a DNA template, while translation is the process of synthesizing proteins based on the sequence of the mRNA. Together, these processes enable the expression of genes and the production of proteins necessary for cellular functions.