Question
Write a prediction that answers the lab question, "How are proteins built using the information provided by a molecule of RNA?" Remember, you are describing processes, so your prediction should include steps.
Answers
GPT-4o mini
Prediction: Proteins are built using the information provided by a molecule of RNA through a series of steps known as transcription and translation, involving critical processes as outlined below.
1. **Transcription**: The process begins in the nucleus (in eukaryotic cells) where a specific segment of DNA is transcribed into messenger RNA (mRNA). RNA polymerase binds to the promoter region of a gene and unwinds the DNA strands. It then synthesizes a single strand of mRNA by adding complementary RNA nucleotides (adenine pairs with uracil, cytosine pairs with guanine) to the growing chain, effectively converting the genetic information encoded in the gene into an RNA format.
2. **RNA Processing**: Before the mRNA can function in protein synthesis, it undergoes several modifications. Introns (non-coding regions) are removed through a process called splicing, while exons (coding regions) are joined together. A 5’ cap is added to the beginning of the mRNA transcript, and a poly-A tail is added to the 3’ end. These modifications enhance mRNA stability and facilitate its export from the nucleus to the cytoplasm.
3. **Translation Initiation**: In the cytoplasm, the processed mRNA binds to a ribosome, which consists of rRNA and proteins. The ribosome identifies the start codon (AUG) on the mRNA, signaling the beginning of translation. The initiator tRNA molecule, carrying the amino acid methionine, binds to the start codon through complementary base pairing.
4. **Elongation**: During elongation, additional tRNA molecules, each carrying a specific amino acid, sequentially bind to the ribosome at the A site according to the mRNA codons. The ribosome catalyzes the formation of peptide bonds between the amino acids, linking them together to form a growing polypeptide chain. As the ribosome moves along the mRNA, the empty tRNA exits from the E site, and the process continues, with the polypeptide elongating in the N-terminus to C-terminus direction.
5. **Termination**: The translation process continues until the ribosome encounters a stop codon (UAA, UAG, or UGA) on the mRNA. No corresponding tRNA binds to these stop codons; instead, release factors bind, prompting the ribosome to release the completed polypeptide chain.
6. **Post-Translational Modifications**: After synthesis, the newly formed polypeptide undergoes various post-translational modifications, such as phosphorylation, glycosylation, or cleavage, which are essential for its proper folding and functionality.
In conclusion, proteins are assembled through the coordinated actions of transcription, mRNA processing, translation, and post-translational modifications, all guided by the genetic information stored in RNA. This intricate process ensures that the correct amino acid sequence is produced, ultimately defining the protein's structure and function within the cell.
1. **Transcription**: The process begins in the nucleus (in eukaryotic cells) where a specific segment of DNA is transcribed into messenger RNA (mRNA). RNA polymerase binds to the promoter region of a gene and unwinds the DNA strands. It then synthesizes a single strand of mRNA by adding complementary RNA nucleotides (adenine pairs with uracil, cytosine pairs with guanine) to the growing chain, effectively converting the genetic information encoded in the gene into an RNA format.
2. **RNA Processing**: Before the mRNA can function in protein synthesis, it undergoes several modifications. Introns (non-coding regions) are removed through a process called splicing, while exons (coding regions) are joined together. A 5’ cap is added to the beginning of the mRNA transcript, and a poly-A tail is added to the 3’ end. These modifications enhance mRNA stability and facilitate its export from the nucleus to the cytoplasm.
3. **Translation Initiation**: In the cytoplasm, the processed mRNA binds to a ribosome, which consists of rRNA and proteins. The ribosome identifies the start codon (AUG) on the mRNA, signaling the beginning of translation. The initiator tRNA molecule, carrying the amino acid methionine, binds to the start codon through complementary base pairing.
4. **Elongation**: During elongation, additional tRNA molecules, each carrying a specific amino acid, sequentially bind to the ribosome at the A site according to the mRNA codons. The ribosome catalyzes the formation of peptide bonds between the amino acids, linking them together to form a growing polypeptide chain. As the ribosome moves along the mRNA, the empty tRNA exits from the E site, and the process continues, with the polypeptide elongating in the N-terminus to C-terminus direction.
5. **Termination**: The translation process continues until the ribosome encounters a stop codon (UAA, UAG, or UGA) on the mRNA. No corresponding tRNA binds to these stop codons; instead, release factors bind, prompting the ribosome to release the completed polypeptide chain.
6. **Post-Translational Modifications**: After synthesis, the newly formed polypeptide undergoes various post-translational modifications, such as phosphorylation, glycosylation, or cleavage, which are essential for its proper folding and functionality.
In conclusion, proteins are assembled through the coordinated actions of transcription, mRNA processing, translation, and post-translational modifications, all guided by the genetic information stored in RNA. This intricate process ensures that the correct amino acid sequence is produced, ultimately defining the protein's structure and function within the cell.