Question

review: transcription and translation

1. dna
2. mrna
3. codon
4. trna
5. anticodon
6. amino acid
7. ribosome
8. polypeptides
9. what is the role of mrna in the process? copy the dna out of nucleus and transform to ribosome in cytoplams.
10. what is the role of trna in the process? transform amino acid to the right place.
11. what is the role of the ribosome in the process? help protein sythesis, match the amino acid
12. where is the anticodon located? on the trna.
13. where does transcription take place? inside the nucleus
14. where does translation take place? cytoplasm where ribosome is.
15. summarize the relationship between proteins and genes. genes decide the result in proteins function and shape.

Explanation:

• mRNA: Messenger RNA (mRNA) is synthesized from DNA during transcription. It carries the genetic code from the nucleus (where DNA is located) to the ribosomes in the cytoplasm. The sequence of nucleotides in mRNA (in the form of codons) dictates the sequence of amino acids in the polypeptide chain during translation.
• tRNA: Transfer RNA (tRNA) has an anticodon loop that pairs with the codon on mRNA. Each tRNA molecule is specific for a particular amino acid. It transports the amino acid to the ribosome, where it is added to the growing polypeptide chain.
• Ribosome: Ribosomes are the sites of protein synthesis. They consist of rRNA and proteins. The ribosome has binding sites for mRNA and tRNA. It facilitates the alignment of tRNA (with attached amino acids) according to the mRNA sequence and catalyzes the formation of peptide bonds between amino acids.
• Anticodon location: The anticodon is a three - nucleotide sequence on tRNA. It is complementary to the codon on mRNA.
• Transcription location: Transcription is the process of making RNA from DNA. DNA is located in the nucleus (in eukaryotes), so transcription occurs in the nucleus. Enzymes like RNA polymerase use the DNA template to synthesize RNA.
• Translation location: Translation is the process of making proteins from mRNA. Ribosomes, which are the sites of translation, are located in the cytoplasm (either free - floating or attached to the endoplasmic reticulum).
• Protein - gene relationship: Genes are segments of DNA. The sequence of nucleotides in a gene (through transcription to mRNA and then translation) determines the sequence of amino acids in a protein. The amino acid sequence of a protein determines its three - dimensional structure and function. So, genes carry the information that is ultimately expressed as proteins.

Answer:

1. mRNA carries the genetic code from DNA in the nucleus to the ribosomes in the cytoplasm.
2. tRNA transports specific amino acids to the ribosome based on the mRNA codon - tRNA anticodon pairing.
3. Ribosomes are the sites of protein synthesis; they facilitate the assembly of amino acids into polypeptide chains according to the mRNA sequence.
4. The anticodon is located on tRNA.
5. Transcription takes place in the nucleus.
6. Translation takes place in the cytoplasm (at the ribosomes).
7. Genes (segments of DNA) contain the information that is transcribed to mRNA and then translated into proteins. The nucleotide sequence of genes determines the amino acid sequence of proteins, which in turn determines protein structure and function.