A: Initiation, Elongation, and Termination.
Q: What are introns and exons?
A: Introns are the noncoding segments of nucleic acid that lie between coding regions, also called intervening sequences. Exons are the other regions because they are eventually expressed, usually by being translated into amino acid sequences.
Q: How many arrangements of triplets of nucleotide bases would be sufficient to specify all the amino acids?
A: (4^3) 64
1. Genes specify protein via transcription and translation
2. Transcription is the DNA-directed synthesis of RNA: a closer look
3. Eukaryotic cells modify RNA after transcription.
4. Point mutations can affect protein structure and function.
5. While gene expression differs among the domains of life, the concept of a gene is universal.
Figure 17. 13
Translation: the basic concept
As a molecule of mRNA is moved through a ribosome, codons are translated into amino acids, one by one. The interpreters are tRNA molecules, each type with a specific anticodon at one end and a corresponding amino acid at the other end. A tRNA adds its amino acid cargo to a growing polypeptide chain when the anticodon hydrogen-bonds to a complementary codon on the mRNA. The figures that follow show some of the details of translation in a bacterial cell.
The DNA inherited by an organism leads to specific traits by dictating the synthesis of certain proteins. Proteins are the links between genotype and phenotype.
The DNA to RNA flow of genetic information is termed transcription. The term transcription reflects that the information in DNA is copied into a similar code in RNA. Then, the RNA to protein flow of genetic information is termed translation. The term translation reflects that the information in mRNAs is translated into a new language.Transcription occurs within the nucleus, where the DNA resides . Translation occurs within the cytosol, where the functional ribosomes reside. The three nucleotides that specify an amino acid during translation are called codons.
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