- What is the basic structure of DNA?
The DNA’s basic structure is of a 3D double helix, which is consisted of two chains; each one of these chains is constituted by subunits that are called the nucleotides. Having four different kinds of nucleotides present on those chains in a given sequence, these are defined as polynucleotide chains. The polynucleotide chains, on their turn, are known as DNA chains or strands and the nucleotides of each chain are interlinked by hydrogen bonds, keeping the two together.
- A gene has three triplets: AAT, ATA and TAC. What are the codons that match up with the triplets? What are the anticodons that match up with the codons? What are the three amino acids produced?
For those triplets, the codons are, respectively: UUA, UAU, AUG.
The anticodons that match up with the codons are, respectively: AAU, AUA, UAC.
The three amino acids produced are: Asparagine, Isoleucine and Tyrosine.
- Describe the lactose operon of gene regulation.
The lactose operon – lac operon – is consisted by three structural genes, which are adjacent to one another: the promoter gene, the terminator gene and an operator gene. This lactose operon promotes gene regulation through mechanism constituted by two parts, which is built to ensure that the prokaryotic cell only expends energy on the production of the enzymes that the lac operon encodes when it is absolutely necessary. Therefore, it is essential for the transport of lactose and its metabolism, permitting the adequate digestion of such sugar, through the use of β-galactosidase, which is encoded by the structural genes of the lactose operon. If the lactose is not present, then this operon’s transcription is stopped by the lactose repressor, which binds to the DNA chain right before the operator gene of lactose operon.
