The BRCA 1 and BRCA 2 genes are two genes that are sought in the genetic study of an individual in order to seek a predisposition to breast cancer (in women and also in men).
The genes of Tay-sachs, are researched in order to diagnose or eliminate Tay-sachs disease.
The first difference lies in the goal of the research: for the BRCA (screening) genes, a predisposition is sought and for the Tay-sachs genes, it is sought to confirm the disease.
The second lies in the technique used:
The first step in the study of these genes is to isolate and replicate them. The best technique for this is the PCR (polymerase chain reaction). By using primers we can amplify the gene we want. So the primers used in BRCA and Tay-Sachs research are necessarily different.
Answer:
Lactose present, glucose absent.
Explanation:
Lac operon may be defined as a cluster of genes that regulate the metabolism of lactose in bacteria. The bacteria always prefer glucose if both glucose and lactose is present in the medium.
The conditions that causes the maximal expression of lactose is the presence of lactose and absence of glucose. This is due to the action of catabolite activator protein and cyclicAMP.
Thus, the correct answer is option (1).
Decomposers, fungi, and microbes play an important role because they break down the remains of dead plants and animals.
