Answer:
Please find the detailed explanation of this statement below
Explanation:
Firstly, a repressed gene is a gene whose expression has been inhibited or repressed. The lac operon in E.coli bacteria is a regulatory unit containing structural genes, a single promoter and operator regions. The promoter is the region where the transcription enzyme (RNA polymerase) binds to in order to transcribe the genes in the lac operon. The structural genes in the lac operon can only be expressed in the presence of lactose sugar.
However, in the absence of lactose, LAC REPRESSOR, which is a transcription factor (protein), prevents the binding of RNA polymerase to the PROMOTER region by binding to the OPERATOR region of the lac operon. This inhibits the expression of the lactose genes in the operon.
Note that, the structural genes in the lac operon (lacZ, lacY, lacA) code for proteins that help break down lactose sugar for energy in the E.coli bacteria. Therefore, a bacteria cell with a repressed lac operon will be unable to degrade lactose sugar.
A pollutant is a substance or energy introduced into the environment that has undesired effects, or adversely affects the usefulness of a resource.
Answer:
The Six Kingdoms. When Linnaeus developed his system of classification, there were only two kingdoms, Plants and Animals. But the use of the microscope led to the discovery of new organisms and the identification of differences in cells. Today the system of classification includes six kingdoms.
Explanation:
The general trend for hormones after ovulation as an individual when it approaches menstruation is that hormone levels generally rise. This increase levels of estrogen and progesterone would cause a negative feedback to the hypothalamus and the pituitary, which would result in the decline of the FSH and LH. BTW: Not to be TMI but i started mine and there is nothing to be scared of.
An ectotherm gets its heat from external sources
(Remember "ecto" means outer, "endo" means inner)
