The cell’s DNA is replicated or copied before cell division because it is important for the cell to have 2 DNA molecules because the cell is going to divide into 2. Each new cell need a 1 DNA
CFCs are Chlorofluorocarbon substances used in refrigerants (subtances used to keep other things cold) and in aerosol products.
they are both relatively nontoxic(nonpoisonous) and nonflammabale - at least as compared to alternatives.
They are rather volatile - they are not very stable. Therefore it does not make sense to say that they are strong - the correct answer is then strength.
Answer:
A) A corepressor must be present
Explanation:
The key to operon expression lies in the sequence of the operator and the presence or absence of a repressor. When the repressor binds the operator, it prevents RNA polymerase from initiating transcription. The capability of the repressor to bind the operator and inhibit transcription depends on the conformation of the repressor, which is regulated allosterically by a key compound in the metabolic pathway, such as lactose or tryptophan. In a repressible operon, such as the tryptophan (or trp) operon, the repressor is unable to bind to the operator DNA by itself. Instead, the repressor is active as a DNA-binding protein only when complexed with a specific factor, such as tryptophan , which functions as a corepressor.
When tryptophan is plentiful, tryptophan molecules act as corepressors by binding to the (1) inactive repressor and (2) change its shape, allowing it to bind to the operator, (3) preventing transcription of the structural genes
Answer:
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