Answer:
Colchicine
Explanation:
Colchicine is an alkaloid derived from the autumn crocus (Colchicum autumnale).
The effect of colchicine, which inhibits microtubule polymerization and thus assembly of the mitotic spindle, demonstrates the presence of another checkpoint in the cell cycle. When colchicine is added to cultured cells, the cells enter mitosis and arrest with condensed chromosomes. With increasing time, a large fraction of the cells in a culture become arrested, thus permitting determination of the size, shape, and number of mitotic chromosomes — that is, the karyotype — in multiple cells. A checkpoint control somehow senses when the mitotic spindle has not assembled properly and prevents activation of the APC polyubiquitination system that normally leads to degradation of the anaphase inhibitor, required for onset of anaphase, and later to the degradation of mitotic cyclins, required for the exit from mitosis. As a result, MPF activity remains high, chromosomes remain condensed, and the nuclear envelope does not re-form.
I would have to agree with the student who claims cells are the building blocks of organs because cells are the building blocks of life. cells are all around us, even in inanimate objects.
What Artists and Scientists have in Common. ... I guess it is common knowledge that analytical scientists and creative artists are on opposite sides of a spectrum. But are they so different? Artists and scientists both have to be creative: they both have to develop original ideas and push frontiers.
The correct answer is: B) continuous transcription of the structural gene controlled by that regulator
A regulatory gene is gene that encodes for a protein, such as a repressor (or activators) that controls the transcription of another gene or group of genes.
The regulatory gene of a repressible operon encodes for the repressor that inhibits gene transcription. So, when that repressor isn’t active, transcription occurs continuously.
