Answer:
An amino acid activates the repressor so that the repressor binds to the operator and prevents transcription.
Explanation:
In an operon, promoter is followed by operator which is finally followed by the structural genes to be transcribed. RNA Polymerase binds to the promoter and initiates transcription. A repressor can negatively control the transcription process by binding to the operator so that the RNA Polymerase is not able to move forward and transcription is halted.
For example: in trp operon, tryptophan amino acid binds to the repressor molecule which leads to change in repressor's shape. The repressor is now able to bind to the operator and prevent transcription.
Answer:
D) a genetic bottleneck
Explanation:
Genetic bottleneck refers to the sudden reduction in the population size due to some adverse climatic factors such as natural calamities. It changes the allele frequencies since the survivor population mostly have different allele frequencies than the original population.
In the given example, an earthquake kills 98% of the squirrels. The survivor population exhibits different allele frequencies for the gene responsible for the thickness of stripes. Therefore, it represents a genetic bottleneck.
Answer:
Workers worked longer hours.
Explanation:
Answer:
too much phosphorus can slow down the growth of a plant.
Explanation:
Excessive soil phosphorus reduces the plant’s ability to take up required micronutrients, particularly iron and zinc.
The answers are
1. nitrogenous
2. acid-base
3. fluid
