Answer:
A = Activator
B = Effector
Explanation:
An activator is a protein which typically binds to a short (50–1500 bp) region of DNA which might be located either upstream (mainly) or downstream of a gene so as to cause increased transcription. This particular region of DNA is known as enhancer and activator is also known as transcription factor. Activator is a trans-acting factor which binds to the cis-acting factor which is enhancer so as to enhance transcriptional expression.
But another protein named as effector may restrict activator from binding to the enhancer leading to a decrease in transcriptional expression by binding to the activator allosterically. Allosteric binding of effector to the activator causes conformational change in activator so it can no longer bind the enhancer.
Answer:
Natural selection, the keystone of evolution, can switch direction in a matter of months, a novel experiment on lizards reveals.
Crowded between the collagen fibers are rows of fibroblasts, fiber-forming cells, that generate the fibers. Dense connective tissue<span> forms strong, rope-like structures such as tendons and ligaments.</span>
Analagous structures. For example, both penguins and dolphins have torpedo shaped heads that help them adapt to their enviroments. They were both in different environments, but they developed similar adaptations to increase their ability to survive in their environments.
Water enters a plant from the roots absorbing the water from the soil.
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