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:
A <u><em>receptor</em></u> is a protein that recognizes and responds to a signal.
Explanation:
A receptor is a protein molecule present on the cells on which the signalling molecules can bind and generate a physiological response. Some receptor molecules can also respond to Sun and light. Each type of cell has specific receptors molecules and hence can respond to specific signals. The receptor molecules hence tend to receive signals for a cell. Molecules such as hormones bind to the receptors.
Answer:
Chlorophyll absorbs the red and blue segment of the white light and photosynthesis occurs most efficiently at these wavelengths.
When the light falls on the plant, the chlorophyll pigment absorbs this light and electrons in it gets excited.
This process occurs in a complex protein system which is collectively called as a photosystem.
Explanation:
There are several types of microscopes: compound microscopes 0 the most commonly used microscope, uses light illumination and the image that is seen is two dimensional, stereoscope- uses light illumination and the image that appears is 3 dimensional, confocal microscope - uses laser light ,scanning electron microscope - uses electron illumination.
Im going to say that its <span>d. The head of the phospholipid, which is hydrophilic, helps to control the movement of large hydrophobic molecules, and the tails of the phospholipid, which are hydrophobic, help to control the movement of large hydrophilic moleculeus. </span>
