Chemoreceptor is a specialized sensory receptor cell, which responds to a chemical substance and generates a biological signal.
The type of chemoreceptor responsible for our sense of smell is called olfactory receptor. It is also known as odorant receptor, these are found in a small patch of tissue high inside the nose. These cells directly connected to the brain.
Answer:
Embedded in the lipid bilayer are large proteins, many of which transport ions and water-soluble molecules across the membrane. Some proteins in the plasma membrane form open pores, called membrane channels, which allow the free diffusion of ions into and out of the cell.
Regulatory proteins control the cell cycle.
If the regulatory proteins are malfunctioning or absent, the cells may reproduce abnormally fast, causing a tumor.
Generally, these vacuoles acquire 80% of the cell space. Vacuole is an important organelle present in the cells of plants, animals, protists, fungi and bacteria. Apart from water, vacuoles also contains different kinds of organic/inorganic molecules, solid materials and enzymes.
I can already say it's not option 1 nor 4 as these go against everything science is. I'd say it's option 3 since it takes a bit and though yes they can be rejected, many scientists build off another individual studying the same material for a lead on where they should look. I hope this works for you and I'm not wrong. It's just that option 3 is most understandable in my mind with common sense of previous schooling.
