Answer:
1. Signaling molecule
2. Signaling receptors
Explanation:
Hormones, growth factors, neurotransmitters, etc. serve the function of signaling molecules for cells. These molecules are released by one cell and bind to the receptors present on/in the target cells to elicit the desired response. Thereby, the signaling molecules serve in cell-cell communication.
For example, insulin hormone synthesized and released from beta cells of pancreas binds to its cell surface receptors present on the surfaces of liver cells and muscle cells to stimulate the uptake of the glucose from the blood.
Likewise, neurotransmitters released from the presynaptic neuron bind to receptors present on the membrane of postsynaptic neuron and serve to carry the nerve impulse to the postsynaptic neuron.
A trait is a characteristic, such as color or size, that is inherited by an offspring from its parents. The genes that control a trait come in pairs, one gene from each parent. We represent these gene pairs by writing a combination of two letters. For example, if one parent contributes a gene for blue eyes (c), and other parent contributes a gene for brown eyes(C), then we write the offspring’s eye color trait as Cc. This combination, of the two genes that determine the trait, is called a genotype. If gene pair contains a dominant allele, the the offspring will show this dominant trait
