What is the most likely mechanism of action for #2 (transduction) in the model above?
les )
A)The ligand creates changes within the cell that eventually leads to DNA
mutation.
B)The original molecule changes conformation (shape) several times within
the cytoplasm.
C)The original ligand is converted into a carbohydrate for energy use in the
transduction pathway.
D)The original binding of the ligand initiates an intracellular cascade that
includes a second messenger and amplification of the message.

option D

Explanation:

The model depicts the transduction pathway in cell signalling. Cells have proteins called receptors that may be found on the surface of the membrane that bind to signaling molecules also called ligand outside the cell and subsequently transmit the signal through a sequence of molecular switches to internal signaling pathways initiating physiological responses. Once a receptor forms a complex with a ligand, it undergoes a conformational change, which initiates a series of biochemical reactions within the cell. These intracellular signaling pathways, also called signal transduction cascades, functions in the amplification of the signal, producing multiple intracellular signals for every one receptor that is bound.

Receptor activation can stimulate the synthesis of small molecules called second messengers, which initiate and coordinate intracellular signaling pathways. an example include the cyclic AMP.

In summary, the process of cell signaling or communication involves:

Reception- a receptor at the cell surface detects chemical signals.

Transduction-a conformational change in receptor stimulates other changes including signal-transduction pathways.

Response-almost any cellular activity including activation of cell division, apoptosis etc.

the oxygenated blood then leaves the lungs through pulmonary veins, which return it to the left heart, completing the pulmonary cycle. this blood then enters the left atrium, which pumps it through the mitral valve into the left ventricle. from the left ventricle, the blood passes through the aortic valve to the aorta.

deoxygenated blood leaves through the right ventricle through the pulmonary artery. from the right atrium, the blood is pumped through the tricuspid valve (or right atrioventricular valve), into the right ventricle.