A) in a coil, connected through hydrogen bonds.
Answer:
Exocrine glands are characterized by discharging their secretions into duct systems.
Explanation:
Exocrine glands:
These glands transport their secretions through a network of ducts that ultimately connect to the body's exterior. This means there is a direct continuity between the interior surfaces of the glands and their duct system with the external surfaces of the body (like the skin).
Examples of exocrine glands include gastric glands, salivary glands, and sweat glands.
The AraC protein associated with the ara operator functions as a repressor to prevent transcription of the ara operon. In the presence of arabinose, the AraC protein acts as an activator; however, in its absence, it serves as a repressor. When arabinose is not available, AraC remains as a
homodimer. One AraC molecule attaches to the ara initiator while another binds to a distinct regulatory region in the DNA known as the ara operator.
The last one: cell, tissue, organ, organ system, organism.
Answer:
Cells within a large multicellular organism communicate through chemical signals. These signals are relayed from one cell to another. A cell must have a receptor for that chemical to interpret and respond to a signal.
Explanation:
To initiate a physiological response, all body cells possess specific proteins known as receptors. These receptors are essential for detecting chemical signals and eliciting responses. Different receptors are tailored for various chemical signals; for instance, a dopamine receptor engages with dopamine molecules, whereas an insulin receptor specifically binds to insulin molecules. Additionally, certain cells may also respond to mechanical signals.
