The answer is; B.
Cells have different receptors on their surfaces that are responsive to particular signals (such as hormones). When a signal interacts with the particular receptor, a particular response is invoked in the cell. This signal may be produced even by a cell that may be far away from the target cells. This is how cells communicate with each other to maintain homeostasis in the body.
Answer:
Proteins are a class of macromolecules.
Explanation:
Proteins are a class of macromolecules, that can perform a diverse range of functions for the cell. They help in metabolism by providing structural support and by acting as enzymes, carriers or as hormones. The building blocks of proteins are amino acids.
Ans.
There are twenty amino acids that take part in protein synthesis. These amino acids act as precursor for all protein molecules and are known as essential amino acids. Plants can synthesize all twenty amino acids from simple precursors, while animals can make only twelve amino acids. Animals obtain remaining eight amino acids by eating plants.
Thus, the correct answer is 'option) D.'
The Lock-and-key mechanism was first proposed by Emil Fischer which described as the enzymatic reactions whereby an enzyme with a single substrate binds temporarily to form a substrate complex.
The lock-and-key mechanism is usually associated with the complementary shapes of an enzyme with a single substrate, wherein the lock that is being referred to is the enzyme and the substrate is the key. One right sized substrate (key) fits into the active site (key hole) of the enzyme (lock).
The active site which is mentioned above is structurally complementary to the substrate. This is the temporary binding site on the enzymes. Just like a lock and key, the enzyme as the lock and the substrate as the key is said to fit together.
