Question

Which of the following provides molecular evidence that signal transduction pathways evolved early in the history of life?Cell signaling is observed in organisms that do not utilize sexual reproduction.The pathways in primitive organisms, such as bacteria, are short, whereas those in advanced forms, such as mammals, are long.Receptor molecules have been identified in preparations of fossilized organisms billions of years old.The molecular details of cell signaling are quite similar in organisms whose last common ancestor was a billion years ago.Simple forms of life, such as prokaryotic cells, utilize cell signaling.

Answer 1

Signal transduction pathways evolved early in the history of life as evidenced by their presence in organisms that do not utilize sexual reproduction, the identification of receptor molecules in fossilized organisms, and the similarity of molecular details in organisms with a common ancestor.

Step-by-step explanation:

The molecular evidence that signal transduction pathways evolved early in the history of life can be seen in several ways. One piece of evidence is that cell signaling is observed in organisms that do not utilize sexual reproduction, such as bacteria. This suggests that signal transduction pathways were already present in simple life forms. Additionally, receptor molecules have been identified in preparations of fossilized organisms billions of years old, indicating that signal transduction was occurring in ancient organisms. Furthermore, the molecular details of cell signaling are quite similar in organisms whose last common ancestor was a billion years ago, further supporting the idea that signal transduction pathways have a long evolutionary history.

Answer 2

Option (4).

Step-by-step explanation:

Signal transduction may be defined as the process by which the physical or chemical signal can be transmitted in the body by the series of the different molecular events. Proteins kinases are important for the signal transduction pathway.

The signal transduction pathway occurs in the early as well as in the modern life. Molecular techniques has provided the evidence that cell signalling process is quite similar in the common ancestors and modern organism. Some biochemical molecules are similar that takes part in the signal transduction pathway.

Thus, the correct answer is option (4).