Final answer:
Jacob's argument is justified through the complementary roles of chloroplasts in photosynthesis and mitochondria in cellular respiration, which together maintain cellular homeostasis. This is further supported by the endosymbiotic theory, which suggests that both organelles evolved from a symbiotic relationship with prokaryotic cells.
Step-by-step explanation:
Jacob's argument that chloroplasts and mitochondria both work together to maintain homeostasis within the cell is justified because they play complementary roles in cell metabolism. Chloroplasts function in photosynthesis, using sunlight to convert carbon dioxide and water into glucose and oxygen. This process not only produces food for the plant but also releases oxygen into the atmosphere. Conversely, mitochondria are involved in cellular respiration, where they use the glucose produced by photosynthesis to generate energy in the form of ATP, while consuming oxygen and releasing carbon dioxide. These processes are interlinked as the outputs of photosynthesis are the inputs for cellular respiration and vice-versa, thus maintaining a balance within the cell and the environment.
The endosymbiotic theory helps explain the presence of DNA and ribosomes in both organelles, suggesting their evolution from an ancestral symbiotic relationship with prokaryotic cells. This theory also notes the similarity between organelles like mitochondria and chloroplasts with bacteria in terms of size, DNA, and ribosomes. During endosymbiosis, host eukaryotic cells ingested aerobic and autotrophic bacteria but did not destroy them, letting these bacteria evolve into mitochondria and chloroplasts over many millions of years.