Euglena is microbial eukaryote that has chloroplasts and can thus perform phtosynthesis. when deprived of light and treated with specific chemicals in lab, the chloroplasts are completely destroyed. based on the information above, if we re-expose euglena to light what do you predict will happen?

Euglena have diversed nutritional requirements. They are autotrophic when kept in light and heterotrophic when deprived of light.

The Euglena contains chloroplast in it to perform photosynthesis in the presence of light.

When the Euglena is kept in the dark it starts deriving energy from the organic matter around it and shows heterotrophic mode of nutrition.

When light will be provided to Euglena it will start resynthesizes its photosynthetic pigment and it will start perform photosynthesis.

consider how they arose in evolution. The most fundamental of all such problems is the expression of hereditary information, which today requires extraordinarily complex machinery and proceeds from DNA to protein through an RNA intermediate. How did this machinery arise? One view is that an RNA world existed on Earth before modern cells arose (Figure 6-91). According to this hypothesis, RNA stored both genetic information and catalyzed the chemical reactions in primitive cells. Only later in evolutionary time did DNA take over as the genetic material and proteins become the major catalyst and structural component of cells. If this idea is correct, then the transition out of the RNA world was never complete; as we have seen in this chapter, RNA still catalyzes several fundamental reactions in modern-day cells, which can be viewed as molecular fossils of an earlier world.

Figure 6-91. Time line for the universe, suggesting the early existence of an RNA world of living systems.

Figure 6-91

Time line for the universe, suggesting the early existence of an RNA world of living systems.