Lífgrænukornum

Lífgrænukornum, a term originating from Icelandic, translates to "chloroplasts" in English. These are specialized organelles found in plant cells and eukaryotic algae that conduct photosynthesis. Photosynthesis is the process by which light energy is converted into chemical energy, in the form of glucose, which the organism can then use for fuel.

Chloroplasts are characterized by their distinctive green color, due to the presence of chlorophyll, the primary pigment responsible for absorbing sunlight. The structure of a chloroplast is complex, featuring an outer and inner membrane that enclose a fluid-filled space called the stroma. Within the stroma are stacks of flattened sacs known as thylakoids, which are organized into grana. The chlorophyll and other photosynthetic pigments are embedded within the thylakoid membranes.

The process of photosynthesis within the chloroplasts occurs in two main stages. The light-dependent reactions take place in the thylakoid membranes, where light energy is captured and used to produce ATP and NADPH. These energy-carrying molecules are then used in the light-independent reactions, also known as the Calvin cycle, which occur in the stroma. During the Calvin cycle, carbon dioxide from the atmosphere is converted into glucose. Lífgrænukornum are therefore essential for the survival of plants and play a critical role in most ecosystems on Earth by producing oxygen as a byproduct of photosynthesis.