Question

Distinguish between the process by which membrane-bound organelles such as lysosomes and the nucleus formed, and the process by which mitochondria and chloroplasts arose.

Answer 1

Lysosomes are the digesters of the cell, they contain enzymes which can digest macromolecules. Process of formation of lysosomes is that the fusion of vesicles from the Golgi complex with endosomes take place. A section of plasma membrane pinch off and is internalised by the cell this process is called endocytosis results in vesicles known as endosomes. In this whole process cells takes up the extracellular material. Endosomes upon maturing known as late endosomes which get fused with transport vesicles of Golgi that contains acid hydrolases . After fusion endosomes develops into lysosomes.

      The nucleus contains the genetic material the DNA of the cell. It formed when a cell divides itself forming nuclei which is enclosed by a membrane called nuclear envelope.

Formation of mitochondria and chloroplasts takes place by engulfing independently living aerobic prokaryotes , which in term formed a endosymbiotic relationship with eukaryote host which gradually formed mitochondria. On the other hand eukaryotic cells which contains mitochondria engulfed photosynthetic prokaryotes evolved to become chloroplasts.