It has a double-walled structure. Its inner wall is produced into folds known as cristae. It is generally sausage-shaped.

  It is a clear space filled with water or other substances in the form of solutions. It has a covering called tonoplast.

  It contains one or two centrioles, and is surrounded by microtubules or the centrosphere. It is situated near the nucleus.

  It is chiefly composed of a dense fluid. It contains chromatin fibres, which are made up of DNA (Deoxyribonucleic acid).