question_answer 26)

  Which of the following are covered by a single membrane? (a) Mitochondria              (b) Vacuole                         (c) Lysosome                     (d) Plastid

Answer:

  (c) Lysosomes are simple, tiny spherical sac-like structures evenly distributed in ?the cytoplasm each lysosome is surrounded by a double membrane and contains powerful enzymes capable of digesting or creaking down all organic material. These enzymes are made by rough endoplasmic reticulum. They perform following functions in our body 1. They help in breaking down (digesting) large molecules of the cell. 2. They help in defence against bacteria and viruses. 3. During starvation, lysosomes act on their own cellular organelles and digest them. This results in cell death. The lysosomes are also called suicide bags or demolition squads of the cell.