question_answer 23)

  What is a tonoplast? (a) Outer membrane of mitochondria (b) Inner membrane of chloroplast (c) Membrane boundary of the vacuole of plant cells (d) Cell membrane of a plant cell

Answer:

                  (c) Tonoplast In plant cell the vacuole in bound by a single membrane called tonoplast. The tonoplast facilitates the transport of ions and other material against theconcentration gradient into the vacuole. Hence, their concentration is higher in thevacuole than in the cytoplasm. The outer membrane of mitochondria is formed of porin proteins and inner membranebounds of chloroplast the stroma The cell membrane of the plant cell is not a tonoplast. It is 'simple biological/unit membrane present in every cellular organism.