Question

Membrane bound organelles are absent in
(a) Streptococcus
(b) Chlamydomonas
(c) Plasmodium
(d) Saccharomyces

Answer 1

Hint: Membrane-bound organelles are the structures within the cell that are bound by a membrane such as the mitochondria, chloroplasts, etc. They are present in the eukaryotic cells and are absent in unicellular prokaryotes such as bacteria.

Complete Step by Step Answer:
Membrane- bound organelles such as mitochondria and chloroplasts are not seen in unicellular prokaryotic organisms belonging to the Kingdom Monera. They are absent in Streptococcus which is a species of bacteria.
Bacteria belong to the Kingdom Monera and are prokaryotic organisms and hence the membrane- bound cell organelles are absent in them.

Additional Information:
- Chlamydomonas is a species of unicellular eukaryotic organisms. They were formerly classified under the Kingdom Plantae as Chlorophyceae but they are now classified under the Kingdom Protista.
- Plasmodium is also a unicellular eukaryotic organism belonging to the Kingdom Protista. Since it is a eukaryotic organism too, it possesses membrane- bound cell organelles.
- Saccharomyces is a species of unicellular eukaryotic Fungi which belongs to the Kingdom Mycota.
- Some examples of membrane- bound organelles are Mitochondria, Chloroplasts, Golgi Apparatus, Lysosomes, etc.
- According to the endosymbiotic hypothesis, the membrane- bound organelles mitochondria and chloroplasts were prokaryotic cells that were engulfed by eukaryotic cells and over a period of time developed a symbiotic relationship. This is supported by the fact that they have their DNA and 70S ribosomes which are characteristics of prokaryotic cells.
So, the correct answer is, ‘(a) Streptococcus.’

Note:
- All eukaryotic cells do not possess all the membrane- bound organelles.
- Mitochondria are present in almost all eukaryotic cells as the energy- producing machinery. However, they are absent in certain cells that respire anaerobically such as mammalian RBCs.
- Chloroplasts are membrane-bound organelles that are present only in the plant kingdom and certain unicellular eukaryotes like euglena which perform photosynthesis.