Question

Cup-shaped chloroplast present in
A. Spirogyra
B. Chlamydomonas
C. Ulothrix
D. Chara

Answer 1

Hint: It is a unicellular genus which has red pigment spots which are light sensitive.Chloroplast are the organelles found in the plants and eukaryotic cells which conduct photosynthesis.

Complete answer :A cup shaped chloroplast is present in Chlamydomonas .A cup-shaped chloroplast has a single pyrenoid where starch is formed from the photosynthetic products. In cup-shaped chloroplast, the nucleus is enclosed within it. Pyrenoids are the microcompartment that is present within the chloroplast and they promote photosynthetic carbon dioxide fixation.

Spirogyra is charophyte green algae in which spiral arrangement of the chloroplast is present that consists of thin unbranched chains of cylindrical cells.
 Ulothrix is a non-branching green algae which is found in fresh and marine water. Ulothrix has a single girdle-like and parietal chloroplast.
Chara is a charophyte belonging to the family of Characeae. It is a green algae. They contain discoidal shaped chloroplasts. So, that’s why cup shaped chloroplasts are found in Chlamydomonas from the given options.

Additional information: Spirogyra are multicellular. They reproduces by vegetative propagation and sexual reproduction. They have around 400 species. Spirogyra grows under water. It has a cell wall, nucleus, pyrenoid and they are very slippery. Chlamydomonas are unicellular and they can be reproduce by both sexual and asexual reproduction. The most important feature is that they contain ion channels that are directly activated by light. Ulothrix is normally reproduced by vegetative propagation . They are eukaryotic multicellular organisms. Chara are the multicellular. They reproduces vegetatively and sexually.

Thus, the correct answer is option B. i.e. Chlamydomonas.

Note: Chlamydomonas is the most widely used laboratory species. It can be grown on a simple medium using light to provide energy. They can also grow in total darkness if a carbon source is provided to them.