Question

The enzyme that performs the light-generating reaction in fireflies is called luciferase. Luciferase is a single polypeptide chain, located in the cytoplasm of firefly lantern cells. Luciferase protein is synthesized by ribosomes1) free in the cytoplasm 2) attached to the rough endoplasmic reticulum 3) attached to the plasma

Answer 1

Luciferase is responsible for the light-generating reaction in fireflies and is synthesized by ribosomes in the cytoplasm. Bioluminescence has evolved multiple times in nature, exhibiting convergent evolution. The luminescence in dinoflagellates differs structurally from that in fireflies and is related to chlorophyll.

Step-by-step explanation:

The enzyme luciferase is responsible for the bioluminescent reaction in fireflies and performs a light-generating reaction. Luciferase is structured as a single polypeptide chain found in the cytoplasm of the firefly lantern cells. The production of this protein involves ribosomes, which are crucial for protein synthesis. The luciferase protein in fireflies is synthesized by ribosomes that can either be free in the cytoplasm or attached to the endoplasmic reticulum. In contrast, photosystems, which play a significant role in the light-dependent reactions of photosynthesis, are found in the membranes of thylakoids in plant cells. These systems harness light energy and convert it into chemical energy.

It is important to note that bioluminescence has evolved independently multiple times and different organisms have differing enzymes and substrates involved in the light-emitting reactions. For example, the luciferase in dinoflagellates is different from that of fireflies and is structurally related to chlorophyll. Thus, bioluminescence in various organisms is a classic example of convergent evolution.

Answer 2

The correct answer to the question is: 1) free in the cytoplasm.

Step-by-step explanation:

• Ribosomes are responsible for synthesising polypeptide chains by the process of translation from mRNA or messenger Ribonucleic Acid.
• They are found free in the cytoplasm or remain bound to the Endoplasmic Reticulum (ER) to form the Rough Endoplasmic Reticulum (RER).
• The cytoplasmic proteins are synthesised by the free ribosomes.
• The membrane proteins, secretory proteins and the organelle specific proteins are synthesised by the Ribosomes located on the Endoplasmic Reticulum.
• This is because these proteins need to be translocated to the target organs through vesicles that buds out of the ER and and the Golgi bodies.
• As the luciferase polypeptide is located in the cytoplasm, it is synthesised by the free ribosomes present in the cytoplasm.