Problem 99 - Objective Biology for NEET

Question

In which plant Calvin experimented the radioactive isotopy to discover the stable product of \(\mathrm{C}_{3}\) cycle? (a) Chlorella (b) Cycas (c) Carrot (d) Tobacco

Step-by-Step Solution

Answer

The plant in which Calvin experimented the radioactive isotopy to discover the stable product of \(\mathrm{C}_{3}\) cycle is (a) Chlorella.

Step 1: Understand the Context of the Question

This question refers to the set of experiments conducted by Melvin Calvin to identify the pathway of carbon fixation in plants. Calvin used a method involving radioactive isotopes to trace the journey of carbon through the plant during photosynthesis.

Step 2: Recall the Correct Information

Melvin Calvin used the algae Chlorella in his experiments where he traced the path of carbon dioxide in photosynthesis using radioactive isotopes.

Key Concepts

Chlorella

Chlorella is a genus of single-celled green algae that are spherical in shape and about 2 to 10 micrometers in diameter. These microorganisms are known for their high chlorophyll content, which gives them a strong green color and makes them highly efficient at photosynthesis. As such, they are often studied in research contexts related to photosynthetic processes.

Chlorella is unique due to its fast growth rate and has been explored for various applications including biofuel production, nutritional supplements, and even as a potential component in space travel for oxygen production and waste recycling. In the context of scientific experiments, Chlorella provides an ideal model organism due to its simplicity and the ease with which it can be cultured in a laboratory setting.

Radioactive Isotope Tracing

Radioactive isotope tracing is a technique used in biological and chemical studies to track the movement and chemical transformations of elements through different systems. A radioactive isotope, or radioisotope, is an atom that has excess nuclear energy, making it unstable. As it decays, it emits radiation that can be detected and measured. By incorporating radioisotopes into molecules, researchers can then trace their path through chemical reactions or biological processes.

This powerful tool allows scientists to follow the intricate pathways of substances in complex systems, such as following carbon's route during photosynthesis in plants. It essentially acts as a microscopic tracking device that can provide valuable quantitative and qualitative data about molecular processes occurring within living organisms.

Carbon Fixation

Carbon fixation is a fundamental process in biology where inorganic carbon, typically in the form of carbon dioxide (CO2), is converted into organic compounds by living organisms. In the context of photosynthesis, carbon fixation is the step where CO2 is incorporated into sugars, which are then used as energy by the plant or stored for later use.

The process of carbon fixation is critical for the survival of plants and, by extension, all life that depends on plants for oxygen and nutrition. It is also a major component of the global carbon cycle, playing a crucial role in regulating Earth’s climate and atmospheric chemistry. The Calvin Cycle, a series of biochemical reactions taking place in the stroma of chloroplasts in plants, is the predominant pathway used by plants for carbon fixation.

Melvin Calvin

Melvin Calvin was an American biochemist most renowned for his work on the carbon-fixing reactions in photosynthesis. The series of reactions responsible for the conversion of CO2 into glucose within plant cells is referred to as the Calvin Cycle in honor of his research. In 1961, Calvin was awarded the Nobel Prize in Chemistry for his discovery of this pathway.

Utilizing the alga Chlorella and the technique of radioactive isotope tracing, Calvin and his colleagues at the University of California, Berkeley were able to map the journey of carbon during photosynthesis, identifying intermediate compounds and the stable products that result from this intricate series of chemical reactions. His work was groundbreaking and provided deep insight into the biochemical basis of life’s dependency on the sun’s energy.