Question

Calvin cycle occurs in
A. Cytoplasm
B. Mitochondria
C. Glyoxysomes
D. Chloroplasts

Answer 1

Hint: The plants are known as the producers as they are capable of performing the process of photosynthesis. During the photosynthetic process, the plants utilize carbon dioxide, water in the presence of light energy of the sun to produce organic compounds such as simple sugars. The photosynthetic process involves certain specific pathways such as the Calvin cycle.

Complete answer:
> Chloroplast are the organelles related with the process of photosynthesis and it contains the green chlorophyll pigment which traps the energy of sunlight and converts it energy and glucose. During the photosynthetic process, oxygen is released. Carbon dioxide that is available in the atmosphere enters the plant cell through the stomatal pores. The carbon dioxide is in inorganic form and it is converted into organic compounds. The conversion of carbon dioxide into other compounds or into glucose takes place through the light-dependent reaction or the Calvin cycle. It is also known as photosynthetic carbon reduction(PCR).

The Calvin cycle is performed in the stroma of the chloroplast. The stroma is a fluid containing area which is present outside the thylakoid membranes of the chloroplast.

> The cytoplasm is the site of aerobic cellular respiration which breaks down the glucose into pyruvic acid and energy is liberated in the form of ATP. The energy is then utilized for performing different other biological reactions of the cell.

> The pyruvic acid formed from the process of glycolysis further moves to the mitochondria especially to the matrix and enters a cycle known as the Krebs cycle. The Krebs cycle occurs in the mitochondrial matrix and energy is produced.

> Glyoxysomes are special functional peroxisomes which are associated with the initial breakdown of fatty acids. They are found in plant cells and are present in the germinating seeds. Due to the breakdown of fatty acid, hydrogen peroxide is produced and oxygen is consumed by the seeds and it helps in germination of seeds.

Hence, the correct answer is option (D).

Note: Calvin acid cycle is also known as light dependent reaction or biosynthetic phase of the photosynthetic carbon reduction. In some cases, it is also referred to as the dark reaction, as the process requires NADP which is received from the light reaction. This process occurs in the stroma, which is present in the internal region of chloroplast. It occurs in the daytime and not in the dark or at night.