Question

Answer the following question. ${C_4}$ cycle is:
A. adjunct to Calvin cycle
B. independent cycle
C. with high RuBP carboxylase efficiency
D. with PEP carboxylase in bundle sheath cells

Answer 1

Hint: Plants do photosynthesis at a very slow rate in the night. They need sunlight to make their food. Conversion of sunlight to chemical energy needs electrons, ATP, NADPH etc. they run through a cascade to produce Carbon dioxide, water and energy. The various cycles for energy oxidation were discovered by Melvin Calvin.

Complete answer:
Photosynthesis is the process of making plant food in the presence of sunlight. This process occurs in the chlorophyll in the plastids. The photosynthesis process is done by absorbing the sunlight and converting it into chemical energy.
${C_4}$ cycle takes place in the monocots and some dicots. It is also called the Hatch-Slack pathway. The first step in the process is the extraction of carbon from carbon dioxide. It is the carbon fixation process. The name ${C_4}$ is named after the first product in this product is the 4 carbon compound.
Option A: an adjunct to the Calvin cycle: ${C_4}$ cycle forms the extra essential part of the Calvin cycle. It decreases the photorespiration process.
Option B: independent cycle: These are independent cycles which are light-independent.
Option C: with high RuBP carboxylase efficiency: The pyruvic acid enters with RuBP, giving rise to sugars in bundle sheath cells. Thus the RuBP carboxylase activity is less.
Option D: with PEP carboxylase in bundle sheath cells: ${C_4}$ plants will use the PEP carboxylase to capture carbon dioxide in the mesophyll cells not in the bundle sheath cells.

So the answer is option A: Adjunct to Calvin cycle.

Note: The examples of ${C_4}$ cycle plants are maize and sorghum. In these plants, palisade cells in mesophyll tissues are not there. There is a large chloroplast without grana present. This anatomy is referred to as Kranz anatomy.