NEET BIOLOGY

Previous
Next

PLANT PHYSIOLOGY

MINERAL NUTRITION

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
I. Component of chlorophyll II. Helps to maintain ribosome structure III. Activator for Rubisco and Pepco IV. Activates the enzymes of respiration and photosynthesis V. Involved in synthesis of nucleic acids The above roles are played by-
A
Ca+2
B
Mg+2
C
Mn+2
D
Cl-
Explanation: 

Detailed explanation-1: -It is a part of the ring structure of chlorophyll. A non-ionic magnesium is held in the centre of porphyrin head by nitrogen atoms of pyrrole rings. Mg is also responsible for the maintenance of ribosome structure.

Detailed explanation-2: -RuBisCo and PEPcase are carbon-dioxide fixing enzymes. In C3 cycle. RuBisCo plays the role of fixing carbon dioxide to RuBp. In C4 cycle, PEP carboxylase fixes carbon dioxide with Phosphoenol pyruvate in mesophyll cells.

Detailed explanation-3: -RuBisCO has a high optimal pH (can be >9.0, depending on the magnesium ion concentration) and, thus, becomes “activated” by the introduction of carbon dioxide and magnesium to the active sites as described above.

Detailed explanation-4: -Magnesium: It is absorbed by plants in the form of divalent Mg2+. It activates the enzymes of respiration, photosynthesis and are involved in the synthesis of DNA and RNA. Magnesium is a constituent of the ring structure of chlorophyll and helps to maintain the ribosome structure.

There is 1 question to complete.
Previous
Next