Question

Who gave the cytochrome pump theory?
a. Sachs
b. Lundegardh
c. Bose and Renner
d. Bennet and Clark

Answer 1

Hint: Cytochrome pump theory states that there are two different absorption methods for anion and cation. Anion absorption is an active process that requires energy whereas cation absorption is a passive process that does not require energy.

Complete answer:
Sachs was a prominent German Botanist. He grew plants in a defined nutrient solution in the absence of soil. This soil-less growth of plants in a nutrient solution is known as Hydroponics. He also demonstrated the importance of transpiration and the role of chlorophyll in plants.

Lundergardh proposed cytochrome pump theory. According to this theory, the anion is absorbed through an active process whereas cation is absorbed through a passive process. The cation movement is passive through the cytochrome membrane due to the accumulation of ions in the inner surface of the membrane. The outer surface of the cytochrome membrane undergoes oxidation which results in the loss of an ion. Anions are picked up and transported to the inner surface of the membrane where cytochrome gets reduced by dehydrogenase.

Bennet and Clark proposed the Protein Lecithin Theory. According to this theory, the cell membrane mainly consisted of protein and phospholipids and the carrier could be protein in association with a phosphate called lecithin.

Hence, the correct answer is option (B).

Note: Lundergardh cytochrome pump theory is based on the following two assumptions:
- The absorption for cation and anion is different.
- The electrons are released by taking the anions in its place.
- Anions are absorbed actively through the cytochrome chain.
- Cations absorption takes place passively.