Theory suggesting that carbon dioxide in respiration helps in mineral absorption is called

Options

A. Carbonic acid exchange theory
B. Contact exchange theory
C. Active mineral absorption
D. Donnan equilibrium

Answer

To solve the question regarding the theory that suggests carbon dioxide in respiration helps in mineral absorption, we can break it down into the following steps:

### Step-by-Step Solution:

1. **Understanding Plant Respiration**:
- During aerobic respiration, plants take in oxygen and release carbon dioxide (CO2) as a byproduct. This CO2 is released from the roots into the surrounding soil.

**Hint**: Remember that respiration in plants occurs in the roots and produces CO2.

2. **Formation of Carbonic Acid**:
- The CO2 released into the soil combines with water (H2O) to form carbonic acid (H2CO3). This reaction is crucial as it leads to further processes that aid in mineral absorption.

**Hint**: CO2 + H2O → H2CO3 is a key reaction to remember.

3. **Dissociation of Carbonic Acid**:
- The carbonic acid (H2CO3) dissociates into hydrogen ions (H+) and bicarbonate ions (HCO3-). The release of H+ ions is particularly important for mineral absorption.

**Hint**: H2CO3 dissociates into H+ and HCO3-; focus on the role of H+ ions.

4. **Interaction with Soil Particles**:
- Soil particles, especially clay, are negatively charged. The positively charged H+ ions can bind to these negatively charged clay particles, which helps in the release of other positively charged mineral ions like magnesium (Mg2+), calcium (Ca2+), and potassium (K+).

**Hint**: H+ ions interact with negatively charged clay particles to facilitate the release of minerals.

5. **Mineral Absorption**:
- Once the H+ ions bind to the clay particles, they displace the mineral ions, making them available in the soil solution. These free ions can then be absorbed by the plant roots.

**Hint**: The displacement of minerals by H+ ions is crucial for their availability to plants.

6. **Identification of the Theory**:
- The entire process described above is known as the **Carbonic Acid Exchange Theory**. This theory explains how the CO2 produced during respiration aids in the absorption of essential minerals by plants.

**Hint**: The name of the theory directly relates to the role of carbonic acid in mineral absorption.

### Final Answer:
The theory suggesting that carbon dioxide in respiration helps in mineral absorption is called the **Carbonic Acid Exchange Theory**.