Respiratory Quotient (RQ) of organic acid is – (a) Zero (b) One (c) Less than one (d) More than one

Respiratory substrate & Respiratory Quotient (RQ)

• The most prevalent respiratory substrate in plants is glucose.
• O is consumed during aerobic respiration, and CO is exhaled.
• The Respiratory Quotient (RQ) or Respiratory Ratio is the ratio of the volume of CO evolved to the volume of O consumed in respiration.
• A respirometer is a device that measures both R.Q. and the respiration rate.

The following formula is used to determine RQ Value:

RQ = Volume of CO2 evolved/ Volume of O2 consumed

The type of respiratory substrate used during respiration affects the respiratory quotient.

RQ of Organic acids (Greater than 1)

When organic acids are oxidized during respiration, the value of R.Q. is greater than one because organic acids such as malic acid (see below reaction), tartaric acid, and oxalic acid are rich in oxygen and require less oxygen for their oxidation. The following is the response and RQ:

C4 H6 O5 (Malic acid) + 3O2 → 4CO2+ 3H2 O + Energy

RQ = Volume of CO2 evolved/ Volume of O2 consumed = 4/3 = 1.33

Importance of Respiratory Quotient (RQ)

It aids in identifying the type of breathing being done.

Identify the biochemical mechanism of respiration as well as the characteristics of the respiratory substrate that oxidised the substrate’s transformation.

Summary:

Respiratory Quotient (RQ) of organic acid is – (a) Zero (b) One (c) Less than one (d) More than one

Organic acid has a higher respiratory quotient (RQ) than one. The respiratory substrate is broken down during respiration in order to release energy.