Ch 12Respiration in Plants — Class 11 Biology, concept-first.

Every living organism needs a continuous supply of energy to carry out its everyday life processes — absorption, transport, movement, reproduction, and even the act of breathing itself.

Do plants breathe? The answer is not quite so direct. Plants do require O2 for respiration and they give out CO2, so they need systems that ensure the availability of O2.

The term glycolysis originates from the Greek words glycos (sugar) and lysis (splitting). The scheme of glycolysis was given by Gustav Embden, Otto Meyerhof and J.

In fermentation, say by yeast, the incomplete oxidation of glucose is achieved under anaerobic conditions by sets of reactions where pyruvic acid is converted to CO2 and ethanol.

Aerobic respiration is the complete oxidation of organic food in the presence of oxygen, and it is the pathway that releases the bulk of the energy stored in respiratory substrates.

The TCA cycle starts with the condensation of the acetyl group (from acetyl CoA) with oxaloacetic acid (OAA) and water to yield citric acid.

The following steps in the respiratory process are to release and utilise the energy stored in NADH + H+ and FADH2.

It is possible to make calculations of the net gain of ATP for every glucose molecule oxidised, but in reality this can remain only a theoretical exercise.

Glucose is the favoured substrate for respiration. All carbohydrates are usually first converted into glucose before they are used for respiration.

During aerobic respiration, O2 is consumed and CO2 is released. The ratio of the volume of CO2 evolved to the volume of O2 consumed in respiration is called the respiratory quotient (RQ) or respirator…

Plants, unlike animals, have no special systems for breathing or gaseous exchange. Stomata and lenticels allow gaseous exchange by diffusion, and almost all living cells in a plant have their surfaces…

Higher-order thinking problems from the NCERT Exemplar.