NCERT Book Class 11 Biology Chapter 12 Respiration in Plants

RESPIRATION IN PLANTS 153

CHAPTER 12
RESPIRATION IN PLANTS
12.1 Do Plants All of us breathe to live, but why is breathing so essential to life? What
Breathe? happens when we breathe? Also, do all living organisms, including plants
12.2 Glycolysis and microbes, breathe? If so, how?
All living organisms need energy for carrying out daily life activities,
12.3 Fermentation be it absorption, transport, movement, reproduction or even breathing.
12.4 Aerobic Where does all this energy come from? We know we eat food for energy –
Respiration but how is this energy taken from food? How is this energy utilised? Do
all foods give the same amount of energy? Do plants ‘eat’? Where do plants
12.5 The
get their energy from? And micro-organisms – for their energy
Respiratory
requirements, do they eat ‘food’?
Balance Sheet
You may wonder at the several questions raised above – they may
12.6 Amphibolic seem to be very disconnected. But in reality, the process of breathing is
Pathway very much connected to the process of release of energy from food. Let us
try and understand how this happens.
12.7 Respiratory
All the energy required for ‘life’ processes is obtained by oxidation of
Quotient
some macromolecules that we call ‘food’. Green plants and cyanobacteria
can prepare their own food; by the process of photosynthesis they trap
light energy and convert it into chemical energy that is stored in the bonds
of carbohydrates like glucose, sucrose and starch. We must remember
that in green plants too, not all cells, tissues and organs photosynthesise;
only cells containing chloroplasts, that are most often located in the
superficial layers, carry out photosynthesis. Hence, even in green plants
all other organs, tissues and cells that are non-green, need food for
oxidation. Hence, food has to be translocated to all non-green parts.
Animals are heterotrophic, i.e., they obtain food from plants