Define the following Respiration

Define the following
(i) Respiration (ii) Respiratory substrate
(iii) How does a tree trunk exchange gases with the environment although it lacks stomata ?
(iv) Which is the most important energy carrier ? Is this compound mobile ?
(v) Name the two phases of glycolysis.

(i) Enzymes controlled process of biological oxidation of various organic food materials in a living cell, producing $CO_{ 2 }$ and $H _{ 2 }O$ and releasing energy in the form of ATP, is called respiration.
(ii) The organic compounds catabolised in the living cells to release energy are called respiratory substrates.
(iii) Due to the presence of lenticels in the periderm which is connected internally to the network of parenchyma with outside world.
(iv) The most important energy carrier is ATP. This energy rich compound is mobile but can not pass from one cell to another.
(v) Glycolysis, has two phases, i.e., preparatory phase and pay off phase.