CELLULAR RESPIRATION

RESPIRATION  

•process of breaking down of food molecule with the liberation of energy in the form of ATP.

•consists of many reactions that include oxidation, in which energy liberated is used to link phosphate to ADP forming ATP.

•also called cellular respiration as the process happens inside the cell.

 ATP

 ATP acts as energy “currency” and used for many physiological processes:

a)  Anabolic reactions - reactions involving building or synthesis of substances in which energy or phosphate group is obtained from ATP

b)  Active transport - passage of solutes across membrane against concentration gradient. 

ATP acts as energy “currency” and used for many physiological processes: 

(c)  Contraction of muscles - breaking and formation of bonds between muscle proteins at molecular levels.

ATP acts as energy “currency” and used for many physiological processes:

d)  Transmission of impulse - maintenance of sodium pump function after membrane is depolarised.

ATP acts as energy “currency” and used for many physiological processes

e)  Bioluminescence - conversion of special molecule that can give out light.

ATP is converted into ADP and phosphate with the liberation of energy.

SUBSTRATES used for respiration are :

1.Glucose : the first choice of substrate in both animal and plant cells. 

  When free glucose is used up, it can be derived from glycogen in animals and starch in plants.

  Other sources of carbohydrates include sucrose, lactose, fructose and galactose.

SUBSTRATES used for respiration are :

2.Fats : usually used when all the carbohydrate reserves are used up.

 

  Fats are hydrolyzed to glycerol and fatty acids, and then oxidized. 

  Skeletal muscles prefer the use of fatty acids to glucose.

SUBSTRATES used for respiration are :

3.Proteins : proteins are used only under extreme starvation.  They are first hydrolyzed to amino acids.

  Then the amino acids are deaminated to form organic acids before they are oxidized.