need for energy in living organisms

respiration

series of enzyme catalysed reactions that break down glucose to release energy in living cells

aerobic respiration

break down of energy in the presence of oxygen

anaerobic respiration

break down of energy without oxygen

photosynthesis

converts light energy to chemical potential energy…building blocks of the food chain

synthesis of complex molecules

polysaccharides from monosaccharides…triglycerides from fatty acids and glycerol…polypeptides from amino acids…polynucleotide from nucleotides

active transport

movement of substances against the concentration gradient…activity of the sodium-potassium pump

movement

for muscle contraction and other cellular movement like cilia, flagella and vesicles in cytoplasm

body temperature

maintain constant temperature…mammals and birds use heat energy released from metabolic reactions

bioluminescence and electrical discharge

emission of light by organisms like insects and some marine animals