Biology 2485B Lecture Notes - Lecture 5: Chemosynthesis, Cyanobacteria, Photosynthesis

• School: Western University
• Department: Biology
• Course: Biology 2485B
• Professor: Nusha Keyghobadi

Document Summary

Two laws of thermodynamics: the total amount of energy in the universe is constant - energy is never lost, only transformed, entropy (disorder or randomness) is always increases. Biological systems (cells, organisms, ecosystems) represent islands of order in an increasingly disordered universe. They are (cid:272)o(cid:374)sta(cid:374)tly (cid:862)fighti(cid:374)g(cid:863) e(cid:374)tropy a(cid:374)d the se(cid:272)o(cid:374)d la(cid:449) of ther(cid:373)ody(cid:374)a(cid:373)i(cid:272)s (cid:894)i(cid:374)(cid:272)reasi(cid:374)g e(cid:374)tropy of the universe. They achieve their order by acquiring energy from external sources. Light is the ultimate source of energy for most living systems, through the process of photosynthesis. In some systems, such as deep sea hydrothermal vents, energy contained in bonds of inorganic molecules is the ultimate energy source: and is harnessed via chemosynthesis. These sugar (c6h12o6) molecules produced provide: energy for other metabolic activities, basic building materials for growth, cellular respiration and basic metabolic activities, growth. Heterotrophs: consumers, those organisms that must acquire their energy by consuming other organisms, organisms either alive or dead, they (cid:272)a(cid:374)(cid:374)ot (cid:858)(cid:373)ake their o(cid:449)(cid:374) food(cid:859)