The Biosphere Blog

Drilling Down There are two types of photosynthesis: anoxygenic and oxygenic. Anoxygenic photosynthesis was the first to appear on Earth around 3.5 billion years ago, was and is performed solely by several groups of bacteria to this day, and… more »

Electron Flow Chemical reactions involve atoms and molecules, but chemistry at its heart is really the study of the electron flow between those atoms and molecules when these react. Similarly, biochemistry at its heart is the study of the electron flow… more »

Drilling Down In the cells of plants and algae are structures called chloroplasts (Fig. 1). (And there is much evidence that these chloroplasts were once independently-living cyanobacteria.) Chloroplasts have an inner and outer membrane (just like… more »

What Are Thylakoids? Thylakoids are unique to chloroplasts and their ancestral cyanobacteria, and are where photosynthesis begins for both. This chapter will focus on the thylakoids in chloroplasts, but with references to cyanobacteria where relevant.… more »

Backstory: Of Prokaryotes and Eukaryotes Prokaryotes Prokaryotes (pronounced ‘pro-carry-oats’) comprise the two Domains Bacteria and Archaea. Prokaryotes are defined as unicellular organisms without membrane-bound nuclei, and contain a… more »

Photons and the Electromagnetic Spectrum ‘Photons’ are commonly thought of as the particles of light, but they are actually the particles of radiation, of which light is just one form. Radio waves, microwaves, infrared waves, visible light… more »

What is Photosynthesis? Photosynthesis (from the Ancient Greek combining form φωτω-, phōtō-, from φῶς, phôs, ‘light’, and σύνθεσις, synthesis, ‘a putting together’:  ‘a putting together with light’) is the process by which plants, algae, cyanobacteria,… more »

Metabolism An organism’s metabolism — the sum of all the chemical reactions going on inside it — can be precisely defined by its energy source, its electron donor source, and its carbon source. The Macro World People who study plants, animals,… more »

Life Needs a Carbon Flow All organisms are made of carbohydrates, lipids and proteins, which are needed for growth, reproduction and movement. These molecules all contain carbon, making them organic molecules. The Law of Conservation of Mass states that… more »

Life Needs an Electron Flow Just as electricity is the flow of electrons, so too is life the flow of electrons. Chemistry is the study of the reactions between atoms and molecules, which are all driven by electron flow. Biochemistry is the study of the… more »

Life Needs an Energy Flow All living things need energy to constantly fuel the biochemical pathways that enable them to grow, reproduce and move. The Law of Conservation of Energy states that energy can neither be created nor destroyed. It can only be… more »

Until 1859, it had always been accepted that life on Earth had always been around, unchanged and unchanging. Until the publication of a single book that year turned everything on its head, and changed the theological and scientific worlds forever:… more »

The Spheres of Earth Planet Earth is a complex system, made up of sub-systems called ’spheres’, as they too are round like Earth. It is possible to divide the Earth into at least 17 spheres (and possibly more), beginning with its core and… more »

Back in 1648, Johannes Baptista van Helmont took a young willow sapling weighing 5 pounds (2.3 kg*), and planted it into 200 pounds (90.7 kg) of soil. Five years later he uprooted the tree and determined its weight to be 169 pounds and 3 ounces… more »

Have you ever seen these very smooth round and oval shapes in leaves before, and not known what made them? These aren’t caused by caterpillars, which produce jagged edges. These very smooth edges are the tell-tale sign (to those in the know!) of… more »