Cryptococcosis caused by the encapsulated yeast Cryptococcus neoformans affects mostly immunocompromised individuals and is a frequent neurological complication in AIDS patients. Recent studies support the idea that intracellular survival Cryptococcus yeast cells is important its pathogenesis. However, the initial steps of Cryptococcus internalization by host cells remain poorly understood.
The entire process of cellular respiration can be broken down into three separate stages: Gycolysis (meaning splitting sugars), the Citric Acid Cycle, and the Electron Transport Chain.
And to reward you for reading through all that, here's a cute little song I found on youtube about the relationship between cellular respiration and photosynthesis.
Oxidative phosphorylation synthesizes the bulk of a cell’s ATP during cellular respiration. A , in the form of a large proton concentration difference across the membrane, provides the energy for the membrane-localized (a molecular machine) to make ATP from ADP and inorganic phosphate (Pi). The proton gradient is generated by a series of oxidation-reduction reactions carried out by protein complexes that make up an electron transport chain in the membrane. The term oxidative phosphoryation, then, refers to phosphorylation of ADP to ATP coupled to oxidation-reduction reactions.
Organisms that use cellular respiration, such as humans, use that oxygen to kick-start and propel the reactions of cellular respiration, especially those occurring during the Electron Transport Chain.
Energy Transformation: Both Cellular Respiration and Photosynthesis need to transform energy into different forms in order for their reactions to initially take place and continue onward.
Photosynthesis uses those products from cellular respiration as its reactants and in turn produces glucose and oxygen- the reactants needed for cellular respiration.
Cellular energy metabolism features a series of redox reactions. Heterotrophs oxidize (take electrons from) organic molecules (food) and reduce (give them to) an electron carrier molecule, called NAD+ (in the oxidized form) that accepts electrons from food to become NADH (the reduced form). NADH then cycles back to NAD+ by giving electrons to (reducing) the first complex of the membrane electron transport chain. Thus NAD+/NADH is a key intermediary in shuttling electrons from food molecules to the electrons transport chain for respiration.
The NAD and FAD are then reduced in the following few steps so that their reduced forms NADH and FADH2 may carry the electrons onto the next part of cellular respiration.
The earliest cells, prokaryotes living in an early Earth devoid of free oxygen, used various alternative electron acceptors to carry on anaerobic cellular respiration. After cyanobacteria invented oxygenic photosynthesis and pumped oxygen gas into the oceans and atmosphere, bacteria that adapted their electron transport chains to exploit oxygen as the terminal electron acceptor gained higher energy yield and thus a competitive advantage. One line of aerobic bacteria took up an endosymbiotic relationship within a larger host cell, providing ATP in exchange for organic molecules. The endosymbiont was the evolutionary ancestor of mitochondria. This endosymbiosis must have occurred in the ancestor of all eukaryotes, because all existing eukaryotes have mitochondria (Martin and Mentel, 2010). The evidence for the endosymbiont origin of mitochondria can be found in:
Revised 9/2016 to reorder LOs and some sections (begin with different types of cellular metabolism before diving into respiration), add summary of cellular respiration essentials, drop redundancies in evolution, cleaned up some typos and streamlined some explanations.