That time, there was no selective pressure for rubisco to discriminate between CO2 and O2. 

The Km for CO2 is about 9 microM, and that for O2 is about 350 microM. The modern atmosphere contains about 20% O2 and only 0.04% CO2, so an aqueous solution in equilibrium with air at room temperature contains about 250 microM O2 and 11 microM CO2—concentrations that allow significant O2 “fixation” by rubisco and thus a significant waste of energy.

TLS Online TPP Program

#Id: 3326

#Unit 6. System Physiology – Plant

Mitochondrial ATP synthase is an F-type ATPase and also called Complex V.

TLS Online TPP Program

#Id: 7880

#Unit 2. Cellular Organization

MICOS has an integral membrane protein subunit that homo-oligomerizes and bends the inner membrane to produce high curvature.

TLS Online TPP Program

#Id: 7285

#Unit 6. System Physiology – Plant

Evolution of oxygenase activity occurred before the time, about 2.5 billion years ago, when production of O2 by photosynthetic organisms started to raise the oxygen content of the atmosphere.

TLS Online TPP Program

#Id: 3025

#Unit 3. Fundamental Processes

A preformed RNA (often a tRNA) pairs with the template, allowing its 3'-0H end to be used to prime DNA synthesis.

TLS Online TPP Program

#Id: 1142

#Unit 7. System Physiology – Animal

Nephron contains 

• Glomerulus

• A long tubule