Study "Meet Zeus L ecture 3 The struggle for existence of living", a flashcard deck on FORKSAI.
According to Ludwig Boltzmann, what is the fundamental struggle for existence of living beings?
Boltzmann stated that the struggle for existence is not for the fundamental constituents of food, but for the possession of free energy, chiefly obtained from green plants, which transfer radiant energy from the hot sun to the cold earth.
What is the role of reduced bonds in energy capture and storage within living organisms?
Energy is captured and stored in reduced bonds such as C=O, C-C, and C-H. This stored energy is then ultimately transferred to ATP following the oxidation of these bonds.
Explain the significance of ATP's phosphate bond as an energy store.
The phosphate bond of ATP is an ancient energy store that now functions as a short-term energy source for various biological work processes. The hydrolysis of ATP to ADP and inorganic phosphate releases most of the free energy stored in ATP.
What is the relationship between ΔG o' and the likelihood of a reaction occurring?
ΔG o' represents the free energy released on ATP hydrolysis, which is used for biological work. The more negative the ΔG o', the greater the likelihood that a reaction will occur spontaneously.
How do the three stages of catabolism contribute to energy extraction?
The three stages of catabolism involve: 1) hydrolysis of complex molecules into their building blocks, 2) conversion of these building blocks to Acetyl CoA, and 3) oxidation of Acetyl CoA, which occurs via oxidative phosphorylation to extract energy.
What are the two main types of cellular work powered by ATP, and how does ATP facilitate them?
ATP powers transport work and mechanical work. In transport work, ATP phosphorylates transport proteins, making them less stable and enabling solute transport. In mechanical work, ATP binds non-covalently to motor proteins and is then hydrolyzed, causing movement.
Why is ATP considered life's universal currency, despite other similar compounds existing?
ATP is the most abundant and likely ancestral energy currency. Its phosphoanhydride bond is relatively stable in water at physiological pH, and its hydrolysis releases energy exothermically. While other bonds can yield more energy, they are less water-stable.
Describe the first and second laws of thermodynamics and how they relate to Gibbs Free Energy (ΔG).
The first law states that energy cannot be created or destroyed, only changed in form (ΔH = q + w). The second law states that the universe tends towards disorder (increased entropy, ΔS). These laws are combined in the Gibbs Free Energy equation: ΔG = ΔH - TΔS, which predicts reaction spontaneity.
How does the second law of thermodynamics explain the generation of a membrane potential by partitioning charged ions?
The second law states that the universe tends towards disorder (increased entropy). Partitioning charged ions, such as H+ or Na+, across a membrane creates an ordered, non-equilibrium state (low entropy). Life actively fights this tendency towards equilibrium, using energy to maintain these gradients, which in turn can be used to power metabolism.
What is the primary source of 'power' from ATP hydrolysis, and how much energy does it typically yield?
Most of the 'power' used in life comes from the hydrolysis of the terminal (third) phosphate group of ATP. The hydrolysis of ATP to ADP and inorganic phosphate (Pi) typically yields a ΔG o' of -30.5 kJ.mol-1.