Biomolecules - Bioenergetics And Overview Of Metabolism

Question 1

Heat transfer

Answer 1

Heat is the amount of energy transferred due to a change in temperature.
Temperature is the average kinetic energy of molecules. Absolute quantity.
Enthalpy helps describe heat transfer for a chemical reaction - change in heat energy from the perspective of the system. Losing heat is exothermic and absorbing heat is endothermic

Question 2

Thermodynamics and kinetics

Answer 2

Thermodynamics is about free energy and kinetics is about activation energy.
The lower the activation energy, the faster the rate of the reaction.
Neither kinetics nor thermodynamics solely determines if a reaction proceeds
* an unspontaneous reaction (positive delta G) has an equilibrium constant (K) between 0 and 1. A spontaneous reaction has a K value greater than 1.
*exergonic reactions have negative changes in free energy and release free energy (this is about the number not the sign)
*delta G =0 for a system at equilibrium

Question 3

Standard reduction potential

Answer 3

Measure of the tendency of a chemical species to be reduced. If they are more likely to be reduced, the have a potential less than 0.

ADP and AMP both have positive free energy, but ADP has more.

Question 4

Redox

Answer 4

During cellular respiration, glucose is oxidised and oxygen is reduced. Glucose is oxidised to carbon dioxide and glucose is reduced to water.

Glucose and oxygen have high levels of energy and water carbon dioxide have lower levels.

Question 5

Intro to ATP

Answer 5

*Respiration is a catabolic process. Hormones regulate Catabolism and anabolism.
*The hydrolysis of ATP releases energy. ATOP is used for biosynthesis, ion movement and muscle contraction.
*Coupled reactions often happen simultaneously
*During cellular respiration, the flow of electrons is harnessed to release chemical energy in the form of ATP
*Using the analogy of an electrochemical cell, the wire is the electron transport chain. The separate containers are the inside and outside of the mitochondrion.

Question 6

Electron carriers AKA coenzymes

Answer 6

They are like molecular shuttles. Metabolites are the smaller structures formed when glucose is broken down. As respiration continues, these metabolites are more and more oxidised. Electron carriers carry the electrons that are being lost to the electron transport chain where enzymes can facilitate the transfer of these electrons to the final electron acceptor, oxygen.

Benefits of enzymes to breakdown glucose
- we can produce more metabolites and this allow for recycling
- we have a slow and controlled oxidation of glucose, which allows us to harness all energy in the form of electrons released

Most of the enzymes are dehydrogenases (take away hydrogens and electrons).