Week 6 Flashcards
(31 cards)
What are the 3 types of systems of energy transfer ?
Isolated systems
Close Systems
Open systems
What are Isolated energy systems?
No exchange of matter or energy
What are closed energy systems?
Exchange of energy may occur
What are open energy systems?
Energy exchange and exchange of matter may occur
What is the first law of thermodynamics?
Energy is neither created nor destroyed but can change forms
Write the equation for the first law of thermodynamics.
Change in energy = Final energy - initial energy.
OR
change in energy = Heat absorbed by the system from surroundings + work done on the system by the surroundings.
What is the second law of thermodynamics?
The universe moves towards a state of high entropy.
What does the ‘q’ represent in the equation for the first law of thermodynamics?
The heat absorbed by the system from the surroundings.
What does the ‘w’ represent in the equation for the first law of thermodynamics?
The work done on the system by the surroundings.
What is metabolism?
The sum of all the chemical reactions in a cell.
What are the 2 phases of metabolism ?
Catabolism and Anabolsim
What are the energy containing nutrients of catabolism in the body?
Carbohydrates
Fats
Proteins
What are the end products of catabolism in the body?
Carbon dioxide, water, ammonia (NH3)
How does the energy state of the substrates compared with the products of catabolic reaction vary?
Substrates have more energy than products.
What are the precursor molecules of anabolic reactions in the body?
Amino acids, sugars, fatty acids and nitrogenous bases.
What are the final cellular macromolecules produced by anabolic reactions in the body?
Proteins, polysaccharides, lipids, nucleic acids.
Do catabolic reactions in metabolism converge or diverge and what to ?
Converge to a common intermediate.
Do anabolic reactions in metabolism converge and diverge and what from?
Diverge from a common precursor.
What is the main control mechanism of metabolic reactions?
Compartmentilisation
What types of enzyme regulation occur in metabolism ?
Allosteric enzyme regulation.
Feedback inhibition by enzymes.
Covalent modification.
Isoenzymes.
Outline how allosteric enzyme inhibition works.
One ligand binds non-covalently to the enzyme and effects the binding of other ligands to other protein sites on the enzymes.
What type of molecules are allosteric enzymes?
Oligomers
How do enzymes of metabolism cause covalent modification of a target enzyme?
In response to a hormonal signal, an enzyme covalently modifies they target enzyme.
Give an example of a method which may be used for covalent modification of a target enzyme.
Phosphorylation to turn the enzyme on or off.
