Chapter 1 - Bioenergetics Flashcards
(25 cards)
The conversion of mass into energy results in a large increase of what?
Disorder
The energy needs of all organisms are provided either directly or indirectly by what?
The sun
Any spontaneous chemical or physical change is always accompanied by an increase of what?
Disorder
The second law of thermodynamics states that all natural processes result in an increase of
disorder or entropy
The chemistry of life is done mostly by these 6 elements
Carbon
Hydrogen
Oxygen
Nitrogen
Sulfur
Phosphorus
What is the most electronegative element in biological systems?
Oxygen
What is free energy (G)?
The amount of energy capable of doing work in a reaction.
What is an exergonic reaction?
An exergonic reaction is one that releases free energy. Delta G is negative.
What is an endergonic reaction?
An endergonic reaction is one that absorbs free energy. Delta G is positive.
What is Enthalpy (H)?
Enthalpy is the heat content of a reaction.
What is an exothermic reaction?
A reaction that releases heat during it. Delta H is negative.
What is an endothermic reaction?
A reaction that absorbs heat during it. Delta H is positive.
What is Entropy (S)?
A quantitative expression for the randomness or disorder in a system. There is always an increase of entropy in any reaction.
Delta S is always positive.
What is an isothermal system?
A system that works in constant temperature and pressure. Example: Cells.
They can only use free energy to do work.
The process of turning free energy into ATP or other energy-rich compounds is known as…
Catabolism
The process of breaking down energy-rich compounds to synthesize other various compounds is called…
Anabolism
Are standard free energy changes additive?
Yes (see slide 26, Chp 1, for example)
What are the 4 reasons for the basis of high energy of hydrolysis of ATP?
Or
Why is ATP so desperate to be Hydrolized
- Resonance stabilization products
- Electrostatic repulsion between negatively charged Oxygen atoms in ATP
- High solvation energy of products
- Protons produced by hydrolysis of ATP are diluted ten-thousand fold immediately after being produced
Is the hydrolysis of ATP an exergonic or endergonic reaction?
Exergonic. It releases energy
What is the oxidizing ability of atoms?
The capacity ot ability to accept electrons. (based on electronegativity - the more electronegative, the higher oxidizing ability)
What are the 4 ways in which an electron can be transferred from one molecule to another?
- Direct electron transfer (Ionic reaction)
- As a hydrogen atom
- As a hydride ion (in the case of NAD-linked Hydrogenases)
- Through direct combination with oxygen: covalent incorporation of Oxygen into organic molecule.
What is oxidation referred to as in biological systems?
Dehydrogenation
What is Standard Reduction Potential (E^o)?
The electric potential generated by a redox reaction against a hydrogen electrode.
AKA the ability to get reduced (gain electrons)
NADH and NADPH are what kind of electron carriers that act with dehydrogenases?
soluble
