Chapter 6 Bioenergetics and Thermodynamics

Question 1

Free Energy

1. The direction and extent to which a chemical reaction proceeds are determined by the degree of how many factors ?
2. what are these two factors ?
3. enthalpy and entropy can be used to define a third quantity, what is this quantity ?

Answer 1

1. determined by two factors
2. Enthalpy and Entropy (AH and AS)
3. free enrgy (G)

Question 2

NADH Dehydrogenase

1. free H+ and the Hydride ion carried by NADH are transfered to ?
2. what orther name can we call NADH dehydrogenase ?
3. Complex I (NADH Dehydrogenase) contains FMN, what does it stand for ?
4. what type of enzyme is FMN ?
5. what does FMN accept ?
6. FMN accepts how many hydrogen atoms ?
7. when FMN accepts 2 hydrogens, what does it convert to ?
8. Fe-S centers are found in ?

Answer 2

1. NADH Dehydrogenase
2. Complex I
3. Flavin Mononucleotide
4. coenzyme
5. Hydrogen atoms
6. two hydrogen atoms
7. FMNH₂
8. NADH Dehydrogenase

Question 3

Standard Free Energy Change

1. Standard free enrgy change states that AG⁰ is equal to ?
2. This condition states; that is when reactants and products are at
3. The general equation is written as

Answer 3

1. the free energy change (AG) under standard conditions
2. 1 mol/ 1 concentration
3. AG = AG⁰ + 0

Question 4

NADH Formation

• Reducing is “adding” a Hydrogen

1. how is NADH formed in general terms (what is reduced) ?
2. NAD⁺ is reduced to NADH by the enzyme called ?
3. how many hydrogens are removed from their substrate ?
4. Iron and Cu are part of the _______________grp of heme
5. how many electrons are trasfered NAD^{+ ,} forming NADH plus a free H+ ?

Answer 4

1. NAD⁺ is reduced to NADH
2. Dehydrogenases
3. two hydrogens
4. Prophyrin prosthetic
5. only one is transfered

Question 5

A. AG and reaction direction

1. AG can be used to predict the direction of a rxn at a constant value of
2. AG negative represents ?
3. AG positive represents ?
4. AG is ZERO repressents ?

Answer 5

1. Temperature and Pressure
2. loss of energy ( rxn is spontaneous) EXERGONIC
3. gain of energy ( rxn is not spontaneous)ENDERGONIC
4. the reaction at EQUILIBRIUM

Question 6

1. What is lost when electrons flow ?
2. The energy lost is used as a pump to push out how many hydrogen atoms; across what ?
3. what does NADH stand for ?
4. Does complex 2 and 3 contain Fe-S center as well ? yes or no ?
5. What is the name of complex 2 ?

Answer 6

1. energy
2. four hydrogen atoms; across the inner mitochondrial membrane
3. Nicotinamide Adenine Dinucleotide
4. yes
5. Succinate dehydrogenase

Question 7

1. high energy compound because of its large negative AG⁰
2. Adenine nucleotides are interconverted by ?

Answer 7

1. ATP
2. ( 2 ADP <=> ATP + AMP ) by Adenylate kinase

Question 8

1. AG
2. AH
3. AS

• the energy available (free energy) to do work
• heat released or absorbed ( does NOT predict whether a reaction is favorable)
• measure of randomnes

Answer 8

1. change in free energy predicts
2. change in enthalpy does not predict
3. change in entropy does not predict

Question 9

Energy carried by ATP

1. ATP consist of a molecule of adenosine which are ?
2. the removal of one phosphate ?
3. removal of two phosphates ?

Answer 9

1. adenine + ribose + 3 phosphate groups
2. ADP adenosine diphosphate
3. AMP adenosine monophosphate

Question 10

Overview

please fill in the blanks.

Bioenergentics uses the idea from the feild of 1. ________

2. particulary the concept of _______________________3. Bioenergetics predicts if a process is possible, whereas _________________ measures the reaction rate

Answer 10

Answers

1. Thermodynamics
2. free energy
3. Kinetics

Question 11

Succinate Dehydrogenase

Complex II

1. FADH₂ to Fe-S protein and then to CoQ
2. will the flow of electrons from one enzyme to another in complex two include a “lost in energy” ?
3. Are hydrogens pumped out in the process of Complex 2 ?

Answer 11

1. Complex II, electrons from succinate dehydrogenase-catalyzed oxidation of succinate to fumarate
2. no lost in energy
3. NO hydrogens are pumped out

Question 12

Free Energy AG

1. when a reaction tries to approach ZERO it is trying to reach a level of ?
2. The CHANGE IN ENERGY is represented in TWO ways, how is it represented ?
3. AG (with out the 0 subscript) represents the change in free energy and the direction of a reaction at
4. AG⁰ (with the subscript) represent change in free energy when the reactants and products are at a concentration of how many moles ?

Answer 12

1. 1. equilibrium
2. 2. AG and AG⁰
3. ANY specified concentration of the products and reactants
4. concentration of 1 mole/1

Question 13

AG of the forward and back rxns

1. the forward reaction is equal to the back reaction but in opposite what ?
2. The free energy (AG) of the reaction A ——-> B depends on the concentration of ?

Answer 13

1. in opposite signs
2. the reactant and the product

Question 14

Co Enzyme Q

CoQ

1. describe CoQ ?
2. Another name for CoQ is
3. is CoQ a mobile or stationary enzyme ?
4. Accepts electrons from ?
5. What other enzymes can it receive electrons from ?
6. CoQs transfer electrons to dump in which complex?
7. What is another name for Complex III ?

Answer 14

1. has a hydrophobic tail and a derivative of Quinone
2. Ubiquinone
3. mobile electron carrier
4. NADH Dehydrogenase (complex I) (Complex 2)
5. Glycerol - 3- Phosphate Dehydrogenase and Acyl CoA Dehydrogenases
6. Complex III
7. cytochrome bc ₁

Question 15

Cytochromes

1. Heme groups contain ?
2. Heme group of cytochromes; unlike hemoglobin (what is their differnece in function)

Answer 15

1. Porphyrin ring plus IRON
2. Fe⁺³ can reversibly convert to Fe⁺²