Bioenergetics Flashcards

midterm 1

1
Q

bioenergetics definition

A

describes the transfer and utilization of energy in biological systems, concerned with the initial and final energy states, not the rxn mechanism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

system

A

all the reactants and products with a regard to a chemical rxn, the solvent, and immediate atmosphere

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

types of systems

A

isolated system: no exchange of matter or energy
closed system: exchanges energy but not matter
open system: exchanges both energy and matter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

thermodynamics

A

study of energy and its effect on matter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

1st law of thermodynamics

A

energy is conserved but can be converted from one form into another

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

2nd law of thermodynamics

A

all processes involving energy changes under a given set of conditions of temp and pressure, some energy is lost

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

entropy (S)

A

the randomness/disorder of the components of a chemical system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

change of entropy (S)

A

max value at equilibrium
S positive randomness increases
S negative randomness decreases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

enthalpy (H)

A

measurement of energy in a thermodynamic system equivalent to total heat content of the system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

change of enthalpy (H)

A

reflects the number/kinds of chemical bonds and non-covalent interactions broken and formed during a rxn
H positive: heat is absorbed (endothermic/breaking bonds)
H negative: rxn releases heat (exothermic/making bonds)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

thermodynamics in biological systems

A

all rxns comply to thermodynamics, and occur under physioloigcal conditions
potential energy -> heat, simpler metabolic products (increase S), or more complex macromolecules (decrease S)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

coupled rxns

A

happens commonly in metabolic pathways, when biochemical rxns must consume energy to make them occur

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Gibbs free energy (G)

A

free energy of a system is the portion of the total energy in a system that is available for useful work
-determines if rxn is favorable

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

change of free energy (G)

A

G=0 process is at equilibrium
negative G: favorable, exergonic, spontaneous
positive G: unfavorable, endergonic, non-spontaneous

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

free energy equation

A

(delta)G= (delta)H - T(delta)S

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

thermodynamic favorability depends on what

A

energy differences & conc. of [S] & [P]

17
Q

transition state

A

a state of higher free energy than both the reactant and product

18
Q

activation energy

A

the energy required to reach the “transition state” of the molecule
-decreased w/ catalysis

19
Q

oxidation

A

loss of electrons

20
Q

reduction

A

gain of electrons

21
Q

redox reactions

A

electrons are transferred from the reductant to oxidant

22
Q

redox reactions examples

A

NAD+ and FAD

23
Q

NAD+ and FAD

A

important role in citric acid cycle
-reduced to NADH and FADH2
-subsequent e- donation liberates free energy

24
Q

ATP role in free energy

A

exergonic processes are coupled to the formation of ATP
endergonic processes are coupled to the consumption of ATP

25
ATP
contains adenine, ribose, and a triphosphate group energy carrier/energy transfer agent
26
ATP structure
adenosine linked by phosphoester bond followed by two phosphoanhydride bonds
27
ADP, AMP, ATP
large free energy change from ATP to ADP, small free energy change from ADP to AMP ADP + Pi much more stable than ATP
28
why is ADP and AMP are more stable
ATP has four closely spaced negative charges w/ strong repulsion between them more resonance with ADP than ATP ionization Mg 2+
29
ATP synthesis
requires energy, so utilizes processes with more negative G values
30
ATP exception
ATP hydrolysis isn't kinetically favorable, so needs to an enzyme