101 Bioenergetcis

Question 1

What is entropy?

Answer 1

a measure of disorder, it is energy that cannot be reused and it is the dispersal/diffusion of energy

-the ACTUAL meaning is that energy tends to be dispersed, i.e., any spontaneous process will result in an increase in entropy of the whole universe

Question 2

Metabolic pathways that are energy producing are called? (

Answer 2

catabolic pathways or catabolism. this degrades molecules to produce energy

Question 3

Pathways that use energy to build complex structures are called?

Answer 3

Anabolic pathways or anabolism. They use energy to build

Question 4

What is a metabolic pathway?

Answer 4

a series of reactions that can be either catabolic or anabolic in function

Question 5

In a living system, what is the main source of energy used to reverse the trend of entropy?

Answer 5

the sun/sunlight

Question 6

For living systems, that have no access to sunlight, what is the main source of energy used to reverse entropy?

Answer 6

thermal energy

Question 7

What does thermodynamics describe?

Answer 7

describes the behavior of matter as well as the transformation between different forms of energy ( The flow of matter and energy through systems)

Question 8

What is a system?

Answer 8

a definite region of space w/in a real or imaginary boundary e..g., cell, an organelle, the contents of a breaker

Question 9

what is meant by surroundings?

Answer 9

everything else outside the system

Question 10

What is meant by universe

Answer 10

the system + surroundings

Question 11

are biological systems open, closed, or isolated?

Answer 11

can be all three but biological systems that are not open would be thermodynamically dead

Question 12

How does energy and matter move in an isolated system?

Answer 12

there is no movement of energy or matter w/its surroundings

Question 13

How does energy and matter move in a closed system?

Answer 13

there is no exchange of matter but there is exchange of energy with system surrounds

Question 14

How does energy and matter move in an open system?

Answer 14

can exchange both matter and energy w/surroundings

Question 15

What is deltaH?

Answer 15

the change in enthalpy, which measures the amount of heat. It also measures the difference in number of bonds and strength of those bonds between the substrate and products

Question 16

What is the basic equation n bioenergetics of deltaG?

Answer 16

DeltaG=DeltaH-T(DeltaS)

Question 17

What is deltaG?

Answer 17

the MAX AMOUNT of useful work that can be produced from or is required by a process

Question 18

What is meant by absolute temperature (T)?

Answer 18

the absolute temperature, which measures the intensity of heat

Question 19

What is meant by deltaS?

Answer 19

change in entropy, which measures change in chaos/disorder/randomness. This is the form of heat-energy that cannot be reused in chemical rxns

Question 20

When talking about free energy, what is meant by free?

Answer 20

the term free means available in the form of useful work

Question 21

What is a spontaneous process?

Answer 21

Processes that are spontaneous do not require energy, instead they release energy. Those process that are not spontaneous, require energy and there must be a source of energy to drive the reaction.

-any spontaneous process will result in an increase in entropy of the whole universe

Question 22

TRUE OR FALSE: enzymes alter the rate at which a reaction proceeds and the overall energetic parameters of the reaction?

Answer 22

FALSE: enzymes do not alter energetic parameters. Enzymes do not affect thermodynamics

Question 23

FILL IN THE BLANKS: Enzymes in a reaction affect ______ but not the overall ________

Answer 23

enzymes alter the rate at which a reaction proceeds but not the equilibrium of the reaction

Question 24

What assumption do we have to make about biological systems/reactions when thinking of free energy change (DeltaG)?

Answer 24

that temp and pressure are constant

Question 25

What is required for processes that are not spontaneous to proceed (drive the reaction forward)?

Answer 25

energy source is required

Question 26

What is enthalpy?

Answer 26

the change in the amount of heat. enthalpy is an extensive factor and depends upon how much is burning

Question 27

What is the units of absolute temperature?

Answer 27

absolute temperature 0 Kelvin or -273 degrees Celsius.

Question 28

In gibbs free energy, which energy can be used? which cannot be used?

Answer 28

entropy - form of energy that cannot be used (Delta s)

enthalpy - form of energy that CAN be used (HEAT) (delta H)

Question 29

What is extensive vs intensive?

Answer 29

extensive factors depend upon how much product is present. intensive does not.

Question 30

in delta G equation, what is extensive and what is intensive?

Answer 30

Ethalpy, delta H is extensive

Entropy, delta S is extensive

Free energy, deltaG is extensive

Absolute temperature, intensive factor b/c it does not depend upon how much is present.

Question 31

What is meant by a strong bond vs a bond that is not as strong?

Answer 31

it means it takes “a lot” of energy to break that bond. e.g., if bond A has more energy than bond B than bond A is more stable (harder to break) than bond B

Question 32

When is deltaH more negative?

Answer 32

DeltaH is more negative when the products (compared to substrates) have more bonds, and stronger bonds (e.g., C-triple bond-C > C=C > C-C)

• products < substrates
• when energy is released or the energy level is lower, that means there is a negative value.

Question 33

When is delta H more positive?

Answer 33

when the products compared to substrates have less bonds, weaker bonds

Products < substrates

Question 34

When is delta S more negative?

Answer 34

-when there are more substrate molecules than products

Substrate > product

-when entropy is more negative, the reaction tends to flow downhill. in other words SPONTANEOUS

Question 35

When is delta S more positive?

Answer 35

deltaS is more positive when there are more product molecules than substrate molecules.

product > substrates

Question 36

Why do some reactions require energy?

Answer 36

some reactions are not spontaneous, meaning they roll uphill, not downhill (downhill = spontaneous)

-in order for the reaction to proceed, work is required to get that reaction to go uphill. The measure of how much work is required is deltaG

Question 37

What is work?

Answer 37

the amount of energy required when moving a mass

Question 38

The number of energy in bonds is dependent on what factors? how is this related to enthalpy?

Answer 38

The number of bonds after and the strength of the carbon-carbon bonds.

(the more bonds, the more energy in there)

Question 39

In terms of enthalpy, when is a reaction spontaneous?

Answer 39

When enthalpy is negative, the reaction tends to flow downhill, aka SPONTANEOUS. The products have more bonds and are stronger

In other words, when a reaction flows downhill, you end up with substrates that have weaker bonds

Question 40

When is entropy more positive?

Answer 40

When going from substrate to product, entropy is more positive, that is things become more chaotic, more disordered, when there are more product molecules than substrate molecules.

Question 41

Consider the reaction S → P+Q, will the entropy (deltaS) be negative or positive?

Answer 41

Positive b/c there are more product molecules, hence more disorder, hence more chaos (more thermal motion in two molecules vs one molecule)

Question 42

Consider the reaction X+Y → Z, will the entropy (deltaS) be negative or positive?

Answer 42

The entropy will be negative, because we went from a chaotic substrate to a less chaotic (less product) product.