Chapter 5

Question 1

What are the energy sources for cells

Answer 1

Sun and oxidizable organic molecules (carbs, fats, proteins)

Question 2

What are the 6 kinds of biological work

Answer 2

Synthetic, mechanical, concentration, electrical, heat, and bioluminescence

Question 3

what is the difference between an open and closed system

Answer 3

an open one can exchange energy (heat or work) with its surroundings

Question 4

What are thermodynamics

Answer 4

governs flow of energy through a cell

Question 5

what is the first law of thermodynamics

Answer 5

conservation of energy

energy cannot be created or destroyed, it may be changed from one form to another

Question 6

what is an exergonic reaction

Answer 6

final state is less than initial state

energy is released

Question 7

Enthalpy

Answer 7

measure of energy in a thermodynamic system

^H

Question 8

what is an endergonic reaction

Answer 8

Final state is greater than initial state

input of energey

Question 9

Which kind of reaction has a positive ^H

Answer 9

Endergonic

Question 10

During photosynthesis, what form of energy is utilized and what is it converted to

Answer 10

Utilized: light
Converted: light, heat, chemical

Question 11

During respiration, what forms of energy are created

Answer 11

Chemical and heat

Question 12

What is the second law of thermodynamics

Answer 12

law of spontaneity

any system tends to spontaneously increase in entropy

Question 13

Entropy

Answer 13

Measure of randomness (disorder)
^S
When ^S > 0, indicates disorder

Question 14

Are naturally occurring processes are exergonic or endergonic

Answer 14

Exergonic, because it doesn’t require the input of energy

Question 15

As the system becomes more random, what happens to the change in ^S

Answer 15

^S becomes less

Question 16

What is Gibbs Free Energy

Answer 16

^G
measure of the spontaneity of a reaction
tells us if a reaction is thermodynamically feasible (that it can go, not that it will go)

Question 17

What is the equation for Gibbs Free Energy

Answer 17

^G = ^H - T x ^S

Question 18

what is the equation for enthalpy

Answer 18

^H = Hproducts - Hreactants

Question 19

What does it mean when ^G < 0

Answer 19

the reaction can occur spontaneously (it’s exergonic)

Question 20

What two factors must occur for the reaction to be able to occur

Answer 20

^G being negative and the availability of a pathway

Question 21

Keq

Answer 21

equilibrium constant
At 25C for reactions that are reversible
it is the ratio of product concentration to reactant concentration

Question 22

What is the equation for the equilibrium constant

Answer 22

Keq = [product]eq / [reactant]eq

Question 23

How does ^G compare to Keq

Answer 23

^G is lowest at equilibrium and higher the further you deviate

Question 24

When the stuff is at chemical equilibrium, what will the Keq be

Answer 24

1.0

Question 25

So what happens if concentration ratio is greater than 1

Answer 25

reaction goes to the left because it needs to produce more reactants

Question 26

What happens if concentration ratio is less than 1

Answer 26

reaction goes to the right to produce more products

Question 27

what are the standard conditions

Answer 27

at 25C, 1 atm pressure, pH=7, all products and reactants at 1 mole L-1

Question 28

what is the difference between ^G0' and ^G'

Answer 28

the first one is at standard conditions and the second is at normal cellular conditions and pH=7

Question 29

what does it mean when ^G' is positive

Answer 29

need to supply energy and a pathway

Question 30

what does it mean when ^G'=0

Answer 30

no work done so no energy required | Keq=1 at equilibrium

Question 31

equation for ^G0'

Answer 31

^G0' = -R T Ln(K'eq)

Question 32

What does pr stand for

Answer 32

prevailing conditions

Question 33

equation for ^G'

Answer 33

^G' = ^G0' + R T Ln([products]pr / [reactants]pr)

Question 34

what is the gas constant

Answer 34

R= 1.987

Question 35

what is the T going to be at standard conditions

Answer 35

298K

Question 36

what is the meaning of the relationship between ^G0' and K'eq

Answer 36

indicates how far from equilibrium the reaction lies

Question 37

What is the relationship between ^G0' and K'eq

Answer 37

inverse | K'eq=1, ^G=0

Question 38

What is a steady state

Answer 38

where cells usually maintain themselves through which matter is flowing. it is not equilibrium because then the cell would stop having reactions

Question 39

Why is the ^G' for ATP and underestimate

Answer 39

because of nonstandard conditions