Lecture 2 Thermodynamics

Question 1

Define thermodynamics

Answer 1

A set of principles that apply to all physical and biological processes and govern the conditions under which they can occur

Question 2

What are the 3 laws of thermodynamics?

Answer 2

1st- energy can neither be created nor destroyed only interconverted between forms
2nd- Level of disorder in a system and its surroundings always increases
3rd - Entropy approaches a constant value when temp is 0

Question 3

Define system

Answer 3

Whatever part of the universe we are interested in

Question 4

Define closed system

Answer 4

Cannot exchange matter across boundaries but some energy

Question 5

Define open system

Answer 5

Matter and energy back and forth across boundaries

Question 6

Define surroundings

Answer 6

Everything that surrounds the system

Question 7

Define enthalpy (H)

Answer 7

Heat storage capacity of a system

Question 8

What is the equation of enthalpy?

Answer 8

H = E + (P x V)
Enthalpy (J) = internal energy (J)+ (pressure (Pa) x volume (m3))

Question 9

How is the change in enthalpy and energy in liquids and solids similar?

Answer 9

There is little change in volume

Question 10

Define exothermic

Answer 10

Release of heat in a reaction

Question 11

Define endothermic

Answer 11

Heat is absorbed in a reaction

Question 12

Define entropy

Answer 12

Levels of disorder in a system
High entropy = gas
Low entropy = solid

Question 13

What is Gibbs Free Energy (G)?

Answer 13

The amount of available energy to do work

Question 14

Gibbs free energy calculation

Answer 14

Change in G= Change in H - Tx change in entropy
G= change in gibbs free energy KJ/mol
H= change in enthalpy (J)
T= Temp (K)
S= Change in entropy (J/K)

Question 15

How to convert from degrees to temp?

Answer 15

Add 273

Question 16

What is the standard biological conditions?

Answer 16

37 degrees 310K AND pH 7 so we use Change in G degrees sign ‘

Question 17

Define exergonic

Answer 17

Excitable - releases energy

Question 18

Define endergonic

Answer 18

Requires energy to initiate

Question 19

What is activation energy?

Answer 19

Energy put into the system for a reaction to occur

Question 20

What are the 5 rules of delta G

Answer 20

1. Reactions occur spontaneously if change in G is less than 0
2. Reactions cant occur if change in G is greater that 0
3. At equilibrium G= 0
4. Free energy of reactants and products not the path
5. No info on rate

Question 21

What is a coupled reaction?

Answer 21

A reaction that cant occur spontaneously so an energy input is required. Fundamental in metabolism

Question 22

What is an anabolic reaction?

Answer 22

Constructing molecules from smaller units

Question 23

What is a catabolic reaction?

Answer 23

Breaking down molecules to form smaller units

Question 24

What is the most used activated carrier?

Answer 24

ATP
Hydrolysis has a change in G of -30.5 KJ/mol

Question 25

What do activated carriers do?

Answer 25

They store energy from the oxidation of organic molecules so they can transfer energy by transferring a chemical group or electrons to an endergonic reaction

Question 26

How do cells obtain energy?

Answer 26

Through the oxidation of organic molecules
The energy is stored in the covalent bonds

Question 27

Define oxidation

Answer 27

Loss of electrons

Question 28

Define reduction

Answer 28

Gain of electrons

Question 29

What does NAD+ do?

Answer 29

Stores and releases 2 electrons and a proton H+