Energy and Metabolism

Question 1

Define kinetic energy

Answer 1

The energy possessed by moving objects

ex. raindrops falling, heart muscles contracting in heartbeat

Question 2

Define potential energy

Answer 2

Stored energy- due to its position within an attractive or repulsive force field (ex. gravitational potential or chemical potential energy)

Question 3

Define a catabolic reaction

Answer 3

The breakdown of complex substances

Question 4

Define anabolic reactions

Answer 4

The build up of complex substances from simpler subunits

Question 5

Define metabolism

Answer 5

The sum of all anabolic and catabolic processes (chemical reactions) in a cell or organism

Question 6

Define the first law of thermodynamics

Answer 6

Principle that states the total amount of energy is in the universe is constant- energy cannot be created or destroyed but only converted from one form to another
- if an object has energy it does at the expense of loss of energy elsewhere

Question 7

Define bond energy

Answer 7

The minimum energy required to break one mole of bonds between two types atoms
- equal to the amount of energy released when a bond forms

Question 8

Is energy added or released when a bond is broken?

Answer 8

Added

Question 9

Is energy added or released when a bond is created?

Answer 9

Released

Question 10

Define activation energy

Answer 10

The amount of energy required to strain and break the reactants’ bonds
- to start a chemical reaction

Question 11

What is activation energy equal to?

Answer 11

The difference between the potential energy level of the transition stage and the reactants

Question 12

Define the transition state

Answer 12

Temporary condition in which the bonds within reactants are breaking and bonds between products are forming

Question 13

Define an exothermic reaction

Answer 13

A chemical reaction in which energy is absorbed, giving the products more chemical potential energy than the reactants
- negative H value

Question 14

Define an endothermic reaction

Answer 14

A chemical reaction in which energy is absorbed, giving the products more chemical potential energy than reactants
- positive H value

Question 15

Define work

Answer 15

The ability to apply a force to move an object

- examples are breathing,

Question 16

Define the second law of thermodynamics

Answer 16

In every energy transfer or conversion, some of the useful energy in the system becomes unstable and increases the entropy of the universe

Question 17

Define entropy

Answer 17

The degree of disorder in a measurable quantity

Question 18

Do all systems in the universe tend toward order or disorder?

Answer 18

Disorder

Question 19

What causes an increase in entropy?

Answer 19

Any change, such as a chemical reaction

Question 20

When does entropy increase in chemical reactions?

Answer 20

• solids react to form liquids or gasses
• liquids react to form gaseous products
• the total number of product molecules is greater than the total number of reactant molecules

Question 21

Do living organisms defy the second law of thermodynamics?

Answer 21

No, energy can be expanded to establish and maintain order

- there is a greater increase in entropy in the universe than there is a decrease of entropy in the organism

Question 22

Define a spontaneous change

Answer 22

A change that once started will proceed to completion without any input of energy
- ex lighting a match, burning paper, melting ice above 0

Question 23

Are spontaneous changes catabolic or anabolic?

Answer 23

Catabolic

Question 24

Define a non-spontaneous change

Answer 24

A change that once started, will not go to completion unless a constant supply of energy is input
- ex water melting at -10 degrees

Question 25

Are non-spontaneous reactions catabolic or anabolic?

Answer 25

Anabolic

Question 26

What is responsible for the chemical and physical work in living organisms?

Answer 26

Free energy

Question 27

Equation of change in free energy

Answer 27

G final equation- G initial equation

Question 28

What does a negative change in free energy mean?

Answer 28

Free energy of products is less than free energy of reactants

Question 29

What does positive change in free energy mean?

Answer 29

Products have more free energy than the reactants

Question 30

Do reactions with negative change in free energy occur spontaneously? Do they gain or give off energy?

Answer 30

Yes, give off free energy

Question 31

Do reactions with positive change in free energy occur spontaneously? Do they gain or release energy?

Answer 31

No, they occur non spontaneously and must gain energy from an external source

Question 32

When is an exothermic reaction spontaneous with an increase in entropy?

Answer 32

Spontaneous at all temps

- burning wood, cellular respiration

Question 33

When is an exothermic reaction spontaneous with an decrease in entropy?`

Answer 33

Spontaneous at low temps only

- water freezing

Question 34

When is an endothermic reaction spontaneous with an increase in entropy?

Answer 34

Spontaneous at high temps only

Ex. Ice melting

Question 35

When is an endothermic reaction spontaneous with an decrease in entropy?

Answer 35

Not spontaneous at any temp

- formation of diamonds or glucose

Question 36

Define free energy

Answer 36

The energy that is not lost, and can perform work in the body

Question 37

Describe Gibbs free energy in non/spontaneous reactions

Answer 37

Free energy released in spontaneous changes

Free energy absorbed in non spontaneous changes

Question 38

Describe an exergonic reaction

Answer 38

• catabolic
• spontaneous
• release free energy
• useful energy
• negative value

Question 39

Describe an endergonic reaction

Answer 39

• anabolic
• not spontaneous
• require free energy
• positive value