Unit 1 Topic 2 - Thermodynamics

Question 1

What type of molecule has a better source of potential energy for a cell?

Answer 1

Non-polar covalent bonds

Question 2

First law of thermodynamics

Answer 2

The total amount of energy in a system and its surroundings remains constant

Question 3

Second law of thermodynamics

Answer 3

The entropy of a system and its surroundings is always increasing

Question 4

At the equilibrium point of an exercising reversible reaction,

Answer 4

An equal number of reactant molecules are being converted to products as there are product molecules being converted to reactants

Question 5

What is true of exergonic reactions?

Answer 5

Free energy decreases as the reaction proceeds and the reactants have more free energy than the products

Question 6

Is energy released or absorbed in the breakdown of complex molecules? (catabolic reaction)

Answer 6

Released

Question 7

Why is ATP useful in living cells?

Answer 7

The free energy released when ATP is hydrolyzed can be used to drive endergonic cell functions

Question 8

How do cells replenish ATP supplies?

Answer 8

By coupling endergonic ATP synthesis with exergonic catabolic reactions

Question 9

In an exergonic reaction, activation energy is

Answer 9

The amount of energy that must be absorbed by reactants before the reaction can proceed

Question 10

Energy

Answer 10

Capacity to do work

Question 11

Kinetic energy

Answer 11

Energy of motion

Question 12

Potential energy

Answer 12

Energy stores in an object because of its location or chemical structure

Question 13

What is potential energy related to?

Answer 13

The position of electrons

Question 14

The farther away an electron is from the nucleus of an atom, the greater or lesser its potential energy?

Answer 14

Great

Question 15

Isolated system

Answer 15

Does not exchange energy or matter with its surroundings

Question 16

Closed system

Answer 16

System that exchanges energy but not matter with its surroundings

Question 17

Open system

Answer 17

System that exchanges both energy and matter with its surroundings

Question 18

Entropy

Answer 18

Tendency of energy to become dispersed or spread out

Question 19

Processes with a negative delta G are

Answer 19

Spontaneous and exergonic

Question 20

Processes with a positive delta G are

Answer 20

Endergonic and require free energy

Question 21

Exergonic reactions…

Answer 21

Release free energy and the reactants have more free energy than the products

Question 22

Diffusion is an example of an exergonic or endergonic reaction?

Answer 22

Exergonic. It is driven by the increase in entropy as molecules spread out and it is spontaneous!

Question 23

What happens at chemical equilibrium?

Answer 23

Reactants are converted to products and products are converted back to reactants at equal rates

Question 24

Living systems are highly organized but still follow the second law of thermodynamics… why?

Answer 24

They are open systems and use energy and matter from the surroundings. The entropy of the surroundings increases

Question 25

Why is a constant supply of energy (food) required to sustain life?

Answer 25

All biological molecules breakdown (entropy increases

Question 26

Metabolism

Answer 26

Biochemical modification and use of energy in the synthesis and breakdown of organic molecules

Question 27

Catabolic pathway

Answer 27

Releases the potential energy of a molecule in breaking it down to a simpler molecule (exergonic)

Question 28

Anabolic pathway

Answer 28

Uses energy to convert a simple molecule to a more complex molecule (endergonic)

Question 29

How does the cell make the endergonic reaction associated with ATP proceed spontaneously?

Answer 29

By coupling the exergonic reaction of ATP breakdown (which is not technically a hydrolysis reaction)

Question 30

In exergonic reactions, the products must have ___________ than the reactants

Answer 30

Less free energy

Question 31

Photosynthesis is an endergonic or exergonic process

Answer 31

Endergonic

Question 32

Enthalpy

Answer 32

The potential energy in a system

Question 33

Energy coupling

Answer 33

The process by which ATP is brought in close contact with a reactant molecule involved in an endergonic reaction, and when the ATP is hydrolyzed, the terminal phosphate group is transferred to the reactant molecule.

Question 34

Coupled reaction

Answer 34

Reaction that occurs when an exergonic reaction is joined to an endergonic reaction, producing an overall reaction that is exergonic

Question 35

ATP Cycle

Answer 35

Continued breakdown and resynthesis of ATP

Question 36

How do cells harness the energy of ATP to drive endergonic reactions?

Answer 36

Hydrolyze ATP and use the released phosphate group to phosphorylate a reactant in the endergonic reaction, thereby increasing the energy of the reactant and changing the reaction from a positive delta G to a negative delta G

Question 37

What happens to the phosphate group that is removed when ATP is converted to ADP?

Answer 37

It is acquired by a reactant in an endergonic reaction