Bioenergetics

Question 1

Living organisms require a continual input of free energy for: (3)

Answer 1

1. the performance of mechanical work in muscle contraction and cellular movements
2. the active transport of molecules and ions
3. the synthesis of macromolecules from simple precursors

Question 2

Metabolism

-definition

Answer 2

Complex regulated system of energy- producing and energy utilizing chemical reactions, cell depend on

Question 3

Metabolism

-a linked series of chemical reactions that: (3)

Answer 3

• begins with a particular biomolecule
• converts it into some other required biomolecule
• does not generate wasteful or harmful side products

Question 4

Metabolic pathways

• catabolic
• anabolic

Answer 4

• convert energy from fuels into biologically useful forms, such as ATP.
• the synthesis of complex molecules in living organisms from simpler ones

Question 5

Bioenergetics (3)

Answer 5

• the study of energy changes accompanying chemical reactions
• it describes the transfer and utilization of energy in biologic systems
• it concerns only the initial and final energy states of reaction components. It predicts if it is possible

Question 6

Fundamental Law of thermodynamics (2)

Answer 6

The principal of the conservation of energy: total amount of energy in the universe remains constant

The universe always tends towards increasing disorder: in all processes, the entropy of the universe increases

Question 7

Gibbs free energy - (G)

-2

Answer 7

• the amount of energy capable of doing work during a reaction at constant temperature and pressure
• free- energy change: is a measure of the chemical energy avaiable from a reaction

Question 8

Enthalpy - (H)

-3

Answer 8

• the heat content of the reacting system
• reflects the number and kinds of chemical bonds in the reactants and products
• Exothermic (reaction releases heat), endothermic (reaction takes up heat)

Question 9

Entropy - (S)

Answer 9

-expression for the randomness or disorder in a system

Question 10

If delta G is …. the reaction will be spontaneous or not

• negative
• positive

Answer 10

• delta G negative: spontaneous

- delta G positive: non- spontaneous

Question 11

Exergonic reactions (4)

Answer 11

• when a reaction proceeds with the release of free energy.
• delta G is negative
• thermodynamically favored reactions
• mainly catabolic pathways

Question 12

Endergonic reactions (5)

Answer 12

• the system gains free energy
• delta G is positive
• thermodynamically unfavored reactions
• mainly anabolic pathways
• not spontaneous

Question 13

ΔGo (2)

Answer 13

• equal to the free energy change under standard conditions

- when reactants and products are at 1 mol/L concentrations and pH 0

Question 14

ΔG’ & coupling reactions

• definition
• example

Answer 14

• when an energetically favorable reaction is directly linked with an energetically unfavorable reaction.
• ex: hydrolysis of ATP + endergonic reaction

Question 15

Chemical structure of ATP

Answer 15

• adenine
• ribose
• 3 phosphate groups

Question 16

The standard free energy of hydrolysis of ATP is:

Answer 16

ΔGo is -7.3 kcal/ mol

Question 17

Why is ATP called a high- energy phosphate compound?

Answer 17

Because it has a large negative ΔGo

Question 18

High energy bonds

-definition

Answer 18

Any bond that can be hydrolyzed with the release of approximately as much, or more, energy than ATP

Question 19

Name

-2 high energy and 2 low energy compounds

Answer 19

• high: creatine, phosphoenolpyruvate, 1,3-bisphosphoglycerate
• low: glucose- 6 and glycerol- 3

Question 20

How is ADP converted back to ATP?

Answer 20

By the process of oxidative phosphorylation, using energy supplied by fuel oxidation or substrate level phosphorylation

Question 21

ATP can be formed from…

Answer 21

Two ADP by adenylate kinase transferring a phosphate from one ADP to another ADP to form ATP and AMP

Question 22

Extraction of energy from fuels

-steps (4)

Answer 22

1. fats, polysaccharides, proteins
2. Acetyl CoA
3. Citric acid cycle
4. Oxidative phosphorylation

Question 23

Metabolic pathways

Answer 23

Fuels are degraded and large molecules are constructed step by step in a series of linked reactions

Question 24

ATP links two types of pathways, name them

Answer 24

energy-releasing pathways with energy- requiring pathways

Question 25

What powers the formation of ATP?

Answer 25

The oxidation of carbon fuels