Chapter 3

Question 1

Metabolic pathways

Answer 1

sequence of enzymes mediated reactions leading to the formation of a particular product

Question 2

metabolic pathways can be?

Answer 2

• Linear
• circular
• Branched or all three

Question 3

metabolism
Anabolic
Catabolic

Answer 3

• Sum of all chemical processes in the cell
• needs energy
• takes complex molecules and break them down into small molecules (release of energy)

Question 4

Law of Thermodynamics

Answer 4

• 1st law - total energy in the universe is contant, energy is neither created nor destroyed
  2nd law - universe is continually moving to an increased state of entropy (msome energy becomes unavailable to use).
  3rd law as temperature approaches absolute zero, the entropy of a system approaches a costant minimum.

Question 5

Entropy (S)

Answer 5

thermodynamic quantity that measures that amount of disorder within a system (higher S means ore disorder); unusable energy within a systems.

Question 6

Two types of chemical reactions

Answer 6

1. exergonic - loses energy, products have less energy than the starting substance(s).
2. Endergonic - gains energy, products have more energy than the starting substance(s).

Question 7

Energy coupling

Answer 7

idea that energy can be transformed

Question 8

Enthalpy (H)

Answer 8

in thermodynamic systems, the measure of energy within a system; internal energy plus pressure x volume

Question 9

Gibbs Free Energy (G)

Answer 9

the usable energy of a system that can be used to drive a reaction

Question 10

In any system:

Answer 10

otal energy=usable energy + unusable energy
or:
enthalpy (H) = free energy (G) + entropy (S)
H= G + TS (T= absolute temperature)
Thus, usable energy is
G= H-TS

Question 11

Redox reactions

Answer 11

transfer the energy of electrons

Question 12

reduction

Answer 12

• A gain of one or more electrons or hydrogen atoms

Question 13

oxidation

Answer 13

• the loss of or more electrons or hydrogens atoms