Exam 3

Question 1

Redox reactions

Answer 1

exchange of electrons between molecules
LEO= loss electrons oxidized
GER= gain electrons reduced

Question 2

Common redox coupling molecule

Answer 2

NADH (reduced state)
-> donates high energy electrons to other molecules
-> becomes NAD+ (oxidized state)
NAD+ can become reduced to NADH again, in a constant cycle.

Question 3

Metabolism

Answer 3

sum of all anabolic and catabolic reactions in a cell, connected in a network of reaction pathways

Question 4

Anabolic reactions

Answer 4

synthesize or “build” molecules with more bonds,
-higher free energy products
-use or store energy (endergonic)
-reduce entropy
-non-spontaneous

Question 5

Catabolic reactions

Answer 5

degrade or “break” molecules
-lower free energy products with fewer bonds
-increase entropy
-release energy (exergonic)
-spontaneous

Question 6

Second Law of Thermodynamics

Answer 6

universe always wants to increase in entropy

Question 7

First Law of Thermodynamics

Answer 7

energy can be converted from one form or another but can never be created or destroyed

Question 8

Free energy (G)

Answer 8

chemical energy available to do work and is expressed as the difference between enthalpy (total energy) and entropy.

Question 9

∆G

Answer 9

Any reaction involves a change in free energy, ∆G, between reactants and products. The direction of change in free energy tells if it is positive or negative ∆G (anabolic or catabolic).

Question 10

Enzymes

Answer 10

proteins that reduce the activation energy of a reaction

Question 11

Enzyme specificity and function

Answer 11

result of the structure (shape) of the protein. Substrates interact with enzymes at the active site, forming an enzyme-substrate complex with a close interaction through induced fit.
Enzymes are proteins

Question 12

-∆G

Answer 12

energy released
-catabolic
-lower G products
-increase entropy
-exergonic
-spontaneous (reaction keeps going)

Question 13

+∆G

Answer 13

energy required
-anabolic
-higher G products
-decrease entropy
-endergonic (stores energy)
-non-spontaneous

Question 14

Entropy

Answer 14

measure of disorder
things like to be spread out/ equilibrium
no organization
High entropy= low potential energy
Even= low potential energy
Uneven= high potential energy

Question 15

What does reaction coupling do?

Answer 15

Turns a positive delta G to a negative delta G

Question 16

NADH

Answer 16

-commonly used high energy electron carrier in metabolism
-used in electron transport chain to do work

Question 17

Photosynthesis location (light and dark reactions)

Answer 17

->it all occurs in the chloroplasts
->specifically, light reactions are in the thylakoid floating in the stroma
->dark reactions (Calvin cycle) are found in the stroma