Biothermodynamics

Question 1

What is anabolic?

Answer 1

small molecules assemble to form a large molecule

Question 2

What is catabolic?

Answer 2

large molecules are broken into smaller molecules

Question 3

What is exergonic?

Answer 3

free energy is released (spontaneous with - delta G)

Question 4

What is endergonic?

Answer 4

free energy is absorbed (nonspontaneous with +G)

Question 5

What is kinetic energy?

Answer 5

energy in motion (i.e., jumping)

Question 6

What is potential energy?

Answer 6

stored energy (i.e., glycogen)

Question 7

For the structure of enzymes, most are proteins, but some enzymes are made of…

Answer 7

RNA (ribozymes)

Question 8

What is an active site?

Answer 8

the area of the enzyme where the substrate binds

Question 9

What is an allosteric site?

Answer 9

a secondary location where an effector binds (effector can be activators or inhibitors)

Question 10

What is the mechanism of reactions?

Answer 10

1. substrates (aka reactants) enter the ACTIVE SITE of the enzyme
2. enzyme and substrate change shape slightly to better CATALYZE the reaction (induced fit model) PRO-TIP–> when the substrate binds the enzyme, it forms the ENZYME-SUBSTRATE complex
3. the enzyme facilitates the reaction by LOWERING THE ACTIVATION ENERGY
4. the PRODUCTS are released and the cycle repeats

Question 11

What are the characteristics of enzyme function:

Answer 11

-substrate specific
-enzymes are unchanged by the reaction
-catalyze forward and reverse rxns
-have varying functions depending on pH and temperature
-have an active site that binds substrates via induced fit

Question 12

What is competitive inhibition?

Answer 12

a substance that mimics the substrate inhibits enzyme by binding to ACTIVE SITE, thus preventing binding of substrate
-can be overcome by increasing substrate concentration
-Km increases
-Vmax stays the same

Question 13

What is noncompetitive inhibition?

Answer 13

a substance inhibits the enzyme by binding to a secondary location called the allosteric site
-substrate can still bind, but the inhibitor prevents the rnx
-Km stays the same
-Vmax decreases

Question 14

What is ATP formed by?

Answer 14

It is formed via phosphorylation, which creates energy-rich triphosphate bond (ATP formation is endergonic)

Question 15

What is ATP broken apart by?

Answer 15

It is broken apart via hydrolysis, which releases energy and phosphate (ATP hydrolysis is exergonic)

Question 16

What is Vmax?

Answer 16

the maximum velocity of the rxn at peak substrate saturation

Question 17

What is Michalis constant (Km)?

Answer 17

the substrate concentration at which the rate of the rxn is half of the maximum velocity
-inversely represents binding affinity
-small Km= less substrate needed to reach Vmax (i.e., higher binding affinity)