biothermodynamics

Question 1

chemical rxns and energy

Answer 1

determined by concentration of reactants and products

Question 2

anabolic

Answer 2

small molecules assemble to form larger molecule

Question 3

catabolic

Answer 3

large molecules are broken into smaller molecules

Question 4

exergonic

Answer 4

free energy is released
spontaneous with -G

Question 5

endergonic

Answer 5

free energy is absorbed
nonspontaneous +G

Question 6

ATP hydrolysis is exergonic or endergonic?

Answer 6

exergonic&raquo_space; then facilitates endergonic rxns

Question 7

kinetic energy

Answer 7

energy in motion

Question 8

potential energy

Answer 8

stored energy
i.e. glycogen

Question 9

structure of enzymes

Answer 9

most are proteins but some enzymes are made of RNA (ribozymes)

Question 10

active site

Answer 10

area of the enzyme where the substrate binds

Question 11

allosteric site

Answer 11

secondary location where an effector binds
effectors can be activators or inhibitors

Question 12

mechanism of rxns (for enzymes)

Answer 12

1. substrate (reactant) enters the active site of the enzyme
2. enzyme and substrate change shape slightly to better catalyze the reaction - forms the enzyme-substrate complex
3. enzyme facilitates the rxn by lowering the activation energy
4. products are released and the cycle repeats

Question 13

enzyme function

Answer 13

act as catalysts by lowering activation energy needed for a reaction

Question 14

what does lowering the activation energy do the rxn

Answer 14

increases rate of the rxn / makes it go faster

Question 15

characteristics of enzyme function:

Answer 15

• substrate specific
• enzymes are unchanged by the rxn
• catalyze forward + reverse rxns
• have varying function depending on pH and temp
• have an active site that binds substrates via induced fit

Question 16

competitive inhibition

Answer 16

substance that mimics the substrate inhibits enzyme by binding to active site thus preventing binding of substrate

Question 17

how to overcome competitive inhibition?

Answer 17

increasing substrate concentration

Question 18

what happens to Km and Vmax with competitive inhibition

Answer 18

Km increases
Vmax stays the same

Question 19

noncompetitive inhibition

Answer 19

substance inhibits the enzyme by binding to a secondary location called the allosteric site
substrate can still bind but the inhibitor prevents rxn

Question 20

what happens to Km and Vmax with noncompetitive inhibition

Answer 20

Km stays the same
Vmax decreases

Question 21

ATP

Answer 21

source of chemical energy
stores energy generated from the exergonic rxns in the ETC that can then be used to fuel endergonic rxns

Question 22

how is ATP formed

Answer 22

phosphorylation - which creates energy rich triphosphate bond (ATP formation is endergonic)

Question 23

how is ATP broken apart

Answer 23

hydrolysis - releases energy and phosphate (ATP hydrolysis is exergonic)

Question 24

what is Vmax

Answer 24

maximum velocity of the rxn at peak substrate saturation

Question 25

what is Km

Answer 25

substrate concentration at which the rate of the rxn is half of the max velocity

Question 26

what does Km inversely represent

Answer 26

binding affinity