Unit 3 - Reactions and Enzymes (pt.2)

Question 1

Catalysis

Answer 1

Speeding up a chemical reaction, one of the fundamental functions of proteins

Question 2

Transition State Theory states

Answer 2

during a chemical rxn, there is an intermediate molecular form in which old and new covalent bonds are partially formed

Question 3

Enzymes

Answer 3

bind to substrates (reactants) in precise orientation and lowers the transition state energy needed to arrive at the transition state, thereby speeding up the rate of the reaction. Can carry out rxns over and over again.

Question 4

Enzyme or Not
1.Kinase
2.Intermediate Filament Proteins
3.Na-K+ pump
4.Ion Channel
5.Cadherin
6.Ribosome

Answer 4

1.Enzyme
2.Not
3.Enzyme (change ADP->ATP)
4.Not
5.Not
6.Enzyme
No reaction=no enzyme

Question 5

Model and Stages of Enzyme Action

Answer 5

1.Initiation: reactants bind to active site in specific orientation, forming e-s complex

2.Transition State Facilitation: Interactions between enzyme and substrate lower the activation energy

3.Termination: products have lower affinity for active site and are released. Enzyme is unchanged after the rxn.

Question 6

Active Site

Answer 6

where substrates bind in an enzyme

Question 7

Induced Fit

Answer 7

When substrate binds to active site and enzyme changes shape slightly. Results in tighter binding of substrate to active site.

Question 8

Allostery

Answer 8

process by which biological macromolecules (usually proteins) transmit the effect of binding at one site to another from a different functional site allowing for activity regulation

Question 9

Competitive Inhibition

Answer 9

substrates cannot bind when regulatory molecule binds to enzyme’s active site first

Question 10

Allosteric Activation

Answer 10

Active site becomes available to substrates when regulatory molecule binds to different site on enzyme

Question 11

Allosteric Deactivation

Answer 11

active site becomes unavailable to substrates when regulatory molecule binds to different site on enzyme

Question 12

Metabolic Pathway

Answer 12

refers to series of chemical rxns needed to get from one useful molecule to another

Question 13

Feedback Regulation

Answer 13

occurs when amount of product controls activity earlier in pathway

(too much product, goes to beginning to stop even more product)

Question 14

Stereospecific

Answer 14

a property of enzymes=only binding to one stereoisomer form of their substrates

(need correct arrangement)

Question 15

Energetic Coupling

Answer 15

driving an endergonic rxn with an exergonic rxn (like coupled transport and Hess’s Law)