Enzymes and Reactions

Question 1

Metabolism

Answer 1

All chemical reactions in an organism
Necessary for obtaining the energy for all other aspects of life

Question 2

Catabolic

Answer 2

Reactions that break down complex molecules

Question 3

Anabolic

Answer 3

Reactions that build up complex molecules

Question 4

Describe the

Energy of Metabolic Reactions

Answer 4

Catabolic - breaks down molecules and releases energy; exergonic
Anabolic - builds up molecules and requires the input of energy; endergonic

Question 5

Define

Energy

Answer 5

Capacity to cause change
Ability to do work
Ability to move matter

Question 6

Two categories of energy

Answer 6

Kinetic and Potential

Question 7

Define

Kinetic Energy

Answer 7

Energy of moving objects

Question 8

Define

Potential Energy

Answer 8

Energy of position, which can transform to kinetic energy

Question 9

Chemical Energy

Answer 9

Potential energy related to the chemical bonds of compounds

Question 10

First Law of Thermodynamics

Answer 10

Energy cannot be created or destroyed

Question 11

Second Law of Thermodynamics

Answer 11

Entropy increases every time energy is transferred or transformed

Question 12

Define

Entropy

Answer 12

Disorder / randomness
Constantly increases

Question 13

Exergonic

Answer 13

Reactions where the reactants have more potential energy than the products
Energy is released

Question 14

Endergonic

Answer 14

Reactions where the products have more potential energy than the reactants
Energy must be absorbed

Question 15

What can you determine about this reaction?

Question 16

What can you determine about this reaction?

Question 17

Stability, energy, and entropy

Answer 17

”

Simplest molecules have the least potential energy, most entropy, and are the most stable

Building molecules requires the input of energy, a decrease in entropy, and increases order

”

Question 18

ATP

Answer 18

”

Adenosine tri-phosphate

Hydrolysis of ATP to ADP releases energy that can be coupled with endergonic reactions

”

Question 19

Describe this molecule

Answer 19

”

Adenosine tri-phosphate

Nitrogenous base = Adenine

Ribose

Adenine and ribose makes adenosine

Three phosphate groups; the last phosphate is easily removed to release energy

”

Question 20

ADP

Answer 20

”

Adenosine di-phosphate

Phosphate group can be added via dehydration reaction to make ATP to “store” energy

”

Question 21

Define

Enzyme

Answer 21

Biological catalyst

Question 22

Properties of

Enzymes

Answer 22

Reduce activation energy
Increase the rate of chemical reactions
Specific to one reaction
Made of proteins or RNA

Question 23

Activation energy

Answer 23

The energy required to break bonds in the reactants of a reaction
Energy needed to start a chemical reaction

Question 24

Describe this graph

Answer 24

Black line = Reaction without an enzyme present; activation energy is energy above the dotted line
Red line = Reaction with an enzyme present
Difference between reactants and products is NOT changed!

Question 25

## Footnote **How enzymes work**

Answer 25

1. Can allow for proper orientation of particles 2. Stresses covalent bonds 3. Creates a better environment for the reaction to occur

Question 26

## Footnote *Define* **Substrate**

Answer 26

Reactant that binds to an enzyme to react

Question 27

## Footnote *Define* **Active site**

Answer 27

Part of enzyme that binds substrate

Question 28

## Footnote *Describe the* **Induced Fit Model**

Answer 28

The binding of the substrate to the active site causes a change in the enzyme, enabling it to work

Question 29

## Footnote *How are enzymatic reactions affected by* **Temperature**

Answer 29

" Low temp: Low reactions due to fewer collisions 
Optimal temp: Highest rate of reactions 
High temp: Low enzyme activity because enzyme denatures "

Question 30

## Footnote *How are enzymatic reactions affected by* **pH**

Answer 30

" Too acidic or too alkaline: Low enzyme activity because enzyme denatures 
Optimal pH: Highest rate of reaction "

Question 31

## Footnote *How are enzymatic reactions affected by* **Enzyme concentration**

Answer 31

Increasing enzyme increases overall rates of reactions in cells (assuming excess substrate)

Question 32

## Footnote *How are enzymatic reactions affected by* **Substrate concentration**

Answer 32

Increasing substrate concentration increases overall rates of reactions *until enzymes are saturated* at which point the reaction rate will level off

Question 33

## Footnote *How are enzymatic reactions affected by* **Cofactors**

Answer 33

Increase rate of reactions

Question 34

## Footnote *How are enzymatic reactions affected by* **Competitive inhibitors**

Answer 34

" Decrease/stop reactions 
Increasing substrate concentration can increase reaction rate "

Question 35

## Footnote *How are enzymatic reactions affected by* **Allosteric regulators**

Answer 35

" Decrease/stop reactions 
Substrate concentration does not affect reaction rate "