Enzymes

Question 1

Thermodynamics doesn’t adress

Answer 1

Reaction speed

Question 2

Table sugar breakdown

Answer 2

No reactions in the bag, it does in the cells because there are enzymes present

Question 3

Chemical reaction occur when

Answer 3

Bonds are broken or established

Question 4

Activation energy (Ea)

Answer 4

The initial energy investment required to start a reaction

Question 5

Transition state

Answer 5

The necessary Ea was gained. Bonds are unstable and ready to be broken

Question 6

What provides Ea

Answer 6

Particles natural movement or one reaction provides energy for another

Question 7

Too much energy

Answer 7

Creates to much movement, leading to too much heat, which causes too many reaction and there is often burning (propane)

Question 8

Why biology cannot use heat as Ea

Answer 8

Heat destroys the cell (specifically proteins) by destroying the structure
All reactions in the cell would start, killing the cell

Question 9

Catalyst

Answer 9

Used in biology. A chemical agent that speeds up a reaction without taking part in it.

Question 10

The most common catalyst

Answer 10

Enzymes

Question 11

Importance of the transition state

Answer 11

A kinetic barrier as only some molecules have enough energy to react. Allows reactions to go one at a time

Question 12

Enzymes job

Answer 12

Lower the transition state so more molecules can react. The do not alter thermodynamics or provide energy for a reaction

Question 13

Substrates

Answer 13

The reactant an enzyme works on

Question 14

Enzyme specificity

Answer 14

Each enzyme can only catalyze one of a couple similar molecules. This is why there are many enzymes per cell

Question 15

Active site

Answer 15

The location on the enzyme where the catalysis takes place. A grove is formed when the protein folds, a very small section of the enzyme

Question 16

Lock and key theory

Answer 16

Substates (keys) use the lock (Enzyme) to unlock the door (start a reaction) this is an old theory from the 1900’s

Question 17

Induced fit hypothesis

Answer 17

Current view on enzyme function. Before a substrate bonds an enzyme goes though conformation so the active site is the most precise shape

Question 18

Conformation

Answer 18

The process of an enzyme changing shape

Question 19

Enzyme cycle

Answer 19

The process of grabbing substrates, catalyzing them, releasing them…

Question 20

Cofactor

Answer 20

A non protein group that binds to an enzyme. Often a metal in which very little is required for catalysis

Question 21

Cofactor metals

Answer 21

Fe, Cu, Zn, Mn

Question 22

Coenzyme

Answer 22

A cofactor made of organic molecules, often derived by a vitamin

Question 23

3 ways enzymes lower Ea

Answer 23

Bring reactant molecules together
Exposing the molecule to altered changed environments
Changing the shape of the substrate molecule

Question 24

Bring reactant molecules together

Answer 24

Makes them collide in the right orientation so there is a reaction

Question 25

Exposing the molecule to altered changed environments

Answer 25

Active sites may contain ionic group with positive or negative charges

Question 26

Changing the shape of the substrate molecule

Answer 26

Strain the molecule into a conformation that mimics the transition state

Question 27

Without enzymes

Answer 27

Reactions would still happen, just not frequently

Question 28

Factors that effect enzyme activity

Answer 28

Substrate and molecule concentration, temperature, pH

Question 29

Common way to study enzymes

Answer 29

Rate of reaction by the enzyme and how it changes in response to experimental parameters

Question 30

Procedure

Answer 30

Purify the enzyme from the cell, incubate it in a buffered solution, five the reaction a substrate, look at the rate of the product being formed

Question 31

Excess substrate

Answer 31

Rate of catalysis is proportional to the amount of enzyme. The amount of enzymes limits the reaction

Question 32

Constant enzyme concentration- low to high concentration

Answer 32

Low- few collisions, few reactions As it increases it is linear until the maximum amount of an enzyme can be catalysis is reached. Then concentration has no effect

Question 33

Saturated with substrate

Answer 33

When the catalyic cycle is going as fast as possible

Question 34

Competitive regulation (competitive inhibition)

Answer 34

When molecules that resemble substrates, and substrates fight for the same active sight

Question 35

Strength of competitive regulators

Answer 35

Some are covalently bonded, strong and irreversible | Non covalent bonds are weaker and reversible, can be overcome by high substrate concentration

Question 36

Cyanide

Answer 36

An inhibitor that prevents cellular respiration.

Question 37

Drugs are..

Answer 37

both helpful and harmful inhibitors

Question 38

Non competitive regulation

Answer 38

Competitors interact with the parts of the enzyme that are not the active site. Can increase of decrease enzyme function

Question 39

Allosteric site

Answer 39

A irreversible bond on this site controls enzyme activity

Question 40

Allosteric enzyme

Answer 40

An enzyme controlled by a allosteric site. Can have a high or low affinity state

Question 41

High affinity state

Answer 41

Enzyme binds strongly to the substrate

Question 42

Low affinity state

Answer 42

Enzyme binds weakly to the substrate

Question 43

Allosteric inhibitor

Answer 43

Converts an enzyme from high to low affinity

Question 44

Allosteric activator

Answer 44

Converts an enzyme from low to high affinity

Question 45

How cell reactions are controlled

Answer 45

1. Abundance of specific enzymes 2. Allosteric control 3. Covalent modification

Question 46

Abundance of specific enzymes

Answer 46

The amount of enzymes is regulated by gene expression (only how many is needed is made). Can take up to 30 minutes

Question 47

Allosteric inhibitors are...

Answer 47

A form of feedback inhibition

Question 48

Feedback inhibition

Answer 48

If too much of a product is made, it becomes an inhibitor for its own reaction. When not enough is present the inhibitors leave and the reaction starts again

Question 49

Multi step feedback inhibition

Answer 49

The product inhibits the production of the starting product to avoid wasting intermediate products

Question 50

pH of enzymes

Answer 50

Each function in a specific pH and the farther from their optimum the less they work. Outside of the range the charge groups differ (H+ and OH- concentration)

Question 51

Most enzymes pH

Answer 51

7 because that is what cells sit at

Question 52

Pepsin

Answer 52

An enzyme with a ideal pH of 1.5 because it lives in the stomach

Question 53

Trypsin

Answer 53

An enzyme with an ideal pH of 8 because it lives in the small intestine

Question 54

Effects of temperature

Answer 54

1. Reactions naturally increase as temp increases | 2. With more, stronger collisions enzymes may become dismembered

Question 55

Denaturation

Answer 55

The enzyme unfolding. Occurs when the amino acids start moving and more collisions in high heat.

Question 56

0-40 c

Answer 56

Reaction rate doubles for every 10 increase

Question 57

Above 40

Answer 57

Denaturation causes a level peak, then falls to 0.

Question 58

Most enzymes peak temperature

Answer 58

40-50, and drop around 45-55

Question 59

Corn enzymes

Answer 59

Peak at 30 and is harmed above that. Hot days are bad for corn