LO7

Question 1

Energy

Answer 1

The capacity to do work

Question 2

Kinetic (motion)

Answer 2

used when work is performed

Question 3

Example of Kinetic Energy

Answer 3

Na+/K+ pump uses kinetic energy when it changes shape to pump ions

Question 4

Potential (stored) energy

Answer 4

the capacity to do work due to the position or state of an object

Question 5

First Law of Thermodynamics

Answer 5

energy cannot be created or destroyed; it can only be converted

Question 6

Potential energy example

Answer 6

concentration gradients are a form of potential energy because of the position of substances across a membrane

Question 7

Open Systems

Answer 7

organisms capture energy from their environment and convert it to a usable form

Question 8

Open System example

Answer 8

during photosynthesis, plants convert light energy(a form of kinetic energy) into chemical energy (potential energy stored in chemical bonds)

Question 9

Closed System

Answer 9

does NOT exchange energy with its surroundings

Question 10

Second Law of Thermodynamics

Answer 10

entropy is continuously increasing

Question 11

Entropy

Answer 11

disorder/randomness

Question 12

Entropy increases when

Answer 12

A larger molecule is being broken down to smaller molecules

Question 13

Energy is lost in the form of ——– in energy conversions

Answer 13

heat(unusable form of energy)

Question 14

Living organisms

Answer 14

• highly ordered (low entropy)
  -require a constant input of energy (work) to maintain this order

Question 15

Metabolism

Answer 15

Sum of All Chemical Reactions in an organism

Question 16

Free Energy (G)

Answer 16

is the amount of energy available to do cellular work

Question 17

Exergonic

Answer 17

• release free energy
• products have less free energy than the reactants

Question 18

Catabolic Reactions

Answer 18

• exergonic
  -break down larger molecules into smaller ones through hydrolysis reactions
• increases entropy

Question 19

Endergonic

Answer 19

• require free energy
  -products have more free energy than reactants

Question 20

Anabolic reactions

Answer 20

• endergonic
  -synthesize larger molecules from smaller ones through condensation reactions
  ATP (energy) + small molecule = larger molecule

Question 21

Hydrolysis of ATP

Answer 21

exergonic reaction ; releases free energy than can be used by the cell

Question 22

ATP provides energy to other molecules by

Answer 22

transferring its 3rd phosphate group to another molecule

Question 23

the formation of sucrose is an anabolic endergonic reaction that cannot proceed without an energy source

Answer 23

endergonic reactions occur by being coupled to the hydrolysis of ATP

Question 24

oxidized molecules

Answer 24

donate electrons and their energy

Question 25

reduced molecules

Answer 25

accept electrons and their energy

Question 26

NADH

Answer 26

reduced form

Question 27

NAD+

Answer 27

oxidized form

Question 28

Catalyst

Answer 28

Speed up chemical reactions

Question 29

Biological Catalyst

Answer 29

- protein enzymes -RNA molecules(ribozymes)

Question 30

Enzymes

Answer 30

- highly specific (active site where their specific reactant molecules bind) -only catalyze exergonic reactions(DO NOT CHANGE FREE ENERGY)

Question 31

Activation Energy (EA)

Answer 31

is required for a chemical reaction to get started

Question 32

Enzymes work by

Answer 32

lowering the Activation Energy

Question 33

Breaks the bonds of the reactant molecules

Answer 33

Activation Energy

Question 34

Enzymes reduce the EA by

Answer 34

bringing the reactant molecules close together and putting strains on their bonds

Question 35

Substrates

Answer 35

reactant molecules once they interact with their enzyme

Question 36

Enzyme- catalyzed Reaction Steps

Answer 36

1. Substrate(s) molecule(s) binds to an enzyme active site 2.Unstable enzyme- substrate complex is formed 3. The substrate(s) is converted into one or more products which are released from the enzyme 4. The enzyme is recycled and can catalyze that same reaction over and over

Question 37

Enzyme- Substrate complex

Answer 37

- Binding changes the shape of both the enzyme and substrate(s)

Question 38

Activation energy is lowered because

Answer 38

Induced fit, shape change, puts strain on the bonds of the substrate molecule(s) and helps break existing bond(s) and form new bond(s)

Question 39

Denaturation

Answer 39

an enzyme unfolds and becomes nonfunctional

Question 40

Catalytic activity increases

Answer 40

as temperature increases

Question 41

Temperature decreases

Answer 41

catalytic activity decreases

Question 42

Enzymes under very acidic or very basic conditions

Answer 42

Enzymes denature i.e pepsin and typsin are adapted to breakdown proteins in specific pH environments, but denature outside of those environment

Question 43

What type of bond types are particularly sensitive to changes in pH?

Answer 43

ionic bonds

Question 44

Cofactors

Answer 44

- are required for an enzyme to function

Question 45

Trace elements act as cofactors by

Answer 45

binding to and activating specific enzymes (e.g MG2+, Ca2+)

Question 46

How does NADH function as a cofactor?

Answer 46

NADH activates enzymes by transferring electrons

Question 47

How does ATP act as a cofactor?

Answer 47

ATP activates enzymes by by transferring a phosphate group and some vitimins

Question 48

Feedback inhibition

Answer 48

product of one enzymatic reaction controls the activity of another enzyme in the pathway i.e as product 'D' increases in concentration, some of it will bind to and inhibit 'Enzyme 1' , this stops the pathway, preventing the cell from wasting energy making too much of D (negative)

Question 49

allosteric regulation

Answer 49

a molecule binds to an enzyme at a site other than its active site (allosteric site) this changes the shape of the active site making substrate binding possible(activation) or preventing substrate binding (deactivation) i.e protein kinase is in its inactive form until needed due to an allosteric inhibitor - camp binds to and removes the allosteric inhibitor, which activates the kinase

Question 50

Competitive inhibition

Answer 50

- molecules temporarily binds to an enzyme's active site and competes with its normal substrate i.e sulfa drugs are taken to treat bacterial infections because they inhibit bacterial growth - competitive inhibitors of the normal substrate of bacterial enzyme used to form folic acid(needed for growth)

Question 51

irreversible inhibition

Answer 51

Chemical permanently binds to an enzyme at its active site or elsewhere , making an enzyme nonfunctional i.e cyanide is deadly because it binds to an enzyme involved in aerobic respiration, preventing the formation of ATP