Energy And Metabolism

Front 1

What produces energy from the sun?

Back 1

Plants and other phytosynthetic organisms

Front 2

Define:
Metabolism

Back 2

Sum of all chemical reactions that occur in an organism

Front 3

Define:
Metabolic Pathway

Back 3

A series of steps that converts a molecule into a product

Front 4

What catalyzes each step in a metabolic reaction?

Back 4

A specific enzyme catalyzes each specific step

Front 5

Define:
Anabolic Pathways

Back 5

Metabolic pathways that breakdown complex molecules into simpler ones

Releases Energy

Front 6

Define:
Anabolic Pathways

Back 6

metabolic pathways that build complex molecules from simpler ones.

consumes energy

Front 7

What is an example of a catabolic pathway?

Back 7

Cellular Respiration. Releases energy by breaking down glucose and other organic fuels

Front 8

What is an example of an anabolic pathway?

Back 8

Photosynthesis. Consumes energy (light) to produce glucose and oxygen

Front 9

Define:
Energy

Back 9

The capacity to do work

Front 10

What is kinetic energy?

Back 10

The energy of motion

Front 11

What is potential energy?

Back 11

stored energy

Front 12

What are the three types of energy?

Back 12

Chemical Energy, Radiation Energy, and Thermal Energy

Front 13

Define:
Chemical Energy

Back 13

The energy stored in molecular bonds

Front 14

What kind of energy is released by catabolic pathways?

Back 14

Chemical Energy

Front 15

What kind of energy is used during photosynthesis?

Back 15

Radiation Energy

Front 16

Define:
Radiation Energy

Back 16

light

Front 17

Define:
Thermal Energy

Back 17

Kinetic energy of atomic motion. Heat.

Front 18

Define:
The First Law of Thermodynamics

Back 18

Any form of energy can be converted to any other form of energy BUT is never created or destroyed.

Front 19

Define:
The Second Law of Thermodynamics

Back 19

All transfers and transformations increase the entropy of the universe.

Front 20

Define:
Entropy

Back 20

a quantity that measures disorder or randomness

Front 21

What is lost in all energy transformations?

Back 21

useful energy in the form of heat

Front 22

As heat increases atomic motion _____ increases

Back 22

entropy

Front 23

Define:
Free Energy

Back 23

The energy in a system that is available to do work. Useful energy.

Front 24

Define:
Gibb's Free Energy Equation

Back 24

ΔG = ΔH - TΔS

Δfree energy = Δtotal energy - (Kelvin temp X Δsystem's entropy)

Front 25

What happens to a system as the free energy increases?

Back 25

The system becomes less stable -> can do more work

Front 26

What happens to a system as the free energy decreases?

Back 26

The system becomes more stable -> can do less work

Front 27

How can all energy transformations be described?

Back 27

by the change in free energy

Front 28

What must happen in order for a process to occur spontaneously?

Back 28

There must be a decrease in free energy. (-ΔG)

Front 29

List:
Characteristics of an Exergonic Reaction

Back 29

-reactions that release energy
- -ΔG
- spontaneous

Front 30

List:
Characteristics of Endergonic Reactions

Back 30

- reactions that absorb energy
- +ΔG
- not spontaneous

Front 31

What are the equations for cellular respiration and photosynthesis?

Back 31

C₆H₁₂O₆ + O₂ ⇔ CO₂ + H₂O

Front 32

What can the released free energy do in a spontaneous metabolic reaction?

Back 32

The released free energy can be harnessed to do work.

Front 33

How does a cell keep its metabolic pathways from reaching equilibrium?

Back 33

By using catabolic pathways in which a series of exergonic reactions release energy. The products of one reaction are the reactants to the next.

Front 34

How do cells drive endergonic reactions?

Back 34

By using the energy released from exergonic reactions.

Front 35

Why does a phosphate molecule break off from the triphosphate group of ATP sponateously?

Back 35

Because the negative charges on the phosphate groups repel one another.

Front 36

Define:
Energy coupling

Back 36

the use of exergonic reactions to drive endergonic reactions. The overall ΔG is negative, so together the reaction is sponateous.

Front 37

Define:
Catalyst

Back 37

a substance that speeds up a reaction without being consumed or changed by the reaction

Front 38

Define:
Enzyme

Back 38

A catalytic protein

Front 39

Define:
Activation Energy

Back 39

The initial energy required to place reactant molecules in an unstable state.

Front 40

What types of molecules are most likely to undergo energy transformations?

Back 40

Unstable molecules

Front 41

What often provides activation energy?

Back 41

heat. It causes the molecules to be less stable.

Front 42

What lowers activation energy?

Back 42

enzymes

Front 43

Define:
Substrate

Back 43

reactant molecule that enzymes bind to

Front 44

Define:
Active Site

Back 44

Region of enzyme that binds substrate

Front 45

Define:
Enzyme-Substrate Complex

Back 45

combination of enzyme and substrate molecules

Front 46

Define:
Induced Fit

Back 46

When substrate binds, enzyme changes shape to hold substrate tightly

Front 47

Where does enzyme specificity arise from?

Back 47

The shape of the active site.

Front 48

How do enzymes lower activation energy?

Back 48

1. Position two substrates so that bonds can form
2. Contort substrate, creating an instability of bonds
3. Create a favorable microenvironment
4. Active site amino acids participate in reaction.

Front 49

What factors effect enzyme specificity?

Back 49

pH and Temperature

Front 50

How does temperature effect enzyme specificity?

Back 50

Low temps decrease molecular motion, making substrate-enzyme collisions less likely. High temps denature the enzyme

Front 51

How does pH effect enzyme specificity?

Back 51

enzyme denatures at too high or too low of pH.

Front 52

Define:
competetive inhibition

Back 52

Inhibitor molecule binds to active site, preventing binding of substrate.

Can be overcome by adding more substrate

Front 53

Define:
Noncompetitive inhibition

Back 53

inhibitor molecule binds to site other than active site, changing the shape of the active site, therefore not allowing binding of substate.

Cannot be overcome by adding more substrate

Front 54

Define:
Allosteric Regulation

Back 54

binding of a molecule at one site of an enzyme affects function at another site.

Front 55

Define:
Allosteric activator:

Back 55

molecule that stabilizes the active form of an enzyme

Front 56

Define:
Allosteric Inhibitor

Back 56

molecule that stabilizes the inactive form of an inhibitor

Front 57

What does allosteric regulation control?

Back 57

metabolic pathways

Front 58

Define:
feedback inhibition

Back 58

allosteric inhibition of a metabolic pathway by the product of that pathway. The end product binds inhibitorily to an enzyme that acts early in the pathway.

Front 59

What are the three stages of cellular respiration?

Back 59

1. Glycolysis
2. Citric Acid Cycle
3. Oxidative Phosphorylation

Front 60

What happens between glycolysis and the citric acid cycle?

Back 60

Pyruvate from glycolysis enter mitochondria and is converted to acetyl CoA

Front 61

What does glycolysis produce?

Back 61

1 glucose produces 2 pyruvate, 2 ATP and NADH

Front 62

What does the glycolysis/citric acid junction produce?

Back 62

2 pyruvate produce 2 acetyl CoA, 2 NADH and 2 CO2

Front 63

Where does he citric acid cycle occur and what does it require?

Back 63

The krebs cycle occurs in the mitochondrial matrix and requires oxygen

Front 64

What is the finction of the krebs cycle?

Back 64

oxidation of organic compounds derived from acetyl CoA

Front 65

How many steps are in the citric acid cycle?

Back 65

8

Front 66

How many turns of the citric acid cycle are there for every glucose?

Back 66

2 turns

Front 67

For every acetyl CoA, what does the citric acid cycle produce?

Back 67

3 NADH, 1 FADH2, 1 ATP, 2 CO2

Front 68

For every glucose, what does the citric acid cycle produce?

Back 68

6 NADH, 2 FADH2, 1 ATP, 2 CO2

Front 69

Define:
Oxidatitive Phosphorylation

Back 69

The production of ATP using energy derived from the redox reactions of an electron transport chain.

Front 70

Where does the tranformation of chemical energy come from?

Back 70

The transfer of electrons from one atom to another

Front 71

Define:
Oxidation Reduction Reaction

Back 71

the transfer of electrons from one reactant to another

Front 72

Define:
Oxidation

Back 72

Loss of electrons.

Front 73

Define:
Reduction

Back 73

addition of electrons

Front 74

Define:
Reducing Agent

Back 74

atom that loses electrons

Front 75

Define:
Oxidizing agent

Back 75

atom that gains electrons

Front 76

Describe the potential energy of polar vs nonpolar molecules

Back 76

Nonpolar- high potential energy
polar- low potential energy

Front 77

What makes oxygen a strong oxidizer?

Back 77

its high electronegativity

Front 78

Define:
Cellular Respiration

Back 78

extracting chemical energy from complex organic molecules

Front 79

How much energy does cellular respiration produce?

Back 79

686 kcal/mole

Front 80

What is the energy from cellular respiration used to produce?

Back 80

ATP

Front 81

What is the oxidizing agent of cellular respiration?

Back 81

Nicotinamide adenine dinucleotide (NAD+)

Front 82

During respiration, electrons are transferred from _____ to _____ throught the electron transport chain.

Back 82

NADH to oxygen

Front 83

How does respiration harvest chemical energy?

Back 83

Through transfer of electrons from organmic compounds to oxygen.

Front 84

Where does glycolysis occur?

Back 84

In the cytosol

Front 85

What is the only stage of respiration that does not require oxygen?

Back 85

glycolysis

Front 86

What is the function if glycolysis?

Back 86

Glycolysis breaks down glucose into two pyruvate molecules

Front 87

Glycolysis is a catabolic pathway that involves how many steps?

Back 87

10 steps

Front 88

For every glucose molecule, how many ATP are invested during glycolysis?

Back 88

2 ATP

Front 89

What is the energy payoff of every glucose molecule?

Back 89

4 ATP and 2 NADH