An introduction to metabolism (ch 8)/cellular respiration & fermentation (ch 9)

The free-energy change of a reaction tells us whether or not the reaction occurs spontaneously (8.2)

ATP powers cellular work by coupling exergonic reactions to endergonic reactions (8.3)

An organism's metabolism transforms matter & energy, subject to the laws of thermodynamics

Enzymes speed up metabolic reactions by lowering energy barriers (8.4)

spontaneous energy/non-spontaneous

entropy

free energy

enthalpy

energy that can do work when temperature and pressure are uniform, as in a living cell

Anabolic

Catabolic

metabolism

energy

Metabolism is the totality of an organism’s chemical reactions. Metabolism is an emergent property of life that arises from orderly interactions between molecules

Anabolic means consuming energy to build complex molecules from simpler ones

Catabolic means releasing energy by breaking down complex molecules into simpler compounds.

the synthesis of glucose

sugars joining together to form glycogen

the synthesis of protein from amino acids

the breakdown of glucose
in the presence of oxygen

Cellular respiration

fatty acids forming a triglyceride

A + B = AB

AB = A + B

the capacity to cause change; some forms of energy do work by moving matter

potential energy

the energy that matter possess based as a result of its location or structure (stored energy).

kinetic energy

energy associated with the relative motion of objects (energy in motion)

thermal energy

heat (thermal energy in transfer from one body of matter to another)

temperature (a measure of the average kinetic energy of the molecules in a body of matter)

chemical energy

Gibs free energy equation

laws of thermodynamics

According to the first law of thermodynamics, the energy of the universe is constant, energy can be transferred and transformed, but it cannot be created or destroyed.

According to the second law of thermodynamics, every energy transfer or transformation increases the entropy of the universe; entropy is a measure of molecular disorder, or randomness. Stating as energy changes from one form to another, disorder in a closed system increases.

ΔG = ΔH – TΔS

ΔH: the change in enthalpy (change in total energy)

ΔS: change in entropy

ΔG: change in free energy

T: temperature in Kelvin units

spontaneous energy: A reaction that occur without energy input; they can happen quickly or slowly

Reactions don’t normally happen spontaneously because some reactions need energy and have less entropy than others

ΔG is negative for all spontaneous processes, as no energy would be required

processes with zero or positive ΔG are never spontaneous, as energy would be required

Entropy is a measure of molecular disorder, or randomness

the system's internal energy plus the product of its pressure and volume

ATP is composed of ribose (a sugar), adenine (a nitrogenous base), and three phosphate groups

When ATP is hydrolyzed, Energy is released from ATP when the terminal phosphate bond is broken. This release of energy comes from the chemical change to a state of lower free energy, not from the phosphate bonds themselves.

ATP becomes ADP after it is hydrolyzed, it becomes “recharged” through the addition of a phosphate to ADP

mechanical

transport

chemical

ATP facilitates these activities as the exergonic process of ATP hydrolysis is used to drive an endergonic process

Through energy coupling, the exergonic process of ATP hydrolysis drives endergonic reactions by transfer of a phosphate group to specific reactants, forming a phosphorylated intermediate

Regulation of enzyme activity helps control metabolism (8.5)

An Enzyme is a protein that is often called a catalyst

Enzymes can only affect very specific reactions through the use of an active site & induced fitting ( the tightening of the binding between a substrate and an enzyme)

Two major environmental factors can hinder an enzyme’s ability to function

temperature

pH level

Enzyme-substrate complex: when the enzyme binds to its substrate

Substrate: The reactant that an enzyme acts on

Active site: refers to the specific region of an enzyme where a substrate binds and catalysis takes place

Enzymes are regulated in an organism through, In feedback inhibition

competitive inhibitor

Enzymes are regulated in an organism through allosteric regulation

noncompetitive inhibitator

Cooperativity is a form of allosteric regulation that can amplify enzyme activity as, One substrate molecule primes an enzyme to act on additional substrate molecules more readily

occurs when a regulatory molecule binds to a protein at one site and affects the protein’s function at another site.

the end product of a metabolic pathway shuts down the pathway, as feedback inhibition prevents a cell from wasting chemical resources by synthesizing more product than is needed.

binds to the active site

does not bind to the active site

intermediate step (9.2)

glycolysis (9.1)

Reactants

2 ATP

1 Glucose

products

2 Pyruvate

4 ATP

2 NADH

reactants

products

2 Pyruvate

2 Acetyl CoA

2 CO2

2 NADH

citric acid cycle (9.3)

reactants

products

2 Acetyl CoA

2 ATP

6 NADH

2 FADH2

4 CO2

releases stored energy through the oxidation of acetyl-CoA derived from carbohydrates, fats, and proteins, into adenosine triphosphate and carbon dioxide

Oxidative Phosphorylation and Electron Transport Chain (9.4)

reactants

product

10 NADH

Up to 34 ATP

2 FADH2

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In the electron transport chain, electrons are passed from one molecule to another, and energy released in these electron transfers is used to form an electrochemical gradient.

Glycolysis is a sequence of ten enzyme-catalyzed reactions

transforms glucose into pyruvate acid

between glycolysis and Krebs cycle

Acetyl coA formed by the removal of -CO2 & H+ from pyruvic acid