9.1 oxidizing organic molecules

the flow of energy into an ecosystem

comes in as sunlight and leaves as heat

ATP is used instead of food molecules

ATP produces the right amount of Kilo calories instead of the overly large amount that food molecules produces. reactions do not need a lot of energy, so its good to split it smaller

catabolic pathways

breaks high energy less complex molecules into lower energy less complex molecules

organic compounds possess potential energy as a result

of the arrangement of electrons in the bonds between atoms

compounds that can act as fules

compounds that participate in exergonic reactions

energy transfers

plays a major role in the release of energy via these pathways

organic compounds posses potential energy

as a result of the arrangement of electrons in the bonds between atoms

with the help of enzymes to catalyze exergonic reactions

a cell systematically degrades complex organic molecules that are relatively high in potential energy into simple molecules

Some of the energy extracted from

higher energy organic molecules can be used to do work while the rest dissipates as heat

cellular respiration

transforms larger molecules into ATP and smaller waste molecules

Areobic Respiration

requires the presents of oxygen (O₂)

Anaerobic Respiration

Similar to aerobic but does not require the presents of oxygen

Fermentation

a partial degradation of sugar that does not require the presents of oxygen, but it yeilds very little ATP

what is this

the basic process for the conversion of compounds into energy

Why is glucose often the example for the organic compound broken down for ATP

it is helpful to trace cellular respiration

what releases the energy stored in molecules

the transfer of the repositioning of electrons during chemical reactions

Electrons in chemical bonds posses potential energy based on

their position within the bond

during a catabolic reaction when electrons are either

transferred from one reactant to another or repositioned energy is released

chemical reactions that transfer electrons between reactants are called

oxidation reduction reactions or redox reactions

Oxidation

a substance loses electrons or is oxidized

reduction

a substance gains electrons or is reduced (the amount of positive chnarge is reduced)

LEO says GER

Lose electrons oxidize gain electrons reduced

In NaCL

Na becomes oxidized and loses an electron, Cl becomes reduced and gains electrons

what is the reducing agent

Xe- is the electron donor

What is the oxidizing agent

(Y) is the electron acceptor

some redox reactions do not transfer electrons but

Change how the electrons are shared within covalent bonds

the reaction releases energy to the surrounding because the

electrons lose potential energy when they end up being shared unequally spending more time near more electronegative atoms

During aerobic cellular respiration

C₆H₁₂O₆ is oxidized and O₂ Is reduced

Organic molecules with an abundance of electrons associated with hydrogen atoms

are excellent high energy energy fuels, because they have equally shared electrons that become less equally shared

NAD+

coenzyme, that is formed first from the electrons from organic compounds

as an electron acceptor NAD+ functions

as an oxidizing agent during cellular respiration

When NAD+ accepts electrons and is reduced it becomes

NADH and represents stored energy that can be tapped to syntheize ATP

what is this

the synthesis of NADH

what is this

NAD+

what reduces NAD+ to NADH

the enzymatic transfer of 2 electrons and one proton (H+) from an organic molecule in food to NAD+ reduces the NAD+ to NADH the second proton (H+) is released most of the electrons are transferred initially to NAD+

NADH passes the elctrons to the electron transport chain which consists of a number of molecules located

in the inner mitochondrial membrane

the electron transport chain

passes electrons in a series of steps

Electrons removed from glucose are shuttled

by NADH to the higher energy end of the chain

at the “bottom” or lower energy end

O₂ captures these electrons along with hydrogen (H+) to form H₂O

energy yielded form the transfers is used to

regenerate ATP

what does this show

during aerobic cellular respiration most electrons travel the following energetically downhill route

what is this

an uncontrolled reaction

what is this

cellular respiration

Harvesting energy from glucose has three stages

1) Glycolysis

• Brakes glucose into two molecules of pyruvate

2) the citric acid cycle

• completes the breakdown of glucose

3) oxidative phosphorylation

• accounts for most of the ATP synthesis

what cycle is this

Aerobic cellular respiration

the process that generates the most ATP

is oxidative phosphorylation

why is oxidative phosphorylation the best producer of ATP

it is powered by redox reactions and oxygen must be present

what percent of ATP is produced by oxidative phosphorylation

90%

A smaller amount of ATP is formed by

substrate-level phosphorylation, which does not require oxygen

for each molecule of glucose degraded how much ATP was formed

32 molecules of ATP

what is this

some ATP is made by direct phosphate group transfer from organic substrate to ADP by an enzyme. Only way that ATP is formed during glycolysis and citric acid cycle