Ch. 9 Cellular respiration and fermentation

what is the structure of NAD+?

The molecule consists of two nucleotides (adenine and nucotinamide) joined together at their phosphate groups.

catabolism is linked to work by

a chemical drive shaft--ATP

NAD+

a coenzyme thatcycles easily between oxidized (NAD+) and reduced (NADH) states, thus acting as an electron carrier

An electron transport chain consist of

a number or molecules, mostly protiens, built into the inner membrane of the mitochondria of eukaryotic cells and the plasma membrane of aerobically respiritng prokaryotes

electron transport chain

a sequence of electron carrier molecules (membrane protiens) that shuttle electrons down a series of redox reactions that release enrgy used to make ATP

the most prevalent and efficient catabolic pathway is

aerobic respiration

cellular respiration is usually refer to _why?

aerobic respiration because of the relationship of that process to organismal respiration (animals breath oxygen)

cellular respiration includes which processes?

anaerobic and aerobic processes

At the "bottom" of the electron transport chain what happens?

at the lower-energy end O2 captures these electrons along with hydrogen nuclei (H+), forming water

What holds back the flood of electrons to a lower energy state?

barrier of activation

The main energy-yielding foods,_,are reservoirs of_

carbohydrates and fats electrons associated with hydrogen

The waste products of cellular respiration,which are_,are the raw materials for photosynthesis

carbon dioxide and water

Insted of energy being released and wasted in a single explosively step, electrons_

cascade down the chain from one carrier molecule to the next in a series of redox reaction, losing a small amount of energy with each step until they finally reach oxygen (terminal electron aceptor)

anaerobic respiration

catabolic pathway in which inorganic molecules other than oxygen accept electrons at the "downhill" end of the electron transport chains

aerobic respiration

catabolic pathway, using oxygen as the final electron acceptor in an electron transport chain and ultimately producing ATP.

The breakdown of organic molecules is _... and is_

catabolism exergonic

a redox reaction that moves electrons closer to oxygen, therefore releases

chemical energy that can be put to work

aerobic respiration is similar to_, in which who provides the fuel for respiration? who is the exhaust of this process?

combustion of gasoline food carbon dioxide and water

catabolic pathways _move flagella, pump solutes across membranes, polymerize monomers, or perform cellular work

do not directly

Some redox reactions change the degree of

electron sharing in covalent bonds

who plays a major role in the catabolic pathways?

electron transfers

Each "downhill" carrier is more_than the previous electron carrier, and thus capable of oxidizing, its "uphill" neighbor, with _ at the bottom of the chain

electronegative oxygen

At key steps of the series of steps in cellular respiration, _are stripped from the glucose

electrons

Organic compounds possess energy as a result of the arrangement of...

electrons in the bonds between their atoms

ATP is the immediate_for almost all organism function... life's currency!

energy source

Hydrogen is transferred from glucose to oxygen, but the _of the electron changes as _.

energy state hydrogen (with its electron) is transferred to oxygen

Matabolic pathways are controlled by

enzymes

who will low the barrier of activation energy in glucose? what allows this?

enzymes allows the sugar to be oxidized in a series of steps

who can carry aerobic respiration?

eukaryotic and prokaryotic cells

the breakdown of glucose is endergonic or exergonic?

exergonic

ex of catablic process

fermentation

Where does all the energy utlimately comes from?

from the sun

Compounds that can participate in exorgenic reactions can act as

fuels

Cells require_to perform their many tasks

transfusions of energy from outside sources

Electrons lose_of their potential energy when they are transferred from glucose to NAD+

very little

NAD+ is a derivated of

vitamin niacin

Life is

work

Some energy taken out in catabolic pathways from the chemical storage of molecules can be used to_; the rest is dissipated as_

work heat

Catabolic pathways_due_

yield energy to the transfer of electrons down energy gradients

from NAD+ and NADH, who is the reduced form?

NADH

what is the free energy change when one mole of glucose is breakdown?

-686 kcal per mole of glucose descomposed

What are some examples that imply the use of energy?

-Assembling polymers -Pumping substances across the plasma membrane -Moving -Reproducing

Energy flows into a systems as_and leaves as_

-Flows into as sunlight -Exits as heat

3 Key pathways of cellular respiration

-GLYCOLYSIS -THE CTRIC ACID CYCLE -OXIDATE PHOSPHORYLATION

Electrons transfer from NADH to oxygen is _reaction, which the energy is released_; What the e- transport chain allows for is _

-exergonic -explosively -gradual "fall" of electrons, and conversion of that energy to a usable form (proton gradient).

there are two important differences when cellular respiration is bringing the electrons stored on NADH to oxygen, what are these?

1st- In cellular respiration, the hydrogen reacts with oxygen is derived from organic molecules rather than H2. -2nd-Instead of occuring in one explosive reaction, respiration uses an electron transport chain to break the fall of electrons to oxygen into several energy-releasing steps.

If we supply energy by igniting glucose how much energy it releases?

686 kcal of heat per mole of glucose

Reduction

A substance gains electrons, or is reduced

Oxidation

A substance loses electrons, or is oxidized

Cellular respiration yields

ATP

to keep working, the cell must REGENERATE its supply of_from_

ATP ADP + Pi

Cellular respiration formula

C6H12O6 + 6O2----->6CO2 + 6H2O + Energy (ATP + heat)

_breaks the fuel produced in phototsynthesis (oxygen and organic molecules) generating_

Cellular respiration ATP

How does NAD+ trap electrons from glucose and other organic molecues?

Enzymes called Dehydrogenases removes a pair of hydrogen atoms (2 electrons and 2 protons) from the substrate (glucose), thereby oxidizing it. The enzyme delivers 2 electrons and 1 proton to coenzyme, NAD+.

In cellular respiration formula, who of the reactants becomes reduced?

oxygen

what the electron transport chain does?

It PUMPS H+ across the inner membrane creating a H+ gradient (potential energy).

What process produces the most NAD+ during respiration?

the oxidation of NADH

Who is the most versatile electron acceptor in cellular respiration and functions in several redox steps during breakdown of glucose?

NAD+

from NAD+ and NADH, who is the oxidized form?

NAD+

NAD+ stands for

Nicotinamide adenine dinucleotide

metabolic pathways

Sequence of chemical reactions

cellular respiration is

the oxidation of glucose and other molecules in food

So how NADH enters in the concept of electron transport chain?

The electrons removed from glucose are shuttled by NADH to the "top", higher-energy end of the electron transport chain.

What process produces the most NADH during respiration?

the reduction of NAD+

In an uncontrolled reaction, the one-step exergonic reaction of hydrogen and oxygen to form water releases a large amount of energy in the form of heat and light: explosion. In the case of cellular respiration, what happens?

The same reaction occurs in stages: an electron transport chain breaks the "fall" of electrons in this reaction into a series of smaller steps and stores some of the released energy in a form that can be used to make ATP (the rest of the energy is released as heat).

Redox reactions

Transfer electrons from one reactant to another by oxidation and reduction

In cellular respiration formula, who of the reactants becomes oxidized?

glucose

which is the sugar that cells most often use in cellular respiration?

glucose

Cellular respiration can be seen as the process of ...

harvesting chemical energy

What the electron transportation chain allows to?

it allows for is gradual "fall" of electrons, and conversion of that energy to a usable form (proton gradient).

since oxygen is so electronegative

it is one of the most potent of all oxidizing agents

In metabolic pathways the products are_to build up

less likely

In respiration, the oxidation of glucose transfer electrons to a

lower energy state, liberating energy that becomes available for ATP synthesis

catabolic pathways

metabolic pathways that released stores energy by breaking down complex molecules

A way to remember that reduction consist of the gaining of electrons is by

molecules gain electrons, thus become negatively charged so it reduces the amount of positive charge of that atom. Also steal is bad so reduction is gain (steal) electrons

when the NAD+ receives 2 electrons and 1 proton, it charge becomes_and thus it changes to_

neutral NADH

the electron transport chain directly or not directly produces ATP?

not directly

what types of molecules are the excellent fuels? why?

organic molecules that have an abundance of hydrogen because their bonds are a source of "hilltop" electrons, whose energy may be released as these electrons "fall" down an energy gradient when they are transferred to oxygen.

As an electron aceptor, NAD+ functions as an_during respiration

oxidizing agent

Catabolic pathways yield energy by

oxidizing organic fuels

aerobic respiration consumes_as a reactant along with _

oxygen organic fuels

cellular respiration consumes

oxygen and organic molecules such as glucose

Phtotsynthesis generates _used by_of eukaryotes as _for cellular respiration

oxygen and other organic molecules mitochondria fuel

The hydrogen atoms are not transferred directly to oxygen, but instead are usually

passed first to an electron carrier, coenzyme called NAD+

anaerobic respiration is carry out by

prokaryotic cells

Each electrons travels with a_-thus as _

proton hydrogen atom

chemical elements essential to life are transformed or recycled?

recycled

chemical elements essential to life are...

recycled

Energy is not_it must be_

recycled transformed

energy is not_, it must be_

recylced transformed

an electron loses potential energy when it

shifts from a less electronegative atom toward a more electronegative one

Each NADH molecule formed during respiration represents

stored energy that can be tapped to make ATP when the electrons complete their "fall" down an energy gradient from NADH to oxygen

how does the catabolic pathways that descompose glucose and other organic fuels yield energy?

the answer is based on the transfer of electrons during the chemical reactions. Thus the relocation of electrons releases energy stored in organic molecules, and this energy ultimately is used to synthesize ATP

what happens in catabolic pathways? (transformation from what to what)

the cell systematically degrades complex organic molecules that are rich in potential energy to simpler waste products that have less energy

oxidizing agent

the electron acceptor, it oxidizes another molecules by removing the molecule's electrons.

Reducing agent

the electron donor, it reduces another molecules by donating electrons to the other reactant

what happens to one proton when dehydrogenases delivers the other 2 electrons with 1 proton?

the hydrogen ion is released into the surroundings

How does electrons that are extracted from glucose and stored as potential energy in NADH finally reach oxygen?

the mix of H2 and O2, provide a spark for activation energy, and the gases combine explosively. The explosion represents a release of energy as the electrons of hydrogen "fall" closer to the electronegative oxygen atoms. Cellular respiration also brings hydrogen and oxygen together to form water.

the more electronegative the atom

the more energy is required to take and electron away from it

cellular respiration is

the most prevalent and energetically efficient catabolic pathway