Cellular Respiration

Glycolysis Energy investment: products

(-2ATP) 2 three-carbon molecules (G3P) Glyceraldehyde 3 phosphate

how much ATP is produced in oxidative and substrate- level phosphorylation

(28 oxidative phosphorylation + 4 substrate- level phosphorylation) = 32 or 30

why is phosphofructokinase so important

- (Remember) phosphofructokinase is used to catalyze fructose 6- phosphate into fructose 1, 6-bisphosphate with the use of ATP. - when this happens, the glucose HAS to go through glycolysis. (irreversible) - it's an allosteric enzyme, which can be used to regulate the rate at which cellular respiration occurs

inhibitors of phosphofructokinase?

- ATP (from pyruvate, citrate, or ETC) - citrate (citric acid cycle)

Glycolysis Energy payoff: How is ATP made

- ATP is made through oxidation reactions 1. Phosphates are added when the glucose molecule is oxidized 2. the electrons lost in oxidation create NADH 3. Enough energy is released to attach a phosphate to the end of the three carbon molecule 4. That same phosphate is then used for phosphorylation of ADP 5. ADP + P = ATP 6. Then, there's a remaining phosphate, which is also converted into ATP.

Glycolysis: energy payoff

- ATP is produced through substrate level phosphorylation - NAD+ -> NADH because of the electrons released through oxidation of glucose

Final electron acceptor in Fermentation? Aerobic respiration? anaerobic respiration?

- Alchohol Fer (acetaldehyde) - Lactic Acid Fer (pyruvate) - Aerobic (oxygen) - Anaerob (ion sulfate)

fermentation

- a catabolic pathway that produces a limited amount of ATP from glucose without the use of an electron transport chain (oxygen) and that produces either ethyl alcohol or lactic acids

what is common for fermentation, anaerobic, and aerobic?

- all go through glycolysis - 2 ATP production in glycolysis - electron carrier is NAD+ - go through substrate- level phosphorylation

Fermentation versus anaerobic respiration

- anaerobic respiration still uses the electron transport chain and has a final respiratory electron acceptor, but it's just not oxygen. - Fermentation does not use the electron transport chain. It doesn't have a final respiratory electron acceptor

NAD+

- electron carrier - electron acceptor - oxidizing agent (because it accepts electrons) - coenzyme

substrate-level phosphorylation

- enzyme catalyzed production of ATP by direct addition of a phosphate to ADP by an intermediate substrate in catabolism of glucose.

types of catabolic pathways

- fermentation - aerobic respiration

oxidative phosphorylation versus substrate-level phosphorylation

- oxidative produces more ATP than substrate - Oxidative adds an inorganic phosphate to ADP whereas substrate-level adds a phosphate to ADP from an organic (intermediate) molecule that resulted from the catabolism of glucose in glycolysis

oxidative phosphorylation

- production of ATP from the redox reactions that occur in the electron transport chain

NADH symbolizes

- trapped energy (from electrons accepted) that can be "tapped" later to create ATP when it is given to oxygen

Which of the following give off electrons to NAD+ to be transported to the electron transport chain? 1. Citric Acid Cycle 2. Glycolysis 3. Pyruvate oxidation

1 & 2

Products of the Citric Acid Cycle per pyruvate

1 ATP 2 CO2 1 FADH2 3 NADH

Citric Acid Cycle: step 4

1. CO2 is lost 2. oxidation occurs again, producing NADH 3. CoA is attached to the unstable molecule

Cellular Respiration steps

1. Glycolysis 2. Pyruvate oxidation +Citric Acid Cycle 3. Oxidative Phosphorylation

General overview of what occurs in the three steps

1. Glycolysis= breaks down glucose > pyruvate 2. A. Pyruvate oxidation= pyruvate > Acetyl CoA B. Citric Acid Cycle = Acetyl CoA > CO2 3. Oxidative Phosphorylation= electrons given off from the first two stages as NADH are given off to oxygen forming water

OK. one last time state what fermentation is

1. fermentation includes glycolysis plus the regeneration of NAD+ by giving the electrons from NADH to pyruvate. 2. then NAD+ can go back to oxidizing glucose without the use of oxygen 3. The pyruvate is then turned into either alcohol or lactic acid

What happens in glycolysis

1. glucose a 6 carbon molecule is split into 2 three carbon molecules 2. the three carbon molecules become oxidized (losing electrons and hydrogens) 3. Formation of 2 pyruvate

explain what happens in the electron transport chain in terms glucose and oxygen

1. glucose loses two hydrogens (2 electrons 2 protons) 2. 2 electrons and a proton are carried in NAD+ 3. NAD+ > NADH 4. the lone proton is lost as a hydrogen ion (H+) 5. NADH travels to the top of the electron transport chain 6. O2 is at the bottom where it will accept the electrons and the hydrogen proton. 7. results in H2O

Citric Acid Cycle: step 6

1. oxidation of succinate 2. 2 hydrogens are added to FAD making FADH2

Citric Acid Cycle: step 5

1. phosphate group replaces CoA (released) 2. Phosphate turns GDP into GTP 3. GTP has the ability of producing ATP (1 ATP is made here)

how many ATP can an FADH2 molecule make

1.5

Pyruvate molecules make

2 ATP 1 H2O 1 NADH

All together (2 pyruvates) what are the prodcuts from the citric acid cycle

2 ATP 4 CO2 2 FADH2 6 NADH

Glycolysis: energy investment

2 ATP molecules are used to start glycolysis

What are the products of Pyruvate oxidation all together (2 pyruvates, not one)

2 Acetyl CoA 2 NADH 2 CO2

FAD accepts how many electrons ? how many protons?

2 electrons 2 protons it keeps the two H+ protons unlike NADH

how many ATP can an NADH molecule make

2.5

how many hydrogens are needed to make one ATP

3

1 molecule of glucose produces ____ ATP

32

how many ATP molecules have been made so far and where do they come from?

4: 2 from Glycolysis 2 from citric acid cycle

redox-reactions

A chemical reaction involving the partial or complete transfer of electrons from one reactant to another.

what is a stimulus to phosphofructokinase?

AMP (from ADP)

products of aerobic respiration

ATP

Glycolysis: one glucose molecule can make...

ATP = 2 (net 4-2) NADH = 2 Pyruvate = 2 H2O = 2

Citric Acid Cycle: Step 1

Acetyl CoA + Oxaloacetate= citrate + CoA 1. 2 carbons from Acetyl CoA bind with oxaloacetate 2. Oaxloacetate + Acetyl form citrate 3. release CoA

The direct product of glycolysis reactions must be converted to which molecule before it can enter the Krebs Cycle?

Acetyl-CoA

Glycolysis Energy investment: phase 4

Adolase cleaves the Fructose 1- 6 bisphosphate into 2 three carbon molecules (isomers)

Cellular Respiration equation

C6H12O6 + 6O2 > 6CO2 + 6H2O

Cellular Respiration is an (endergonic/exergonic) reaction because it's delta G - free energy- is (positive/negative), which indicates that the reaction (doesn't occur spontaneously/occurs spontaneously), which means it (does need energy/ doesn't need energy)

Cellular Respiration is an exergonic reaction because it's delta G is negative, which indicates that the reaction occurs spontaneously, which means it doesn't need energy.

Citric Acid Cycle: Step 2

Citrate > isocitrate

end of pyruvate oxidation *******

Citric Acid Cycle begins now

Oxygen (O2) is used directly in which part of cellular respiration?

ETC

(T/F) The citric acid cycle and glycolysis do NOT produce ATP

FALSE. The citric acid cycle and glycolysis do produce small amounts of ATP through substrate-level phosphorylation

Glycolysis: (T/F) Glycolysis can only occur in the presence of oxygen.

False. Glycolysis can occur in the absence of oxygen, but if there is oxygen present, it then proceeds through pyruvate oxidation , citric cycle, oxidative phosphorylation. IF No oxygen is present -> Fermentation

(T/F): Since in the electron transport chain, ATP is produced because of the highly electronegative oxygen pulling the electrons down, if no oxygen was present, then no ATP would be produced.

False. It's true that the oxygen is highly electronegative and pulls down the electrons in the electron transport chain, but ATP can still be produced through fermentation ( NO ETC) or anaerobic respiration (ETC)

GDP> > _____>_____>ATP

GDP > GTP > ADP > ATP

Glycolysis Energy investment: phase 1

Hexokinase adds a phosphate to the end of the glucose molecule (-1ATP)

Citric Acid Cycle: Step 3

Isocitrate is oxidized, 1. makes one NADH first 2. Then makes a CO2

The electron carriers in citric acid cycle are

NAD+ FAD

oxidized acronym for NAD is.... because

NAD+ because the positive sign attracts a negative sign, meaning it's acting as an electron acceptor

reduced acronym for NAD is ... because

NADH because reduction means an adding of an electron and since electrons travel with hydrogens, the NAD gains a hydrogen

Cellular Respiration stated in words

Organic compound + oxygen -> carbon dioxide + water + energy

Pyruvate oxidation starting molecule: Pyruvate oxidation ending molecule:

Pyruvate Acetyl CoA

Alcohol Fermentation process

Pyruvate > release of CO2 > makes acetaldehyde > NADH releases hydrogens and electrons to acetaldehyde> ethyl alcohol > NAD+ oxidizes glucose > Pyruvate

end of Glycolysis ********

Pyruvate Oxidation begins now

what's the big idea of the ETC

The ETC shows how ATP is not made directly. Instead of energy from glucose going straight to ATP (which would cause a great loss of energy), the ETC uses electron carries (NADH & FADH2) to break the fall of energy into smaller steps which releases energy at a manageable amount

What is Cellular Respiration

The process of converting chemical energy stored in organic molecules into ATP

Which is the best description of ATP use and production in glycolysis?

There is an initial cost of 2 ATP per glucose

(T/F) Glycolysis produces 2 ATP regardless of the presence of oxygen or not

True

electron transport chain

a sequence of electron carriers molecules (membrane proteins) that shuttle electrons down a path through a series of redox reactions that release energy used to produce ATP

Chemiosmosis

an energy coupling mechanism in which H+ concentration gradient energy is used to drive the synthesis of ATP through ATP synthase. basically: ATP Synthase + electron transport chain (H+ gradient) = ATP

ATP synthase

an enzyme that produces ATP from ADP and an inorganic phosphate

Potential energy and electrons

as electrons are transfered, Potential energy is lost (released)

why does glucose yield energy ?

because it becomes oxidized, which means it loses electrons and when something loses electrons, it releases potential energy

how much ATP is produced in oxidative phosphorylation

bout 28

what is the importance of the electron transport chain

breaks the "fall" of electrons, to prevent them from giving off too much energy all at once.

How does NADH reach oxygen

by using an electron transport chain

electron transport chain + ATP synthase =

chemiosmosis

Glycolysis Energy investment: phase 5

cleavage results in Di----phosphate and Glyceraldehyde 3 phosphate (which is used in the energy payoff phase)

oxidizing agent

electron acceptor

reducing agent

electron donor

the production of ATP is (endergonic/exergonic)

endergonic

Glycolysis can be divided into two parts:

energy investment energy payoff

products of fermentation

ethyl alcohol lactic acid

NADH losing electrons to oxygen is (exergonic/endergonic)

exergonic, release of electrons, comes with a release in p.e.

fatty acids go through

fermentation bc no oxygen ? or anaerobic? (C-H-C-H body)

reduction

gain of electrons, gain of hydrogen

reducing agent in cellular respiration

glucose

Glycolysis Energy investment: phase 2

glucose -> Fructose 6- Phosphate

map out the "downhill" path taken by an electron in cellular respiration

glucose > NADH > electron transport chain > O2

when ATP is made there's a (low/high) concentration of H+ protons, which means the PH level is (low/high) or (acidic/basic)

high/ low / acidic

anaerobic respiration produces.... instead of H2O

hydrogen sulfide (H2S)

how does NAD+ trap electrons

hydrogenases removes a pair of hydrogens from glucose (2 electrons 2 protons). 2 electrons and one proton are added to NAD+, neutralizing it. The other proton is lost as an ion

In eukaryotic cells, the enzymes controlling reactions of glycolysis are:

in the cytoplasm

as electrons travel down the ETC what happens to the free energy

it drops

Citric acid cycle is also called ....

krebs cycle tricarboxylic acid cycle

Types of fermentation

lactic acid fermentation alcoholic fermentation

Photosynthesis and Cellular Respiration coupled

light energy > photosynthesis > glucose + oxygen > cellular Respiration > ATP production (released as heat energy) > CO2 + H2O > back to photosynthesis

oxidation

loss of electrons, loss of hydrogen

where does the krebs cycle take place

matrix of mitochondria

where is the ETC located

membrane of a mitochondria (cristae)

Pyruvate oxidation occurs in the _____ and is the process between the ___ and ___

mitochondria glycolysis and citric acid cycle (Krebs)

In eukaryotic cells, the enzymes controlling reactions of Krebs Cycle (citric acid cycle) are located:

mitochondrial matrix

Citric Acid Cycle: step 8

oxidation occurs, NAD+ > NADH - oxaloacetate is regenerated

Electron transport chain + Chemiosmosis =

oxidative phosphorylation

electron transport chain + chemiosmosis =

oxidative phosphorylation

which of the three steps accounts for the most ATP production

oxidative phosphorylation

end of citric acid cycle *****

oxidative phosphorylation begins now

in cellular respiration what becomes oxidized? reduced?

oxidized: glucose C6H12O6 -> 6CO2 reduced: oxygen 6O2 -> 6H2O

How does fermentation occur without the use of an electron transport chain or oxygen ?

oxidizing glucose does not need to involve an oxygen because all oxidizing means is losing electrons to an electron acceptor. So in order for fermentation to occur, it has to oxidize the NADH to become NAD+ to continue using that same NADH. the electrons lost are given to pyruvate (made in glycolysis) which is then produced into alcohol or lactic acid

oxidizing agent in cellular respiration

oxygen

Glycolysis Energy investment: phase 3

phosphofructokinase binds another phosphate to the fructose 6- phosphate. (-2ATP)

The main pupose of cellular respiration is to

produce ATP

purpose of citric acid cycle

produce reduced electron carriers

in redox reactions, the electrons travel with a ____, which can also be called a _____

proton; hydrogen

Alcohol fermentation

pyruvate is converted into ethyl alcohol in two steps 1. release of CO2--> acetaldehyde 2. Acetaldehyde is reduced by NADH to ethyl alcohol

Lactic Acid Fermentation

pyruvate is reduced directly by NADH which makes lactate , with no release of CO2

FAD is (oxidized/reduced) when turned to FADH2

reduced

glycolysis means

sugar splitting

anaerobic respiration uses another respiratory molecule called

sulfate ion

How does the mitochondria use energy released from the ETC to produce ATP ?

through chemiosmosis

How do catabolic pathways that breakdown glucose or other organic molecules yield energy

transfer of electrons; the relocation of electrons releases energy stored in organic molecules

aerobic respiration

type of catabolic pathway that produces ATP by consuming O2 and using an electron transport chain where O2 is the final electron acceptor AKA Cellular Respiration

ETC runs from

uphill to downhill

ETC explanation

uphill> downhill: electrons from an uphill molecule(reducing agent) are donated to a downhill molecule (oxidizing agent) because the uphill molecule is less electronegative than the one at the bottom. The same happens until the electrons reach an oxygen to create H2O

one turn of the citric acid cycle means what

using only one pyruvate

Citric Acid Cycle: step 7

water is added, rearranging the molecule

how is a hydrogen concentration established

when electron carriers pass through ETC complexes, hydrogens are released.

example of alcohol fermentation occurs in

yeast