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where does energy come from

sun is a key source


produces glucose + O2 ->respiration-> CO2H2O+ energy celles must capture

-energy in bonds of glucose


where glycolysis takes place

energy stored in glucose

in bonds, all cells metabolize glucose for energy

long term and storage energy

stored in glucose and fat

short term storage energy is stored in

energy carriers

how is cell energy metabolized

Input: glucose
1) glycolysis
2)respiration if there is oxygen , fermintation if there is no oxygen
Output: energy+CO2+H2O

glucose activation

energy in

energy harvest

energy out


1 glucose+2ATP-> 2 pyruvate+ 2NADH+ 4ATP net energy yield to 2ATP + 2NADH

three stages of respiration

1) pyruvate is broken in matrix down releasing energy and CO2
2) high energy electrons that travel through the electron transport chain inner membrane
3) ATP is generated by chemiosmosis

Stage 1 of cellular respiration

pyruvate is broken down releasing energy and CO2, formation of acetyl CoA-> CO2 released in this prices high energy electrons + Hydrogen transfers oxygen

krebs cycle

appears in mitcohondria
krebs consist of 1ATP,3NADH, 1FADH2

1 glucose equal _ pyruvate

two pyruvate

1pyruvate equals_


double energy from 1 glucose equals_

4NADH and 1FADH2

Stage 2 of cellular respiration

high energy electrons travel through the electron transport chain
- each electron carrier releases 2 electrons into ETC
definition: series of electron carriers in the inner mitochondria embedded membrane that extract energy from ATP synthesis.

how many electron carries are produced from 1 glucose

12= 10 NADH 2FADH2

Stage 2 of cellular respiration- electron transport chain: mechanism

electrons jump from one molecule to the next losing small amount of energy at each step

output of electron transport chain

the energy issued to pump hydrogen across the membrane space
- produce a concentration gradient of H+
low energy electrons and new transferred to O-> H2O

Stage 3 of cellular respiration: ATP is generated by chemiosmosis definition

the generation of ATP by the movement of hydrogen ions across a semi permeable membrane down the gradient

Stage 3 of cellular respiration: ATP is generated by chemiosmosis: mechanism:

high concentration of H+ diffuse across membrane then ATP synthesis channel

Stage 3 of cellular respiration: ATP is generated by chemiosmosis:Output


how would the rate of ATP production be affected by absence of energy?

It would stop because it needs O2 to produce H2O

Glucose breakdown

1) glycolysis
2)cellular respiration
3)pyruovate-> acetyl acid +CO2
4) krebs cycle
5) total 36 or 38 ATP

how is NAD+ replenished?

fermentation, provides alternate mechanism


lack of O2, how energy metabolized

how can you get more energy from your muscles?

electron transport channels exercise regiment to create more mitochondria

lactic acid fermentation

high energy electrons from NADH and H+ generate the 3C lactate from pyruvate produce NAD.

alcohol fermentation

high energy electrons form NADH and H generate 2C ethanol + CO2 from pyruvate

how much ATP is produced per NADH molecule?



primary energy carrier for cells. This energy carrier is used by almost all of the enzymes in a cell

Why do cells convert the energy stored in the bonds of glucose into energy stored in the bonds of ATP?

Glucose is not a usable energy source for most enzymes.The energy in the bonds of glucose can only be extracted by the enzymes of glycolysis and respiration. The rest of the cellular enzymes require energy in the form of an energy carrier, usually ATP.

net products of glycolysis?

two ATP, two NADH, and two pyruvate
The reaction produces four ATP, two NADH, and two pyruvate, but two ATP were used to provide activation energy.

What would happen if a cell converted all of its NAD+ into NADH?

Glycolysis would stop due to lack of a reactant.
Glycolysis requires NAD+. Storing electrons in the bonds of NADH is not an optional step

How many of the carbons originally present in glucose continue to other reactions after glycolysis?

Six carbons are left in pyruvate moleculesThe original six carbon molecules are present in two molecules of pyruvate.
Pyruvate has three carbon molecules and is taken on to respiration for further energy extraction.

For each glucose that enters glycolysis, _____ NADH enter the electron transport chain.

For each glucose molecule that enters glycolosis, a total of 10 NADH are produced -- 2 are produced in glycolysis, 2 are produced in acetyl CoA production, and 6 are produced in the citric acid cycle.

In cellular respiration, most ATP molecules are produced by _____.

oxidative phosphorylation

This process utilizes energy released by electron transport.

The final electron acceptor of cellular respiration is _____.

oxygen. Oxygen is combined with electrons and hydrogen to form water.

During electron transport, energy from _____ is used to pump hydrogen ions into the _____.

NADH and FADH2 ... intermembrane space
The energy released as electrons, which have been donated by NADH and FADH2, is passed along the electron transport chain and used to pump hydrogen ions into the intermembrane space.

The proximate (immediate) source of energy for oxidative phosphorylation is _____.

kinetic energy that is released as hydrogen ions diffuse down their concentration gradient Concentration gradients are a form of potential energy.

steps as energy is extracted from glucose during cellular respiration.

glycolysis → acetyl CoA → citric acid cycle → electron transport chain

Glycolysis produces pyruvic acid, which enters the mitochondrion. There, it is converted to acetyl CoA, which enters the citric acid cycle. Electron carriers bring electrons from the first three steps to the electron transport chain, and ATP is made.

general equation for cellular respiration?

C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + ATP energyCellular respiration extracts energy from glucose (C6H12O6) to produce smaller energy packets (ATP).

what process takes place in the cytosol of a eukaryotic cell?

Glycolysis, the breakdown of glucose into two molecules of pyruvic acid, takes place in the cytosol, outside the mitochondria.

In what organelle would you find acetyl CoA formation, the citric acid cycle, and the electron transport chain?

All of the steps of cellular respiration except glycolysis take place in the mitochondrion.

glycolysis best definition

This process splits glucose in half and produces 2 ATPs for each glucose.

citric acid cycle?

This process produces some ATP and carbon dioxide in the mitochondrion.
breaks down carbon molecules, releasing carbon dioxide and forming some ATP.


This process uses energy captured from electrons flowing to oxygen to produce most of the ATPs in cellular respiration.

How many high-energy molecules are produced in one round of the Krebs cycle?

three NADH, FADH2, and ATP

How many of the carbons originally present in acetyl CoA continue on to respiration after the Krebs cycle?

No carbons are left, all are lost as CO2.
The two carbons originally present in acetyl become two molecules of CO2.

Where have the carbon atoms orignially present in glucose gone after the Krebs cycle has been completed?

Two were lost in acetyl CoA formation and four were lost in the Krebs cycle.

What is the net gain of energy carrier molecules from glycolysis, acetyl CoA formation, and the Krebs cycle?

four ATP, 10 NADH, and two FADH2

What occurs immediately after a cell runs out of oxygen?

The electron transport chain stops.
Oxygen is used at the end of the electron transport chain to remove used, low-energy electrons.

What is a proper description of the path of hydrogen ions during the electron transport chain and chemiosmosis?

Hydrogen ions from the matrix are pumped into the intermembrane space, then flow back into the matrix through ATP synthase.
Hydrogen ions go back and forth between the matrix and the inner membrane space.

What property of oxygen allows it to form bonds with the electrons found at the end of the electron transport chain?

Oxygen forms polar, low-energy bonds.
Highly polar bonds can be formed from very low-energy electrons, like those found at the end of the electron transport chain.

What is the purpose of fermentation?

to convert NADH back into NAD+

NAD+ is necessary to perform glycolysis.

Imagine you could inject molecules into the leg muscles of a sprinter, right before a race. Which of the following would be most useful?

NAD+, A large supply of NAD+ will allow the leg muscles to rapidly run glycolysis and avoid fermentation for a time.

Why don't we use bacteria that perform lactic acid fermentation to make bread?

because lactic acid fermentation doesn't produce a gas
Ethanol fermentation from yeast produces CO2 gas, which causes the bread to rise.

How much usable energy is produced by lactic acid fermentation?

zero ATP and zero NADH
Fermentation does not produce usable energy. It actually wastes the energy in NADH to return it to NAD+ for use by glycolysis.

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