Cellular Respiration. Homework Objectives Know the chemical formula for three-stage cellular respiration Know the differences between cellular respiration

Cellular Respiration

Homework

Objectives

Know the chemical formula for three-stage cellular respiration

Know the differences between cellular respiration and photosynthesis: What kinds of organisms perform them Where in the cell they happen Inputs Outputs Energy movement ATP and glucose’s roles

Photosynthesis Review

Summarize the main points of chemical batteries and photosynthesis in a paragraph.

Aerobic Respiration

Recall that aerobic respiration uses oxygen.

After glycolysis, some cells (humans included) can put the pyruvate through two aerobic respiration stages.

Aerobic respiration charges more ATP than anaerobic respiration.


Break down glucose, get energy… what’s the rest?

C6H12O6 + _____ -> ____ + ____ + energy


C6H12O6 + 6O2 -> 6CO2 + 6H2O + energy

What was the equation for photosynthesis again…?

Cellular RespirationGlucose is broken down in three stages, each of

which captures some of the stored energy and uses it to make some ATP molecules. Not all organisms do all 3 stages all the time. These

are the “normal” stages for heterotrophs like us, we’ll talk last about other ways to do it.

http://www.qcc.cuny.edu/BiologicalSciences/Faculty/DMeyer/respiration.html

Three stages: Glycolysis Krebs Cycle Electron Transport Chain

Glycolysis

Where glycolysis happens:

What goes into glycolysis:

What comes out of glycolysis:

Krebs CycleAlso called Citric Acid Cycle.The Krebs Cycle happens in the

mitochondria. If it only happens in mitochondria, which

organisms cannot do the Krebs Cycle?

QuickTime™ and a decompressor

are needed to see this picture.



Krebs CycleThe Krebs Cycle happens in the

mitochondria. Only eukaryotes can do it.

Krebs Cycle breaks pyruvic acids down into CO2. Remember, energy is released when bonds are

broken. This energy charges more ATP and NADH batteries.

Krebs Cycle Breaks down 2

pyruvates (3 carbons each) into 6 CO2

Charges 6 total ATP. (These ATP charges

are not all just from ATP, but are the equivalents of an ATP. Each NADH, for instance, holds two times as much energy as an ATP, so we’ll count it as just “2 ATP” to make things easier.)

Krebs Cycle

http://www.youtube.com/watch?v=lvoZ21P4JK8

http://www.johnkyrk.com/krebs.htmlThe charged ATP is used to power

cellular activities. It also charges other chemical batteries, which carry that energy to the next stage…

Electron Transport Chain

Electron Transport Chain (E.T.C.) happens along membranes inside the mitochondria.






http://www.johnkyrk.com/mitochondrion.html

http://highered.mcgraw-hill.com/sites/0072437316/student_view0/chapter9/animations.html#

ETC takes the energy from chemical batteries charged in the Krebs Cycle and glycolysis, and charges 24 ATP with it.

Electron Transport ChainThe electron transport chain works by taking energetic electrons from charged batteries like NADH and FADH2, which depowers them back to NAD+ and FAD.

These electrons are given to proteins embedded in the membranes inside the mitrochondria. The proteins use the energy they’ve received to move protons across the membrane, out of the matrix.

Electron Transport ChainThe protons are now highly

concentrated in the intermembrane space and not concentrated in the matrix, and they want to reach equilibrium again. Another protein in the membrane called ATP synthase lets them do that, using their movement like a water wheel uses water.


The protons moving down along the ATP synthase to get back where they started “turns the wheel,” which churns out ATPs.

At the end, oxygen gets rid of the low-energy electrons that are left over, combining with hydrogen ions to make water. Water = electron transport chain waste product.


http://www.qcc.cuny.edu/BiologicalSciences/Faculty/DMeyer/respiration.html

Cellular respiration charges 36 ATP total using the energy in one glucose.

_______ + ____ -> _____ + _____ + 36 ATP

Cellular Respiration Review

Summary sentence of aerobic cellular respiration: Stage 1:

Stage 2:

Stage 3:

Cellular Respiration ReviewCellular respiration is breaking down glucose to

get energy. Glycolysis (in the cytoplasm)

Glucose (C6H12O6) broken down into two three-carbon molecules, pyruvic acid. Charges some batteries: 6 ATP and some medium-sized “bad” batteries that go to Electron Transport Chain.

Krebs Cycle (in mitochondria) The 2 pyruvic acids are broken down into 6 CO2. Charges

some batteries: 6 ATP and some medium-sized “bad” batteries that go to Electron Transport Chain.

Electron Transport Chain (in mitochondria) Medium-sized “bad” batteries are decharged, that energy

charges 26 ATP.

Other pathways

A final word:Glucose is not the only way to get and

store energy. Other things we eat that we might get energy from?

Other pathways Pyruvic acid can be converted back into glucose or

glycogen, but once you’re in the Krebs cycle, you can’t go back.

Lipids, glycogen, protein are other long-term energy molecules besides glucose. Glycogen is a chemical battery, stores energy long-term in

the liver. Can be an alternative outcome instead of going through glycolysis to get pyruvic acid.

Lipids are good for storing energy, proteins not so much. Glucose energy can be stored as a lipid, instead of going

through the Krebs cycle and electron transport. Proteins aren’t good for storage, but they can be broken down

for energy if needed.

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Cellular Respiration. Homework Objectives Know the chemical formula for three-stage cellular respiration Know the differences between cellular respiration