Cellular Respiration!

Cellular Respiration!

(It's pretty cool.)

Open Ended

First, tell me about your weekend/Halloween!

Poll

How many stages do you think are in cellular respiration?

• 1

• 2

• 3

Poll

What do you think is the final product of cellular respiration?

• glucose

• ATP

• ADP

Poll

Where do you think cellular respiration happens in Eukaryotes?

• mitochondria

• nucleus

• endoplasmic reticulum

Poll

Do only animal cells complete cellular respiration?

• yah

• nah

Cellular Respiration happens in three phases. (some texts argue 4, but we're going with three.)

• Glycolysis

• Kreb's Cycle

• and the Electron Transport Chain

Open Ended

What do you see here? What's going on? Please think deeper than just "glycolysis."

Glycolysis- The first step of Cellular Respiration

• Glycolysis means "splitting glucose."

• In order for the cell to get usable energy (ATP) from glucose, it must first be broken down or "split." Split glucose is called Pyruvate.

• This step happens in the cytoplasm.

• To start Glycolysis, the cell must use 2 ATP, but the process of Glycolysis yields 4 ATP (so, net gain of 2 ATP.)

• In addition to making 2 ATP, 2 NADH is made (another energy carrying molecule) which is used later in cellular respiration. 

Glycolysis in more detail

• Glycolysis breaks down glucose into a 2 molecules of pyruvate, or pyruvic acid

• 2 "uncharged" NAD+ (no hydrogen attached) are also used in glycolysis that will become 2 "charged" molecules of NADH

• 2 ATP start gycoloysis, but 4 our produced in this first step.

Multiple Choice

Why does the cell need to split glucose?

• Glucose is an unstable molecule.

• Energy stored in glucose is too great to be usuable as is, so it must be reduced through glycolysis.

• Glucose is toxic to the cell, so breaking it down prevents any damage.

Multiple Choice

Where does Glycolysis happen?

• In the Nucleus

• In the Mitochondria

• In the Cytoplasm

Multiple Choice

Along with some ATP, what other molecule is produced in glycolysis?

• NADH

• ADP

• FADH

Multiple Choice

What is the name of the molecule created from the split glucose?

• Citrate

• Phosphate

• Pyruvate

The Kreb's Cycle

• Stage II is called the Krebs cycle, It happens in the mitochondria.

• The Kreb's cycletakes the pyruvate made in glycolysis and splits it further; whilesimultaneously combining it with a co-enzyme called CoA. This gives us acetyl-CoA.

• Other secondary molecules form in the Kreb's cycle that release energy. They are the molecules NADH, ATP, and FADH2 take and hold this energy for the final step of Cellular Respiration.

Kreb's, cont.

• When pyruvate is broken down and combined with CoA to become AcetylCoA, it releases a carbon group that binds with oxygen in the mitochondria.

  • This is where CO2 is released

• The Kreb's cycle is a series of reactions that charge energy carrying molecules, they are "charged" in a way that they can be used in the final stage to generate lots of ATP.

• These molecues are NADH, ATP, and FADH2.

Multiple Choice

Where does the Kreb's Cycle take place?

• Nucleus

• Mitochondria

• Cytoplasm

Multiple Choice

The Kreb's cycle breaks down pyruvate further to release a carbon molecule. What happens to that carbon?

• It bonds with 2 oxygen molecules to form carbon dioxide.

• It gets transferred to ATP.

• It re-enters the cycle.

Multiple Choice

What is the whole point of the Kreb's Cycle?

• To store pyruvate acid from glycolysis.

• To generate energy storing molecules that will be used in the last stage of CR.

• To produce carbon dioxide as a biproduct of CR.

Multiple Select

What energy storing moleucles are made in the Kreb's cycle? (Check all that apply.)

• ATP

• NADH

• FADH2

• CO2

Phase 3: Electron Transport Chain (oxidative phosphorylation)

• Here's where we see the bulk of ATP made! All the previous reactions and steps lead to the amount of energy made here on the ETC.

  those "super-charged" molecules (FADH2 and NADH) will now release their high-powered electrons.

• The ETC lies along the inner-membranes of the mitochondria. (CRISTAE)

• Oxygen finally comes into play, it acts as the final electron acceptor so the ETC can finish its series of reactions. It binds with hydrogen in this acceptance, to form water molecules.

Look at the inner membrane!

• The ETC is a series of reactions that release electrons from the NADH and FADH2. These electrons form an electric gradient, and eventually power the protein pump ATP Synthase.

• One cycle of Cellular Respiration is finished, 32-34 ATP are produced.

• (Not every cycle produced the same number of ATP, that is an average.)

Multiple Select

What molecules from previous steps in cell respiration are used in the electron transport chain? Check all that apply.

• C6H12O6

• NADH

• FADH2

• H20

Multiple Choice

Where is the electron transport chain located?

• nucleus

• stroma

• cytoplasm

• Inner-mitochondrion membrane

Multiple Choice

True or False? Each cycle of CR makes the same amount of ATP everytime.

• True

• False

Multiple Choice

Where does oxygen come into play in the electron transport chain?

• It bonds to ATP to stabalize it.

• It is the final electron acceptor in the ETC, generating water as a biproduct.

• It diffuses out of the cell to end Cellular respiration.

CR without Oxygen: Anerobic Respiration

Some organisms can undergo glycolysis and then generate ATP without then using the Krebs Cycle or the ETC.

Anerobic, cont.

• When oxgen is not present, pyruvate can't be turned into acetyl-coA, and subsequently, the Kreb's cycle and ETC cannot happen.

• Instead, the pyruvate goes into fermentation, meaning it is broken down into another molecule to release ATP. In animal cells, this new molecule is called Lactic Acid.

Anerobic, aka Fermentation isn't that efficient!

• Anerobic makes far less ATP than aerobic respiration. Lactic acid will continue to "fix" NADH so that it can accompany ATP formation, but at a low rate. See the picture to the right!

• Fermentation comes at a price- Lactic acid also builds up, it can't be used in another cycle. This is why you feel extra sore after a hard workout- lactic acid build-up!

Multiple Choice

True or false? Anerobic respiration happens without oxygen and all in the cytoplasm.

• True

• False

Multiple Choice

Glycolysis is the first step in either anerobic or aerobic CR. If the pyruvate formed from glycolysis can't be turned into Acetyl-CoA to start the Kreb's cycle, it is instead turned in to:

• lactose

• acetic acid

• lactic acid

• citric acid

Multiple Choice

True of False: Anerobic cellular respiration makes much more ATP than aerobic cellular respiration.

• True

• False