Bell Work: What is this diagram trying to tell us?

SUGARSUGAR

Cellular Respiration: (Or, How to turn Glucose

into ATP)

Oxygen + Glucose => ATP + Carbon Dioxide+ Water

Review: What is ATP?

• ATP stands for Adenosine TriPhosphate.

• It looks like this:

A-P-P-P

•There is a large amount of energy between the bonds of the last two phosphates…..

How Cells Generate ATP

Cellular Respiration: The process of a Cell making ATP (energy) using oxygen and glucose.

•Involves 3 steps:

– Glycolysis

– Kreb’s Cycle (Citric Acid Cycle)

– Electron Transport Chain

Step 1 Glycolysis • The first step of cellular respiration takes place in the Cytoplasm.

• The process of breaking down glucose (6 C’s) into pyruvic acid (3 C’s)

Spiral back review…. Facilitated Diffusion is how the glucose gets

into your cells!• Glucose is helped

across the membrane by transport proteins.

• Doesn’t require energy

Energy Carriers

• Glucose contains lots of STORED energy.

• When glucose gets broken down, high energy Hydrogen atoms (and their electrons) are carried from Glycolysis to the Kreb’s Cycle and Electron transport chain for later use.

• These “energy carriers” are called “NADH” and “FADH2”

Energy Carriers: NADH and FADH2

Energy Cost

Glycolysis requires some energy to get started…..it costs the cell 2 ATPs to get started, but in the end 4 ATPs get made. This gives a net gain of 2 ATPs!!!

Now what do we do with those Pyruvic Acids???

Recall: There are 3 main steps of Cellular Respiration, so what was

step 2???

The Kreb’s Cycle! (Or Citric Acid Cycle)

But before the Kreb’s Cycle…

• There is a mini-step that takes the Pyruvic Acid and turns it into a compound called Acetyl Co-A.

• This enters the “Powerhouse” of the Cell to kick off the Kreb’s Cycle.

Mitochondria: label the matrix and cristae

Cristae(Folded inner membrane)

Matrix(liquid)

Kreb’s Cycle

• Happens inside the mitochondrial Matrix.

• Turns twice to process each glucose molecule

• Results in 2 more ATPs made!!!

1. Where is CO2 released? (Circle in the diagram)

2. How many ATP’s are released for 1 pyruvic acid? (count!)

So…4 ATPs so far…where do the rest come in?

Electron Transport Chain• Last stage of Aerobic Respiration• Takes place on the Cristae• High energy electrons go between proteins.

Oxygen accepts the

electrons at the end and combines with H+ to

make water.

32-34 ATPs made per glucose in the ETC.

Summary Picture

But what if the cells run low on Oxygen???

Anaerobic Respiration

Fermentation

• When Cells don’t have enough oxygen for Cellular Respiration (anaerobic)

• They do either Alcoholic or Lactic Acid as a byproduct

• Only 2 ATPs are made…but that is better than none!

Lactic Acid Fermentation

Alcoholic Fermentation

Dry Erase Review

Facilitators: Please grab a white board for each student at your table.

Appoint someone else to fetch a beaker of markers!

1. What is the name of the energy molecule of all cells?• ATP

2. What charge do the Posphate groups have on the ATP molecule?

• Negative

3. List the 3 steps of cellular respiration.

• Glycolysis,

• Krebs Cycle

• Electron Transport Chain

4. What is the organelle that converts glucose into ATP?

• Mitochondria

5. What are the 2 parts to a mitochondria?

• Cristae, Matrix

6. Which part of the mitochondria does the Kreb’s cycle occur?

• Matrix

7. How many ATP are made in Glycolysis?

• 4 total (but 2 are used up).

8. Which step of Cellular Respiration releases Carbon Dioxide?

• Kreb’s Cycle

9. What essential gas is the final electron acceptor in the Electron Transport Chain?

• Oxygen

10. What is the name of the anaerobic process that cells fall back on when oxygen runs low or is unavailable?

• Fermentation

11. List the 2 types of Fermentation.

• Lactic Acid and Alcoholic

12. Write the equation for Cellular Respiration. **How is this different than the photosynthesis equation?

• Glucose + Oxygen ATP + Carbon Dioxide + Water

• This is nearly flipped from photosynthesis!

Individual Practice

Complete the Cellular Respiration Overview worksheet. I will be coming around to check on your progress!