Transcript Cell Boundaries Chapter 7.3

Chapter 9
Pages 221-225
I. Chemical Energy & Food
A. Energy cannot be created or
destroyed.
– Our body converts the stored energy in
glucose to usable energy called ATP
II.
Overview of Cell Respiration
A. Definition:
- Process that releases energy by
breaking down glucose, or other
organic molecules, in the
presence of oxygen.
Example: There is too much energy stored in
glucose, so its broken down slowly in
order not to lose any energy. This
energy is stored in ATP.
B. What is Energy?
- The ability to do work.
C. ATP is a nucleotide.
1. Consists of 3 phosphate groups, the
sugar ribose, and the nitrogen base
adenine.
2. The energy in ATP is stored
between the bonds of its
phosphate groups.
3. When a -P group is added to
another molecule, it will have
enough energy to react with other
molecules.
Calories
• One gram of glucose releases 3811
calories of heat when burned.
• What is a calorie?
• The amount of energy needed to raise 1
gram of H2O 1°C.
• The Calorie that is used on food labels is 1
kilocalorie or 1000 calories
B. Overall Equation
6O2 + C6H12O6  6CO2 + 6H2O + “Energy(ATP)”
III.
Stages of Cellular Respiration
A. Glycolysis
1. Process where one molecule of glucose is
broken in half, making two molecules of
Pyruvate (3-Carbon Molecule).
2. Takes place in the cytoplasm.
3. 2 ATPs needed to start reaction.
(Activation Energy)
4. 4 ATPs and 2 NADH are produced.
- These two molecules will drive
further reactions.
5. Oxygen is NOT NEEDED for this step.
• Glycolysis Animation
Glycolysis review activity
• Draw a flow chart of the process of
glycolysis. Include the following words in
the flowchart:
– Glucose
– Pyruvate
– NAD+
– NADH
– ATP
– ADP
What about when oxygen is NOT present?
B. Alcoholic Fermentation
Pyruvic Acid + NADH  Alcohol + CO2 + NAD+
- Used by yeast and other microorganisms.
- This process causes bread dough to rise.
Do you know why????
C. Lactic Acid Fermentation
Pyruvic Acid + NADH  Lactic Acid + NAD+
-The production of Lactic acid produces a
painful,burning sensation in muscles.
When do you think this happens?
- Prokaryotes that undergo Lactic Acid
Fermentation are used to produce some
beverages, cheese, yogurt, buttermilk
and sour cream.
What about if oxygen “IS” present?
D. Krebs Cycle (Citric Acid Cycle)
- An aerobic reaction (Oxygen is needed).
- Takes place within the mitochondria.
- The Mitochondria has two parts:
1. Cristae (Inner Membrane)
2. Matrix
(Liquid portion inside inner
membrane)
- Named after Hans Krebs (British Biochemist)
- Occurs within the MATRIX.
What Happens Here?
- Pyruvic acid is first converted into Acetyl CoA.
- Acetyl CoA then enters the Krebs Cycle and is
broken down over the course of several reactions.
- As Acetyl CoA is broken down, CO2 is released as
a byproduct.
* This is what we exhale!
- In this cycle, two electron carriers are
used:
1. NAD+  NADH
2. FAD  FADH2
-
These two electrons carriers will be
used to make ATP in the last step of
aerobic respiration.
• krebs cycle animation
Sum of the Krebs Cycle:
1 Molecule of Glucose Produces =
8 NADH
2 FADH2
2 ATP
* NADH and FADH2 will be used to create ATP
during the Electron Transport Chain (ETC).
E. Electron Transport Chain (ETC)
- Uses high-energy electrons from the
Krebs cycle to convert ADP into ATP.
- Occurs along the inner membrane of
the mitochondria.
- The electrons from NADH & FADH2 are
passed along a series of proteins.
- This movement of electrons pumps H+
ions into the intermembrane space.
- Oxygen is the final electron acceptor!
- The H+ ions will move from high to low
concentration through the enzyme
ATP Synthase.
- This movement causes the enzyme to
move like a turbine and bind ADP to P
forming ATP.
Click for animation!
III. Totals of Aerobic Respiration
* Remember that anaerobic respiration
only produces 2 ATPs per glucose.
- With aerobic respiration, a total of 36
ATPs are produced per glucose.