1. Cellular Respiration (pg. 220)
Respiration is the process by which cells obtain energy from glucose.
It’s during respiration that cells break down food molecules (carbohydrates) to release the energy that they contain.
A calorie is the amount of energy needed to raise the temperature of water 1 degree
All living things carry out cellular respiration.
Begins with Glycolysis (splitting glucose) releases a small amount of energy
If oxygen is present glycolysis leads to two other pathways, if no oxygen it leads to a different pathway.
Requires some ATP to start

2. B. Types of Glycolysis
Glycolysis in the presence of oxygen leads to cellular respiration
Cellular Respiration is a 3 stage process
Glycolysis
Krebs cycle
Electron transport chain
Glycolysis without oxygen leads to fermentation
Cells convert NADH into NAD+
Because fermentation happens without oxygen it is called an anaerobic process
What kinds of yummy foods ferment?

3. Fermentation
Fermentation provides energy for cells without using oxygen while breaking down food. However, the amount of energy released is much lower for fermentation than for respiration.
There are two types of fermentation:
Alcoholic fermentation is used by some single celled organisms. This is called alcoholic fermentation because alcohol is one of the products produced. (example: yeast)
Lactic Acid fermentation takes place in your muscles. When you are running you cannot breathe in enough oxygen to supply your muscle cells with oxygen as quickly as they are using it. Your cells use fermentation for the energy that they need, one product of this fermentation is lactic acid and it creates soreness and weakness in your muscles.
When would Fermentation be mechanically advantageous?

4. Different Stages of Cellular Respiration
Respiration is a three stage process:
The first stage is glycolysis, this takes place outside the mitochondria
This is the process in which one molecule of glucose is broken in half, producing 2 molecules of pyruvic acid (pyruvate), a 3-carbon molecule. Does this sound familiar?
Uses 2 ATP and yields 4 ATP for a total of 2 ATP
Uses 2 NAD+ and yields 2 NADH (these go the electron transport chain)
Stage 3
Stage 2
Stage 1

5. The second stage is the Krebs cycle (aka the citric acid cycle), this takes place inside the mitochondria
Named after Hans Krebs who demonstrated its existence in 1937
Pyruvic acid is broken down into CO2 in a series of energy-extracting reactions
3-C pyruvic acid enters the Krebs cycle where a C is removed and makes CO2, NAD+ is turned into NADH and Coenzyme A is added to the 2 remaining C to become acetyl-CoA it then adds itself to a 4-C forming citric acid
Citric acid is then broken down into a 5-C compound and then to a 4-C compound, during this 2 more CO2 are released, the e- are joined to NAD+ & FAD to make NADH & FADH2. One molecule of ATP is created.
1 pyruvic acid nets 4 NADH, 1FADH2, AND 1 ATP (*the purpose of NADH and FADH2 is to carry electrons)

6. Total for Cellular Respiration = 36 ATP, 10 NADH, & 2 FADH2
The third stage is the electron transport chain, this takes place in the inner membrane of the mitochondria (what does this remind you of…?)
Uses high energy e- from the Krebs cycle (NADH & FADH2) to convert ADP into ATP
Combines H+ to oxygen to create water (byproduct)
The H+ cause a charge difference between the inside & outside of the mitochondria, the H+ go through the ATP synthase and help the ADP to grab another phosphate to make ATP
Uses NADH & FADH2 to turn 3 ADP into 3 ATP
Total for Cellular Respiration =
36 ATP,
10 NADH,
& 2 FADH2

7. Raw Materials & Products
The raw materials of respiration are glucose and oxygen and the products of respiration are water and carbon dioxide, these materials and products move into and out of the cell through the process of diffusion (a good example of this is yeast).
Oxygen is taken into the body when you inhale
Carbon dioxide and water are released when you exhale
C6H12O6 + 6O CO2 + 6H2O + energy

8. Page 221-225: 1-6 In science notebook with seat partners
Reading and Questions
Page : 1-6
In science notebook
with seat partners

9. Discussion questions:
Is it better to be a photosynthesizer or a consumer?
When would it be beneficial to go through fermentation instead of cellular respiration?