Cellular RespirationAerobic Respiration

Let’s ReviewAnaerobic Respiration:

Does not require Oxygen

Aerobic Respiration:REQUIRES Oxygen

Name 2 types of Fermentation1. Alcoholic Fermentation

2. Lactic Acid Fermentation

Where does GLYCOLOSIS occur in the cell?In the CYTOPLASM

Do you need Oxygen for glycolysis?NO

Last time…We discussed that our CELLS need to produce ATP as a means on energy to function

We begin this process by breaking down FOOD MOLECULES such as GLUCOSE in a process known as GLYCOLYSIS

In the ABSENCE of oxygen, our cells perform anaerobic cellular respiration (FERMENTATION)

GlycolysisFIRST step in ALL TYPES of cellular Respiration

Breaks down one Molecule of Glucose into 2 molecules of Pyruvate

Where?: in the CYTOPLASM of the cell

Produces a net amount of ATP USE 2 ATP to start (-2)

Produces 4 ATP (+4)

4-2= 2 ATP

http://highered.mcgraw-hill.com/sites/0072507470/student_view0/chapter25/animation__how_glycolysis_works.html

Glycolysis: No Oxygen Needed

CYTOPLASM

MITOCHONDRIA

GLYCOLYSIS

INPUTS:• 1 Glucose• 2 ATP

OUTPUTS:• 2

Pyruvates• 4 ATP (2

net)

Glycolysis

Steps – A fuelmolecule is energized,using ATP.

1 3

1

GlucoseStep

2

3

4

Glucose-6-phosphate

Fructose-6-phosphate

Glyceraldehyde-3-phosphate (G3P)

Step A six-carbonintermediate splits into two three-carbon intermediates.

4

Step A redoxreaction generatesNADH.

55

1,3-Diphosphoglyceric acid(2 molecules)

6

Steps – ATPand pyruvic acidare produced.

6 9 3-Phosphoglyceric acid(2 molecules)7

2-Phosphoglyceric acid(2 molecules)8

2-Phosphoglyceric acid(2 molecules)

9

(2 moleculesper glucose molecule)

Pyruvic acid

Fructose-1,6-diphosphate

Energy In: 2 ATP

Energy Out: 4 ATP

NET 2 ATP

Glucose

Pyruvic Acid

1. Glycolysis

OxygenAerobic

No OxygenAnaerobic

2. Krebs Cycle

3. ETC

36 ATP

2. Fermentation

Lactic Acid Fermentation

Or

Alcoholic Fermentation

General Outline

Aerobic Respiration

In AEROBIC respiration, Oxygen is present

After Glycolysis, the Pyruvates produced enter the KREBS CYCLE (aka- Citric Acid Cycle)

The next step after the Krebs Cycle is the ELECTRON TRANSPORT CHAIN

General Outline for Aerobic Respiration

Starts with GLYCOLYSIS

Then goes into

Krebs Cycle (AKA- Citric Acid Cycle

Ends in Electron Transport Chain

Net Products(per 1 glucose

molecule)2 Pyruvates2 ATP

2 ATP6 NADH2 FADH

~34 ATP

Pyruvate to Acetyl Co-APyruvate is converted into Acetyl

Co-A which enters the Krebs Cycle

This is done by a series of Redox reactions which involve the gaining or loss of electrons between NAD+ and NADH

(electron carriers)

LEO the lion says GER

Oxidation reactions are either a REDUCTION reaction or an OXIDATION reaction

LEO: Lose Electron- Oxidation

GER: Gain Electron- Reduction

When NAD+ gains an H (NADH) it is reduced

When NADH loses an H (NAD+) it is oxidized

Electron Carriers: NADH and FADH

NADH and FADH are molecules that carry and transfer ELECTRONS

This transfer of electrons is similar to how electricity works

Think about how you get electricity to a hair dryer

http://highered.mcgraw-hill.com/sites/0072507470/student_view0/chapter25/animation__how_the_nad__works.html

2nd pathway: Krebs CycleAKA- Citric Acid Cycle

WHERE? In the MITOCHONDRIA MATRIX

Each Pyruvate activates one turn in the cycle

Thus, 1 glucose molecule =2 pyruvates = 2 turns

Products of Krebs:-CO2-NADH-FADH-ATP

Krebs Cycle Products

For every 1 glucose molecule (i.e- 2 pyruvates) Krebs produces:

2 ATP (energy!)6 NADH (???)2 FADH (???)4 CO2 (by product)

http://highered.mcgraw-hill.com/sites/0072507470/student_view0/chapter25/animation__how_the_krebs_cycle_works__quiz_2_.html

3rd Pathway: Electron Transport Chain

WHERE?: the INNER MEMBRANE of the Mitochondria

-This is where the MOST ATP is generated through what we call oxidative phosphorylation

-Electron carriers (NADH) transfer electrons along the membrane and a proton gradient forms, fueling the process to create ATP

-the ETC produces between 32-34 ATP moleculeshttp://highered.mcgraw-hill.com/sites/0072507470/student_view0/chapter25/animation__electron_transport_system_and_formation_of_atp__quiz_1_.html

Oxidative Phosphorylation (Chemiosmosis)

Remember, Aerobic Respiration occurs when there is oxygen present

Role of oxygen comes into play in the Electron Transport Chain

When the electrons transfer through the membrane, they eventually get transferred to the Oxygen

When O2 picks electrons up and then forms WATER by bonding to the H+ protons

Oxygen is the ELECTRON ACCEPTER

ATP Synthasehttp://highered.mcgraw-hill.com/sites/0072507470/student_vie

w0/chapter25/animation__electron_transport_system_and_formation_of_atp__q

uiz_1_.html

Along the Mitochondria’s membrane, there are proteins aiding in the electron transport process

One Protein is the ATP-making machine (ATP synthase)

H+ ions pass down through ATP synthase, and allow the bonding of ADP to P to create ATP

Why do we care? Cyanide Poisoning

Watch Video

When Cyanide poisoning occurs, it stops the process of electron transfer at Cytochrome A3 (right before ATP synthase)

ATP production stops

Build up of Oxygen occurs

Symptoms: flushed, red skin, rapid breathing, death within minuts

Cell Respiration Song

Because we love science in a song….

http://www.quia.com/rr/216170.html

Respire to be a Millionaire

Summary of Cellular Respiration Reactions (make

sure to know these!)Aerobic Cellular Respiration:

C6H12O6+ 6O2 6CO2 +6H2O + (36-38ATP)

(remember- it’s the reverse of photosynthesis!)

Anaerobic Cellular Respiration:

Alcoholic Fermentation:

Glucose + (NADH) Alcohol (i.e- ethanol) + CO2 + 2 ATP

Lactic Acid Fermentation:

Glucose + (NADH) Lactic Acid + 2 ATP + (NAD+)