Download What is Energy? The Role of Oxygen

Where does the Alcohol in
Beer come from or…
How do Cells Obtain Energy?
•What is Energy?
•The Role of Oxygen and Enzymes
•Cellular Respiration
–Glycolysis
–Krebs Cycle
–Electron Transport Chain
What is Energy?
• Energy is the term used to
denote anything that can do
work
• Energy can take different forms
(light, heat, movement)
• Energy can be converted from
one form to another
The Role of Oxygen
• Connection between breathing &
life is an ancient one
– Exchange of gases is part of what
it means to be alive &
– Outward sign of metabolism
– Joseph Priestly experiment
– Postulated that poisonous
phlogiston is PRODUCED.
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The Role of Oxygen
• Antoine Lavoisier
– Found that it is oxygen from air that is
CONSUMED
– In a fire, Organic Molecules combine with
Oxygen (O 2) in the air to form
CO2 & H2O
– he called the process OXIDATION
– Oxidation also occurs when organisms
metabolize food
Chemical Reactions in
Non-living vs. Living Organisms
•Lower temperature for reactions
•Reactions can be highly Regulated
ENZYMES make Chemical Reactions
Possible inside CELLS
2
ENZYMES
are Proteins
Enzymes
•L o w T e m p s
•S p e c i f i c
•H a r n e s s E
Cellular Respiration
– The name given to metabolic
pathways in which Cells
harvest the energy from the
metabolism of food molecules
Food is Broken Down
ATP is Produced
3
ATP Cycle
- ATP is the Common Currency for
Energy Transfer in Cells
- ATP is used to fuel Biological Work
Glucose →
→ CO2+ H2O
Amino →
→ Proteins
Acids
Cellular Respiration
Glucose breakdown is one of the main
pathways by which cells obtain ATP
1. Glycolysis
2. Krebs Cycle
3. Electron Transport
The production of Beer relies on
Cellular Respiration
in YEAST Cells
Magnified
Yeast
Cells
4
Beer Production Requires ….
•Germinating Barley Seeds
Barley Seeds contain chains of
GLUCOSE molecules in ……
Beer Production Requires….
•Germinating Barley Seeds
•Enzymes that can breakdown these
chains into individual GLUCOSE
molecules
This mixture is MALT
YEAST cells are added to the malt
They begin to grow using the
glucose as an energy source
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Glycolysis
• Universal energy-harvesting
process of life, very primitive
– Evolved early in life’s history
– Means “sugar-splitting”
• 6-C sugar glucose is split in half to
• Make two 3-C compounds
Glycolysis converts sugars to
Pyruvic Acid + ATP + NADH
C-C-C-C-C-C → 2(C-C-C)
NAD+
→
→
NADH
NADH is a KEY product in Cellular Respiration
Glycolysis
Uses NO oxygen
-An ANaerobic process
(…. one not requiring oxygen)
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Krebs Cycle
Completes the breakdown of
Pyruvic Acid (from Glucose) to
Carbon Dioxide (CO2) and Water (H2O)
-This process is Aerobic
(requires oxygen)
The Krebs Cycle occurs in the
Mitochondria of Cells
The Krebs Cycle occurs in the
Mitochondria of Cells
•Pyruvate ( C- C-C ) is OXIDIZED to 3 CO2
•In the process ATP & NADH are produced
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NADH from Glycolysis & the Krebs
Cycle must be RECYCLED to NAD+
If Oxygen is present
è NADH is recycled by
ELECTRON TRANSPORT
Occurs in the Mitochondria
Additional ATP is produced
Electron Transport
Glucose +
NAD+
NADH
- from
glycolysis
2
The production of Beer relies on
Cellular Respiration
in YEAST Cells using MALT
Magnified
Yeast
Cells
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The Malt/Yeast mixture is kept in
large VATS
-BUT the Yeast
eventually uses up all it’s
OXYGEN
- NOW under Anaerobic
conditions yeast can still
obtain Energy from
Glucose by a process
known as
FERMENTATION
FERMENTATION
• NADH is in LIMITED Supply in
cells and must be RECYCLED
NO OXYGEN
NAD+
→
→ NADH
X
Fermentation
• Yeast can recycle NADH by first
Converting Pyruvic Acid to Acetaldehyde
è Acetaldehyde
C-C-C-C-C-C è
è 2(C-C-C) è 2(C-C)+ CO2
NAD+
è
è NADH
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Fermentation
• And then converting
Acetaldehyde to ETHANOL
è Acetaldehyde è ETHANOL
C-C-C-C-C-C è
è 2(C-C-C) è
è 2(C-C)+ CO2
NAD+
è
è
NADH
NADH è
è NAD+
Alcohol and CO2 are the
Final Products of
Fermentation
Pyruvic Acid è Acetaldehyde è Ethanol + CO2
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