Download Chemical Energy is stored in fuels

What is energy?
– ability to do work
Cars need energy to move
Animals need energy to grow,
move, make noise, etc
Where do cars get energy?
– from burning fuel
–Specifically oil and gasoline
Chemical Energy is stored in fuels
- Burning oil and gasoline release energy
in the form of heat and light ; The
energy also allows the car to move.
- Gasoline is organic. When gasoline
reacts with oxygen you get a
combustion reaction. The products of
ALL combustion reactions are carbon
dioxide (CO2) and Water (H20)
What is our fuel?
- Food!
- Specifically
Glucose
(simple
carb)
But where does the glucose in our
food come from?
THE SUN!!!
Really? How?
• Let go through step by step.
1. Where did your glucose come from?
2. How did the glucose get in the
food?
3.How did she get the
glucose?
4. How did the glucose get in the
grass?
5. Where did the energy
to make the glucose
come from?
SO, long story short,
- the chloroplasts take energy from
the sun and put it into a glucose
molecule (Photosynthesis)
- through the food chain, glucose gets
passed from organism to organism
- eventually mitochondria of some
organism takes the energy back out,
by breaking down the glucose (Cell
respiration)
Types of Batteries
• Adenosine Triphosphate: ATP
– cycles between ATP (high energy)
and ADP (low energy) by adding or
removing a phosphate
Types of Batteries
• Electron Carriers: cycle between low
energy “empty” form and high energy
“full” form by adding or removing
electrons.
–We can “empty” these electron
carriers to charge ATP
Types of Batteries
–There are three different electron
carriers: NADPH; NADH and
FADH2
Photosynthesis
Let’s start by getting the energy from
the sun into the glucose molecule
Key terms:
• Heterotrophs: Organisms that get
food from somewhere else
–Examples??
• Autotrophs: organisms that make
food for themselves
–Photoautotrophs use light energy to
make their food
• Examples?
–Chemoautotrophs use the energy in
inorganic compounds to make their
food
• Examples?
• Understanding a little about light is
important! Refer to your “Science
of light and Color” assignment to
help!
Photoautotrophs undergo
Photosynthesis
• So what organelle is in their cells?
Granum
Thylakoid
(plural
Stroma
Grana)
What makes it Green?
• Pigment called Chlorophyll
(There are two chlorophylls)
• A pigment is a substance that
absorbs light
What color light bounces off
chlorophyll?
GREEN!!!
• Carotenes and xanthophylls*: other
plant pigments (orange and yellow)
that absorb different wavelengths of
sunlight than the chlorophylls do.
• When can we see these??
FALL!!!
* ZAN-tho-fills
Overall Reaction
• Photosynthesis requires MANY reactions but
we can summarize it with the following reaction
6CO2 + 6H2O  C6H12O6 + 6O2
(Glucose)
• Like all reactions, photosynthesis needs:
• Two Phases of Photosynthesis
Light reactions: need light;
- uses light energy to “charge” two
energy molecules: ATP and NADPH
- proteins needed for the reaction are
embedded in the thylakoid membrane
- Uses: 6H2O
produces: 6O2
• Two Phases of Photosynthesis
Calvin cycle: doesn’t need light;
- Uses the ATP and NADPH “charged”
by the light reactions to link CO2
together to build C6H12O6
- Enzymes for the calvin cycle are
found in the stroma
Reactant: 6CO2
Product: C6H12O6
Putting it Together
Glucose will do one of two things:
1. Move to the mitochondria to be converted
into ATP through Cell respiration
2. Go through dehydration synthesis to build
a big starch chain and be stored for future
use
Follow the Energy
• Where did the energy start?
• Where did it go next?
• Where is it at the end of photosynthesis?
Factors that affect Photosynthesis
• Light intensity (how bright/strong)
• CO2 levels
• Water
• Wavelength (color of light)
• Temperature: 0 – 35 degrees C
Why do each of these affect
photosynthesis?
Exceptions to the Rules:
• Autotrophic Bacteria:
–Example: Cyanobacteria
(“Blue” bacteria)
Exceptions to the Rules:
• Autotrophic Protists:
–Example: Algae, volvox and
Euglena
Exceptions to the Rules:
• Heterotrophic plants: some plants
get food from other organisms
–Mistletoe: makes food AND
takes sap (high in sugar) from
other trees
Exceptions to the Rules:
Venus Flytrap: traps and digests
insects as a food source
Exceptions to the Rules:
Dodder plant: roots grow into
other plants and steals water
and glucose
How do we get the energy back out?
Cell Respiration – a series of chemical
reactions that extract energy from glucose
to “charge” ADP to make ATP.
Starts in the cytoplasm and ends in the
mitochondria.
How do we get the energy back out?
Overall reaction
C6H12O6
+ 6O2  6CO2 + 6H2O
ATP
Two types of Cellular Respiration
Anaerobic: no free oxygen required
- performed by most bacteria
- Also by yeast and animal cells when
lacking O2
- two steps: Glycolysis, fermentation
- makes 2 ATP per glucose
Two types of Cellular Respiration
• Aerobic: requires FREE oxygen, O2 gas to get
ATP from glucose
– three steps: glycolysis, krebs, electron
transport chain
– performed by plants, animals, yeast,
protists, fungus.
– Generates 36 ATP per glucose
Anaerobic step 1: Glycolysis
• Occurs in cytoplasm
• Summary: split glucose in half to charge a few
ATP and NADH
• Reaction: Glucose  2 pyruvate
• Energy molecules used: 2ATP
• Energy molecules made: 4ATP and 2NADH
Fermentation
• Occurs in cytoplasm
• Summary: “empty” the NADH so we can
repeat glycolysis with the next glucose
–2Pyruvate  CO2 and Ethanol (yeast)
or
- 2Pyruvate  Lactic Acid (bacteria and
muscle cells)
• NO MORE ATP CHARGED!
ATP Tallies:
Anaerobic:
- Glycolysis: used 2, made 4
- Fermentation: used 0, made 0
Total: +2 per glucose
Aerobic step 1: Glycolysis
• SAME AS STEP 1 OF ANAEROBIC!
Krebs
• Occurs in mitochondria
• Summary: break down pyruvate into
CO2; use energy in pyruvate to
charge ATP, NADH and FADH2
Krebs
Reaction:
–2Pyruvate  2Acetyl-CoA + CO2
–2Acetyl-CoA  4CO2
–Energy molecules made: 2ATP +
2FADH + 6NADH
–Can bacteria do Krebs??
Electron Transport Chain
• Occurs in mitochondria
• Summary: Gather up ALL the electron
carriers and “empty” them to “charge”
lots of ATP
Electron Transport Chain
• Reaction:
–O2 H2O
Energy molecules USED: 10 NADH (from
krebs and glycolysis) + 2 FADH (from
krebs)
Energy molecules MADE: 32 ATP
ATP Tallies:
Aerobic:
- Glycolysis: used 2, made 4
- Krebs: used 0, made 2
- ETC: used 0, made 32
Total: +36 ATP per glucose
Overall Energy Summary for Aerobic Respiration
Reactants (used up/broken down)
Products (created/built up)
Glucose + 2ATP

2 Pyruvate

2Acetyl-CoA

10NADH + 2FADH2 + 6O2

2 Pyruvate + 4ATP + 2NADH
2CO2 + 2Acetyl-CoA + 2NADH
6NADH + 2FADH2 + 2ATP+ 4CO2
32ATP + 4CO2 + 6H2O
What’s Left?

Final Reaction for Aerobic Respiration
Putting it together:
Sun
Chloroplast
C6H12O6 + O2
CO2 + H2O
Mitochondria
36ATP