Transcript Photosynthesis, Respiration & Chemical Energy

Photosynthesis, Respiration
& Chemical Energy
Quick review: Chemical Changes
• Chemical reactions occur when old bonds
break and new bonds form.
Chemical reactions involve two main
changes that you can observe:
– formation of new substances
– changes in energy (ex: chemical to mechanical)
Pow
H Pow
H
C
Pow
H Pow
H
Snap
OPow O
Snap
OPow O
Snap
Old Bonds
Break
New Bonds
Form
© Beadle, 2009
Living things get their energy from chemical
reactions called: Photosynthesis and
Respiration
• Photosynthesis:
– The energy of the sun powers the reactions of
Water (H2O) and Carbon Dioxide (CO2) in
plants to make Glucose (C6H12O6) and
Oxygen (O2 )(plant poop)!
So what is the Photosynthesis rxn formula?
• Respiration:
– Animals breath in O2 and eat plants for
Glucose (the most basic food). Then they
exhale Carbon Dioxide and water.
So what is the Respiration rxn formula?
Photosynthesis
(endothermic reaction)
Photosynthesis takes place in the Plant Cells
The Chloroplasts are where
Light, water and Carbon Dioxide
are processed into glucose and
oxygen
Chloroplast
Photosynthesis
(Molecules go in…)
Carbon
Dioxide
molecules
Chloroplasts
Water molecules
© Beadle, 2009
Sun
Photosynthesis
(New ones come out…)
Oxygen is a waste product
that leaves the plant (plant poop!)
Energy
Stored Inside
(Potential Chemical)
Glucose is used by
the plant for it’s food
Chloroplasts
Without Photosynthesis, nothing else could exist
on this planet! YEAH! Go hug a tree and say
“thanks!”
Respiration
(Exothermic Reaction)
Respiration takes place in
the animal cells
Mitochondria
(Human Cell)
© Beadle, 2009
The “Mitochondria” is where chemical
energy is converted into mechanical
and heat energy
Respiration
(Molecules go in…)
Glucose
Molecule
Oxygen Molecules
Mitochondria
(Human Cell)
Oxygen and Glucose molecules
react with each other in the
mitochondria and
form
neware
molecules
Our
bodies
designed to unpack that energy
our bodies usestored
the released
energy
in the sugar
through a series of
to exothermic
do stuff reactions.
© Beadle, 2009
Respiration
(Different ones come out…)
Unpack
Stored Energy
(Released Energy)
Mitochondria
(Human Cell)
© Beadle, 2009
Note: The process by which sugar is broken
down is a lot more complicated than a just a
simple reduction of sugar – You’ll learn how
in your Biology class in High School.
Energy Transformation Sequence:
Sun
Unpack
Stored Energy
Released in Mechanical
& Heat Energy
Light Energy
1. Light comes from the sun
2. Plants convert that energy
into chemical energy via
sugar
3. We eat the sugar and
convert that energy into heat
& mechanical energy
Chemical Energy
Mechanical
& Heat Energy
Now we send back our “waste
products” to the plants!
Every time we exhale, we send CO2 and H2O back to plants
Plants change the CO2 and H2O into Glucose
and O2 that comes back to us
Why is this cycle so important?
• Remember
the
tragedy
4 Billion years ago, the
atmosphere
was mostly COof
, the
Which is GREAT for photosynthesis!!!
Stromatolites…
2
Moral: NOTHING CAN
Some still survive today
as you can see in this picture:
SURVIVE
They are living bacteria that form rock like features when they
IN IT’S
OWN
grow together.
It looks a bit WASTE!!!!
like a coral reef
They (like modern plants) did Photosynthesis
Moral: NOTHING CAN
But there were NO animals around yet…why is this a problem?
SURVIVE
A: There were no critters to turn the O back into CO ,
the Stromatolites
died off!!!
Poor things…
IN and
IT’S
OWN
WASTE!!!!
All the CO2 in the atmosphere eventually became O2.
Stromatolites are the earliest form of life we have
Which means what for our Stromatolite friends…?
ever found… the first ones, maybe as long as 4 BILLION years ago!!!
2
2
How long would you last…?
Stuck in a sealed room with nothing but CO2?