Download Photosynthesis

Photosynthesis:
Life from Light and Air
Plants are energy producers
• Like animals, plants need energy to live
– Unlike animals, plants don’t need to eat food
to gain that energy.
• Plants make FOOD
– animals are heterotrophs
– plants are autotrophs
How do plants make food?
• Plants use the energy from the sun in the
process of photosynthesis
– to make ATP energy
– to make sugars
• glucose, sucrose, cellulose, starch, & more
sun
ATP
sugars
What do plants need to do
photosynthesis?
• The “factory” for making
energy & sugars
sun
– chloroplast
• Fuels
– sunlight
– carbon dioxide
– water
• The Helpers
– enzymes
Make ATP!
Make sugar!
I can do it all…
And no one
even notices!
CO2
ATP
enzymes
H2 O
sugars
Chloroplasts are only in plants
animal cells
plant cells
Chloroplasts
Leaf
Leaves
absorb
sunlight & CO2
sun
CO2
Chloroplasts
in cell
Chloroplast
Chloroplasts
contain
Chlorophyll
Chloroplast
make
ENERGY & SUGAR
Building plants from sunlight & air
• Photosynthesis
– 2 separate processes
– Light Reactions
• ENERGY building reactions
• collect sun energy
• use it to make ATP
– Calvin Cycle
• SUGAR building reactions
• take the ATP energy
• collect CO2 from air
• use all to build sugars
sun
ATP
H2O
+
CO2
sugars
Photosynthesis
sun
Light
Reactions
ENERGY
building
reactions
ADP
Calvin Cycle
SUGAR
building
reactions
H2O
ATP
used immediately
to synthesize sugars
sugar
CO2
Cellular Respiration
Harvesting Chemical Energy
ATP
2009-2010
Energy needs of life
• All organisms are energy consumers.
– What do we need energy for?
• Metabolism
• Repair
• Growth
Where do we get energy?
• Energy is stored in organic molecules
– carbohydrates, fats, proteins
• Animals eat these organic molecules and plants make
them food
• All organisms digest food for:
ATP
• energy (ATP)
• raw materials for building more molecules
– carbohydrates, fats, proteins, nucleic acids
“Burn fuels” to make energy
Food is our fuel!
Combustion is making heat energy by burning fuels
in one step. This would kill cells!
fuel
(carbohydrates)
O2
CO2 + H2O + heat
Cellular Respiration is making ATP energy (& some
heat) by burning fuels in many small steps. This is
what occurs in our cells.
ATP
food
(carbohydrates)
O2
ATP + CO2 + H2O (+ heat)
What do we need in order to release
energy from our food?
• The “Furnace” for making energy
– mitochondria
• Fuel
– food: carbohydrates, fats, proteins
• Helpers
– oxygen
– enzymes
Make ATP!
Make ATP!
All I do all day…
And no one
even notices!
food
• Product
enzymes
– ATP
• Waste products
– carbon dioxide
• then used by plants
– water
O2
ATP
CO2 H2O
Mitochondria are everywhere!!
animal cells
plant cells
Harvesting energy stored in food
• Cellular respiration
– breaking down food to produce ATP in 3 Main Steps
1. Glycolysis
2. Krebs Cycle
3. Electron Transport Chain
food
Gycolysis and the Krebs
cycle break down food.
The Electron Transport
chain makes sure all the
released energy is in ATP
- This process is aerobic meaning it
requires oxygen.
ATP
O2
CO2 H2O
Using ATP to do work?
Can’t store ATP
 too unstable
 only used in cell
that produces it
 only short term
energy storage
carbohydrates & fats
are long term
energy storage
Whoa!
Pass me the
glucose & oxygen!
ATP
Adenosine TriPhosphate
Adenosine DiPhosphate
ADP
A working muscle recycles over
10 million ATPs per second
work
What if oxygen is missing?
• No oxygen available = can’t complete
aerobic respiration
• Anaerobic respiration
O2
– also known as fermentation
• alcohol fermentation
• lactic acid fermentation
– no oxygen or
no mitochondria (bacteria)
– can only make very little ATP
– large animals cannot survive
yeast
bacteria
Anaerobic Respiration
• Fermentation
– alcohol fermentation
• yeast
– glucose  ATP + CO2+ alcohol
– make beer, wine, bread
– lactic acid fermentation
• bacteria, animals
– glucose  ATP + lactic acid
– bacteria make yogurt
– animals feel muscle fatigue
Tastes good…
but not enough
energy for me!
O2
How are Photosynthesis and Cellular
Respiration connected?
Respiration
glucose + oxygen  carbon + water + energy
dioxide
C6H12O6 +
6O2
 6CO2 + 6H2O + ATP
Photosynthesis
carbon
sun
+ water + energy  glucose + oxygen
dioxide
C6H12O6 + 6O2
6CO2 + 6H2O + light

energy
Energy cycle
sun
Photosynthesis
plants
CO2
glucose
H2O
sugars
animals, plants
Cellular Respiration
The Great Circle
of Life!
Mufasa?
ATP
O2
Another view…
Photosynthesis
synthesis
producers, autotrophs
CO2
waste
sun
capture
light energy
organic
molecules
H2O
waste
food
consumers, heterotrophs
waste
digestion
Cellular Respiration
release
chemical energy
O2
ATP
The poetic perspective
• All of the solid material of every plant
was built out of thin air
• All of the solid material of every animal was
built from plant material
air
Then all the cats, dogs,
mice, people & elephants…
are really strands of air woven
together by sunlight!
sun