CELL ENERGY
Photosynthesis &
Cellular Respiration
(Chapter 5)
PHOTOSYNTHESIS
is converting light energy
into chemical energy (= carbs = FOOD).
– Done by PLANTS
Things that can make their own food are
called “AUTOTROPHS”.
Auto- = self
- troph = feeding
– Autotrophs are “self-feeding:” mostly plants,
also cyanobacteria (green bacteria),
& some protists (like algae & plankton)
Photosynthesis in Plants
Photosynthesis is made possible by the
green chlorophyll pigments found within
chloroplasts in plants.
Chlorophyll a & b can ABSORB the energy
from most wavelengths of light (but they
reflect green & yellow light).
(There are other pigments [carotenoids] that
absorb different wavelengths of light. You
see these in Fall leaves).
Pigment Graphs
Inside each Chloroplast
There are structures that look like
“stacks of coins”.
These are
THYLAKOIDS,
the chlorophyll
actually in them.
and
is
Gases (O2, CO2)
enter or exit
leaves through
holes called
“stomata”
Sugars go to
storage (as
simple sugars
in fruits, starches
in tubers, etc.)
Photosynthesis Chemistry
Basic formula (*know this!):
CO2 + H2O -light-> C6H12O6 + O2
“Carbon dioxide and water, in the presence
of light, produce glucose and oxygen.”
____ = Carbon dioxide
____ = water
_______ = glucose
__ = Oxygen
The balanced equation is:
___CO2 + ___H2O -light-> __C6H12O6 + ___O2
Photosynthesis Chemistry
Basic formula (*know this!):
CO2 + H2O -light-> C6H12O6 + O2
“Carbon dioxide and water, in the presence
of light, produce glucose and oxygen.”
CO2 = Carbon dioxide
H2O = water
C6H12O6 = glucose
O2 = Oxygen
The balanced equation is:
6 CO2 + 6 H2O -light-> C6H12O6 + 6 O2
Just be glad I’m not asking
you to memorize each step!
PHOTOSYNTHESIS happens
in the CHLOROPLASTS of
PLANTS
THE REST happens in the
MITOCHONDRIA of PLANTS
and of ANIMALS that eat plants.
(happens in ALL eukaryotes, really)
CELLULAR RESPIRATION
Is using energy from food to make ATP,
which gives cells the energy needed to live
(= metabolism).
Plants make the food (glucose) during photosynthesis, and they
use some of it to fuel their own lives (they are autotrophs).
Animals cannot make their own food, and
must eat plants to get it (or eat animals that ate plants)
Animals are heterotrophs
(“hetero” means “mixed”, “troph” = feeding)
2 Main TYPES of Cell. Resp.
AEROBIC = “needing oxygen”
– More efficient than anaerobic
– Produces more ATP than anaerobic
• (makes a gain of 36 ATP overall)
ANAEROBIC = “without oxygen”
– Less efficient (produces only 2 ATP)
– Done by muscles that run out of oxygen
= LACTIC ACID FERMENTATION” = muscle soreness
– Done by yeast = “ALCOHOLIC FERMENTATION”
In the Mitochondria
There are 2 membranes, and the inner
one has lots of folds (= more surface
area for cellular respiration to happen).
Cellular Respiration
Chemistry
Basic formula (*know this!):
C6H12O6 + O2 -enzymes-> CO2 + H2O+ energy
“Glucose and oxygen, in the presence of enzymes,
produce carbon dioxide, water, and energy (ATP).”
Remember:
CO2 = Carbon dioxide
H2O = water
C6H12O6 = glucose
O2 = Oxygen
The balanced equation is:
__C6H12O6 + ___O2 -enzymes-> ___CO2 + ___H2O + energy
Cellular Respiration
Chemistry
Basic formula (*know this!):
C6H12O6 + O2 -enzymes-> CO2 + H2O+ energy(ATP)
“Glucose and oxygen, in the presence of enzymes,
produce carbon dioxide, water, and energy (ATP).”
Remember:
CO2 = Carbon dioxide
H2O = water
C6H12O6 = glucose
O2 = Oxygen
The balanced equation is:
C6H12O6 + 6 O2 -enzymes-> 6 CO2 + 6 H2O + energy(ATP)
Again, it
could be
worse!
The whole
process:
So basically, it’s all a big
energy cycle.
What photosynthesis makes
is used in cellular respiration,
&
What cellular respiration makes
is used by photosynthesis!
Another overview:
Image credits
http://vincentimbe.files.wordpress.com/2007/11/kre
bs-cycle.jpg
www.funsci.com
http://www.grow-ahead.com/index/images/stories/photosynthesis.jpg
http://www.zeraim.com/imagesEng/article18-04.jpg
http://www.cartage.org.lb/en/themes/sciences/zool
ogy/AnimalPhysiology/Anatomy/AnimalCellStructur
e/Mitochondria/mitochondria.jpg
http://media.wiley.com/Lux/45/8545.nfg001.jpg