Cell Energy
ATP, Photosynthesis, and
Respiration
The Energy Molecule- ATP

Energy in the body is used to maintain
homeostasis

Homeostasis- maintaining a constant
internal environment even though
external conditions change
The Energy Molecule- ATP

ATP is the molecule in the body that
stores energy in the bonds between
phosphate groups. When a bond
between the phosphate groups is
broken, energy is released.
The Energy Molecule- ATP

Parts of an ATP molecule

ATP contains one base, one sugar, and 3
phosphate groups
Base-adenine
Sugarribose
P
P
P
The Energy Molecule-ATP

ADP- Adenosine Diphosphate- 2
phosphate groups
Base-adenine

Sugarribose
P
P
AMP – Adenosine Monophosphate – 1
phosphate group
Base-adenine
Sugarribose
P
The Energy Molecule-ATP
ADP
ATP
Energy
Adenosine diphosphate (ADP) + Phosphate
Adenosine triphosphate (ATP)
Energy
Partially
charged
battery
Fully
charged
battery
ATP-ADP Cycle
Photosynthesis




Producers like plants, algae and some
bacteria
Plants trap energy from the sun, and
build glucose molecules
Light energy is converted to chemical
energy.
Occurs in the chloroplasts
Photosynthesis

Overall reaction for photosynthesis
Energy, light,

6 CO2 + 6 H2O
& chlorophyll

C6H12O6 +
6O2
Overview of Photosynthesis
Light
Energy
Chloroplast
CO2 + H2O
Sugars + O2
Photo synthesis
Photosynthesis
Light-Dependent Reaction
H2O
sunlight
CO2
O2
Glucose
Cellular Respiration


Cellular Respiration
Process of breaking down
food (glucose) molecules
to produce
energy (ATP)
 Occurs in the mitochondria
Cellular Respiration

Types of respiration

Aerobic respiration requires oxygen

Anaerobic respiration uses no oxygen
Cellular Respiration

Overall Reaction for Aerobic Respiration
C6H12O6 + 6O2  6 CO2 + 6 H2O + 36 ATP

NOTE: Photosynthesis is the opposite reaction of
respiration. The reactants of one are the
products of the other.
Anaerobic Respiration

Two types

Alcoholic Fermentation




by bacteria
Produces ethyl alcohol and CO2
Only 2 ATP are produced
Lactic Acid Fermentation




By animals
Produces lactic acid and CO2
Only 2 ATP are produced
Causes muscle soreness
Cellular Respiration
Comparison of Photosynthesis
and Respiration
Characteristics
Photosynthesis
Aerobic Respiration
Reactants/requirements
CO2, H20, light,
chlorophyll, enzymes
Glucose, O2
Products
Glucose, O2
CO2, H20, 36 ATP
Location
chloroplasts
mitochondria
Use of energy
storage
release
Use of food molecules
Food made
Food broken down
Photosynthesis and respiration