Energy in the Cell
How do cells get, use, and
transform energy?
Shows the flow/transfer
of energy
How important is energy to cells?
• Cells need energy to carry out all functions
including…
– Metabolism, active transport, cell division,
movement of cilia and flagella
• What are some things that you / your cells
need energy for?
Where does all of the energy
available to organisms come
from?
84,000,000,000,000 watts of power
reaches the earth from the sun
every day
That is A LOT!!!!
SUN
Shows the flow/transfer
of energy
Where do all of these
plants get their energy
from???
Plants, algae, and some bacteria all
use photosynthesis
• What is photosynthesis?
Photosynthesis
• Photosynthesis uses the energy of the sun to
build sugar (glucose) from CO2 and Water
• This occurs in the chloroplast
SUNLIGHT
GLUCOSE
SUN
Photosynthesis
Photosynthesis
Sugar (glucose)
So…after plants make their food
(glucose), what do they do with it?
• Remember what carbohydrate polymers
are made from?
• SUGAR!!!
• Glucose and other simple sugars are used
by the plants to build plant parts
– Ex: leaves, stem, wood, roots, fruit, tubers
(potatoes)
- Glucose
SUN
Photosynthesis
Photosynthesis
Glucose
Glucose (sugar)
Stored as
Plant Parts
(tissues)
Cellular Respiration
• Cellular respiration is the process of
making energy in the form of ATP from
sugar (glucose)
• This occurs in the mitochondria of ALL
eukaryotic cells – That means plants and
animals!!!
GLUCOSE
ATP (ENERGY)
SUN
Photosynthesis
Cellular
Respiration
ATP
(Energy)
Glucose (sugar)
Stored in
Plant Parts
(tissues)
So, how do we get energy from
plants
• After we digest the plants
(plant tissues  Glucose), we
use CELLULAR RESPIRATION to
make ATP using glucose
SUN
Photosynthesis
Cellular
Respiration
ATP
(Energy)
Glucose (sugar)
Stored in
Plant Parts
(tissues)
Cellular
Respiration
ATP
(Energy)
The Photosynthesis Equation
Plants take in water (H2O), Carbon Dioxide (CO2), and
Sunlight to build Glucose (C6H12O6), releasing O2 (as a
waste product (Oxygen).
______ + _______ +____________ ________ + _________
Reactants
(what goes in)
Products
(what comes
out)
What are the reactants and the products?
The Photosynthesis Equation
6 H2O + 6 CO2 + Sunlight  C6H12O6 + 6 O2
Products
Reactants
(what goes in)
+
+
(what comes out)

+
The Cellular Respiration Equation
To perform cellular respiration, plants and animals break
down glucose (C6H12O6) using Oxygen (O2). This produces
water (H2O), Carbon Dioxide (CO2), and ATP (energy)
______ + _______ +  ________ + _________ + __________
Reactants
(what goes in)
Products
(what comes
out)
What are the reactants and the products?
The Cellular Respiration Equation
C6H12O6 + 6 O2  6 CO2 + 6 H2O + ATP
Reactants
(what goes in)
+

Products
(what comes out)
+
+
Cellular Respiration is the Reverse
of Photosynthesis
6 H2O + 6 CO2 + Sunlight  C6H12O6+ 6 O2
C6H12O6 + 6 O2

6CO2 + 6 H2O + ATP