Light
energy
6 CO2
+6
Carbon dioxide
H2 O
Water
C6H12O6
Photosynthesis
Glucose
+ 6
O2
Oxygen gas
Photosynthesis and
Cellular Respiration
Ch 8 & 9
Sugar
+
O2
CO2
+
H2 O
Life
Living things need energy to survive.
Organisms get energy through a series of chemical
reactions.
Chemical Reactions – the forming and
breaking of bonds
Reactants
Products
Metabolism: all of the chemical reactions occurring
in an organism; getting energy (digestion), using
energy, etc
Energy Reactions
Photosynthesis: Changes sun’s energy to sugar
Cellular respiration: Changes energy in sugar to
usable energy (ATP)
• Sun light
– Sun light is the primary
source of energy
• Autotrophs/prod
ucers
– Organisms that use energy
from the environment
(sunlight) to make their
own food
• Plants, mosses, Algae
Heterotrophs/Consumers: organisms that
cannot make their own food. They must eat to get
energy
Carnivores
Herbivores
eat only meat
eat only plants
Omnivores
eat both plants and meat
Decomposers/Detritivores
Breakdown plants and animals
Chemical Energy and ATP
Organism store energy in food.
Cells use ATP as energy
• adenosine triphosphate, ATP: An important chemical
compound that cells use to store and release energy
– Energy currency used by all types of cells
ATP
Chemical Energy and ATP
• ATP consists of:
– adenine
– ribose (a 5-carbon sugar)
– 3 phosphate groups
Adenine
ATP
Ribose
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3 Phosphate groups
Chemical Energy and ATP
– Releasing Energy
• Energy stored in ATP is released when a phosphate
group is removed
Adenosine
Adenine
Ribose
Hydrolysis
Triphosphate (ATP)
Phosphate
group
Adenosine Diphosphate (ADP)
Energy Reactions
Photosynthesis: process in which organisms use the
energy of sunlight to make sugar and oxygen.
– Happens in Chloroplasts
– Plant cells
Light
6CO2 + 6H2O
C6H12O6 + 6O2
Carbon dioxide + water
(Reactants)
Light
sugar + oxygen
(Products)
Light
CO2
+
H2 O
Sugar
+
O2
Capturing light energy
Sun’s energy comes down in the form of light in
a mixture of different wavelengths.
– We see these different wavelengths as different
colors.
Capturing light energy
How do plants gather the sun’s energy?
Use Pigments (light absorbing molecules)
– Chlorophyll is the main pigment and is stored
inside the chloroplasts
Capturing light energy
The color we see is the color wavelength that is
reflected from (bounces off of) the object
All other colors are absorbed by the object
WHY ARE PLANTS GREEN?
Light
They reflect green light
Remember: THE COLOR
OF LIGHT SEEN IS THE
COLOR NOT ABSORBED
Reflected
light
Absorbed
light
Transmitted
light
Chloroplast
Building Carbohydrates (light independent
reaction)
• Calvin Cycle: uses carbon dioxide and
products from the light dependent reaction to
make sugar needed for energy and growth
Input
CO2
ATP
NADPH
Output: Sugar
Inside a Chloroplast
CO
H2O
2
Light
NADP+
ADP + P
Light- dependent
reactions
Calvin
Calvin
cycle
Cycle
Chloroplast
Sugars
O2
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Four things are needed for photosynthesis:
SUNLIGHT
Gives the plant energy
WATER
Travels up
from the roots
CARBON DIOXIDE
Enters the leaf through small
holes on the underneath
CHLOROPHYLL
The green
stuff
where the
chemical
reactions
happen
Energy Reactions
Cellular Respiration: process in which organisms take
sugar to make ATP (Energy)
– Happens in the mitochondria
– all eukaryotic cells
C6H12O6 + 6O2
6CO2 + 6H20 + ATP
Sugar + Oxygen → carbon dioxide + water + energy
(Reactants)
Sugar
+
(Products)
O2
CO2
+
H2 O
+
ATP
Glycolysis
• Glycolysis: the breaking of glucose
– does not require oxygen (anaerobic)
– Makes 2 ATP and high energy electrons
ATP
Sugar
ATP
Krebs Cycle
• When there is oxygen present, products from
glycolysis go to Krebs cycle to be broken down
– occurs in the mitochondria
– requires oxygen (aerobic)
– Makes 2 ATP and several high energy e- per
glucose molecule
ATPElectron Transport Chain ATP
When oxygen is present some products from
glycolysis and Krebs cycle go to the Electron
Transport Chain.
– occurs in the mitochondria
– requires oxygen (aerobic)
– Makes 32-34 ATP molecules (a lot of energy)
ATP
ATP
Overview of Cellular Respiration
Electrons carried in NADH
Pyruvic
acid
Glucose
Electrons carried
in NADH and
FADH2
Glycolysis
Cytoplasm
Mitochondrion
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Fermentation
Fermentation: If there
is no oxygen present,
cells go through
fermentation instead
of cellular respiration.
– Allows glycolysis to
continue
• provides some ATP,
as long as the
glucose supply lasts
Fermentation
Lactic acid fermentation: products of glycolysis turn
into lactic acid
Animals
Some Bacteria
Alcohol Fermentation: products of glycolysis turn
into ethyl alcohol and CO2
Fruit
Yeast
Some Bacteria