Lesson Overview
Energy and Life
Lesson Overview
8.1 Energy
and Life
Lesson Overview
Energy and Life
Chemical Energy and ATP
• Energy - ability to do work.
• How do you use energy?
• Build new molecules,
contract muscles,
carry out active transport, etc.
• Without energy,
life would
cease to exist.
Lesson Overview
Energy and Life
Chemical Energy and ATP
• Cells store and release energy as
adenosine triphosphate
(ATP).
• Triphosphate = three phosphate groups.
Lesson Overview
Energy and Life
Storing Energy
• Adenosine diphosphate
(ADP) looks
like ATP, but has two
phosphate groups
instead of three.
ADP contains
some energy, but not
as much as ATP.
Lesson Overview
Energy and Life
Using Biochemical Energy
One way cells use energy from ATP is for
carry out active transport.
Lesson Overview
Energy and Life
Using Biochemical Energy
• ATP powers movement
• Contract muscle
• Power movement of
cilia and flagella.
Lesson Overview
Energy and Life
Using Biochemical Energy
• ATP powers even more!
• Synthesis of proteins
• Responses to
chemical signals.
Lesson Overview
Energy and Life
Using Biochemical Energy
• ATP is not good for
storing energy .
• Better to keep a
small supply
of ATP on hand.
• ATP can be
regenerated
from ADP
Lesson Overview
Energy and Life
Heterotrophs and Autotrophs
• Heterotrophs –
Organisms that obtain food by consuming
other living things.
Lesson Overview
Energy and Life
Heterotrophs and Autotrophs
• Autotrophs –
Organisms that make their own food
• Plants, bacteria, and more can use
light energy from the sun
to produce food.
• Photosynthesis –
Process by which autotrophs use the energy of
sunlight to produce
carbohydrates
that can be used for food
Lesson Overview
Energy and Life
REVIEW Questions
1. T or F - Without the ability to obtain and use
energy, life would cease to exist.
2. One of the most important compounds that cells
use to store and release energy is _______?
ATP
3. How many phosphate groups are on ATP?
3 Phosphate groups
4. What characteristic of ATP makes it exceptionally
useful as a energy source?
It is rechargeable
Lesson Overview
Energy and Life
REVIEW Questions
1. ATP and ______
ADP work together like a
rechargeable battery.
2. ATP is not good at storing energy
Long Term
_________________.
3. Organisms that obtain food by consuming other
Heterotrophs
living things are known as __________________.
4. Organisms that make their own food are called
___________________.
Autotrophs
Lesson Overview
Energy and Life
Lesson Overview
8.2
Photosynthesis:
An Overview
Lesson Overview
Energy and Life
Light
• Energy from the sun travels to
Earth in the form of light.
• Visible spectrum – Light has different
wavelengths, which make up different colors.
Lesson Overview
Energy and Life
Pigments
• Plants gather the sun’s energy using
pigments.
• The plants’ main pigment
is chlorophyll.
Lesson Overview
Pigments
Energy and Life
Lesson Overview
Energy and Life
Chloroplasts
• Chloroplasts contain saclike membranes
called thylakoids,
which are arranged in stacks known as
grana.
• The fluid portion outside of the thylakoids is
the stroma.
Lesson Overview
Energy and Life
Lesson Overview
Energy and Life
Energy Collection
• When chlorophyll absorbs light, the energy is
turned into electrons,
which make photosynthesis work.
Lesson Overview
Energy and Life
High-Energy Electrons
• Electrons are reactive and require a
“carrier.”
• Plants use electron carriers to
transport electrons from
chlorophyll to other molecules.
Lesson Overview
Energy and Life
• Think of electrons as being similar to a hot
potato. If you wanted to move the
potato -the electronsfrom one place to another, you would use an
oven mitt —a carrier—
to transport it.
Lesson Overview
Energy and Life
High-Energy Electrons
• NADP+ is a carrier molecule.
• NADP+ holds two electrons and
a hydrogen ion (H+),
and is converted into NADPH.
• The NADPH can then carry the electrons to
chemical reactions
elsewhere in the cell.
Lesson Overview
Energy and Life
An Overview of Photosynthesis
•Photosynthesis uses the energy of sunlight to
convert water and carbon dioxide into
sugars and oxygen.
•In symbols:
6 CO2 + 6 H2O + light  C6H12O6 + 6 O2
•In words:
Carbon dioxide + Water + light  Sugars +
Oxygen
Lesson Overview
Energy and Life
An Overview of Photosynthesis
• Plants use the sugars
generated
to produce
carbohydrates
and
energy to make other
molecules.
Lesson Overview
Energy and Life
Light-Dependent Reactions
• Photosynthesis involves two reactions:
1. Light-dependent
2. light-independent
• Light-dependent reactions require
light and light-absorbing pigments.
Lesson Overview
Energy and Life
Light-Dependent Reactions
• Light-dependent reactions use
sunlight to produce ATP and NADPH.
• Takes place within the
thylakoid membranes
• Water is required and
oxygen is released.
Lesson Overview
Energy and Life
Light-Independent Reactions
• During light-independent
reactions, ATP and NADPH from the
light-dependent reactions are used to
produce sugars.
• No light is required to power the
light-independent reactions.
• The light-independent reactions take place in
the stroma.
Lesson Overview
Energy and Life
Questions
1. In the process of photosynthesis, plants convert
the energy of sunlight into chemical energy
stored in the form of _________.
Carbohydrates
2. Photosynthetic organisms capture energy from
sunlight with ________.
Pigments
3. The plant’s principal pigment is _______.
Chlorophyll
4. Photosynthesis takes place in ___________.
Chloroplasts
Lesson Overview
Energy and Life
Questions
1. T or F - Chloroplasts contain an abundance of saclike
photosynthetic membranes called thylakoids.
TRUE
2. T or F - The fluid portion of the chloroplast, outside
of the thylakoids, is known as the matrix.
FALSE - STROMA
1. In order to make photosynthesis work, what two
things are required from water?
Electrons and hydrogen
Lesson Overview
Energy and Life
Questions
8. An electron _________is a compound that can
accept a pair of high-energy electrons and transfer
them to another molecule.
Carrier
9. NADP+ is converted to ______________as it
accepts and transfers electrons to chemical
reactions elsewhere in the cell.
NADPH
10. What is the overall equation of photosynthesis?
6CO2 + 6H2O + light  C6H12O6 + 6O2
Lesson Overview
Energy and Life
Questions
11. The light- ______________reactions produce
ATP and NADPH from sunlight in the thylakoid
membranes.
Dependent
12. During light-______________ reaction in the
stroma, sugars are created from carbon dioxide
using the ATP and NAPH from the lightdependent reactions.
Independent
Lesson Overview
Energy and Life
Photosynthesis REVIEW
Lesson Overview
Energy and Life
Photosynthesis REVIEW
Lesson Overview
Energy and Life
Photosynthesis REVIEW
Lesson Overview
Energy and Life
What is the equation for
photosynthesis?
6CO2 + 6H2O + light  C6H12O6 + 6O2
Lesson Overview
Energy and Life
Lesson Overview
9.1 Cellular
Respiration:
An Overview
Lesson Overview
Energy and Life
THINK ABOUT IT
Lesson Overview
Energy and Life
Chemical Energy and Food
• Food contains energy that is released
when its chemical bonds are broken.
• Energy in food is called calories.
• Calorie - amount of energy
needed to raise the temperature of 1 gram
of water by 1 degree Celsius.
• 1000 calories = 1 kilocalorie, or Calorie.
Lesson Overview
Energy and Life
Overview of Cellular Respiration
• If oxygen is available,
organisms get energy through
cellular respiration.
In symbols:
• 6 O2 + C6H12O6  6 CO2 + 6 H2O + Energy
• In words:
• Oxygen + Glucose 
Carbon dioxide + Water + Energy
Lesson Overview
Energy and Life
Stages of Cellular Respiration
•Three main stages of
cellular respiration:
1. Glycolysis
2. Krebs cycle
3. The electron
transport chain.
2 Pyruvic
Acid
Lesson Overview
Energy and Life
Stages of Cellular Respiration
1. Glycolysis produces
little energy.
• Most energy remains
in pyruvic
acid.
2 Pyruvic
Acid
Lesson Overview
Energy and Life
Stages of Cellular Respiration
2. During the
Krebs cycle,
a little more
energy is
generated from
pyruvic acid.
2 Pyruvic
Acid
Lesson Overview
Energy and Life
Stages of Cellular Respiration
3. The electron
transport chain
produces the bulk
of the energy
by using oxygen.
Lesson Overview
Energy and Life
Oxygen and Energy
• Pathways that require
oxygen are
called aerobic.
• Aerobic Processes:
-The Krebs cycle
-Electron transport chain
• Both take place inside the
mitochondria.
Lesson Overview
Energy and Life
Oxygen and Energy
• Gylcolysis is
anaerobic.
• Does not
require oxygen
• But still considered part of
cellular respiration.
• Glycolysis takes place in the
cytoplasm.
2 Pyruvic
Acid
Lesson Overview
Energy and Life
Photosynthesis vs. Cellular Respiration
Lesson Overview
Energy and Life
Lesson Overview
9.3 Fermentation
Lesson Overview
Energy and Life
Fermentation
• Fermentation - energy is
released from food molecules in the
absence of oxygen.
• Occurs in the cytoplasm.
Lesson Overview
Energy and Life
Alcoholic Fermentation
• Yeast and other microorganisms use
alcoholic fermentation
• Produces ethyl alcohol and
carbon dioxide.
• Chemical Equation: Pyruvic acid + NADH 
Alcohol + CO2 + NAD+
Lesson Overview
Energy and Life
Lactic Acid Fermentation
• Most organisms,
including humans, use
lactic acid fermentation.
• Lactic acid fermentation converts
pyruvic acid to lactic acid.
• Chemical equation: Pyruvic acid + NADH  Lactic acid +
NAD+
Lesson Overview
Energy and Life
Quick Energy (not needed for test, just fyi)
• Cells normally contain small amounts of
ATP produced during cellular respiration,
enough for a few seconds of intense
activity.
• Lactic acid fermentation can supply
enough ATP to last about 90 seconds.
However, extra oxygen is required to get
rid of the lactic acid produced. Following
intense exercise, a person will huff and
puff for several minutes in order to pay
back the built-up “oxygen debt” and clear
the lactic acid from the body.
Lesson Overview
Energy and Life
Long-Term Energy (not needed for test,
just fyi)
• For intense exercise lasting longer than 90 seconds, cellular
respiration is required to continue production of ATP.
• Cellular respiration releases energy more slowly than
fermentation does.
• The body stores energy in the form of the glycogen. These
glycogen stores last for 15 to 20 minutes. After that, the body
begins to break down other stored molecules, including fats,
for energy.
Lesson Overview
Energy and Life
•Organisms get energy from food
.
• Calorie
- amount of energy needed to raise
the temperature of 1 gram of water 1 degree Celsius.
•Our familiar Calorie is actually a kilocalorie (1000
calories)
• Cellular Respiration
- process that releases
energy from food in the presence of oxygen.
•Overall respiration - sugars + oxygen  carbon
dioxide + water + energy.
•Equation: C6H12O6 + 6O2  6CO2 + 6 H2O +
Energy
Lesson Overview
Energy and Life
• Cellular respiration involves a series of controlled
reactions that slowly release the energy
• Three steps of respiration: glycolysis,
Krebs
cycle and electron
transport chain.
• Glycolysis releases a small amount of energy and
makes pyruvic acid.
• Pyruvic acid is used in the Krebs cycle and preps
the final stage the electron transport chain where
most energy is made because of oxygen
as the final electron acceptor.