Download Name: Date: Science Period: Section 2.4 Cells and

Name:
Science
Date:
Period:
Section 2.4
Cells and Energy
All Cells Release Energy
 All cells must have energy to
 When bonds of
are broken energy is
 There are two basic processes that release energy


What materials do cells need to bring in and let go to release energy?
What processes do cells use to bring materials in and out?
All cells use Chemical Energy
 To stay alive cells must be able to release the
in the bonds between molecules.

a sugar is the major food source to create energy for cells.
Cellular Respiration

is a series of chemical
reactions that convert the energy in food molecules into a
form of
energy called ATP.
 ATPusable
for the cell
processes

, the
step in cellular
respiration, is a process by which glucose is broken down into smaller
molecules. It occurs in the
.
 Glycolysis
some
molecules and
energy from other ATP molecules.
 Molecules form to release large amounts of energy which include
energy that is
energy that is
as (ATP) (useable)
energy that is
The chemical equation for cellular respirations:
Glucose +
Oxygen Chemical Energy
+ Water + Carbon Dioxide
+
 Chemical Energy +
+
Cellular Respiration
 Cellular Respiration is considered
because it requires oxygen
 It is a complex process that has two stages
 The first stage takes place in the cytoplasm
 Glucose is broken down into smaller molecules that release a small amount of
energy called
.
 The second stage takes place in the
.
Fermentation
is a reaction that eukaryotic and prokaryotic cells use to
obtain energy from food when
levels are
.
 Fermentation occurs in a cell’s
, not in mitochondria.
 Two types of fermentation
Fermentation
Fermentation
 Anaerobic: process in which cells
energy without oxygen –
 Takes place in the
 Breaks glucose down into
molecules
 Releases a small amount of
Alcohol fermentation
 Produces
and
o Occurs in
(fungi) and plant cells
o Important to
causes dough to rise
 Important to brewers creates
Lactic Acid Fermentation
 Occurs in
, bacteria
 Bacteria convert
in milk to lactic acid
 Used to make cheese, yogurt, sourdough bread, sauerkraut, soy sauce, miso
 Gives foods a slightly
taste
 During prolonged
, muscles in your body convert
energy this way – it causes a
sensation
Cellular Respiration
 The formula for cellular respiration is
Glucose + Oxygen  Chemical Energy
+ Water + Carbon Dioxide
C6H12O6 + 6O2  Chemical Energy + 6H2O + 6CO2
 Photosynthesis and Cellular Respiration are two processes in the
cycle
 These processes do not have to occur in the same cell or in the same organism
Photosynthesis
is a series of chemical reactions that convert light
energy, water, and CO2 into the food-energy molecule glucose and give off oxygen.
 Photosynthesis takes place in the
 Chloroplasts contain
 Chlorophyll is the
that traps the energy in sunlight –
reflects
 Is a
Process that has
stages
 The
stage of photosynthesis involves
the sun’s energy in the chloroplasts
 Chlorophyll acts as a “
” to capture light energy and
supply
for the
stage of photosynthesis
 The Second stage requires the
materials
 H2O (water) and CO2 (carbon dioxide)

is provided by the
of the plant
 Carbon Dioxide
the plant through small
on the underside of
called Stomata
 After entering the leaves H2O&CO2 move to the chloroplasts where a series of
reactions happen
In the chloroplasts both water and carbon dioxide go through a series of chemical
reactions powered by the suns energy to create oxygen and glucose
The chemical formula is:
6CO2 + 6H2O + light energy  C6H12O6+6O2
Plants do not immediately use all of the glucose it is stored as starch and also
makes cellulose
 Plants are considered
or autotrophs because they can
make their own food
 Organisms that cannot make their own food are called
or heterotrophs

- breaks down nutrients from environment