Download How does a cell obtain energy?

Cells and Energy
• How does a cell obtain energy?
• How do some cells make food molecules?
Cells and Energy
• cellular respiration
• glycolysis
• fermentation
• photosynthesis
All cells must have energy to function
When bonds of sugars are broken energy
is released
There are two basic processes that
release energy
Cellular Respiration
Fermentation
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
chemical energy
in bonds
Glucose a sugar
is the major
source of energy
for most cells
Cellular Respiration
Cellular respiration is a
series of chemical reactions
that convert the energy in
food molecules into a usable
form of energy called ATP.
Glycolysis, the first step
in cellular respiration, is
a process by which
glucose is broken down
into smaller molecules.
It occurs in the
cytoplasm.
Glycolysis
produces some ATP
molecules and uses
energy from other
ATP molecules.
Cellular Respiration (cont.)
• The second step of cellular respiration
requires oxygen and the smaller molecules of
glucose which move to the mitochondria of
eukaryotic cells.
• A chemical reaction takes place that
produces: Large amounts of ATP—usable
energy—, Water, and carbon dioxide.
• Cells use ATP to power all cellular processes.
• Aerobic reaction: requires oxygen
Molecules form to release large amounts of
energy which include
energy that is used
energy that is stored (ATP) (useable)
energy that is given off as heat
Reactions in the Mitochondria
The chemical equation for cellular
respirations:
Glucose + Oxygen →Chemical Energy +
Water + Carbon Dioxide
C6H12O6 + 6O2 → Chemical Energy + 6H2O +
6CO2
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
Fermentation is a reaction that
eukaryotic and prokaryotic cells
use to obtain energy from food
when oxygen levels are low.
Fermentation occurs in a cell’s
cytoplasm, not in mitochondria.
Two types of fermentation
Alcohol Fermentation
Lactic Acid Fermentation
Anaerobic:proces Fermentation
s in which cells
release energy
without oxygen –
Takes place in the
cytoplasm
Breaks glucose
down into smaller
molecules
Releases a small
amount of energy
Alcohol
fermentation
-Produces alcohol and
carbon dioxide
-Occurs in yeasts (fungi)
and plant cells
-Important to bakers
causes dough to rise
-Important to brewers
creates carbonation
Occurs in animals, bacteria
Lactic Acid
-Bacteria convert sugar in milk to
Fermentation lactic acid
Used to make cheese, yogurt,
sourdough bread,
sauerkraut, soy sauce, miso
Gives foods a slightly sour
taste
During prolonged exercise
muscles in your body convert
energy this way – it causes a
burning sensation
Fermentation (cont.)
How does a cell obtain
energy?
The formula for cellular
respirations is
Glucose
Energy
+
Oxygen →
Chemical
+ Water + CarbonDioxide
C6H12O6 + 6O2 → Chemical
Energy + 6H2O + 6CO2
Photosynthesis and
Cellular Respiration are
two processes in the
energy cycle
These processes do not
have to occur in the same
cell or in the same
organism
Photosynthesis
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
from Greek photo, means
“light”; and synthesis, means
“composition”
Photosynthesis (cont.)
•
The chemical reactions of photosynthesis are powered by light energy.
•
In the chloroplasts of plants, pigments such as chlorophyll absorb light
energy
•
Chlorophyll absorbs all colors except green light, which is reflected as the
green color in leaves.
Photosynthesis (cont.)
How do some cells make food molecules?
Photosynthesis (cont.)
•
.
Chloroplasts
contain
chlorophyll
Chlorophyll is the
pigment that
traps the energy
in sunlight –
reflects green
Photosynthesis
takes place in the
chloroplasts
Photosynthesis
Is a complex Process
that has two stages
The first stage of
photosynthesis
involves capturing the
suns energy in the
chloroplasts
Chlorophyll acts as a
“solar cell” to capture
light energy and supply
power for the second
stage of photosynthesis
Photosynthesis
The Second stage requires the raw
materials
H2O (water) and CO2 (carbon dioxide)
Water is provided by the roots of the
plant
Carbon Dioxide enters the plant
through small openings on the
underside of leaves called Stomata
After entering the leaves H2O&CO2
move to the chloroplasts
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
Photosynthesis
View the process at classzone.com
http://www.classzone.com/books/ml_science_life/page_buil
d.cfm?id=resour_ch2&u=1
Plants do not
immediately use all
of the glucose it is
stored as starch and
also makes cellulose
Plants are considered
producers or
autotrophs because
they can make their
own food
Organisms that can
not make their own
food are called
consumers or
heterotrophs
• When an organism eats plant material it takes in food
energy from the plant’s glucose.
• An organism’s cells use the oxygen released during
photosynthesis and convert the food energy into usable
energy through cellular respiration
• Glycolysis is the first step in cellular
respiration.
• Fermentation provides cells, such as
muscle cells, with energy when oxygen
levels are low.
• Light energy powers the chemical
reactions of photosynthesis.
What does cellular respiration convert the energy in food molecules
into?
A.
B.
C.
D.
ATP
glucose
lactic acid
carbon dioxide
Eukaryotic and prokaryotic cells use fermentation to obtain energy
from what?
A.
B.
C.
D.
water
food
oxygen
pigments
What chemical reactions converts light
energy, water, and CO2 into the foodenergy molecule glucose?
A.
B.
C.
D.
lactic-acid fermentation
cellular respiration
alcohol fermentation
photosynthesis
Do you agree or disagree?
7. ATP is the only form of energy
found in cells.
8. Cellular respiration occurs only in
lung cells.
Key Concept Summary
Interactive Concept Map
Chapter Review
Standardized Test Practice