Photosynthesis and Respiration
• USE THIS FOR SLOT NOTES
Sources of Energy
• All cells need energy to carry out their
functions, such as making proteins and
transporting materials in and out of the cell.
• Many organisms need to eat food in order to
gain this energy.
Sources of Energy
• Some organisms, such as plants, algae, and
some bacteria,don't eat food. Instead, they
use the energy in sunlight to make their own
food.
Sources of Energy
• An organism that uses energy from the sun to
make it's own food is called an AUTOTROPH.
• An organism that obtains energy by eating
other organisms as it's food is called a
HETEROTROPH.
Sources of Energy
• The process by which a cell captures energy in
sunlight and uses it to make food is called
Photosynthesis.
• Nearly all living things obtain their energy
either directly or indirectly from the energy of
sunlight captured during photosynthesis.
DO NOW
Trace the energy in each ingredient in a ham and
cheese sandwich all the way back to the sun.
Photosynthesis
• During photosynthesis plants use the energy
from the sun to convert Carbon Dioxide and
Water into Oxygen and Sugar.
Photosynthesis
Photosynthesis happens in 2 stages
1. Capture the sun's energy.
2. Use the energy to make food.
Capturing the Sun's Energy
step 1
• The chloroplasts in plant cells are full of a
green pigment called chlorophyll.
• This pigment absorbs and traps the sun's
energy.
Using the Captured Energy to Make Food
step 2
• In order to make a sugar, the cell needs two
raw materials...
1. Water (comes up the roots to the leaves)
2. CO2 (comes into the leaf through the
stomata)
• In the chloroplast these materials undergo a
complex series of chemical reactions which
produce sugar and oxygen as products.
Photosynthesis
Cellular Respiration
• During cellular respiration cells take sugar and
break it down, releasing the stored energy.
Cellular Respiration
• In order get energy from sugar, the cell needs two
raw materials...
1. Sugar (comes from the food an organism eats)
2. Oxygen (comes from the air or water surrounding
the organism)
• In the mitochondria these materials undergo a
complex series of chemical reactions which produce
Carbon Dioxide and water as products.
Cellular Respiration
• The first part of cellular respiration takes place in the
cytoplasm. Here molecules of sugar are broken down
and a small amount of energy is made.
• The second part of cellular respiration takes place in
the mitochondria. Here oxygen is used to create a
large amount of energy.
Cellular Respiration
FERMENTATION
• Fermentation is a way of providing energy for cells without
using any oxygen.
• Some organisms, like yeast, use fermentation to make energy
for their cells. This produces alcohol in the process so it is
called alcoholic fermentation.
• In humans, when not enough oxygen is available, muscle cells
use a process called lactic acid fermentation to
provide energy for your cells.