Photosynthesis &

Cellular Respiration

Autotrophs & Heterotrophs• An organism that makes

its own food is called an autotroph.

• An organism that cannot make its own food is called a heterotroph.

• Nearly all living things get their energy directly or indirectly from photosynthesis.

CO2

Photosynthesis• The process by which a

cell captures energy in sunlight and uses it to make food.

• The raw ingredients that go into the plant cells are water and carbon dioxide

• The sunlight energy chemically changes the ingredients into food (glucose)

Photosynthesis• Water is absorbed by

the roots.• Carbon dioxide gas is

taken from the air• Glucose is stored and

used by the plant• Oxygen is released

into the air

The chemical formula for photosynthesis looks like

this:

6H2O + 6CO2 C6H12O6 + 6O2

(water) (carbon dioxide) (glucose) (oxygen)

(Sunlight)

Energy

CO2

O2

Photosynthesis occurs in the chloroplasts of plant cells.

Chlorophyll is the energy absorbing green pigment found in chloroplasts.

Gas Exchange

• Gasses (CO2 & O2) go in and out of leaves through little holes called stomata.

• Sometimes water vapor escapes the stomata through a process called transpiration.

Guard cells control when the stomata open and close.Guard Cells

Since leaves can lose water through stomata, on what part

of the leaves do you think stomata can be found?

Make a prediction.

Stomata are mostly found on the underside

of leaves. This helps the plant lose less

water.

Cellular Respiration

• The process by which cells obtain energy from glucose.

• Respiration means “breathing”

• This chemical reaction takes place in the matrix of the mitochondria

Cellular Respiration

Glucose chemically reacts with Oxygen to form the energy molecule ATP

C6H12O6 (glucose)

O2 (oxygen)

ATP (energy)

H2O (water)

CO2(Carbon dioxide)

The chemical formula for cellular respiration looks

like this:

6H2O + 6CO2 C6H12O6 + 6O2(water)(carbon dioxide) (glucose) (oxygen)(Sunlight)

+ Energy

+ 6H2O + 6CO2 C6H12O6 + 6O2 Energy (water) (carbon

dioxide)(ATP)(glucose) (oxygen)

Does this look familiar?

The Cycle of Cellular Energy

in Plants• The products made by the chloroplasts are used by the mitochondria. • The products made by the chloroplasts are used by the chloroplast.

Why don’t animal cells have this cycle?

• Deep water organisms

Fermentation provides energy for cells without using oxygen.

• Yeast (alcohol is byproduct)

• Muscle Cells (lactic acid is a byproduct = sore muscles)