Unit 3: Cellular Respiration

Cellular Respiration

How do animals get energy from

food?

Cellular Respiration

•Cellular= in the cells
•Respiration is like breathing, but for the cell.
- oxygen is taken into the cell and carbon dioxide
comes out, just like how you breathe

•Cellular respiration is the process living things use
to turn food into energy the cells can use

Cellular Respiration

• In a series of reactions,

fats, proteins, and
carbohydrates, mostly
glucose, are broken
down to make CO2,
water, and energy in the
form of ATP.

Where cellular respiration happens

•Cellular respiration happens
inside our cells
•Inside the cell is an organelle
called the mitochondria
•The mitochondria is called the
“powerhouse” of the cell
because it is where the cell
generates its energy.

Getting energy from food

•We can’t just use the food we eat
•The food has to be converted to cellular energy
•This energy is called ATP
•The sugars get broken down and converted to a
different molecule that has a lot of stored energy that
can be used

ATP

•The biological molecule that provides us with chemical energy is
called adenosine triphosphate- ATP for short
•ATP is an energy carrier- you can think of it like a battery for your
cells
•When one of the phosphates
is broken, energy is released
•This phosphate can be joined
back on and broken off again-
like recharging a battery

https://www.youtube.com/watch?v=NN5Y57NbnrU

How it Works
•The cell needs:
- sugar
- oxygen
•A complex series of chemical reactions happen, and
the cell makes
- water
- carbon dioxide
- 38 ATP molecules (cellular energy)

Three Main Steps of Cellular
Respiration

1) Glycolysis- Break glucose apart
2) Krebs Cycle- Break it down more
3) Electron Transport Chain- Generate

ATP through facilitated diffusion

Formula
•The formula is:
C6H12O6 (glucose)+ O₂ → CO₂ + H₂O + ATP (energy)

•It is the opposite of photosynthesis

CO₂ + H₂O + sunlight (energy) →Glucose + O₂

Aerobic vs Anaerobic Respiration

•Aerobic means with oxygen (normal cellular
respiration)
•Anaerobic means without oxygen
•Aerobic respiration generates most ATP
•Sometimes, respiration happens without
oxygen such as when oxygen levels are low
(fermentation)

Electron
Transport Chain

Video

Simple

https://www.youtube.com/watch?v=Py4R_Up2uBc

Complex
https://www.youtube.com/watch?v=pNzFYBA2Ofg

Photosynthesis and
Cellular Respiration
are Linked
-We exchange gases
needed for the other’s
life processes

Photosynthesis and
cellular respiration
interact in the
global carbon cycle

- Burning fossil

fuels and
deforestation
have upset this
cycle