1. Cellular Respiration

2. Cellular Respiration
Respiration is the process by which plant and animal cells get energy from glucose (sugar).
The glucose came from?
A product from photosynthesis in plants.
During respiration cells break down simple food molecules such as sugar and release the energy that is contained.
There are 2 stages just as in photosynthesis.

3. Respiration Stage 1 The first stage in the cytoplasm.
There, molecules of glucose are broken down into smaller molecules.
Oxygen is not involved, and only a small amount of energy is released.

4. Stage 2 The second stage of respiration happens in the mitochondria.
There, the small sugar molecules are broken down into even smaller molecules.
These chemical reactions require oxygen, and they release a great deal of energy.
This is why the mitochondria are sometimes called the “powerhouses” of the cell.

5. Cellular Respiration Note that energy is released in both stages.
Two other products of respiration are carbon dioxide and water.
These products diffuse out of the cell going from the high concentration in the cell to the low concentration in the blood.
In most animals, the carbon dioxide and some (not all) water leave the body during exhalation, or breathing out.
So when you breathe in, you take in oxygen—a raw material for respiration. When you breathe out, you release carbon dioxide and water—products of respiration.
These products become the raw materials of photosynthesis.

6. Cellular Respiration and Food

7. Cellular Respiration
Notice that the raw materials/reactants for respiration are sugar and oxygen.
Plants and other organisms that undergo photosynthesis make their own sugar.
The glucose in the cells of animals and other organisms comes from the food they eat.
The oxygen used in respiration comes from the air or water surrounding the organism.
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8. Mitochondria Structure
Mitochondria are shaped perfectly to maximize their productivity.
They are made of two membranes (like chloroplasts).
The outer membrane covers the organelle and contains it like a skin.
The inner membrane folds over many times and creates layered structures called cristae.

9. Mitochondria Structure
Cristae are the folds of the inner membrane. They are like booths in a restaurant allowing more seating.
This means more energy can be produced.
The fluid contained in the mitochondria is called the matrix.
Video Clip

10. Respiration Equation
C₆H₁₂O₆ + 6O CO2 + 6H2O + energy

11. Comparing Photosynthesis and Respiration
What do you notice about the equation for respiration?
It is the opposite of the equation for photosynthesis. 
During photosynthesis, carbon dioxide and water are used to produce sugars and oxygen.
During respiration, the sugar glucose and oxygen are used to produce carbon dioxide and water.

12. Comparing Photosynthesis and Respiration
Photosynthesis and respiration can be thought of as opposite processes.
Together, these two processes form a cycle that keeps the levels of oxygen and carbon dioxide fairly constant in Earth’s atmosphere.
Living things use both gases over and over again.

13. Respiration Raw Materials
What are the raw materials of respiration?
Glucose and oxygen
Where does the glucose come from?
Plants that animals eat
Animals we eat that ate plants
Where does the oxygen come from?
A product of photosynthesis
It leaves a plant through its stomata

14. Respiration Products What are the products of respiration?
Carbon dioxide and water and energy
Where does the carbon dioxide go?
Into the air for plants to “breathe” in through their stomata
Where does the water go?
Into the water cycle to be absorbed by plant roots
Where does the energy go?
Used as fuel for plant and animal cells
Burned while moving, breathing, eating, etc.

15. Don’t Forget!

16. Matter Cycle - Elements
How do respiration and photosynthesis work together as a cycle?

17. Energy Cycle

18. Photosynthesis vs. Respiration
Feature
Photosynthesis
Respiration
Raw Materials
Products
Is energy required or released?
Requirement of sunlight
Fate of Carbon Dioxide and Oxygen
Main Function
Occurs in which organisms?
Water and Carbon Dioxide
Sugar (glucose) and Oxygen
Sugar (glucose) and Oxygen
Water and Carbon Dioxide
Required
Released
Can only occur in presence of sunlight
Occurs AT ALL TIMES without sun
CO₂ is absorbed while O₂ is released
O₂ is absorbed while CO₂ is released
Production of food, capture of energy
Breakdown of food, release of energy
Plants, protista (algae), and some bacteria
Occurs in ALL living organisms (plants AND animals)