1. Chapter 8 Section 3 – Cellular Respiration

2. Overview of Cellular Respiration
Living organisms obtain energy by breaking down organic molecules during cellular respiration.
It is a catabolic pathway in which organic molecules are broken down to release energy for use by the cell.

3. The equation for cellular respiration is the opposite of the equation for photosynthesis.

4. The Reactants of Cellular Respiration are: Glucose (C6H12O6) – eat
Cellular Energy
The Reactants of Cellular Respiration are:
Glucose (C6H12O6) – eat
Oxygen (O2) – breathe in
The Products of Cellular Respiration are:
Heat – released throughout your body
Carbon Dioxide (CO2) – breathe out
Water (H2O) – breathe out

5. Cellular respiration occurs in two main stages:
Cellular Energy
Cellular respiration occurs in two main stages:
Glycolysis – occurs in the cytoplasm
Aerobic respiration – occurs in the mitochondria

6. Glycolysis
The splitting of glucose
Occurs in the cytoplasm
Does not require oxygen

7. Glycolysis
Final products of glycolysis for each molecule of glucose are:
2 ATP’s
2 molecules of NADH
2 molecules of pyruvate for each glucose molecule that is broken down
4 molecules of ATP are actually produced when glucose is split, but the energy from 2 of those are needed for the reactions to take place.

8. Cellular Energy
Aerobic Respiration
In aerobic respiration, oxygen is used to break down glucose molecules.
As a result 36 ATP can be made from 1 glucose molecule.
Aerobic respiration follows glycolysis and occurs inside the mitochondria.
The 2 pyruvate molecules are transported to the mitochondria.

9. Cellular Energy
Two pyruvate molecules from glycolysis is transformed into acetyl CoA and enters the Krebs cycle.

11. Krebs Cycle (sometimes referred to as the citric acid cycle)
Cellular Energy
Krebs Cycle (sometimes referred to as the citric acid cycle)
Series of reactions in which pyruvate is broken down into carbon dioxide.
There are two “turns” of the Krebs cycle for each glucose molecule. Why?

12. Krebs cycle results in the net production of:
Cellular Energy
Krebs cycle results in the net production of:
8 NADH
2 FADH2
2 ATP
6 CO2

13. Electron Transport Chain
Cellular Energy
Electron Transport Chain
NADH & FADH2 enter electron transport chain in mitochondria cristae.
High energy electrons and hydrogen ions from NADH and FADH2 produced in the Krebs cycle are used to convert ADP to ATP.

14. Electron Transport Chain Oxygen is the final acceptor of electrons.
Cellular Energy
Electron Transport Chain
Oxygen is the final acceptor of electrons.
Protons and electrons are transferred to oxygen to form water.
Produce 32 more ATP.

15. Summary of Cellular respiration

16. Anaerobic Respiration
Cellular Energy
Anaerobic Respiration
The first step in anaerobic respiration is also called glycolysis.
Anaerobic = without oxygen
Plant and animal cells cannot survive off of anaerobic respiration.
Not very efficient

17. Anaerobic Respiration
Cellular Energy
Anaerobic Respiration
There are 2 types of anaerobic respiration:
Lactic acid fermentation
A process that occurs in animal cells
Causes your muscles to burn when you perform short bursts of activity
Alcohol fermentation
A process that occurs in plants
This is how alcohol, such as wine and beer, is made

18. Lactic Acid Fermentation

19. Alcohol Fermentation

20. Review the two equations for photosynthesis and cell respiration.
They are reversed!

21. Cellular Respiration & Photosynthesis are Interrelated
Cellular Energy
Cellular Respiration & Photosynthesis are Interrelated
Products for photosynthesis are oxygen and glucose, the reactants for cellular respiration.
Cellular respiration uses O2 to break the sugars down and releases the CO2 back into the atmosphere to be used again by plants.

22. Cellular Respiration & Photosynthesis are Interrelated
Cellular Energy
Cellular Respiration & Photosynthesis are Interrelated
Notice! Molecules such as O2 and CO2 are recycled through the environment, however the energy is not!
Energy enters our environment as light and leaves back into outer space as heat.

23. Cellular Respiration & Photosynthesis
Cellular Energy
Cellular Respiration & Photosynthesis