1. Cellular Respiration

2. Cellular Respiration Overview
Transformation of chemical energy in food into chemical energy cells can use: ATP
These reactions proceed the same way in plants and animals. Process is called cellular respiration
Overall Reaction:
C6H12O6 + 6O2 → 6CO2 + 6H2O

3. Obtaining Energy
Photoautotrophs – change light energy into chemical energy stored in bonds of glucose and polysaccharides (green plants, cyanobacteria)
Heterotrophs – feed on other organisms for chemical energy
Chemoautotrophs – microorganisms that can obtain energy from inorganic sources (Fe or S compounds in volcanoes, deep sea vents…)

4. Glucose – primary source of energy for most organisms
Cellular respiration – process by which glucose is broken down and energy stored in bonds is released, can be aerobic or anaerobic
Aerobic – oxygen used as an oxidizing agent (electron acceptor)
Anaerobic – uses a molecule other than oxygen as an oxidizing agent

5. Cellular Respiration Overview
Purpose of Cellular Respiration:
Trap free energy into forming ATP
Move H atoms (electrons) from glucose to oxygen creating 6 H2O
Break bonds between 6C atoms in glucose creating 6 CO2

6. 2 Ways ATP is formed during Cellular respiration:
Formation of ATP
2 Ways ATP is formed during Cellular respiration:
Substrate-level Phosphorylation
ATP formed directly in enzyme catalyzed reaction
P containing compound transfers P to ADP making ATP
4 ATP created this way from 1 molecule glucose

7. Oxidative Phosphorylation
ATP formed indirectly in more complex process
co-enzyme NAD+ (nicotinamide adenine dinucleotide) removes 2 H atoms and is reduced to NADH + H+
another co-enzyme, FAD (flavin adenine dinucleotide) also reduced by 2 H to become FADH2
these co-enzymes act as mobile energy carriers in cell, moving energy from one stage of cellular respiration to another where its used to create ATP

8. 4 Stages of Cellular Respiration
Name
Details
Stage 1
Glycolysis
10 step process in cytoplasm
Stage 2
Pyruvate Oxidation
1 step process in mitochondria
Stage 3
Kreb’s Cycle
8 step cycle in mitochondria
Stage 4
Electron Transport Chain
multi-step process in mitochondrial membrane

9. Glycolysis
A series of reactions which break the 6-carbon glucose molecule down into two 3-carbon molecules called pyruvate.
Occurs in the cytoplasm of the cell and is anaerobic.
Process is an ancient one-all organisms from simple bacteria to humans perform it the same way
Yields 2 ATP molecules for every one glucose molecule broken down (creates 4 ATP but uses 2)
Yields 2 NADH per glucose molecule (used later to create more ATP)
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