1. Cellular Respiration
Chemical Pathways

2. Food = chemical energy
calorie is the amount of energy needed to raise the temperature of 1 gram of water 1 degree Celsius
Calorie = kilocalorie = 1000 calories is what you see on food labels
Gradual process to release energy from food molecules begins with…
Glycolysis

3. Overview
Cellular respiration is the process that releases energy by breaking down glucose and other food molecules in the presence of oxygen
Glycolysis is the process in which one molecule of glucose is broken in half, producing two molecules of pyruvic acid (a 3-carbon compound)

4. Glycolysis, again
Glycolysis will not begin without the input of energy (ATP)
It can only be completed in the presence of the high energy electron carrier NAD+
In the end it makes two more ATP than were “spent”

5. Fermentation To get the most energy from food, cells use oxygen
IF no oxygen is present, cells continue generating energy through an anaerobic pathway (without O2) known as fermentation
The two main types of fermentation are alcoholic fermentation and lactic acid fermentation

6. Fermentation (more)
Yeasts and some microorganisms produce carbon dioxide and ethanol as a waste product of fermentation
YOUR cells and the cells of animals produce lactic acid as a waste product of fermentation
Fermentation makes no ATP but regenerates NAD+ which can be used in glycolysis