L E S S O N 2

You may not know it, but there are organisms living in rocks deep below Earth’s surface. Other organisms hand out in steaming hot lakes. The water in these lakes can be as hot as 86° C (186.8° F)!! Other organisms nestle inside nuclear waste. All of these organisms are extremophiles, organisms that thrive in extreme habitats.
These life forms can get energy in strange ways. Some make food from ocean minerals. Others break down compounds in radioactive rocks!!

Living organisms need a constant supply of energy!!
Cellular Respiration: The process by which cells obtain energy from glucose (C
6
H
12
O
6
).
• During cellular respiration , cells break down glucose and other molecules from food in the presence of oxygen , releasing energy .
The cells of living things carry out cellular respiration continuously.

Storing and Releasing Energy
• When you eat a meal your body stores energy in the form of glucose .
• When cells need energy , they break down glucose through cellular respiration .

Breathing and Respiration
• Breathing brings oxygen into your lungs , which is carried to cells for cellular respiration .
• Breathing also removes the waste product of cellular respiration from your body .

First Stage:
• Occurs in the cytoplasm of a cell.
• Molecules of glucose are broken down into smaller molecules.
• Only a SMALL amount of energy is released.
• Oxygen (O) is NOT involved.
Cellular Releases From
Respiration Energy Food

Second Stage:
• Takes place in the mitochondria.
• Small molecules (left over from stage 1) are broken down even more.
• Requires oxygen.
• Releases large amounts of energy.
Cellular Uses You Get From
Respiration Oxygen Breathing

• Animals get glucose from the foods they eat .
• Plants and other organisms that carry out photosynthesis are able to produce their own glucose .
• The oxygen needed for cellular respiration is in the air or water surrounding the organism .

What do you notice about the Cellular Respiration
Equation and the Photosynthesis Equation.
Photosynthesis Equation
Cellular Respiration Equation

Cellular respiration is the complete opposite of photosynthesis !!!!
Together these two processes form a cycle that keeps the levels of oxygen and carbon dioxide constant in
Earth’s atmosphere .

There are times when there is not enough oxygen for cells to carry out cellular respiration.
Organisms must switch to Fermentation .
Fermentation: An energy releasing process that does not require oxygen .
• During fermentation , cells release energy from food
WITHOUT using oxygen .
**Releases much LESS oxygen than cellular respiration**

Alcoholic Fermentation: Occurs in yeast and other single-celled organisms .
• Produces alcohol, carbon dioxide (CO
2 amount of energy .
), and a small
Why are these products of Alcoholic fermentation important to bakers and brewers??

Why are these products of Alcoholic fermentation important to bakers and brewers??
• Carbon dioxide produced by yeast creates gas pockets in bread dough, causing it to rise .
• Carbon dioxide is the source of bubbles in alcoholic drinks.

Lactic Acid Fermentation: Occurs when your muscle cells used up oxygen faster than it could be replaced .
(When your cells lack oxygen fermentation occurs)
• Muscle cells get energy by breaking down glucose without using oxygen .
• Produces lactic acid .
Build up of lactic acid causes muscle weakness, pain and soreness. (Results from exercise)
When your muscles get more oxygen, lactic acid will break down and the pain goes away.

1.
Plant cells capture energy by way of
Fermentation/ Photosynthesis/ Cellular Respiration
2.
Plants are autotrophs because…
2.
Plant cells release energy for cell function by way of
Photosynthesis/ Fermentation/ Cellular Respiration
2.
A runner jogging through town gets energy by way of
Fermentation/ Photosynthesis/ Cellular Respiration

5. The runner is a heterotroph because he/she gets energy from…
6.
If the runner makes a long, fast push push to the finish his/her muscle cells may energy by way of
Photosynthesis/ Fermentation/ Cellular Respiration
7. Develop a Hypothesis. When a race ends, why do you think runners continue to breathe quickly and deeply for a few minutes?