Cellular Respiration

Mr. MahLiving Environment

Announcements

• Vocabulary Quiz on Friday (Tomorrow)

• Unit 3 Test will be Tuesday of Next Week–December 15th

Do-Now (6 minutes)• What do you rely on for energy?

• Are there particular foods that boost your energy?

Digestion for Energy

• All living things need energy to stay alive.

• Before the energy in the food we eat can be

used, it must be digested into simpler ones, such as glucose.

Respiration• Glucose must be broken down further. This

process involves a series of chemical reactions controlled by enzymes.

• In the final step, the chemical bonds of the glucose are broken, and their energy is released. This process of releasing the energy in chemical bonds is called cellular respiration.

• Where have we seen the word respiration before? – Respiration = breathing– Respiratory System

Aerobic Respiration

• Aerobic: requires oxygen • During cellular respiration, cells capture

much of the energy released from the glucose bonds.

• The captured energy is then used to form new bonds in high–energy molecules known as ATP.

Location, location, location!

• Cellular respiration is completed in the mitochondria. – Note: cells that require more energy contain

more mitochondria i.e. muscles require more energy than skin, therefore, muscle cells usually contain more mitochondria.

• As they generate ATP, mitochondria release carbon dioxide and water.

GLUCOSE OXYGEN

CARBON DIOXIDEWATER

ATP

Mitochondria

Anaerobic Respiration

• Anaerobic: no oxygen• Takes place in the cytoplasm of the cell,

requires enzymes• The organisms that usually use anaerobic

respiration are:1. Bacteria2. Yeast

Anaerobic Respiration

2 Types:• Alcohol Fermentation • Used by yeast to make ethyl alcohol

• Lactic Acid Fermentation• Used by muscles to make lactic acid• Causes muscle fatigue (weakness)

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Which is better?• Anaerobic respiration

1. Alcohol fermentation: glucose 2 ethyl alcohol + 2 CO2 + ATP

2. Lactic acid fermentation: glucose 2 lactic acid + 2 ATP

• Aerobic respirationGlucose + 6 oxygen 6 water + 6 CO2 + 36 ATP

• Aerobic respiration is more efficient because it uses oxygen to release more energy per glucose molecule.

 • Organisms use ATP for energy.

Cellular Respiration is the reverse of photosynthesis!

Reactants Products

CO2 + H2O + Energy (light) Glucose + O2

Glucose + O2 CO2 + H2O + Energy (ATP )