1 Review Why do all organisms need food Relate Cause and Effect Why do macromolecules

differ in the amount of energy they contain2 Apply Concepts How does the process of cellular

respiration maintain homeostasis at the cellular level Use Analogies How is the chemical energy in glucose

similar to money in a savings account

CH 9 CELLULAR RESPIRATION AND FERMENTATION

Chemical Energy and Food

Why do you need food It provides the chemical building blocks they need to

grow and reproduce It contains chemical energy that is released when its

chemical bonds are broken.

Calorie

Amount of energy needed to raise the temperature of 1 gram of water by 1 degree Celsius

1000 calories = 1 kilocalorie, or Calorie.

Cellular Respiration

Series of chemical reactions that breaks down sugar and releases energy

Occurs in all living cells Opposite of photosynthesis Oxygen + Glucose Carbon dioxide + Water +

Energy 6 O2 + C6H12O6 6 CO2 + 6 H2O + Energy.

Cellular Respiration

This occurs in animals AND plants This is the process that whenever your body needs

energy In addition to sugar, fats and proteins may also be

used.

Burn fuel Produce heat Produce H2O Produce CO2

Produce energy

SIMILAR DIFFERENT Cellular Respiration release

energy a little at a time Controlled

Stages of Cellular Respiration Glycolysis Krebs cycle Electron Transport

Chain (ETC).

Glycolysis Produces only a small

amount of energy Most energy (90%)

remains in the chemical bonds.

Krebs Cycle Produces only a small

amount of energy.

Electron Transport Chain (ETC) Produces the bulk of

the energy Uses oxygen.

Aerobic Require oxygen Krebb Cycle and ETC Occurs in the

mitochondria.

Anaerobic Does not need oxygen Glycolysis Occurs in cytoplasm.

Photosynthesis and Cellular Respiration

Opposite processes Photosynthesis

“deposits” energy Cellular respiration

“withdraws” energy.

Glycolysis First stage of cellular

respiration Glucose is broken

down into 2 molecules of the 3-carbon molecule pyruvic acid

ATP and NADH are produced.

Krebs Cycle

Pyruvic acid is broken down into carbon dioxide

A.k.a. Citric Acid Cycle ATP is produced.

Electron Transport

NADH and FADH2 pass their electrons to ETC.

Electron Transport

Electrons combine with H+ ions and oxygen to form water at end of ETC.

Electron Transport

The high energy electrons move H+ ions against a concentration gradient across the inner mitochondrial.

Electron Transport

H+ ions pass back through the ATP synthase causing it to spin

ATP synthase attaches a phosphate to ADP to produce ATP with each rotation.

Energy Totals Complete breakdown

of glucose through cellular respiration results in the production of 36 ATP molecules

The rest of the energy is “lost” as heat (64%).

Fermentation

Process of releasing energy from food in the absence of oxygen.

Fermentation

NADH is converted back to NAD+

Allows glycolysis to continue producing ATP.

Alcoholic Fermentation

Pyruvic acid + NADH Alcohol + CO2 + NAD+

Yeast and other microorganisms Produces alcoholic beverages and causes bread

dough to rise.

Lactic Acid Fermentation

Pyruvic acid + NADH Lactic acid + NAD+

Humans and most organisms.

Quick Energy

Cells have enough ATP for a few seconds of intense activity

Lactic acid fermentation can supply enough ATP to last about 90 seconds

Extra oxygen is required to get rid of the lactic acid produced.

Long-Term Energy

Cellular respiration is required to continue production of ATP for exercise longer than 90 seconds

Body uses glycogen stores for the first 15-20 minutes

Body then will break down other stored molecules, including fats.