9-1: Cellular Respiration

Biology 1

• Respiration is also used to mean “breathing”

• Animals use cellular respiration to break down oxygen and sugar into carbon dioxide and water for energy

Introduction

• 1937: Hans Krebs discovered that sugar gets broken down when oxygen is available

• Sugar gets broken down into citric acid and carbon dioxide gets released by cells (leaves body when you breathe out)

Krebs Cycle

• Quick energy: sprinting runners need FAST energy! They use what cells have stored first, then make more without oxygen

• Long term energy: long distance runners have stored lots of sugar (called glycogen), when that is gone they break down fats or muscle for more energy

Energy and Exercise

Photosynthesis

• Uses sunlight to make energy and sugar (food)

• PLANT CELLS (only) – chloroplast organelle

• Needs Carbon Dioxide and Water

• Makes Sugar and Oxygen

sunlight

6 CO2 + 6 H20 C6H12O6 + 6 O2

Cellular Respiration

• Uses food that is eaten to make energy

• ALL CELLS – mitochondria organelle

• Needs Sugar and Oxygen• Makes Carbon Dioxide

and Water

C6H12O6 + 6 O2 6 CO2 + 6 H20

• Photosynthesis and Cellular Respiration are OPPOSITES!

• Photosynthesis (plants) take carbon dioxide out of air, give back oxygen

• Cellular Respiration (animals) take oxygen out of air, give back carbon dixoide

Comparing Photosynthesis

and Cellular Respiration