Life Science Chapter 3 - secondary

Life Science
Chapter 3
Lesson 3
Cell Energy
• Energy- The ability to do work
• God maintains life with energy to
the sun
• Plants use photosynthesis to turn
sun energy into food
Cellular Respiration
• Defined: the breaking down of
food molecules by cells into
usable energy
• Most cellular respiration is done in
the mitochondria
• (adenosine triphosphate) the
molecule that carries small
packets of energy for the cell’s
• Most energy is released in the
form of heat, helping maintain
body temperature
Metabolic Pathway
• A series of chemical reactions
that breaks down or makes
materials we all need
• They usually contain about a
dozen different steps
• Red blood cells have pathways
that manufacture hemoglobin
• Special proteins that speed up
chemical reactions in an
organism or cell
• Without enzymes, reactions inside
the cell would be to slow to
maintain life
Pop Quiz
• Get a sheet of paper
• Answer the following questions:
• 1. Do cells create energy?
• 2. What is the metabolism of a
• 3. Why do you think there are so
many different types of enzymes?