Cell Energy The Cell in Action

Cell Energy  Why do you get hungry?  Feeling hungry is your body’s way of telling you that your cells need energy.

Cell Energy All cells need energy to live, grow, and reproduce. Plant cells get their energy from the sun Many animal cells get the energy they need from food

From sun to cell  As you know, all energy webs and pyramids start with the sun.  Plants capture the energy of the sun and change it into food through a process called photosynthesis  The food that plants make supplies them with energy.  This food also becomes a source of energy for the organisms that eat the plants

Photosynthesis  Plants have molecules that absorb light energy.  These molecules are called pigments.  Pigments give color  The main pigment used in photosynthesis is called chlorophyll.  This give plants their green color  Chlorophyll is found in chloroplasts

Photosynthesis Plants use the energy captured in the chlorophyll to change the carbon dioxide and water into food. This food is in the form of a simple sugar: glucose When plants make glucose, they convert the sun’s energy into a form of energy that can be stored and used. Photosynthesis also produces oxygen!

Getting Energy from Food /webcontent/animations/co ntent/cellularrespiration.ht ml  Animal cells have different ways of getting energy from food  The first way, cellular respiration, uses oxygen to break down food  The second way, fermentation, no oxygen is needed

Cellular Respiration is not breathing!!!  The word “respiration” means “breathing”  But cellular respiration is different from breathing!  Breathing supplies the oxygen needed for cellular respiration  Breathing also removes carbon dioxide, which is the waste product of cellular respiration.  But cellular respiration is a chemical process that occurs in cells, not the mechanical process that occurs in your lungs

What cellular respiration is  It is a chemical process where food (such as glucose, a simple sugar) is broken down into carbon dioxide and water and energy is released  It is the opposite of photosynthesis.  It is used to make ATP by the mitochondrian, and maintain an animal’s body temperature.

A Symbiotic Relationship

Connection between Photosynthesis and Respiration… Photosynthesis Cellular Respiration  Plants  Changes carbon dioxide to oxygen  Plants need the CO2 for photosynthesis  Animals  Changes oxygen to carbon dioxide  Animals need the O2 for respiration

Fermentation Have you ever had a side stitch after running?

Fermentation When your muscles can’t get the oxygen needed for cellular respiration, they use the process of fermentation for energy. In fermentation, glucose molecules (sugars) are broken down, but oxygen is not used. The waste products of fermentation are lactic acid, alcohol, and carbon dioxide.