Energy in a Cell Unit 3 Chapter 9

Importance of energy Cells need energy to be able to carry out important metabolic functions to sustain life. Ex: Active transport, cell division, movement of flagella or cilia, and the production, transport, and storage of proteins

Autotrophs Plants, algae, some bacteria are able to store sunlight energy for use.

Heterotrophs These organisms cannot store sunlight energy. They must eat (consume) to have energy.

ATP: the “battery” for a cell Adenosine triphosphate 1 adenine + 3 phosphate molecules bonded together Each time a phosphate molecule is removed, energy is released.

Getting energy out of ATP ENERGY RELEASED! Remove 1 phosphate group Adding 1 phosphate back to ADP to make ATP ADP

What process makes ATP? Cellular respiration is the primary way of making ATP molecules from simple sugars. How are simple sugars made?

Photosynthesis: the autotrophic process of making sugars using sunlight energy

Photosynthesis chemical equation 6CO2 + 6H2O→C6H12O6 + 6O2 6 carbon dioxide + 6 water makes simple sugar + 6 oxygen

How autotrophs capture sunlight energy Click image to play video.

Pigments Molecules that absorb specific wavelengths of light Autotrophs primarily rely on chlorophyll pigments to absorb sunlight.

Where are chlorophyll pigments found? Chlorophyll are found inside the chloroplast organelle. These organelles are common in the cells of leaves and sometimes stems.

How do chlorophyll help to make sugar? Chlorophyll absorb sunlight energy. Electrons become energetic from light energy that the only way to lower the energy level is to pass the electrons from one molecule to another like playing “hot potato.” This starts a series of chemical reactions to break bonds and reform bonds that sugar is made in the end. This process is photosynthesis.

What happens to the sugar? Plants can store the sugar in roots or stems (ex: carrot, sugar cane) to make ATP by cellular respiration as needed. Heterotrophs such as humans must eat complex carbohydrates (ex: carrots, potatoes) to have sugar to make ATP by cellular respiration.

Mitochondria All eukaryotes have mitochondria. The mitochondria is necessary to help break down the sugar to make ATP molecules (cellular respiration). Bacteria do not have mitochondria, but they have the ability to break down sugars in their cytoplasm to make ATP.