1. 8.1 Energy and Life

2. k Energy is the ability to do work. For cells, 1. Their growth and development. 2. The building of molecules. 3. The maintaining of homeostasis. 4. Etc, etc, etc… Nearly every activity requires ENERGY

3. Energy comes in many forms – light, heat, electricity. There’s also chemical energy – energy stored in the bonds of molecules. General Rule: When a bond is formed, energy is stored. When a bond is broken, energy is released. Cells utilize chemical energy to power their activities.

4. The most readily available source of chemical energy for a cell is found in a molecule called ATP or… Adenosine Triphosphate *The key to ATP’s success as an energy molecule is its ability to easily make and break the bond between the 2 nd and 3 rd phosphates.

5. When cells release ATP’s energy… When a phosphate group is lost, the molecule is now called ADP, or Adenosine Diphosphate ENERGY!

6. ADP can always be bonded to another Phosphate group. This would recreate ATP. Basically, it’s Cyclical!

8. Cells are not born with an endless supply of Energy, or ATP. Where does the energy come from? FOOD When it comes to living things, you’re either a… 1. Autotrophs – organisms that can make their own food. Examples: Plants, algae, some bacteria. 2. Heterotrophs – organisms that obtain food by consuming other living things. Examples: Cow, cheetah, mushrooms, worms, humans. OR you’re an

9. 8.2 Photosynthesis: An Overview

10. Photosynthesis – plants convert the energy of sunlight into chemical energy stored in the bonds of carbohydrates. The Overall Reaction: In Words:

11. What is the site of Photosynthesis? The Chloroplast Key parts of the Chloroplast

12. How does light get captured? Plants gather the sun’s energy with light-absorbing molecules called pigments Most notable pigment: Chlorophyll – common pigment that does well absorbing all wavelengths of light. However, it reflects green light ***Reflected colors are the colors we see.

15. High-Energy Electrons (e-) When chlorophyll captures/absorbs light, it produces high-energy electrons. In order to complete the process of Photosynthesis, these electrons need transport to sites where sugars are made. NADP + - is a high-energy electron carrier. It can carry 2e- at a time NADP + + 2e-  NADPH

18. Fill in the Blanks of this Photosynthesis Diagram Light-dependent Light-independent Water Carbon Dioxide Sunlight Oxygen Glucose Thylakoid Granum