1. How Organisms Obtain Energy
Chapter 8, Section 1

2. All living organisms use energy to carry out all biological processes
Main Idea
All living organisms use energy to carry out all biological processes

3. Thinking Question 1. What types of cellular processes require energy?
Macromolecules are being assembled and broken down
Substances are being transported into and out of cells
Genetic instructions are transmitted
Cardiac cells are contracting
Nerve cells are transmitting signals

4. Chemical reactions are constantly being carried out in your cells
A. Transformation of Energy
Chemical reactions are constantly being carried out in your cells
In order for them to occur, energy is required
Energy is the ability to do work
Thermodynamics is the study of the flow and transformation of energy in the universe

5. Laws of Thermodynamics
First Law – law of conservation of energy
Energy cannot be created or destroyed, only transformed into different forms

6. Laws of Thermodynamics
Second Law
Energy cannot be converted without the loss of some usable energy
The amount of usable energy decreases as it travels from sun to autotrophs to heterotrophs

7. Autotrophs are organisms that are able to make their own food
Chemoautotrophs use chemicals as a source of energy
Photoautotrophs (plants) use sunlight as a source of energy and convert it to chemical energy

8. Heterotrophs (animals/humans) are organisms that need to ingest food to obtain energy
Nearly all of the energy for life comes from the sun and travels through other organisms

9. Metabolism – all of the chemical reactions in a cell
B. Metabolism
Metabolism – all of the chemical reactions in a cell
2 types of metabolic pathways:
Catabolic – release energy by breaking down larger molecules into smaller molecules
Anabolic – use energy released by catabolic reactions to build larger molecules from smaller molecules

10. Energy flows continuously between metabolic reactions of organisms in an ecosystem
Photosynthesis is an anabolic pathway
Light from sun, carbon dioxide, and water form glucose and oxygen
Energy stored in glucose is transferred to heterotrophs when consumed as food
Cellular respiration is a catabolic pathway
Oxygen is used to break glucose down into carbon dioxide, water, and usable energy

12. C.
ATP: The Unit of Cellular Energy
ATP (adenosine triphosphate) – the most important biological molecules that provides chemical energy for living things

13. ATP Structure
ATP is a nucleotide made up of
Adenine
Ribose sugar
3 Phosphate groups

14. ATP Function
ATP releases energy when the bond between the 2nd and 3rd phosphate groups is broken, forming ADP (adenosine diphosphate) and a free phosphate group
Energy is restored in that bond when a phosphate group is added to ADP