1. How Organisms Obtain Energy
Section 8.1 Pg

2. Energy is the ability to do work!
What is energy?
Energy is the ability to do work!

3. Thermodynamics
Thermodynamics is the study of the flow and transformation of energy in the universe.
2 Laws!
First law — energy can be converted from one
form to another, but it cannot be created nor
destroyed.
Second law — energy cannot be converted
without the loss of usable energy.

4. How do you get your energy?

5. Autotrophs and Heterotrophs
Organisms, such as plants, which make their own food, are called autotrophs.
Organisms, such as animals, that must obtain energy from the foods they consume are heterotrophs.

6. Autotrophs and Heterotrophs
◦ Living things need energy to survive. ◦ This energy comes from food. The energy in most food comes from the sun.

7. Metabolism
All the chemical reactions in a cell is referred to as the cells metabolism.
Brainpop

8. Metabolic pathways
Catabolic-release energy by breaking down large molecules into small ones
Anabolic- use energy to build large molecules from small molecules.

9. Photosynthesis—light energy from the Sun is converted to chemical energy for use by the cell
Is this Catabolic or Anabolic?

10. Cellular respiration—organic molecules are broken down to release energy for use by the cell
Is this Catabolic or Anabolic?

11. Compare the two Formulas
Photosynthesis
Cellular respiration

12. ?Confused?
Don’t worry we will talk more about these two processes in 8.2 and 8.3.

13. Energy comes in many forms including light, heat, and electricity.
Energy can be stored in chemical compounds, too.
ATP = ENERGY!!!

14. ATP
An important chemical compound that cells use to store and release energy is adenosine triphosphate, abbreviated ATP.
ATP is used by all types of cells as their basic energy source.

15. ATP consists of 3 parts:
adenine
ribose (a 5-carbon sugar)
3 phosphate groups

16. ATP: The Unit of Cellular Energy
Chapter 8
Cellular Energy
8.1 How Organisms Obtain Energy
ATP: The Unit of Cellular Energy
ATP releases energy when the bond between the second and third phosphate groups is broken, forming a molecule called adenosine diphosphate (ADP) and a free phosphate group.

17. Storing Energy
ADP or adenosine diphosphate has two phosphate groups instead of three.
A cell can store small amounts of energy by adding a phosphate group to ADP

18. Releasing Energy
Energy stored in ATP is released by breaking the chemical bond between the second and third phosphates.

19. The role of ATP
The energy from ATP is needed for many cellular activities, including active transport across cell membranes, protein synthesis and muscle contraction.
ATP’s characteristics make it exceptionally useful as the basic energy source of all cells.
This is why ATP is known as the
energy currency of the cell!!
ATP

20. Which law of thermodynamics explains
Chapter 8
Cellular Energy
8.1 Formative Questions
Which law of thermodynamics explains
why the ladybug receives the least amount of usable energy?

21. All of the energy from the food you eat comes from the sun.
Chapter 8
Cellular Energy
8.1 Formative Questions
True or False
All of the energy from the food you eat
comes from the sun.

22. Why is cellular respiration a catabolic pathway?
Chapter 8
Cellular Energy
8.1 Formative Questions
Why is cellular respiration a catabolic pathway?
Energy is used to form glucose and
oxygen.
Energy is converted from water to
carbon dioxide.
Energy that is lost is converted to
thermal energy.
Energy is released by the breakdown
of molecules.

23. Why is adenosine triphosphate (ATP) such an
Chapter 8
Cellular Energy
8.1 Formative Questions
Why is adenosine triphosphate (ATP) such an
important biological molecule?
It captures light energy from the sun.
It is produced in anabolic pathways.
It stores and releases chemical energy.
It converts mechanical energy to thermal
energy.