1. Chapter 8: Energy in a Cell

2. 8.1 I. Cell Energy
All life processes require energy = the ability to do work
1. active transport, cell division
2. movement
3. production of protein
4. maintaining homeostasis
5. transmitting impulses
B. Thermodynamics: The study of the flow
and transformation of energy in the universe
1. First Law of Thermodynamics: Law of
conservation of energy, cannot be created nor
destroyed
2. Second Law of Thermodynamics: Energy
cannot be converted without the loss of
energy

3. C. Metabolism: All of the chemical
reactions in a cell
1. Series of chemical reactions
2. Breaks down larger molecules or
uses energy to build large
molecules
3. Examples: Photosynthesis and
Cellular Respiration

4. II. ATP: The Unit of Cellular Energy
A. Energy is stored in biological molecules
B. ATP is the molecule that can store energy and release it easily when the cell needs it.
C. Most abundant energy- carrier in cells
Adenosine
Phosphate groups

5. III. Formation and Breaking Down ATP
Nucleotide made of an adenine base, a ribose sugar, and phosphate groups
Connected by phosphate bonds
C. Different molecules
1.One phosphate added
= adenosine monophosphate (AMP)
2. Two phosphates added
= adenosine diphosphate (ADP)
3. Three phosphates added
= adenosine triphosphate (ATP). This third bond is extremely HIGH energy.

6. D. Breakdown of
ATP  ADP
When the third, high energy bond in ATP is broken, great amounts of energy are released for use by the cell and ADP is formed.
ADP leaves site and is open for another phosphate bond to form= ATP
3. The formation and breakdown of ATP in the cell is cyclic.
ATP
Protein P
Energy
ADP

7. Equation for photosynthesis:
8.2 I Photosynthesis
A. Trapping sunlight and converting light energy to chemical energy as a simple sugar (glucose).
B. Happens in two phases:
1. Light dependent reactions– converts light energy to chemical energy.
2. Light independent reactions – uses ATP formed in the light dependent phase to produce glucose.
Equation for photosynthesis:
6CO2 + 6HO→C6H12O6 + 6O2
REACTANTS PRODUCTS l

8. II. Chloroplasts Plant cell organelle that captures light energy
1. Which organ of the plant are these found?
B Contain chlorophyll in the thylakoid membranes.
1. Light-absorbing pigments are found in the
thylakoid membranes.
2. Most common pigment= Chlorophyll absorbs light wavelengths, except green.

9. III. Chemosynthesis
A. Some bacteria can produce carbohydrates without Sunlight.
B. These organisms use CO2 and water, but the energy comes from breaking chemical bonds in compound, like hydrogen sulfide.

10. 8.3 I. Cellular Respiration
Organisms obtain energy in a process called cellular respiration
Respiration harvests electrons from organic molecules and uses energy to make ATP
Equation for Cellular Respiration
REACTANTS PRODUCTS

11. II. Cellular or Aerobic Respiration
A. Takes place in mitochondria in
the cytoplasm
B. Requires oxygen
C. Produces ATP

12. III. Anaerobic Respiration
A. Respiration without oxygen.
B. Also called Fermentation.
1. Lactic Acid Fermentation
a. Happens in animal cells when oxygen supplies are low.
b. Waste products = lactic acid and CO2.
c. Often produced by skeletal
muscles during exercise d. Produces 2 ATP

13. Alcoholic Fermentation
a. Happens in bacteria, yeasts and plants.
b. Waste products are CO2 and alcohol (used in baking and brewing industries).
c. Produces two molecules of ATP for every glucose molecule respired.

14. Photosynthesis and Cellular Respiration Connection

15. Produced Stored Released Required Yes No Yes No Compare and Contrast
Photosynthesis
Respiration
Glucose
Energy
CO2
Where occurs?
Requires light?
Chorophyll required?
RawMaterials?
(Reactants)
Products?
Produced
Broken Down
Stored
Released
Required
Waste Product
Chloroplast
Mitochondria
Yes No
Yes No
CO2 + H2O
and light energy
C6H12O6 + O2
C6H12O6 + O2
CO2 + H2O and ATP