Energy Transfer (8.1)
State Standard
SB3A. Explain the cycling of energy through the processes of photosynthesis and
respiration.
Transformation of Energy
Energy is the ability to do work.
8.1 How Organisms Obtain Energy
Cellular EnergyChapter 8
•All organisms depend on the flow of energy.
•The sun is the ultimate source of energy for almost all food chains.Exception: Hydrothermal Vents deep in the ocean.
Autotrophs and Heterotrophs
Autotrophs are organisms that make their own food. (They are the entry point for energy into the food chain.)
8.1 How Organisms Obtain Energy
Cellular Energy
Heterotrophs are organisms that need to ingest food to obtain energy.
Chapter 8
Metabolism
All of the chemical reactions in a cell
8.1 How Organisms Obtain Energy
Cellular Energy
Photosynthesis—light energy from the Sun is converted to chemical energy (carboyhydrates) for use by the cell
Cellular respiration—organic molecules (mainly carbs) are broken down to release energy for use by the cell
Chapter 8
Metabolism cont’d.
REMEMBER…
8.1 How Organisms Obtain Energy
Cellular Energy
Photosynthesis = Energy Storage
Cellular respiration = Energy Release
Chapter 8
ATP: The Unit of Cellular Energy
Adenosine Triphosphate - a special molecule that
stores & releases energy in its bonds for the needs of the cell.
8.1 How Organisms Obtain Energy
Cellular EnergyChapter 8
ATP cont’d
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.
8.1 How Organisms Obtain Energy
Cellular EnergyChapter 8
ATP cont’d
Phosphorylation = when the last phosphate group is transferred to another molecule with the help of an enzyme.
8.1 How Organisms Obtain Energy
Cellular EnergyChapter 8
ATP cont’d Energy can be stored by
adding a phosphate group back to the ADP molecule.
8.1 How Organisms Obtain Energy
Cellular EnergyChapter 8
ATP cont’d
Cells use ATP to…
make new molecules build organelles &
membranes maintain homeostasis move transmit impulses produce light etc.
8.1 How Organisms Obtain Energy
Cellular EnergyChapter 8
1. A
2. B
FQ 2
Cellular EnergyChapter 8
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8.1 Formative Questions
All of the energy from the food you eat comes from the sun.
A. true
B. false
1. A
2. B
3. C
4. D
FQ 4
Cellular EnergyChapter 8
8.1 Formative Questions
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A. It captures light energy from the sun.
B. It is produced in anabolic pathways.
C. It stores and releases chemical energy.
D. It converts mechanical energy to thermal energy.
Why is adenosine triphosphate (ATP) such an important biological molecule?
1. A
2. B
3. C
4. D
CAQ 3
Cellular EnergyChapter 8
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Chapter Assessment Questions
Look at the following figure. Which molecule is released when ATP becomes ADP?
A. phosphate group
B. water molecule
C. ribose sugar
D. energy cells