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

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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

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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