Section 9.1Energy and Life

Standard

• LS1.8 Create a model of photosynthesis demonstrating the net flow of matter and energy into a cell. Use the model to explain energy transfer from light energy into stored chemical energy in the product.

I Can…

• LS 1.8 I can develop a model to explain the flow of matter and energy in photosynthesis.

Key Questions

1. How do molecules of ATP store and provide energy for the cell?

2. Describe the transformation of energy that occurs during photosynthesis.

Vocabulary

• ATP

• Photosynthesis

Chemical Energy and ATP

• Energy is the ability to do work.

• All living cells store energy in the chemical bonds of certain compounds.

• Whether they get their energy from food or sunlight

• One of the most important compounds…ATP

Storing Energy

• ATP = adenosine triphosphate

• ATP has three parts: • Adenine

• A 5-carbon sugar called ribose

• Three phosphate groups (key to storing and releasing energy)

• ADP = adenosine diphosphate

• Has two phosphate groups instead of three

• Energy is stored when a phosphate group is added to ADP to make ATP

Releasing Energy

• ATP can release and store energy by breaking and re-forming the bonds between the second and third phosphate groups.

• ATP is exceptionally useful as a basic energy source for all cells.

• ATP functions like a rechargeable battery.

How Cells Use ATP (examples)

• Carry out active transport • Sodium-potassium pump in cell membrane

• Membrane proteins pump sodium ions (Na+) out of the cell and potassium ions (K+) into the cell.

• ATP provides energy to keep this pump working

• Enables cells to move• ATP provides power for motor proteins that contract muscle and

powers the wavelike movements of cilia and flagella

How Cells Use ATP (examples)

• Energy in ATP can be transferred to other molecules in the cell • Protein synthesis

• Responses to chemical signals on the cell’s surface

• Energy in ATP can be converted into light• The “blinking” of a firefly comes from an enzyme that is powered

by ATP

ATP Use

• You would think cells would be packed with ATP, since it is such a useful source of energy… not the case.

• Most cells only have a small amount of ATP.

• It is a great molecule for transferring energy, but not good for storinglarge amounts of energy over time.

ATP Use

• One molecule of glucose stores more than 90 times the energy required to add a phosphate group to ADP to make ATP.

• It is more efficient for cells to keep a small amount of ATP.

• Instead, cells regenerate ATP from ADP as needed (by using the energy in foods- like sugar).

Heterotrophs and Autotrophs

• Cell have to produce ATP constantly because it is used quickly.

• Where do living things get the energy to make ATP?

• Heterotrophs – organisms that obtain energy by consuming other living things• Eating plants

• Eating animals

• Absorbing nutrients from decomposing organisms in the environment

Heterotrophs and Autotrophs

• Autotrophs – organisms that can make their own food

• Ultimately… nearly all life on Earth depends on the ability of autotrophs to capture and convert the energy from sunlight to synthesize high-energy carbohydrates (sugars and starches)

• This process is known as photosynthesis. • Plants convert the energy of sunlight into chemical energy stored in the bonds

of carbohydrates.

Section 9.1 Exit Ticket

1. How do molecules of ATP store and provide energy for the cell?

2. Describe the transformation of energy that occurs during photosynthesis.

3. Explain how a rechargeable battery can be used as a model of ADP and ATP.

The End