Energy and Life

9.1 Energy and Life

Energy is necessary to maintain homeostasis- to move materials, build molecules, and respond to changes in the environment. ​

​Learning Targets

A. Explain how ATP is useful to cells

B. Explain what happens during the process of

photosynthesis

​Chemical Energy and ATP

Energy is the ability to do work - Cells require energy to do work

● The ability to obtain and use energy by converting it to one form or another is critical for life

● What are some forms of energy?

○ Light

○ Heat

○ Electricity

Unit 5: Photosynthesis and Respiration

​Example: Burning a candle

■ When you light a candle, bonds between carbon and hydrogen atoms in

wax are broken.

■ New bonds then form between these atoms producing carbon dioxide

and water

■ These new bonds have less energy than the original bonds in the wax.

■ The energy is lost as heat and light -- the flame.

Unit 5: Photosynthesis and Respiration

Storing Energy

● Whether from food or sunlight, all living things store energy in the chemical bonds of certain compounds

● One of the most important compounds is Adenosine triphosphate or ATP

Unit 5: Photosynthesis and Respiration

Storing Energy in ATP

● The phosphate groups are the key to ATP’s ability to store energy

● Adenosine diphosphate (ADP) is identical to ATP but it has two phosphate groups instead of three

● The difference is key:

○ When a cell has energy available, it can store small amounts of it by adding phosphate groups to ADP to produce ATP.

Unit 5: Photosynthesis and Respiration

Releasing Energy

• Cells can release the energy stored in ATP by the controlled breaking of chemical bonds between atoms in the second and third phosphate groups

  ATP can release and store energy by breaking and reforming the bonds between its phosphate groups. This characteristic of ATP makes it exceptionally useful as a basic energy source for all cells.

Unit 5: Photosynthesis and Respiration

How Cells Use ATP

Active transport

○ ATP is the source of energy for the movement of materials across the cell membrane

■ Examples: membrane pumps that move ions across the membrane to maintain a carefully regulated balance

Unit 5: Photosynthesis and Respiration

How Cells Use ATP

Movement

○ ATP is the source of energy for movement

■ Examples: Cilia and flagella are structures of movement in

in protists and certain cells of our bodies

Unit 5: Photosynthesis and Respiration

How Cells Use ATP

Protein Synthesis

○ ATP is the source of energy for the production of proteins

■ Example: the chemical energy from ATP can be converted to light energy- the flashing seen in fireflies.

● This ability is driven by enzymes- proteins powered by ATP

Unit 5: Photosynthesis and Respiration

How Cells Use ATP

Limitations of ATP

○ Even though it is a great molecule for transferring energy, it is not good for storing large amounts of energy for the long term. ■ Example: glucose stores more than 90 times the energy required to add a phosphate to ADP to make ATP.

● Therefore, it is more efficient to keep small amounts of ATP and regenerate ATP from ADP using the energy of foods like sugar.

Unit 5: Photosynthesis and Respiration

Heterotrophs and Autotrophs

Most animals obtain the chemical energy they require from food.
● Heterotrophs: organisms that obtain energy by consuming other living organisms.
○ Some consume plants. What do we call them?
○ Some consume organisms that feed on plants. What do we call them? ○ Some absorb nutrients from decomposing organisms. Examples?

Unit 5: Photosynthesis and Respiration

Heterotrophs and Autotrophs

Autotrophs: organisms that make their own food

○ Examples: plants, algae, and some bacteria

● Ultimately, nearly all life on earth is dependent on autotrophs capturing
the energy from sunlight to synthesize food.

In the process of photosynthesis, plants convert the energy of sunlight into chemical energy stored in the bonds of carbohydrates.

Unit 5: Photosynthesis and Respiration

Drag and Drop

Cells use a molecule called​ ​

Placeholder

to store and

release energy like a battery. The energy is stored in chemical bonds between​ ​ ​ ​​

Placeholder

groups of the molecule, and the

energy is released when the chemical bonds are brok​en​

Drag these tiles and drop them in the correct blank above

ATP

phosphate

DNA

RNA

CMP

Nucleotide

oxygen

Drag and Drop

Plants, algae, and some bacteria use the energy of sunlight in the

process of​

Placeholder

The

process converts the energy from sunlight into chemical energy stored in the

bonds of ​

Placeholder

(carbon dioxide / carbohydrates / proteins / water molecules).

Drag these tiles and drop them in the correct blank above

Photosynthesis

carbohydrates

herbivory

respiration

carbon dioxide

proteins

water molecules

Multiple Choice

The diagram shows the molecular structure of adenosine triphosphate

(ATP)

Which of these events occurs during the normal function of ATP in the cell?

• A chemical bond forms between the adenine unit and the third phosphate

  group.

• The chemical bond breaks between the adenine and ribose units.

• The chemical bond breaks between the ribose unit and the first phosphate

  group.

• The chemical bond breaks between the second and third phosphate groups.

Multiple Choice

The diagram shows the molecular structure of adenosine triphosphate

(ATP)

Which statement best describes the relationship between adenosine

diphosphate (ADP) and adenosine triphosphate (ATP)?

• With an input of energy, ATP rearranges to become ADP

• Without any energy change, ADP rearranges to become ATP.

• With an input of energy, ADP combines with a phosphate group to become

  ATP.

• With a release of energy, ADP combines with a phosphate group to become

  ATP.

Multiple Choice

Chloe is developing a model of photosynthesis. The first part of the model

is shown to the left.

Which would be the MOST useful next step for Chloe to develop the

photosynthesis model further?

• Extend the lines for sunlight so that they pass through the autotroph.

• Represent a chemical reaction in the autotroph that produces high-energy

  carbohydrates.

• Represent a chemical reaction in the autotroph that produces high-energy

  proteins.

• Draw a circle to represent a heterotroph, and draw a line to connect it to the

  autotroph.

Multiple Choice

A mushroom gains its energy by decomposing the tissues of dead

organisms. Should mushrooms be classified as autotrophs, heterotrophs, in both

groups, or in neither group, and for what reason?

• They are autotrophs because they do not eat their food, as animals do.

• They are autotrophs because decomposition is very similar to

  photosynthesis.

• They are heterotrophs because their food is made by other organisms.

• They are both autotrophs and heterotrophs, because they may grow in

  sunlight or darkness.

Multiple Choice

Neurons are cells of the nervous system. As part of its normal function, a

neuron pumps sodium ions (Na + ) out of the cell and potassium ions (K + ) into the

cell. Which statement describes the role of energy in this process?

• The process releases energy that is used to make ATP.

• The process releases energy in the form of heat.

• The process requires energy that is provided by the sodium and potassium

  ions.

• The process requires energy that is provided by ATP.