Energy and Life

Energy Pyramids:

Autotrophs

• Characteristics: • Use light energy from

sun to produce food• (convert sunlight

energy to chemical energy)

• Requires chlorophyll

• Examples: plants, bacteria, some protozoa, algae

Heterotrophs

• Characteristics:• Consume other

organisms for energy source

• Examples: Animals, fungi, protists

Sun’s light energy

Autotrophs: use pigments to absorb light energy and convert to chemical

energy (unusable directly to cells)

Heterotrophs and Autotrophs: convert chemical energy in food to cellular

energy a cell can use

Adenosine Triphosphate

• ATP: the form of chemical energy that can be used directly by cells for functioning

ATP

• It’s an RNA nucleic acid with two extra phosphate groups

How ATP is used by cells:

How do plants make glucose needed by cells for ATP?

• In order for plant cells to make glucose that can be systematically broken down to make ATP, plant cells need a way to trap the sun’s light energy.

• They do this with the pigments they contain.

Pigments

• Q: What is their purpose?• Answer: Give substances color• Q: How do they function?• Answer: They absorb or reflect light waves

(energy). The reflected light waves are the ones we see.

• So, a red sweatshirt looks red because the pigments in the sweatshirt reflect red light waves and absorb all the others.

Q: Why do plants look green?

• Answer: Because they reflect the green light waves and absorb all the others.

Plant Pigments

• Two main types:• 1. Chlorophyll (green

and greenish-yellow)• Chlorophyll a and

chlorophyll b

• 2. Carotenoids (carotene; orange, red)

What happens in the fall?

• To conserve energy, plants lose their leaves by severing the connection between its branches and leaves. • The first pigment to

be broken down is chlorophyll. So, the other pigments can shine through.