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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.