Energy & metabolism
Metabolism includes a cell's chemical reactions. Photosynthesis allows some light energy to be stored in organic compounds. Cellular respiration helps obtain ATP from those compounds. Both plants and animals use ATP to sustain cellular processes.
Where this sits
- Comes after
- The cell
- Opens up
- Plants and fungi
Exercises from this rung
Generated by the app, from easiest to hardest
Which gas does cellular respiration give off?
- Carbon dioxide (CO₂)
- Oxygen (O₂)
- Hydrogen (H₂)
- Nitrogen (N₂)
Why Carbon dioxide (CO₂). Photosynthesis takes in CO₂ and gives off O₂; respiration takes in O₂ and gives off CO₂: they are the same equation read in both directions. That is why a plant makes more oxygen by day than it uses, and at night, when it only respires, it uses it up like any animal.
easierDuring photosynthesis, a leaf converts light energy into…
- Energy that can be recycled forever
- Matter created without source atoms
- Chemical energy stored in molecules
Why Photosynthesis uses light energy to make organic compounds from CO₂ and water. Atoms are rearranged and some energy is stored chemically. The leaf does not create matter from nothing.
in betweenA leaf makes 7 molecules of glucose (C₆H₁₂O₆). How many molecules of CO₂ did it have to take from the air?
Answer 42
Why 42: each glucose carries six carbons, so 7 glucoses are 7 × 6 = 42 molecules of CO₂, one per carbon. Atoms are not created: all the carbon in a tree came in through its leaves as a gas.
harder