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Cellular Respiration and Photosynthesis Linkage Cheat Sheet
A printable reference covering photosynthesis, cellular respiration, ATP, carbon cycling, chloroplasts, mitochondria, and energy flow for grades 11-12.
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This cheat sheet explains how photosynthesis and cellular respiration are linked through matter and energy in living systems. Students need this connection to understand ecosystems, plant biology, metabolism, and the carbon cycle. The two processes are often taught separately, but together they show how cells capture, store, release, and reuse energy. A clear reference helps compare reactants, products, organelles, and energy transformations without confusion. Photosynthesis uses light energy to convert carbon dioxide and water into glucose and oxygen. Cellular respiration breaks down glucose with oxygen to produce carbon dioxide, water, and usable ATP. The products of one process are the reactants of the other, so carbon, oxygen, and hydrogen atoms cycle between them. Energy does not cycle in the same way because it enters as sunlight, is stored in chemical bonds, and leaves ecosystems mostly as heat.
Key Facts
- The overall photosynthesis equation is 6CO2 + 6H2O + light energy -> C6H12O6 + 6O2.
- The overall cellular respiration equation is C6H12O6 + 6O2 -> 6CO2 + 6H2O + ATP energy.
- Photosynthesis occurs mainly in chloroplasts, while aerobic cellular respiration occurs mainly in mitochondria.
- The products of photosynthesis, glucose and oxygen, are the main reactants for aerobic cellular respiration.
- The products of cellular respiration, carbon dioxide and water, are reactants used in photosynthesis.
- Photosynthesis stores energy in the chemical bonds of glucose, while cellular respiration releases that energy to make ATP.
- Matter cycles between photosynthesis and respiration, but energy flows one way from sunlight to chemical energy to heat.
- Aerobic cellular respiration can produce about 30 to 32 ATP per glucose molecule in many eukaryotic cells.
Vocabulary
- Photosynthesis
- Photosynthesis is the process in which plants, algae, and some bacteria use light energy to make glucose from carbon dioxide and water.
- Cellular respiration
- Cellular respiration is the process cells use to break down glucose and transfer its energy into ATP.
- ATP
- ATP is the main energy-carrying molecule that cells use to power work such as transport, movement, and synthesis.
- Chloroplast
- A chloroplast is the plant and algal organelle where photosynthesis takes place.
- Mitochondrion
- A mitochondrion is the eukaryotic organelle where most ATP is produced during aerobic cellular respiration.
- Carbon cycle
- The carbon cycle is the movement of carbon atoms through organisms, the atmosphere, water, soil, and rocks.
Common Mistakes to Avoid
- Saying photosynthesis and respiration are exact opposites is wrong because they occur through different pathways, enzymes, and energy transfers.
- Forgetting that plants do cellular respiration is wrong because plant cells need ATP at all times, including when light is not available.
- Treating ATP as long-term energy storage is wrong because ATP is used quickly, while glucose and other molecules store energy for longer periods.
- Thinking matter and energy both cycle is wrong because atoms are recycled, but energy flows through ecosystems and is eventually lost as heat.
- Balancing the equations incorrectly is wrong because photosynthesis and respiration require a 6:6:1:6 ratio for carbon dioxide, water, glucose, and oxygen in the overall equations.
Practice Questions
- 1 Write the balanced overall equation for photosynthesis and identify which reactant supplies the carbon atoms in glucose.
- 2 If one glucose molecule enters aerobic cellular respiration and produces 32 ATP, how many ATP molecules are produced from 5 glucose molecules?
- 3 A plant cell produces 18 molecules of O2 during photosynthesis. Based on the overall equation, how many molecules of glucose were produced?
- 4 Explain why a plant kept in darkness for several days can still perform cellular respiration but cannot continue normal photosynthesis.