Photosynthesis

How are photosynthesis and cellular respiration related?

Photosynthesisglossary term (opens in a new window) and cell respiration are two parts of a never-ending cycle, keeping the balance of carbon and oxygen in the atmosphere:

• Organisms that undergo photosynthesis, such as plants, algae, and some types of bacteria, are autotrophs and producers.
• With solar energyglossary term (opens in a new window), photosynthesizing organisms convert carbon dioxide and water into oxygen and energy-rich carbohydrates.
• Photosynthesis provides the oxygen needed for animals to breathe and respire.
• Plants are the main photosynthetic organisms on land, but algae are the main producers in freshwater ecosystems and the upper layers of marine environments. Photosynthesizing bacteria are important in other areas.
• Plants and other photosynthesizing organisms contain chlorophyllglossary term (opens in a new window). When chlorophyll absorbs light, it absorbs the energy contained within it.
• Photosynthesis begins with water and carbon dioxide, which is converted to carbohydrates in the form of simple sugars and oxygen.
• The chemical equation for photosynthesis is: 6 CO₂ + 6 H₂O → C₆H₁₂O₆ + 6 O₂.
• The products of photosynthesis are the reactants to cellular respirationglossary term (opens in a new window).
• Cellular respiration is a process in which cells harvest biochemical energy from nutrients. producing adenosine triphosphate (ATP), waste carbon dioxide and water.
• Molecules of ATP are an organism’s source of energy for all of its cellular activities.

How does the process of photosynthesis work?

A light-dependent reaction and a light-independent reaction are both part of photosynthesis:

• Photosynthesis takes place in the thylakoidsglossary term (opens in a new window) of chloroplasts.
• The light-dependent reaction uses the energy captured from light to make ATP and NADPH through a series of electronglossary term (opens in a new window) transport chains, hydrogen gradients, and splitting water molecules.
• Energy from ATP and NADPH produced by the light-dependent reaction is used in the light-independent reaction to convert carbon dioxide and water into organic compounds (sugars).
• The redox reactions in the light-independent reaction are commonly called the Calvin cycleglossary term (opens in a new window).
• The Calvin cycle removes carbon dioxide from the environment and uses it to produce sugars rich in energy.
• Sugars are used by the producer for growth and development, as well as by other living things that eat the producers.