4.2 Overview of Photosynthesis Ph t th ti organisms i d Photosynthetic are producers. • Producers are organisms that make their own source of chemical energy. • Plants use photosynthesis and are producers. • Photosynthesis captures energy from sunlight to make sugars sugars.
4.2 Overview of Photosynthesis • Chlorophyll is a molecule that absorbs light energy. – In plants, chlorophyll is found in organelles called chloroplasts. chloroplasts
chloroplast
leaf cell
leaf
4.2 Overview of Photosynthesis Ph t th i iin plants l t occurs in i chloroplasts. hl l t Photosynthesis • Photosynthesis takes place in two parts of chloroplasts. 1. (Looks 1 Granum G (L k like lik rollll off Quarters) Q t ) a. Are stacks of thylakoids (Each Quarter in the roll) 2 Stroma (Kind of like the cell’s 2. cell s cytoplasm)
4.2 Overview of Photosynthesis
There are two types of reactions that take place in Photosynthesis. First: Light-dependent Light dependent reactions Second: Seco d Light-independent g t depe de t reactions.
4.2 Overview of Photosynthesis First: • The light-dependent reactions capture energy from sunlight. – – – –
ttake k place l i thylakoids in th l k id water and sunlight are needed chlorophyll absorbs energy energy is transferred along thylakoid membrane then to g reactions light-independent – oxygen is released
4.2 Overview of Photosynthesis Second: • The light-independent reactions make sugars. – take place in stroma – needs carbon dioxide from atmosphere – use energy to build a sugar in a cycle of chemical reactions
4.2 Overview of Photosynthesis • The equation for the overall process is: 6CO2 + 6H2O →→→→→→ C6H12O6 + 6O2 granum (stack of thylakoids)
1
chloroplast
6H2O
thylakoid 6CO2
3
6O2
2 energy
stroma (fluid outside the thylakoids) 1 six-carbon sugar
