Introduction to Photosynthesis PHOTOSYNTHESIS PHOTOSYNTHESIS The Photosynthesis Equation

Introduction to Photosynthesis PHOTOSYNTHESIS

PHOTOSYNTHESIS � The Photosynthesis Equation Sunlight + 6 CO 2 + 6 H 2 O C 6 H 12 O 6 + 6 O 2 Carbon dioxide + water glucose + oxygen � Photosynthesis uses sunlight to convert water and CO 2 into energy (glucose) and oxygen. � Takes place in chloroplasts

PHOTOSYNTHESIS � There are three processes that take place during photosynthesis 1. Light Capturing Events � 2. Light-Dependent Reactions � � 3. This step uses pigments to trap sunlight This step uses photosystems to convert the trapped sunlight into ATP and NADPH Oxygen (O 2) is also produced during this step Light-Independent Reactions (aka: Calvin Cycle) � This step uses the ATP and NADPH from the lightdependent reactions to make sugar

PHOTOSYNTHESIS Light H 2 O CO 2 Chloroplast NADP+ ADP + P Light. Dependent Reactions ATP NADPH O 2 Calvin Cycle Sugars

PHOTOSYNTHESIS 1. Light Capturing Events � Photosynthesis takes place in the chloroplast � Thylakoid � membrane Done using pigments � Main photosynthetic pigment = chlorophyll � This explains why plants are green……chlorophyll reflects green light! � Other accesory pigments include: � � carotenoids (orange) xanthophylls (yellow)

PHOTOSYNTHESIS

PHOTOSYNTHESIS 2. Light-Dependent Reactions � � � REQUIRE LIGHT!!!! Within photosystems, energy from sunlight is used to produce ATP and NADPH Also produces oxygen (O 2)

PHOTOSYNTHESIS

PHOTOSYNTHESIS 3. Light-Independent Reactions � Aka: Calvin Cycle � Uses ATP and NADPH from the light-dependent reactions to produce high energy sugars. � DOES NOT REQUIRE LIGHT!!! � The whole purpose is to remove CO 2 from the atmosphere and turn it into sugar which gives energy to the plant!

PHOTOSYNTHESIS