Photosynthesis

Pages 1-4 in notes

Producers

Organisms that make their own food to provide their own energy

• also called autotrophs 

• Some don’t use light, but instead cause chemical reactions which provide heat for energy (these use chemosynthesis) 

Photosynthesis

Process where energy from the sun is converted to chemical energy, stored in high energy sugar molecules

• like glucose

Chloroplast

Organelle in plant cells where photosynthesis occurs

• specifically a leaf cell

Chlorophyll

Pigment that absorbs light at a specific wavelength

• absorbs light energy

• Absorbs some wavelengths of light and reflects others

• Why leaves appear green

Consumers

Organisms that cannot produce their own food 

• need to obtain it through consumption (eating/drinking)

Structures used for photosynthesis (large to small)

• Leaf

• Plant Cell

• Organelle (chloroplast)

• Thylakoid (stacks of disks)

• Chlorophyll

Chlorophyll A

violet and orange

• H₃C

Chlorophyll B

Blue and yellow

• H-C=O

Types of molecules Photosynthesis utilizes to store energy

• ATP (which becomes ADP after being used)

• NADPH (which becomes NADP+ after being used)

Light Dependent Reactants

• Sunlight

• NADP+

• ADP

Light Dependant products

• NADPH

• ATP

Both are energized forms

First Step of Light Dependent Reactions

Energy absorbed from sunlight

• photosystem II has chlorophyll b, which absorbs sunlight and transfers that energy to elections, which leave and go to the ‘electron transport chain’

Second Step of Light Dependent Reactions

Water molecules split

• Enzymes break down water molecules — electrons from the water molecules replace the ones that have left the chlorophyll — oxygen is released as a waste product

Third Step of Light Dependent Reactions

Hydrogen ions transported

• Electrons are moved along the thylakoid membrane — used to pump hydrogen ions from low concentration to high concentration (active transport)

Fourth Step of Light Dependent Reactions

Energy absorbed from sunlight

• Photosytem I has chlorophyll a, which absorbs sunlight and transfers that energy to electrons

Fifth Step of Light Dependent Reactions

NADPH produced

• Electrons from photosystem I provide energy to NADP+ — creates NADPH

Sixth Step of Light Dependent Reactions

Hydrogen ion diffusion

• H+ ions diffuse (high to low concentration, passive transport_ through the ATP synthase protein (why its diffusion_, which uses that movement to add a phosphate group to ADP

Light Independent Reactants

• NADPH

• ATP

Light Independent Products

• Sugar (glucose) 

First Step of Light Independent Reactions

Carbon Dioxide Added

• A CO₂ molecule is added to an existing 5-carbon molecule — creates a 6 carbon molecule

Second Step of Light Independent Reactions

3-Carbon molecules formed

• 6-carbon molecule splits, forming 2 groups of 3 carbon molecules that are rearranged

• Uses ATP and NADPH as energy

Third Step of Light Independent Reactions

3-carbon molecules exit

• One 3-carbon molecule exit the cycle

• Once it happens twice, the two molecules that have excited can create a 6-carbon sugar molecule (glucose)

Fourth Step of Light Independent Reactions

3-Carbon molecules recycled

• 5 groups of 3 carbon molecules are rearranged into 3 groups of 5-carbon molecules that will stay in the cycle

• used energy from ATP

• Not adding or removing any molecules

• Allows the cycle to restart