Warm – Up

Stomata-small openings in leaves that allow gases and water to diffuse into and out of the leaf

Guard cells – special cells that surround the stomata. Control the opening and closing of stomata

http://www.proprofs.com/quiz-school/upload/yuiupload/717044899.jpg

Warm-up Under what conditions would a plant close the

guard cells on its leaves? Analyze why this is an important ability for

plants. (Hint: Think reactants and products for

photosynthesis)

PHOTOSYNTHESIS

Parts of a Leaf

Most photosynthesis occurs in the palisade/palisade mesophyll layer

8.1 PhotosynthesisDefinition: Process of turning light energy from the sun into chemical

energy

6CO2 + 6H20 + the sun’s energy C6H12O6 + 6O2Carbon Dioxide

Water Glucose OxygenENERGY STORED

Requirements of Photosynthesis

A. Carbon dioxideB. WaterC. Sunlight

Requirements of photosynthesisD. Pigments 1. Pigments – colored substances that absorb or reflect light 2. The process of photosynthesis begins with plant pigments absorbing light energy 3. The main pigment in green plants is chlorophyll. Chlorophyll absorbs mostly red and blue light and reflects most green and yellow light.

http://science.hq.nasa.gov/kids/imagers/ems/visible.gif

Requirement of photosynthesisE. Energy storing compounds

1. Include ATP and NADPH 2. ATP and NADPH are produced during the light reactions 3. ATP and NADPH are used to drive the dark/ light independent reactions/Calvin Cycle

F. Photosynthesis also requires enzymes

8.1 ChloroplastsA. Site of photosynthesis in plants B. Contain CHLOROPHYLLC. Absorbs light energy

2. THYLAKOIDSSaclike photosynthetic

membranes (photosystems found inside)

Light-collecting units of chloroplast (contain pigments

and proteins)

PHOTOSYSTEMS

3. STROMARegion outside

thylakoid membranes (Calvin cycle occurs here)

6. GRANUMStack of

thylakoids

5. INNER MEMBRANE

4. OUTER MEMBRANE

8.1 Photosynthesis: Overview

LIGHT REACTION• Requires Light• Occurs in

Thylakoids

CALVIN CYCLE• Links carbon atoms

to make glucose • Occurs in Stroma

8.1 Photosynthesis: Overview

LIGHT-DEPENDENT REACTIONS

1. Requires light

2. Uses energy from light to produce oxygen gas and energy carriers: ATP and NADPH by splitting water

CALVIN CYCLE (Light Independent)

1. Does NOT require light

2. Uses ATP and NADPH from light-dependent reactions to produce high-energy glucose from CO2. Glucose can be stored for a long time.

The light-dependent reactions KEY CONCEPT-The light reactions convert

the energy from the sun into energy in ATP and NADPH (energy storing compounds).

The light reactions require light. Light energy splits water (this is why these

reactions are sometime called photolysis) When water is split oxygen, hydrogen ions, and electrons are released.

The light-dependent reactions The electrons travel across an electron

transport chain. Electron transport chain – series of

electron carrier proteins that shuttle high-energy electrons.

These electrons are eventually used to make NADPH.

The light-dependent reactions The hydrogen ions travel across the

thylakoid membrane and are eventually used to produce ATP.

The energy storing compounds (ATP and NADPH) that are produced during the light reactions drive the light-independent reactions.

Light-independent reactions/Calvin Cycle Key concept-the light-independent

reactions convert the ATP and NADPH into the high energy sugars (including glucose)

The light-independent reactions do not require light (hence the name)

Calvin Cycle (Light Independent Reactions

CO2 enters the Calvin Cycle and is added to a carbon chain with energy.

Additional Energy is used to modify the carbon chain and create carbohydrates (sugars)

Reactants – ATP, NADPH, and CO2

Products – Glucose, ADP, and NADP+

Location – Stroma

8.3 Photosynthesis Summary

Chloroplast

LightH2O

O2

CO2

Sugars

NADP+

ADP + P

Calvin Cycle

Light- dependent reactions

Calvin cycle

Factors Affecting Photosynthesis

Amount of H2O

Temperature

Intensity of Light