Photosynthesis Chapter 8

Vocabulary—Breaking Down the Definitions Photosynthesis Pigment Chlorophyll Thylakoid Stroma NADP+ Light Dependent Reactions ATP Synthase Calvin Cycle

Photosynthesis—What Do We Already Know? Have them independently brainstorm what they know, share in groups, write on board

Photosynthesis Brain Pop

Chemical Equation—Quiz on this Next Meeting! 6 6

Photosynthesis Photosynthesis uses the energy of sunlight to convert water and carbon dioxide into oxygen and high-energy sugars.

CHLOROPHYLL= a molecule within a chloroplast Light and Pigments In addition to water and carbon dioxide, photosynthesis also requires LIGHT and CHLOROPHYLL. CHLOROPHYLL= a molecule within a chloroplast Chlorophyll is a pigment that absorbs light

IVF to Analyze the Graph! Model, very guided for the first time

2 Stages of Photosynthesis Light Reactions—In the Thylakoids Light Energy (from the sun) is converted to chemical energy, which is temporarily stored in ATP and the energy carrier molecule NADPH. Calvin Cycle—In the Stroma A series of enzyme-assisted chemical reactions that produces a three-carbon sugar.

Inside a Chloroplast Photosynthesis takes place inside a chloroplast The chloroplast contains saclike membranes called THYLAKOIDS THYLAKOIDS are arranged in stacks called GRANA The Chlorophyll is inside the thylakoids The STROMA is the region outside of the thylakoids

The first stage of photosynthesis is the LIGHT REACTIONS. Light is absorbed by the chloroplasts Light Energy is converted to Chemical Energy (stored in ATP and NADPH)

Light Reactions Continued Oxygen is given off during this reaction. --Leaf Demo-- Chlorophyll in the chloroplast contains pigments (compounds that absorb light) that absorb a lot of blue and red light but reflect green light (giving plants their green color.

Light Reactions Continued An oxidation reaction takes place, losing electrons and the primary electron acceptor takes on the lost electrons in a reduction reaction. The primary electron acceptor donates the electrons to a series of molecules in the thylakoid membrane of the chloroplast.

Oxygen as Byproduct Demo Submerge a live leaf in a bowl of water, observe after 30 min.

Label the diagram Have a handout for the kids, then fill in whole class

Dark Reactions/Calvin Cycle In the second set of reactions in photosynthesis plants use the energy that was stored in ATP and NADPH during the light reactions to produce sugars. Most common way this is done is called the CALVIN CYCLE. Calvin Cycle Song! Sciencemusic videos

4 Steps of the Calvin Cycle 3 CO2 molecules diffuse into the stroma and combine with a 5-Carbon molecule, RuBP. This molecule is very unstable and it quickly splits into 2 3-Carbon molecules called 3- PGA. Each 3-PGA is converted into another 3 Carbon molecule, G3P after receiving a phosphate group from ATP and a proton from NADPH. Step 1 Step 2

4 Steps of the Calvin Cycle One of the G3P molecules leave the Calvin Cycle to make carbohydrates which are stored for later use. The remaining 3GP molecules are converted back into RuBP by adding phosphate groups from ATP and then the Calvin Cycle begins again. Step 3 Step 4

Step 1—3 CO2 molecules combine to form RuBP (6 carbon molecule) which splits into 3 PGA Step 4– The rest of the G3P is converted back into RuBP/Rubisco Calvin Cycle Step 3– One molecule of G3P leaves the cycle to make sugars Step 2—Each molecule of 3 PGA is converted to G3P

Factors Affecting Photosynthesis Water, Temperature, Intensity of Light all affect the rate of photosynthesis

Thinking Visually Complete the flowchart on page 216 of your book.

Investigation Photosynthesis District Lab Manual—intensity of light