Lab 7 Photosynthesis 10272015 Basics of Photosynthesis process

Lab 7: Photosynthesis 10/27/2015

Basics of Photosynthesis: process that transforms light energy into chemical energy. occurs on land in water performed by autotrophic plants, algae, and bacteria

Formula of photosynthesis Inputs: CO 2 6 CO 2 carbon dioxide Products: H 2 O 6 H 2 O water C 6 H 12 O 6 glucose 6 O 2 oxygen gas Formula of cellular respiration: (from last week) Inputs: C 6 H 12 O 6 glucose Products: 6 O 2 oxygen gas 6 CO 2 carbon dioxide 6 H 2 O water Nature Recycles: Photosynthesis and Cellular respiration are opposites: Each one takes the products of the others reactions and uses it for inputs.

Photosynthesis: Road Map Photosynthesis can be divided into two parts: 1. Light Reactions 2. Dark Reactions Light reactions: convert solar energy to chemical energy. Dark reactions: convert chemical energy and carbon dioxide into sugars

Photosynthesis: light reactions (convert solar energy to chemical energy. ) So why are plants green? Chloroplasts and chlorophyll Inputs: Light and Water Different colors of light are different wavelengths with different energies. Chloroplast Products: Thylakoids form stacks called grana O 2 Chloroplasts are organelles that absorbs light in plant tissue. Green color in chloroplast comes from chlorophyll – light absorbing pigment. thylakoids which are membranous sacs forming stacks called grana.

Photosynthesis: dark reactions / Calvin cycle (convert chemical energy & carbon dioxide into sugars. ) Input: CO 2 This part is called a dark reaction because it can happen with or without light. Chloroplast Product: glucose Stroma is a thick fluid within chloroplast, this is where enzymes associated with dark reactions occur.

Photosynthetic Pigments Part A: 2. Remember: chlorophyll is a light absorbing pigment. However most chloroplasts contain 4 or more different pigments. These pigments show up as the different colors in fall leaves. Paper Chromatography: Allows us to separate out each pigment based on molecular size. Smaller pigments travel further up the paper than larger ones. We can identify the pigments by color.

Photosynthesis: Light Reaction Part A: 3. Volumeter • As part of the light reaction, oxygen is produced from water. • Mark the solution front on the glass tube initially and when you first notice movement start timing 10 minutes. • After 10 minutes mark front again and measure the distance in mm. water 3% sodium bicarbonate (Na. CO 3) 2 -3 fresh Elodea sprigs, cut end up. Light source Beaker filled with water – heat absorber

Photosynthesis: Light Reaction Part A: 3. Volumeter • Then carefully pick up tube being sure not to disturbing the stopper or bent tube. • Wrap the tube in aluminum foil. • Place back into the light. • Wait 10 minutes and mark where the front is, then measure the distance in mm. water 3% sodium bicarbonate (Na. CO 3) 2 -3 fresh Elodea sprigs, cut end up. Wrap in aluminum foil. Light source Beaker filled with water – heat absorber

Uptake of Carbon Dioxide Part B Blow into straw Beaker filled with water and phenol red (red = basic). Yellow = acidic CO 2 + H 2 O → H 2 CO 3 → H+ + HCO 3− • Add a sprig (or several) of Elodea to one of the test tubes – make sure it is alive! • Stopper both tubes.

Uptake of Carbon Dioxide Part B • Place the test tubes in the test tube rack with the tube from Part A. 3 water Light source Beaker filled with water – heat absorber • Monitor any color change over time. • Swirl the tubes occasionally.

To do: • Lab reports • Visual aid for bioethics presentations will be due in 2 weeks – “Visual aids are due before the beginning of class the week of Nov. 4. So if you have Thursday lab at 12: 00 pm on Nov 7, it’s due Thurs, Nov. 7 at 11: 59 am. You may email your electronic slide to jerome 1. wilson@umconnect. umt. edu. In addition, please bring to class a copy of your visual aid on a thumb drive on the day you present. ” • Research paper topics – due next week on quiz!! • For quiz: – What are inputs and outputs of cellular respiration? Photosynthesis? Know the formulas! – What is the purpose of the light reactions? The dark reactions? Why are they called light and dark reactions, respectively? – What happened to the water in the volumeter in part A 3 when the Elodea was in the light? In the dark? WHY? Be sure your answer to ‘why’ is in terms of the inputs and products of photosynthesis and respiration. – What happened to the color of the acidified solution in part B when Elodea was photosynthesizing? WHY? Be sure your answer to ‘why’ is in terms of the inputs and products of photosynthesis.