Microanalysis in Science and Engineering

The Chemistry of Photosynthesis

Subjects7th grade General ScienceChemistry

Contact Information

Twanelle Majors and Christi Whitworth

Twanellemajors@yahoo.com and altgilas@blomand.net

F.C. Boyd Christian School & White County Middle School

7th grade Life Science Performance Indicators

State Performance Indicators7.3.spi.1 determine which materials are needed by plants to

make food.

7.3.spi.2 identify photosynthesis as the food making process in plants.

7.3.spi.6 identify the reactants and products of photosynthesis.

Teacher7.3.tpi.2 examine and identify the chloroplasts in a leaf.

Chemistry Performance Indicators

State Performance IndicatorsDetermine the number of molecules of a given substance given a

balanced equation

Convert between mass, # of moles, and number of particles

Determine molar ratios expressed in balanced equations

Classify a substance as an acid or base given litmus paper, phenolphthalein, and pH.

Solve mass to mass stochiometry problems Algebra II –

2.3- apply measurement concepts and relationships in algebraic problem solving situations

Chemistry Performance Indicators

Teacher Performance IndicatorsCreate a data table from experimental dataAnalyze data by computing a percent errorRecord measurements and results of calculations using significant

figuresUse conversion factors and/or ratio and proportion to convert

between quantitiesExpress numbers in scientific notationPractice appropriate safety procedures when working in the

laboratoryInvestigate the acidity/basicity of substances by observing their effect

on various indicators

Textbook Reference(s)

7th grade text - Life’s Structure and Function, Glencoe/McGraw-Hill ©2002, Chapter 3, pp. 66-95.

Chemistry: A Modern Course, Merrill ©1990, Ch.6,and p. 496-503.

Materials Needed

7th Grade – Colored pencils– Large segment of butcher paper– Journal– Group vocabulary lists (next 5 slides)

Chemistry– Vinegar, lemon juice, baking soda solution, or other household items

Universal indicator paper, litmus paper, white cups, droppers

Graph paper, ruler, pencil– White well plate of any sort, droppers

White cotton T-shirts, skinny rubber bands, ziploc bags, dishpans

Leaf Section Vocabulary

Cuticle Epidermis Stoma Guard cell Oxygen Carbon

dioxide

Mesophyll cells Air space Palisade

parenchyma Spongy

parenchyma Chloroplasts Stomate

Mesophyll Cell

Palisade parenchyma Spongy parenchyma Chloroplast Air space

Chloroplast Vocabulary List

Outer membrane Inner membrane Thylakoid Starch grains

Genetic material Granum Stroma Ribosomes

Granum Vocabulary List

Thylakoids Granum Stroma lamellae Thylakoid space

Thylakoid Vocabulary List

Photosynthetic membrane

Pigment (CHLOROPHYLL)

Adenosine triphosphate synthetase

Thylakoid space NADPH

Photosynthesis Diagram Rubric

Display Rubric

Plant Indicators Project Rubric

Coming soon.

Special Notes

7th grade Required Time– One - two 45 minute class periods

Chemistry Required Time– One 50 minute class period for introduction– 2 hours weekend at-home lab– One 50 minute class period for indicator scale development

and dyeing of T-shirt

7th grade project completion marks the beginning of the Chemistry project.

Chemistry of Photosynthesis

Also known as

6CO2 + 6H2O + light energy C6H12O6 + 6O2

Catalyst = Chlorophyll

7th grade Engagement

Get into 5 groups according to your teacher’s instructions.

Look at our 3-D models of the plant cell in our classroom in your group.

Point out to your group and the teacher, the organelle you remember to be responsible for photosynthesis in the plant cell.

You should find something that resembles the following images.

Chloroplasts

These images were obtained with a transmitting electron microscope (TEM).

7th grade Exploration

Each group will need colored pencils, butcher paper, any other decorating materials, and their journals.

Following the website example, each group will create one section of the plant cell wall display.

You may use any other resources necessary to obtain correct information to complete the required labels.

7th grade Exploration, part 2

Be sure to include all your vocabulary items. Use your journal to collect your detail information and

brainstorm your design. Be creative but precise for the highest grade. Include a list of the resources used by the group. If you are not sure, ask! Go to http://ftexploring.com/photosyn/chloroplast.html for a

starting point.

Explanation

Each group will present their information orally as their section is mounted to the

wall.

All students should sketch all segments presented on the left side of their

journal.

Other group members should ask questions of presenters and modify their notes on the right side of their journals.

Explanation

Make sure you now have in your journal

•5 drawings with labels

•Arrows labeling the entrances and exit pathways for carbon dioxide, water, and oxygen.

•Arrows labeling the pathways of sugar after it is produced

•Questions asked in class and their answers.

Elaboration

Locate the chloroplasts of plant cells under a light microscope in class. Sketch this object on the left side of your journal.

Find an image of a chloroplast and its parts on the web. Sketch this object on the left side of your journal.

Label and compare these images in a paragraph on the right side of your journal.

This image was obtained using a transmitting electron microscope.

Evaluation

Go to the display evaluation rubric and evaluate your group’s display on the right side of your journal.

Write out why you feel you deserve this total for your project on the left side of your journal.

Compare your evaluation to and reflect on the teacher evaluation given out by the teacher.

Chemistry Excite

7th grade science students will spend 15 minutes showing you photosynthesis projects.– Take notes. You will be responsible for the info

they present to you.– After presentations:

List 5 types of plant parts or fruits that stain clothing. List 5 household acids or bases you consider safe.

Chemistry Mass-Mass Exploration

6CO2 + 6H2O + activation energy C6H12O6 + 6O2

1. What is the source of activation energy for plants?

2. What pigment is the catalyst in the above reaction?

3. In which plastid is this pigment located?

4. What other pigments perform energy roles as well as color plants?

5. What is the number of moles of oxygen gas expected when one mole of carbon dioxide reacts with one mole of water in the presence of adequate activation energy?

6. How many grams of oxygen gas could be produced from 4.30g of CO 2 reacting with excess water and activation energy?

Show all work, conversion factors, units, and observe significant figures.

7. How many molecules of oxygen gas would be produced from the reaction in #3?

Pigment Explanation

Chloroplasts contain chlorophyll, a green pigment. Transmission Electron Microscope Light Microscope

Some More Pigment Explanation

Leucoplasts are white plastids. You would find these in an onion. Chromoplasts are plastids that contain colorful pigments such as

purples, reds, etc.. These images of marigolds show chromoplasts. Notice that color is a

phenomenon created by light. The electron microscope uses electrons rather than light, hence the image does not show colors.

Light Microscope Transmission Electron Microscope

Even More Pigment Explanation

An unripe red bell pepper is colored by chloroplasts. These plastids continue to make sugar until the sweetening process is well underway.

As a fruit turns colors, chromoplasts are responsible for the new color. This color is also a signal to birds and insects that things are sweet to

eat!Light microscope

Expansion- Prelude to Tie-dye

1. Mix 1ml of strawberry juice with 1ml of vinegar.

2. Mix 1ml of strawberry juice with 1ml of baking soda solution.

3. Compare the difference in color in acidic, neutral, and basic solutions.

4. Repeat the above steps with petunia petal juice.

5. Look at the juice spectra on the following slide generated using the Environmental Scanning Electron Microscope.

6. What can you assume is responsible for differences in initial color as well as reactions with varying pH solutions?

Juice ESEM Spectra

Strawberry juice spectrum Purple petunia juice spectrum

Weekend At-Home Lab Extension

1. Choose any fruits, petals, etc. that you find to change color in acid and in base.

1. Simmer plant parts until pigments are leached out.

2. Use indicator papers to determine the pH of reagents you choose.

3. Use household acids/bases listed in class as reagents to determine the pH range of each natural indicator.

4. Create a table or bar graph that represents your data clearly.

5. Refrigerate juices until Monday’s class.

6. Be prepared to tie-dye using the class juices.

Examine

1. In a chemplate, place 1ml portions of reagents ranging from pH=2 to pH=12. You should have 11 wells. You may dilute or combine like reagents to create each pH.

2. Choose one of your juices. Place 1ml of it in each of the 11 wells. 3. Does the range of color change match your values recorded on your

graph?4. Wet, twist, and bind your t-shirt. 5. Use any juice in t-shirt sections of your choice. It may look like a

multicolored pie when you are done. Repeat on the back.6. Now spray an acid on the front and a base on the back.7. Now your shirt represents the acid/base reactions of your plant

indicators.8. Store it in a bag in the fridge until tomorrow!

Exchange

Post your data on the group table. The group table will be submitted to ….http://gemini.tntech.edu/~jbiernacki/

Resources

http://rubistar.4teachers.org http://ftexploring.com/ Eukaryotic Cell