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Light reaction and photophosphorylation
Pigments embedded on thylakoid membranes form photosystems. There are of two types: PS I P700, PS II P680. Components of photosystem I and II transfer the electrons from water to NADP via cyclic electron transfer or non-cyclic electron transfer. During electron transfer, the light energy captured by the photosynthetic organisms is transformed into the phosphate bond energy of ATP. This is called photophosphorylation. NADPH is generated during non-cyclic electron transfer.

How Mitochondria Create Energy

C4 pathway
C4 cycle is the pathway adopted by C4 plants to conserve the carbon dioxide released via photorespiration. It adopts a new enzyme (PEPC, Phosphoenol pyruvate carboxylase) which does not react with oxygen; it also adopted a separated compartment for CO2 up taking and fixation.


How much sun does a seed need to sprout?

C4 pathway
C4 cycle is the pathway adopted by C4 plants to conserve the carbon dioxide released via photorespiration. It adopts a new enzyme (PEPC, Phosphoenol pyruvate carboxylase) which does not react with oxygen; it also adopted a separated compartment for CO2 up taking and fixation.


Can we grow plants on the moon?

During the gallery walk, the groups have the opportunity to look at the concept maps made by other groups. Each group will walk around with a different color Post-It note and make comments and ask questions about other concept maps. The groups then stick their question/comment Post-It note on that particular chart.

Photosynthesis Background Resources

Photorespiration
Under high oxygen and low carbon dioxide conditions, Rubisco favors binding to oxygen instead of carbon dioxide, therefore the energy produced in light reactions are consumed for no productivity of organic carbohydrates. The final result is that oxygen is consumed and CO2 is produced, which mimics respiration, and therefore named photorespiration.

How does the type of light affect the number of leaf stomata?

After the gallery walk, groups return to their orriginal concept map and review the questions/comments posted by other groups. This can provide an opportunity for groups to discuss the comments/questions within their own group. It is best if the teacher keeps these concept maps posted around the classroom so students can revise them at the end of the lesson to demonstrate their understanding of the lesson content.

Effect of different colors of light on the rate of photosynthesis.

Students will be given brief instruction by teacher about plants and photosynthesis, reflecting on the gallery walk and informal observations made during group discussion. Students will then color the to label important components of photosynthesis. The includes carbon dioxide, starch, light energy, and H2O. Teachers are encouraged to add additional note cards with important terms as needed to make the activity more or less challenging. Students can work inside with artificial or real decorative plants or students may locate and apply these concepts to small trees on campus. After the plants are labeled, students will draw the plant with the appropriate labels. If real plants are used outdoors, please remind your students to remove the labels after the drawing is complete.

Investigate the effect of light on seed germination.

Dark reaction – Calvin cycle
Second step of photosynthesis is called Calvin’s cycle. Because it does not require light, so it is called dark reaction. During dark reaction, the ATP and NADPH generated by light reaction are consumed to fix carbon dioxide into organic carbohydrates. The first fixed carbohydrate is a three carbon compound 3-phosphoglycerate (3PGA). The final product is a high-energy 3 carbon compound glyceraldehyde-3-phosphate (G3P) which can be used to synthesize a broad range of organic molecules. An important intermediate molecule for carbon dioxide fixation is ribulose bisphosphate (RuBP), and the enzyme catalyzing the CO2 fixation is Rubisco.