Photosynthesis and cellular respiration



Photosynthesis and cellular respiration

How cell obtain energy


The photosynthesis and cellular respiration are the revolutionary processes that fueled the evolution of life on Earth. Photosynthesis and cellular respiration are in some ways opposites, they share certain characteristics. Photosynthesis is a series of chemical reactions that uses the energy of sunlight to convert carbon dioxide into organic molecules. Cellular respiration is the breakdown of food molecules to release the energy that cells need to function.


In this activity you will explore how photosynthetic organisms get their energy directly from the sun and what kind by-product and metabolites produce inside cell during the photosynthesis and cellular respiration.

Activity 1: Basic of the photosynthesis and cellular respiration

Think about the basic stages of photosynthesis and advantage the first microorganisms over their ancestors.



Look at each of these statements and select  TRUE or FALSE. Then read the feedback.

The first microorganisms had a distinct advantage over their ancestors they were able to produce oxygen.


The first microorganisms had an advantage over their ancestors they were able to utilize carbon dioxide

The first microorganisms had an advantage over their ancestors they were able to harness light energy to produce their own nutrients.

Additional Resources

1. Futyuma, D.J., Evolutionary Biology, 3rd ed., Sinauer Associates Inc., Massachusetts, pp. 365–396, 1998.

2. Hughes, M.A., Plant Molecular Genetics, Addison Wesley Longman Ltd., Harlow, England, pp. 36–50, 1996.

3. Hankamer, B., Barber, J. and Boekema, E.J. Structure and membrane organization of photosystem II in green plants, Annual Review of Plant Physiology and Plant Molecular Biology 48:643, 1997

Activity 2: Metabolism inside the cell

       This task are focused on the cell's metabolism  and products which produce its during biochemical processes. The process in chloroplasts takes place in two stages that usually go on simultaneously. In the first, the light-dependent stage, energy is harvested from sunlight. In a series of reactions, large protein complexes called photosystems use light energy to produce ATP and NADPH. In the second stage, the light-independent stage, the Calvin cycle uses the energy supplied by ATP and NADPH to convert carbon dioxide into sugars and other carbon compounds that can be stored or used to fuel the cell’s activities. Cellular respiration is the breakdown of food molecules to release the energy that cells need to function. It begins in the cytoplasm with glycolysis, which yields a molecule called pyruvate. Pyruvate moves to the mitochondrial matrix, where the Krebs cycle completes its breakdown to carbon dioxide. The cycle also generates a small amount of ATP and, more important, electrons that are ferried by NADH and FADH2 to an electron transport chain on the inner.


A student write the points that apply  the intent of the proposal. Then read  the feedback.

Write the product (1 point) of biochemical processes in the gap.

In yeast, fermentation produces ATP, carbon dioxide and in mucle cells, it produces and ATP.

Write the name of photosynthesis prosesses  in the gap.

Pyruvate is the end product of and essential input for .

Write the name of photosynthesis prosesses in the gap.

For glycolysis to continue, must be present.

Put the processes that make up cellular respiration into the correct order.

To use the following keywords: Krebs Cycle, Glycolysis, Electron transport, ATP synthesis.

1. , 2 , 3 , 4 .

Additional Resources

1. Roy, H. and Andrews, J., Rubisco: assembly and mechanism; in Photosynthesis: Physiology and Metabolism, Advances in Photosynthesis, Vol. 9, Kluwer Academic Publishers, Dordrecht, pp. 53–83, 2000.

2. Lodish, H., Berk, A., Zipursky, S.L., Matsudaira, P., Baltimore, D. and Darnell, J., Protein Sorting: Organelle Biogenesis and Protein Secretion; in: Molecular Cell Biology, 4th Ed., W.H. Freeman and Company, New York, pp. 675–750, 2000.

3. Movie "How cell obtain energy "click here

Activity 3: Difference Between Krebs and Calvin Cycle

This activity is focused on the extremely important processes which to maintain the life on Earth. The Krebs and Calvin cycles are two very important biochemical pathways occurring inside organelles of cells. Both these processes are cyclic, but there are many differences between Krebs and Calvin cycles. The places that these processes take place, and the consumption or production of energy are different from each other.


You task to watch the video and select the all that apply for these processes. Then read the feedback.

Watch the video  about  dark reactions photosynthesiss and  select the following statements about the Cycle Calvin is FALSE.

Watch the video about the Citric Acid Cycle and select the following statements about  Krebs Cycle is TRUE.

Select the tick or cross a box all that apply for Krebs Cycle.

tick icon cross icon
1. Part of the aerobic respiration process
2. Takes place in the stroma of chloroplast
3. Leads to synthesize ATP
4. Takes place in all the organisms with aerobic respiration
5. Takes place in the matrix of the mitochondria
6. Carbon dioxide is produced
7. The process does not take place without oxygen

Select the tick or cross a box all that apply for Calvin Cycle

tick icon cross icon
1. The process does not demand the presence of oxygen
2. Part of the dark reaction of photosynthesis
3. Takes place in the stroma of chloroplast
4. Leads to synthesize ATP
5. Takes place only in the photosynthetic plants
6. Carbon dioxide is used
7. ATP is spent for the process

Additional Resources

1. Xiang V. Zhang; Scot T. Martin (December 2006). "Driving Parts of Krebs Cycle in Reverse through Mineral Photochemistry". J. Am. Chem. Soc. 128 (50): 16032–16033. PMID 17165745. doi:10.1021/ja066103k

2. Blankenship, R.E., Molecular Mechanisms of Photosynthesis, Blackwell Sciences Ltd., Oxford, pp. 220–257, 2002.

© Anna Chernova National Research Tomsk Polytechnic University 2017 Created using the LOC Tool, University of Southampton

Created using the LOC Tool, University of Southampton