BIOLOGY SEMESTER ONE
UNIT 10
Checklist unit 10:Photosynthesis
In this module you will review how the process of photosynthesis converts light energy to the chemical energy of food. Photosynthesis occurs in plant cell organelles called chloroplasts, and is performed in two stages: the light reactions and the Calvin Cycle.
The light reactions convert solar energy into ATP and NADPH. This is accomplished as photosynthetic pigments (such as chlorophyll) absorb visible light waves and transition to an excited state as the light energy boosts their electrons into a higher orbital. As the electrons fall back to the lower orbital energy is given off. This energy is used to produce ATP, NADPH, and oxygen. The Calvin Cycle uses ATP and NADPH to convert carbon dioxide to glucose and other organic molecules. You will review the sequence of chemical reactions in each of the stages.
Photosynthesis requires light, thus occurs during the day. In hot, dry climates this can be costly for plants, as they exchange CO2 for O2 with the atmosphere and, during this gas exchange, they are susceptible to water loss. Some plants have adapted to minimize this loss by using C4 or CAM pathways. The mechanisms of these alternatives will be examined in depth.
Learning objectives
At the end of this module you should be able to:
- Distinguish between autotrophic and heterotrophic nutrition.
- Describe the structure of a chloroplast, listing all membranes and compartments.
- Write a summary equation for photosynthesis, and describethe two main stages of photosynthesis. In general terms, explain the role of redox reactions in photosynthesis.
- Describe the relationship between an action spectrum and an absorption spectrum.
- List the components of a photosystem and explain the function of each component.
- Trace the movement of electrons in linear electron flow. Trace the movement of electrons in cyclic electron flow. Explain the functions of each.
- Describe the similarities and differences in chemiosmosis between oxidative phosphorylation in mitochondria and photophosphorylation in chloroplasts.
- State the function of each of the three phases of the Calvin cycle.
- Describe the role of ATP and NADPH in the Calvin cycle.
- Describe the major consequences of photorespiration. Explain why it is thought to be an evolutionary relict.
- Describe photosynthetic adaptations that minimize photorespiration.
Check List
Read Chapter 10: Photosynthesis of Campbell and Reece’s Biology, 9th Ed.
As you are reading, address each of the learning objectives listed above.
It is recommended that you make flash cards for the terminology list provided. This will be beneficial for studying for the midterm and final exams later in the semester.
You may be able to review the PowerPoint Lecture and other resources for this unit. Refer to your instructor’s notes for more details.
Review the BioFlix Video “Photosynthesis” and complete the accompanying study sheet from the Mastering Biology Website.
For extra practice try the Self Quiz or Practice Test on the Mastering Biology Website. To log onto the website, use the access code provided in your textbook. You will also find other resources, such as downloadable MP3 tutorials for each chapter, a glossary, and an electronic copy of your text—you can catch up on your reading anywhere!
Key Terms
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BIOLOGY SEMESTER ONE
UNIT 10
- absorption spectrum
- action spectrum
- adenosine triphosphate (ATP)
- atom
- autotroph
- bundle-sheath cell
- C3 plant
- C4 plant
- Calvin cycle/reactions
- CAM plant
- carbon fixation
- carotenoid
- chlorophyll
- chlorophyll a
- chlorophyll b
- crassulacean acid metabolism (CAM)
- cyclic electron flow
- electromagnetic spectrum
- glyceraldehyde-3-phosphate (G3P)
- heterotroph
- leaf
- light reactions
- light-harvesting complex
- linear electron flow
- mesophyll
- mesophyll cell
- nicotinamide adenine dinucleotide phosphate (NADP+/NADPH)
- PEP carboxylase
- photoautotroph
- photon
- photophosphorylation
- photorespiration
- photosynthesis
- photosystem
- photosystem I
- photosystem II
- primary electron acceptor
- producer
- reaction center complex
- rubisco
- spectrophotometer
- stoma
- stroma
- thylakoid
- visible light
- wavelength
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BIOLOGY SEMESTER ONE
UNIT 10
Root Words to Know
auto- = self; -troph = food (autotroph: an organism that obtains organic food molecules without eating other organisms)
chloro- = green; -phyll = leaf (chlorophyll: photosynthetic pigment in chloroplasts)
electro- = electricity; magnet- = magnetic (electromagnetic spectrum: the entire spectrum of radiation)
hetero- = other (heterotroph: an organism that obtains organic food molecules by eating other organisms or their by-products)
meso- = middle (mesophyll: the green tissue in the middle, inside of a leaf)
photo- = light (photosystem: cluster of pigment molecules)
sources
Campbell, N. A. (2008). Biology, Eighth Edition. San Francisco: Pearson, Benjamin Cummings.
Krogh, D. (2000). Biology, A Guide to the Natural World. Upper Saddle River: Prentice Hall.
Pearson Education. (2010). Retrieved 2010, from Mastering Biology :
Raven, P. E. (2005). Biology of Plants. New York: W.H. Freeman and Complany.
NANSLO Biology Core Units and Laboratory Experiments
by the North American Network of Science Labs Online,
a collaboration between WICHE, CCCS, and BCcampus
is licensed under a Creative Commons Attribution 3.0UnportedLicense;
based on a work at rwsl.nic.bc.ca.
Funded by a grant from EDUCAUSEthrough the Next Generation Learning Challenges.
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