chapter 8: photosynthesis
How does the leaf anatomy of a plant relate to photosynthesis?
In plants, photosynthesis happens at the leaves, organs which are specialized for the process.At the leaf, mesophyll cells are full of chloroplasts, the site of photosynthesis.
Describe the adaptions of C 4 and CAM plants that enable them to survive in hot, arid climates.
-c4: photosynthesis is a biochemical modification of the C3 photosynthesis process. In C4 plants, the C3 style cycle only occurs in the interior cells within the leaf; surrounding them are mesophyll cells which have a much more active enzyme, called phosphoenolpyruvate (PEP) carboxylase. Because of this, C4 plants are those that thrive on long growing seasons with lots of access to sunlight. Some are even saline-tolerant, allowing researchers to consider whether areas which have experienced salinization resulting from past irrigation efforts can be restored by planting salt-tolerant C4 species. -cam: CAM photosynthesis is an adaptation to low water availability, and it occurs in orchids and succulents from very arid regions. The process of chemical change can be that followed by either C3 or C4; in fact, there's even a plant called Agave augustifolia which switches back and forth between modes as the local system requires.
Compare chemiosmosis in cellular respiration vs. photosynthesis.
-chemiosmosis: specific steps within the electron transport chain utilized to create ATP. This energy is then used to drive ATP synthesis -photosynthesis: uses light energy to release ATP
Photosynthesis process
1) CO2 and H2O broken down 2) sunlight absorbed by chlorophyll 3) CHOH=sugar=carbohydrates formed as energy 4)O2is given off into air CO2+H20 --SUNLIGHT--> CHOH+O2
State the summary equation for photosynthesis
6CO2 + 6H2O ->C6H12O6 + 6O2Carbon Dioxide + Water -> Glucose + OxygenSix molecules of carbon dioxide react with six molecules of water to form 1 molecule of glucose and six molecules of oxygen
Compare the absorption spectrum to the action spectrum
Action Spectrum of Photosynthesis follows Absorption Spectrum of Chlorophyll. The absorption spectrum indicates how much of each wavelength chlorophyll will absorb, whereas the action spectrum can tell us which off those wavelengths are most effective in photosynthesis.
Draw and label the structures in a chloroplast.
Grana- known as thylakoids, contains pigments, and is responsible for the absorption of light energyStroma- Part of the chloroplast that contains enzymes which control the reaction of the carbon fixation stage, contains ribosomesOuter membrane, inner membrane and thylakoid
Which pigments are the least effective for photosynthesis?
Green
Explain the role of NADP+ in photosynthesis.
It is reduced and then carries electrons to the Calvin cycle
Which main enzyme is involved in the Calvin Cycle? How does it relate to photorespiration?
The enzyme, rubisco, not only initiates carbon fixation in the Calvin cycle; it also combines with oxygen to initiate photorespiration. As its name suggests (rubsiCO) the enzyme is both a carboxylase and an oxygenase.
How do the photosystems convert solar energy to chemical energy? (Include a diagram)
The first of two major stages in photosynthesis (before the Calvin cycle). These reactions, which occur on the thylakoid membranes of the chloroplast, convert solar energy to the chemical energy of ATP and NADPH, releasing oxygen in the process.
Compare and contrast light reactions and Calvin cycle.
The key difference between light reaction and Calvin cycle is the dependence of light in each type of reaction in photosynthesis. Light reaction in photosynthesis is light-dependent whereas the Calvin cycle (or dark reaction in photosynthesis) is light-independent. the light reaction takes place in the thylakoid membrane while the Calvin cycle occurs in the stroma of the chloroplast
What is the purpose of the Light Reactions?Where does it occur?What are the main products?
The purpose of the light reactions is to convert light energy into chemical energy in the form of ATP & NADPH.Take place on the thylakoid membrane of the chloroplastDuring these initial reactions, water is used and oxygen is released. The energy from sunlight is converted into a small amount of ATP and an energy carrier called NADPH. Together with carbon dioxide, these are used to make glucose (sugar) through a process called the Calvin Cycle.
Which pigments are most effective for photosynthesis?
They are in the red and blue/violet range. This is because these are the colors that get absorbed the most by plant pigments, particularly chlorophyll.
How does chemiosmosis generate ATP in the light reactions?
chemiosmosis drives ATP synthesis using the potential energy of a concentration gradient of hydrogen ions across the membrane(photophosphorylation)
what is g3p? how is it related to glucose?
the prodyct of the calvin cycle, It is a 3-carbon sugar that is the starting point for the synthesis of other carbohydrates. The fructose diphosphate is then used to make glucose, sucrose, starch and other carbohydrates.
What is the purpose of the Calvin Cycle? Where does it occur? What are the main products?
uses ATP and NADPH from the light-dependent reactions to produce a single 6-carbon sugar molecule.This phase uses the ATP and stored Hydrogens made in the previous phase to make glucose.The reactions of the Calvin cycle add carbon (from carbon dioxide in the atmosphere) to a simple five-carbon molecule called RuBP. These reactions use chemical energy from NADPH and ATP that were produced in the light reactions. FP- glucose