chapter 10

Chapter 10
Question:
1) Dose photosynthesis has different stages like cell respiration?
There are two stages of photosynthesis, they are light reaction and calvin cycle.
2) Where does the photosynthesis take place?
Photosynthesis happens in the chloroplast.
3) What’s the formula for photosynthesis?
6CO2 + 6H2O + light energy = C6H12O6+ 6O2


Factors:
1) Light reaction converts solar energy to chemical energy.
2) Calvin cycle begin by incorporating CO2 from the air into organic molecules already present in the chloroplast. This initial incorporation of carbon into organic compounds is known as carbon fixation. The Calvin cycle then reduces the fixed carbon to carbohydrate by the addition of electrons.
3) Light reaction is a form of electromagnetic radiation. Visible light has the right energy for use in Ps.


Diagram


In this diagram, the chloroplast, the thylakoid membranes are the sites of the light reactions, whereas the Calvin cycle occurs in the stroma. The light reaction use solar energy to make ATP and NADPH, which supply chemical energy and reducing power, respectively, to the Calvin cycle. Calvin cycle incorporates CO2 into organic molecules, which are converted to sugar.


Summary:
Photosynthesis converts light energy to the chemical energy of food. The light reactions convert solar energy to the chemical energy of ATP and NADPH. The Calvin cycle uses ATP and NADPH. The Calvin cycle uses ATP and NADPH to convert CO2 to sugar. Alternative mechanisms of carbon fixation have evolved in hot, arid climates.

Key term
1. Autotrophs: Self-feeders.
2. Heterotrophs: Biosphere’s consumers.
3. Chlorophyll: The green pigment located within chloroplasts.
4. Stomata: A microscopic pore surrounded by guard cells in the epidermis of leaves
and stems that allow gas exchange between the environment and the interior of the
plant.
5. Stroma: The dense fluid within the chloroplast.
6. Thylakoid: A flattened membranous sac inside a chloroplast. Thylakoids exist in
an interconnected system in the chloroplast and contain the molecular
“machinery” used to convert light energy to chemical energy.
7. Photophosphorylation: The lights reactions also generate ATP, using
chemiosmosis to power the addition of a phosphate group to ADP.
8. Carbon fixation: The initial incorporation of carbon from CO2 into an organic
compound by an autotrophic organism.
9. Cyclic electron flow: A route of electron flow during the light reactions of
photosynthesis that involves only photosystem I and that produces ATP but not
NADPH or oxygen.
10. Linear electron flow: A route of electron flow during the light reactions of
photosynthesis that involves both Photosystems (I and II) and produces ATP,
NADPH and oxygen. The net electron flow is from H2O NADP+.



http://www.youtube.com/watch?v=Q_1mxZdF2TY