Prentice Hall BiologyAutotrophs and Heterotrophs
cell division? yes
Active transport? yes
Digestion? yes
Circulation? Yes
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Chemical energy and ATP
Energy is ABSORBED or STORED when ADP reacts or bonds with a phosphate group to form ATP
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Biochemical Energy
Most cells contain only small amounts of ATP which is enough for a few seconds of activity.
ATP is NOT good for diffusion (passive transport)
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After ATP is broken down……
One phosphate group breaks off the end of the ATP molecule, energy is released from the chemical bonds for use by the cells, and ADP is left.
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[Adenine+ribose] Adenosine + 3 phosphate groups
What do the lines between these parts of the molecule represent? Chemical bonds
What would be the result if the 3rd phosphate group were removed? Energy is release when the bond is broken and ADP is formed
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A. Investigating Photosynthesis
Priestley’s Experiment
Plants release oxygen
B. The Photosynthesis Equation
C. Light and Pigments
Reactants: carbon dioxide and water
Products: glucose and oxygen
The light-dependent reactions (which take place in the thylakoids)
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Pigments absorb sunlight to provide energy for energy-containing molecules.
Chlorophyll is a plant pigment that looks green because it reflects light in the green region of sunlight.
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V
B
G
Y
O
R
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Plants USE THE ENERGY FROM SUNLIGHT to convert water and carbon dioxide into HIGH-ENERGY CARBOHYDRATES (SUGARS AND STARCHES) and oxygen, a byproduct
Go to Section:
Energy carrier – NADP+
Where is it found? It is a product of the Calvin cycle, found in the stroma, and used in the light dependent reactions
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Photosystems- clusters of chlorophyll and other pigments
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Light
O2
Sugars
CO2
The end products are glucose + oxygen
The source of energy is sunlight.
The source of carbon dioxide is the atmosphere
The source of water is in thylakoids – originally taken in from plant’s roots
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What is the energy source? sunlight
What reactant is necessary? water
What compounds are produced? Oxygen, ATP and NADPH
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What is the principal product? sugars
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Goal of the light dependent reactions
To use energy … from sunlight and trap it into a chemical form (such as ATP and NADPH)
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Which photosystem occurs first? 2!!
Photosystem I- pigments use energy from light to re-energize the electrons so that they can make NADPH for the Calvin cycle.
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Go to Section:
Electron Transport Train
A series of proteins embedded in the thylakoid membranes of the chloroplast transport the high-energy electrons from Photosystem 2 to Photosystem 1.
The photosystems contain pigments (light absorbing molecules) that transfer energy from sunlight into chemical bonds
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The Calvin Cycle uses ATP and NADPH to produce high-energy sugars in the stroma of the chloroplasts and it does not require light.
Go to Section:
Factors affecting photosynthesis
Temperature (Enzymes function best between 0C and 35C)
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