Chapter 8
Chemical Energy and ATPSection 4-1
1Organisms are classified according to their energy
usage:Autotrophs make their own food. Ex. Plants & algae
2ATP is Adenosine TriphosphateATP is the energy molecule used by
the cell.3Chemical Structure of ATP
3 Phosphates (tri = 3)Ribose: 5-carbon SugarAdenine- Nitrogen
Base4ADPAdenosine Diphosphate is ADP ADP has the same structure as
ATP, except it only has 2 phosphates.
5ADP-ATP Cycle Diagram
6ATP FactsATP is good to transfer energy in the cell, but not to
store energy. Cells depend on the sugar, glucose, for stored
energy.Cells then convert glucose into ATP as
needed.7Photosynthesis OverviewSection 4-28Photosynthesis Defined
Plants use energy from sunlight to convert water and CO2 into
glucose, releasing oxygen as a by-product.The chemical equation of
photosynthesis is: Light 6CO2 + 6H2O C6H12O6 + 6O29Requirements of
photosynthesisPigments are light absorbing compounds. Some are
found in plant leaves and stems.
Chlorophyll is a pigment that absorbs light energy.
In plants, chlorophyll is foundin organelles called
chloroplasts.
10Overview of Photosynthesis
Section 4-211Photosynthesis takes place in the chloroplasts of
the plant cell.
A chloroplast has two primary areas.Grana are stacks of
thylakoid membranes.Stroma is the fluid surrounding the
membranes.
12Diagram of a chloroplast
13Two Stages of PhotosynthesisLight-dependent reactions- need
light and occur in the grana and thylakoid membranes of the
chloroplast. Light-independent reactions- does not need light and
occurs in the stroma. (AKA the Calvin Cycle) 14Light Dependent
Reactionstake place in thylakoidswater and sunlight are
neededchlorophyll absorbs energyenergy is transferred along
thylakoid membrane then to light-independent reactionsoxygen is
released
15Electron Transport System
16The END PRODUCTS of the light reactionsNADPHATPOxygen
(released)17Light Independent Reactionstake place in stroma
needs carbon dioxide from atmosphere
use energy to build a sugar in a cycle of chemical reactions
18Light and Dark reactions combined
19The END PRODUCTS of the light independent reactionsSugar
(C6H12O6)20
Light Reactions
