photosynthesis the flow of energy. atp adenosine triphosphate chemical compound used by living...
TRANSCRIPT
Photosynthesis
The Flow of Energy
ATP adenosine triphosphate chemical compound used by living
things to store energy When the bond between two
phosphate groups is broken – energy is released
ATP ADP + Pi
Photosynthesis Jan van Helmont – plants gain their
mass from water Joseph Priestly – plants release oxygen
Jan Ingenhousz – light is necessary for plants to produce oxygen
6CO2 + 6H2O C6H12O6 + 6O2
Light Visible spectrum – ROYGBIV Red = longest wavelength Violet = shortest
wavelength Color of an object
is determined by
the color the object reflects Plants gather light using pigments
Chloroplasts and Pigments
chloroplast – organelle where photosynthesis occurs– chlorophyll – a green pigment, most
important in photosynthesis– carotenoids – yellow, orange and red
pigments absorbed light is transformed from
light energy to chemical energy
Inside a Chloroplast thylakoids – saclike
photosynthetic membranes
grana – stacks of thylakoids
stroma – space outside the thylakoids
Overview of Photosynthesis
photosynthesis occurs only in producers endergonic reaction – a chemical
reaction that uses or stores energy Two steps of photosynthesis
– Light Reactions– Calvin Cycle
Light Reactions require light use energy from light to produce ATP
and NADPH occurs in the grana energy from “excited electrons” is used
to bond ADP and Pi to form ATP
Light Reactions 3 main events
– Light energy is absorbed by the chlorophyll and ATP is made
– Water is split into hydrogen ions, oxygen and electrons
– The hydrogen ions are used to make NADPH
Light Reactions Inputs:
– Light– Water
Outputs:– ATP – NADPH
– Oxygen (O2)
Calvin Cycle
Also called the dark reactions or light-independent reactions
process of synthesizing sugars occurs in the stroma does not require light converts CO2 to sugar
Calvin Cycle 3-carbon sugars are produced
– Some used as energy sources– Some converted to lipids, amino acids,
parts of nucleic acids– Two can combine to form 6-carbon
sugars
Calvin Cycle Inputs:
– ATP– NADPH
– CO2
Outputs:– Sugars
In the end… a single 6-carbon sugar is formed from
6 molecules of carbon dioxide plants use the sugar for energy and to
build more complex carbohydrates such as starches and cellulose
other organisms eat the plants and use the energy stored in carbohydrates
Factors Affecting Photosynthesis
Shortage of water– Can slow or stop photosynthesis
Temperature– Photosynthesis requires enzymes that
function best between 0°C and 35°C Intensity of light
– Increasing light intensity increases the rate of photosynthesis