Chapter 8: Photosynthesis
Section 8-1 Energy and Life
Energy Energy – the ability to do work. Necessary for cell survival. ATP (adenosine triphosphate) – chemical compound that cells use to quickly transfer energy
Chemical Energy and ATP ATP is like a rechargeable chemical battery Energy is stored in bonds between phosphates.
To “charge up the battery,” the cell uses energy to attach a phosphate to an ADP (adenosine diphosphate) ADP + phosphate becomes an ATP The energy used to make the bond is now stored in the bond Energy Used
To get the energy out of the ATP to use for something, the last phosphate is broken off. ATP turns back into ADP Energy is released from the broken bond Energy Used
Autotrophs and Heterotrophs SO… Where do living things get energy? FOOD Food for a cell = glucose. SO… How do living things get food? Different ways of obtaining food: Autotrophs – organisms that make their own food through photosynthesis (AKA: producer) Examples: plants, algae, certain bacteria Heterotrophs – organisms that consume or eat food (AKA: consumer) Examples: animals, fungi, some bacteria, some protists
Section 8-2 Photosynthesis: An Overview
The Photosynthesis Equation Photosynthesis uses the energy of sunlight to synthesize (assemble) glucose. ____ + ____ sunlight C6H12O6 + ____ (glucose)
The Photosynthesis Equation _CO2 + _H2O sunlight C6H12O6 + _O2 (carbon dioxide) (water) (glucose) (oxygen)
The Photosynthesis Equation 6CO2 + 6H2O sunlight C6H12O6 + 6O2 (carbon dioxide) (water) (glucose) (oxygen)
Section 8-3 The Reactions of Photosynthesis
Inside a Chloroplast Photosynthesis takes place within chloroplasts.
Reactions of Photosynthesis Light Dependent Reactions or Light Reactions: Chlorophyll captures sunlight energy Uses it to “charge up” ADP and similar “chemical batteries” Charged “chemical batteries” carry the energy to the Calvin Cycle
Reactions of Photosynthesis Calvin Cycle or Light-Independent Reactions or Dark Reactions: ATP releases the energy, becomes ADP which recycles to the Light Reactions Calvin Cycle uses that released energy to synthesize (make) glucose
Factors Affecting Photosynthesis Temperature – photosynthesis uses enzymes, which extreme temperatures will slow or denature. Occurs best between 0C and 35C. Water – photosynthesis requires water so low water availability would slow down the rate of photosynthesis Light – more light speeds up the rate of photosynthesis, but there is a maximum photosynthesis speed.