Photosynthesis Using light to make food.
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8-1 Energy and life
• Energy – the ability to do work
• In living things it is needed to move and also to build new proteins and amino acids.
• Where does energy that living things need come from?
Autotroph
• "self-feeding“– any organism that makes its own food
• without eating• decomposing • absorbing other organisms or organic
molecules.
Auto – selfTroph – to feed
Photosynthetic autotrophs• "feed" themselves with light energy
– include plants– photosynthetic protists (algae) – photosynthetic bacteria
Cyanobacteria Algae & bacteria
Heterotrophs
• Get their food from eating autotrophs or from eating other heterotrophs
Hetero - other
Chemical Energy and ATP
• Energy comes in many forms (heat, light, electricity)
• It can be stored in molecules such as carbohydrates and lipids
• The chemical fuel for cells though is ATP
• Adenosine Triphosphate
Tri- three
This is how it works
• Energy from food is used to convert ADP to ATP. As a result of adding a phosphate a small amount of energy is stored.
Di - two
Using biochemical energy
• This energy can be used to do all kinds of cell work
• Active transport– Pumps– Motor Proteins – Synthesis of proteins and nucleic acids
8-2 Photosynthesis Overview
• During Photosynthesis light energy is used to convert water and carbon dioxide into sugar(glucose) and oxygen
Photo – Syn – to put together
Chlorophyll• green pigment that
absorbs light energy
• located in the membranes of chloroplasts– thylakoids in
stacks, called grana
– In stroma •carbon dioxide
is built into sugars.
The absorption spectrum
• White light is composed of the colors of the rainbow
• ROYGBIV
8-3 The reactions of Photosynthesis
Step 1• The light energy strikes the leaf
– passes into the leaf – hits a chloroplast inside an individual cell.
Step 2• light energy enters the chloroplasts
– captured by the chlorophyll inside a grana.
Step 3 Inside the grana -part of the energy is
used to split water into hydrogen and oxygen
Step 4
• Releasing of excess (waste) – As oxygen into the air.
Stomata of cactus plant
Step 5
• hydrogen – taken to the stroma along with the grana’s
remaining light energy.
Step 6• Carbon dioxide enters the leaf
– passes into the chloroplast.
Step 7
• Stroma the remaining light energy – used to combine hydrogen and carbon dioxide
• making Carbohydrates.
Step 8
• The energy rich carbohydrates are carried to the plant’s cells.
Step 9
• Energy rich carbohydrates– used by the plants cells to drive all its life
processes– Holds energy in chemical bonds
Summary of Photosynthesis
Photosynthesis and Respiration
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