Transcript 7.1- The overall equation for photosynthesisis just the reverse of

Photosynthesis
Using light to make food.
.
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 – self
Troph – 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