PHOTOSYNTHESIS
CHAPTER 8
Sthepanie Sierra
Laura Fortin
Alejandro Zuniga
Gabriel Hedman
Alexandra Peña
Energy and Life
Autotrophs and Heterotrophs
Plants and some other types of organisms are able
to use light energy from the sun to produce food.
• Autotrophs are organisms that make their
own food.
• Heterotrophs obtain energy from the food
they consume
Chemical Energy and ATP
Energy comes in many forms, including light, heat, and electricity.
Energy can be stored in chemical compounds, too.
One of the principal chemical compounds that cells use to store and
release energy is Adenosine triphosphate
• The characteristics of ATP make it exceptionally useful as the basic
energy source of all cells.
Using Biochemical Energy
ATP can be compared a fully charged battery
because both contain stored energy, whereas ADP
resembles a partially charged battery
Photosynthesis: An overview
Photosynthesis is a multi-step process that
requires sunlight, carbon dioxide, and water as
substrates.
• Investigating photosynthesis
The experiments performed by van, Helmont, Priestley,
and Ingenhousz led to work by other scientists who
finally discovered that in the presence of light, plants
transform carbon dioxide and water into carbohydrates,
and they also release oxygen.
The Photosynthesis Equation
Photosynthesis uses the energy of sunlight to
convert water and carbon dioxide into high-energy
sugars and oxygen.
• Light and Pigments
In addition to water and carbon dioxide,
photosynthesis requires light and chlorophyll, a
molecule in chloroplasts
The reactions of Photosynthesis
Inside a chloroplast
Plants use energy from the sun in tiny energy factories called
chloroplasts. ... Inside the chloroplasts are stacks of discs called
thylakoids. They are compared to stacks of coins within the walls
of the chloroplast, and they act to trap the energy from sunlight.
The stacks of thylakoids are called grana.
Light- Dependent Reactions
The light-dependent reactions use light energy to make two
molecules needed for the next stage of photosynthesis: the
energy storage molecule ATP and the reduced electron carrier
NADPH.
Here are the basic steps:
The Calvin Cycle
• The Calvin Cycle uses ATP and high-energy sugars.
Factors Affecting
Photosynthesis
• Light. It is one of the major factors affecting
photosynthesis.
• Carbon Dioxide Concentration. The atmosphere contains
0.03% of carbon dioxide amidst other gases
• Temperature
• Water
• Oxygen