What Does It Need? –
Plants need three things in order to live: water, light, and carbon dioxide.
Plants get water from rain, light from the sun, and carbon dioxide from the
air. Plants use a process called photosynthesis to turn water, sunlight, and
carbon dioxide into food for themselves.
QUESTIONS: What Does It Need? –
The first step in photosynthesis requires sunlight, but the second step
doesn't. The second step can take place when there is no sunlight, even
at night. The second step was discovered by a scientist named Melvin
Calvin, so it is called the Calvin Cycle.
Photosynthetic Organisms –
In plants, photosynthesis takes place in organelles called chloroplasts,
which contain a green pigment called chlorophyll. Chlorophyll absorbs
the sunlight that is required to perform photosynthesis.
QUESTIONS: Photosynthetic Organisms –
Bacteria are Prokaryotes, meaning that they have no organelles enclosed
in membranes. Like plants, Cyanobacteria contain chlorophyll and
perform photosynthesis using folded inner thylakoid membranes.
Cellular Respiration –
These two cycles have both similarities and differences. Water, glucose,
oxygen, and carbon dioxide are created and consumed in both cycles,
only in different ways. Using these processes, plants get the carbon
dioxide they need, and animals get the oxygen that they need.
QUESTIONS: Cellular Respiration –
Cellular respiration is almost the opposite of photosynthesis. It is the
process by which living things convert oxygen and glucose into carbon
dioxide and water, which creates energy.
Adenosine Triphosphate (ATP) –
There, cells convert food into a form of energy that can be used by the
organism. This form of energy is called adenosine triphosphate, or ATP.
QUESTIONS: Adenosine Triphosphate (ATP) –
In plants, during photosynthesis, energy in the
form of sunlight is captured by molecules of chlorophyll inside cell
structures called chloroplasts. Inside the chloroplasts, another phosphate
group is added to create ATP, thus storing the energy in a form the plant
The Discovery of Photosynthesis –
The study of photosynthesis began in 1771 with the
observations of the scientist and English clergyman Joseph
Priestley. He burned a candle in a container that was
closed until there was no longer enough air in the container
to feed the fire and the candle went out.
QUESTIONS: The Discovery of Photosynthesis –
In 1782, the relationship between oxygen, which is required for
combustion, and carbon dioxide, which had been identified the year
before, was discovered: oxygen and carbon-dioxide existed in the closed
container in an inverse relationship.
The Importance –
The energy that all organisms
need to survive is created or consumed in the form of food. Plants do not
eat other organisms for energy. Instead, they make (produce) energy for
themselves by converting energy from the sun using photosynthesis.
QUESTIONS: The Importance –
Furthermore, without photosynthesis, which also
replenishes oxygen in the atmosphere, nothing would
be able to breath.
The Emerald Green Sea Slug –
The emerald green sea slug is one of the first animals believed to be able
to produce chlorophyll, the green pigment found in almost all
photosynthetic plants. J
QUESTIONS: The Emerald Green Sea Slug –
Chloroplasts are the organelles inside plants cells and green algae where
photosynthesis takes place in two steps. In the first step, sunlight is
captured by the chloroplasts when molecules of chlorophyll absorb
energy (in the form of sunlight).
Do Plant's Sleep? –
During photosynthesis, plants use a green pigment called chlorophyll,
located in structures called chloroplasts, to capture light.
QUESTIONS: Do Plant's Sleep? –
Research conducted at the University of Sheffield, in England, and
published in the journal Nature Plants, used structured illumination to
reproduce the transition from night to day, and studied the changes that
take place in plant chloroplasts using atomic force microscopes.
Desert Adaptations of Photosynthesis –
Because there is so little water in the desert, plants called succulents have
adapted a slightly different version of photosynthesis that preserves water.
A New Kind of Photosynthesis –
Chlorophyll-a is found in all
plant life, including algae and cyanobacteria, and it was believed that
there was a "red limit" for photosynthesis, that is, a minimum amount of
energy required in order to allow the plant to produce oxygen during the