Chapter 9 Notes Handout

Name: ________________________
Chapter 9-Energy in a Cell Notes
In this Chapter we will discuss two main concepts:
__________________-when autotrophs/producers make sugar using sunlight.
___________________________-when any organism turns a sugar into energy
In our cells, we need energy in order to carry out vital cell processes (and live).
Most of our energy is in the form of a molecule called Adenosine TriPhosphate (_______).
ATP has a related molecule called Adenosine DiPhosphate (______). ADP can store energy
by adding a phosphate group which makes ATP.
When ATP loses a phosphate group, this __________________. It works like a battery that
can be recharged.
ATP is only used for ____________________________________, so only a small amount is
found in cells. To store energy long term, cells use the basic sugar glucose (_________).
The glucose can then be broken down as needed and used to _____________ ADP into ATP.
Photosynthesis is the process of changing __________________ into storable and
__________________ for a cell. ATP is a good storage molecule for the day, but what about
longer periods without light (like night)?
Photosynthesis turns light energy into ___________, which can then be turned into
_________ for longer-term energy storage.
Photosynthesis uses carbon dioxide and water to turn light from the sun into glucose and
oxygen gas.
The formula for photosynthesis is:
Pigments and Light
How do plants do this? They use a ___________ called __________________ which exists in
Sunlight looks white to us, but is actually a _____ of all the different colors (visible and
invisible to us).
Plants gather the sun’s energy with light absorbing molecules called pigments (which are
The three types of pigments in plants are _________________________________________
Chlorophylls are the major pigment in plants, but _________________________green well.
What happens if a color of light is not absorbed? It is _____________.
This is why most plants appear _________ to us.
This is also why we see different colored leaves in the _________…the chlorophyll is no
longer produced and we see the other pigments that still remain (for a time).
There are two main types of Chlorophyll:
When plants absorb light, much of the energy is transferred directly to _________, which
allows photosynthesis to work.
Inside a Chloroplast
Chloroplasts, you should remember, only exist inside __________________ and the cells of
other producers.
Inside the chloroplast are sac-like membranes called __________________. They are
arranged in stacks called _________. (Granum for one.)
Proteins in the thylakoids arrange the pigments into clusters known as ________________.
These are what collect light inside of a chloroplast.
There are two parts to Photosynthesis:
The ____________________________________ which take place within the thylakoids.
The __________________ (or Dark Reactions or Light-Independent Reactions) which takes
place in the stroma. The stroma is the space inside the chloroplast that is not taken up by
Energy Transfer:
When the electrons within chlorophyll are _________, they gain a lot of _________.
Think of it as a hot charcoal briquette from a fire. If you wanted to move it, you wouldn’t
pick it up with your hands, you would use a carrier. Cells treat them the same way.
Cells use __________________ to transport them. The process is called electron transport
(duh) and the carriers are known as ____________________________________.
Some of the notable carriers:
_______ holds two electrons and a Hydrogen ion (H+). This changes it into _______.
_________ holds two electrons and an H+ ion. This changes into _________.
_________ holds two electrons and two H+ ions. This changes into _________.
These carriers can then be used to carry electrons throughout the cell to be used where
The Light-Dependent Reactions (or the Light Reactions)
These reactions __________________. This is why plants need light.
The light reactions produce oxygen gas and turn ADP and NADP+ into ATP and NADPH
respectively. It happens in ___________________________:
First, pigments in __________________ absorbs light. This excites the electrons and raises
their energy levels. These electrons are then passed on to the electron transport chain.
New electrons are gained from __________________. Enzymes inside of the thylakoid
break each H2O into 2 electrons, 2 H+ ions, and 1 oxygen atom.
The two electrons replace the electrons lost by chlorophyll to the electron transport chain.
Oxygen is __________________ and released into the air. This is the source of almost all of
our oxygen on earth.
The _________ hydrogen ions from water are released within the thylakoid.
Second, the excited electrons move through the electron transport chain to _______________
Energy from the electrons is used to transport H+ ions from the _________ to inside the
Third, pigments in Photosystem I use energy from light to ___________________________.
NADP+ picks them and H+ up and becomes NADPH.
Fourth, as electrons are ________ from chlorophyll to NADP+ more H+ ions are pumped across
the thylakoid membrane. The inside of the thylakoid fills up with __________________H+ ions.
This makes the outside membrane negatively charged. The difference between the inside
and outside in charge provides the energy to make _________.
Fifth (and last), H+ ions can’t just cross the membrane. However, they can pass through a
protein called ATP synthase which is a __________________.
As the H+ ions pass through ATP synthase the protein is turned like a ______________ and
it binds ADP and a phosphate group together to make ATP.
This means that the light reactions produce H+ ions and ATP.
But what do we do with all this _________ and _________?
The Dark Reactions
The __________________ are more commonly called the __________________.
They occur in the _________ of the chloroplast.
ATP and NADPH can hold energy, but are ___________________________ to hold onto that
energy for more than a __________________.
During the Calvin Cycle, plants (and other producers) use the ATP and NADPH to build highenergy compounds that can stored for a long time. It does this with __________________
_________ such as glucose.
It happens in 4 parts:
First, ____ carbon molecules enter the cycle from the atmosphere (courtesy of ______). These
each combine with a 5-carbon molecule called RuBP (six total). The result is 12 molecules of
Second, our twelve 3-carbon molecules are converted into higher energy forms. This energy
comes from _______ and _________ made in the light reactions.
This leaves us with _________ and _________ to return to the thylakoids and be used
again. The end product is called _________.
Third, two of the twelve 3-carbon molecules are removed from the cycle.
The cell uses these to make sugars, lipids, amino acids, and other compounds that are
needed for _____________________________________________.
Fourth, the remaining ten 3-carbon molecules are ___________________________ into six 5carbon molecules (_________).
They _________ the cycle again.
The Calvin Cycle needs __________________ of CO2 to produce one glucose (_________).
The plant then uses glucose to make _________ (storage), _____________ (structure), and
just to break down for energy in cellular respiration.
When other organisms eat plants, they get the energy from these __________________.
Rates of Photosynthesis
Amount of _________ available.
_______________ (the essential enzymes must be between 0°C and 35°C (32-95 degrees F).
The intensity of _________.
Because of this different producers are adapted to different conditions! Think of a cactus, vs.
an oak tree vs. a pine tree.