The conversion of light energy to chemical energy that is stored in glucose or other organic compounds; occurs in plants, algae, and certain prokaryotes
photosynthesis
__ are a plant's main photosynthetic organs. __ is closely associated with its photosynthetic function.
Leaves
leaf structure
A loosely arranged photosynthetic cell located between the bundle sheath and the leaf surface.
mesophyll cell
The ____ in leaves are specialized for photosynthesis. These cells contain many ____.
mesophyll cells
chloroplasts
An organelle found only in plants and photosynthetic protists that absorbs sunlight and uses it to drive the synthesis of organic compounds from carbon dioxide and water
chloroplast
A flattened membrane sac inside the chloroplast, used to convert light energy to chemical energy.
thylakoid
A stacked portion of the thylakoid membrane in the chloroplast. Grana function in the light reactions of photosynthesis.
granum
The fluid of the chloroplast surrounding the thylakoid membrane; involved in the synthesis of organic molecules from carbon dioxide and water.
stroma
___ are the sites of photosynthesis. These double-membrane bound organelles enclose additional membranes called ___, which possess an interior space and are stacked to form ___, which are suspended in the ___ of the chloroplasts.
chloroplasts
thylakoids
grana
stroma
The emission of electromagnetic waves by all objects warmer than absolute zero.
radiation
The distance between crests of waves, such as those of the electromagnetic spectrum.
wavelength
The entire spectrum of radiation ranging in wavelength from less than a nanometer to more than a kilometer.
electromagnetic spectrum
The steps in photosynthesis that occur on the thylakoid membranes of the chloroplast and that convert solar energy to the chemical energy of ATP and NADPH, evolving oxygen in the process.
light reaction
Sunlight is a type of energy called ___, or ___, which travels through space in a manner similar to the motion of waves in water. .
radiation
electromagnetic radiation
The distance between the crests of two adjacent waves is called a ___. The full range of electromagnetic wavelengths is known as the ____. What we call visible light--the wavelengths that our eyes see as different colors--is only a small fraction of the spectrum. The light reactions of photosynthesis use only certain wavelengths, or colors, of visible light
wavelength
electromagnetic spectrum
The thylakoid membrane in chloroplasts contains light-absorbing molecules called ___.
pigments
TorF:
Different pigments absorb light of different wavelengths.
True
One pigment, ___, absorbs mainly blue-violet and red light. This molecule participates directly in the light reactions.
chlorophyll a
Another molecule, __, absorbs mainly blue and orange light. We do not see these absorbed colors when we look at a leaf. Instead, we see the green wavelengths that are reflected back from the leaf or transmitted through it
chlorophyll b
Light-capturing unit located in the thylakoid membrane of the chloroplast, consisting of a reaction center surrounded by numerous light-harvesting complexes. There are two types of them, I and II; they absorb light best at different wavelengths.
photosystem
sequence of electron carrier molecules (membrane proteins) that shuttle electrons during the redox reactions that release energy used to make ATP.
electron transport chain
Two ___, two ___, and ___are the key components of the light reactions of photosynthesis. These parts are embedded in the thylakoid membranes of a chloroplast.
photosystems
ETC
ATP synthase
The ____consist of arrays of chlorophyll molecules. ___-- the green pigment of leaves-- absorbs light energy. The absorbed energy ___ electrons to a higher energy level.
photosystems
Chlorophyll
excites
Energized electrons from ___are passed down an __ and added to __ to form __. Meanwhile, energized electrons from __are passed through another __. Their energy is used to pump __from the stroma into the thylakoid compartment, creating a concentration gradient.
PS I
ETC
NADP+
NADPH
PS II
ETC
H+
Electrons leaving this __ enter __, replenishing its lost electrons. __replenishes its electrons by splitting __. Hydrogen ions and oxygen are released into the thylakoid compartment. This is where the __generated by photosynthesis comes from.
ETC
PS I
PS II
water
oxygen gas
single proton with a charge of 1+. The dissociation of a water molecule (H2O) leads to the generation of a hydroxide ion (OH-) and a hydrogen ion (H+).
hydrogen ion
The buildup of __ inside the thylakoid compartment stores ___. This energy is harvested by an enzyme called __.
H+ ions
potential energy
ATP synthase
As hydrogen ions diffuse through ___, down their concentration gradient, the enzyme uses the energy of the moving ions to make __. Next, __and __are used in the sugar-making process of the __.
ATP synthase
ATP
ATP
NADPH
Calvin cycle
In the ___, this stored energy is used to produce sugar molecules.
Calvin cycle
The second of two major stages in photosynthesis (following the light reactions), involving atmospheric CO2 fixation and reduction of the fixed carbon into carbohydrate.
Calvin cycle
The ___ is a complex series of chemical reactions carried out in the stroma.
Calvin cycle
The Calvin cycle begins with ___. Three molecules of ___ are added to three molecules of a five-carbon sugar abbreviated __. These molecules are then rearranged to form six molecules called __, which have three carbons each.
carbon fixation
carbon dioxide
RuBP
3-PGA
In the next two reactions, products from the light reactions are used to boost the energy of these three-carbon molecules. First, ___ groups are added. __contribute phosphate groups, so that each three-carbon molecule receives an additional phosphate group.
high-energy phosphate
six ATP molecules
In the second reaction of the Calvin Cycle, Six molecules of __ are oxidized. The electrons from NADPH reduce the six three-carbon compounds, creating six high-energy molecules of __, which is a sugar, the final product of the Calvin cycle.
NADPH
G3P (glyceraldehyde-3- phosphate)
One of the ___ represents the three carbon dioxide molecules fixed so far. The other five __ are reshuffled to regenerate the original __ molecules.
G3P molecules
G3Ps
RuBP
To summarize, so far the Calvin cycle has used the energy of the light reactions to reduce three molecules of __ and produce one molecule of __.
carbon dioxide
G3P.
Three more carbon dioxide molecules are fixed to form __ in this same complicated way.
G3P
To make each G3P, the Calvin Cycle consumes __ ATP molecules and _ NADPH molecules. These are regenerated in the __.
9
6
light reactions
__ is the actual final product of the Calvin cycle. The cell can combine two _ to make __, which stores the energy that chlorophyll originally captured from the sun.
G3P
G3Ps
glucose
In warm, dry conditions many of the adaptations that plants make to conserve __ reduce the availability of ___ to the chloroplasts.
water
carbon dioxide
A plant that uses the Calvin cycle for the initial steps that incorporate CO2 into organic material, forming a three-carbon compound as the first stable intermediate.