How does light energy travel?
Light travels as a wave.
What is a photon?
A tiny little particle of light, too small to see individually. All light is made up of photons.
What is the relationship between the wavelength of light and the amount of energy that it has?
The shorter/smaller the wavelength the greater the energy, the larger the wavelength, the smaller the energy.
What is the visible light spectrum?
The rainbow of colors visible to the human eye.
What colors make up the visible light spectrum?
R O Y G B I V
What are the units that are used to measure wavelengths of light?
Angstroms (equal to 0.1 nanometer)
The visible light spectrum is within what wavelength range?
Wavelength of 400-700 nanometers
Would a photon of red light have more or less energy than a photon of violet light?
Violet light has a shorter wavelength so it contains more energy than red light.
What kinds of waves exist below the visible light spectrum (have less energy) and above the visible light spectrum (have more energy--and are harmful)?
Below- UV rays, X-Rays, Gamma rays
Above- Infrared (heat), Micro-waves, Radio waves
Why do objects appear the color that they are?
Objects appear to have color since they are able to selectively absorb and reflect certain wavelengths of visible light
Ex: Red objects reflects red light and absorbs all other colors
What is a pigment?
molecules that absorb specific wavelengths (energies) of light and reflect all others
What pigments exist within plant cells?
Chlorophylls and carotenoids
What is the primary pigment that is responsible for photosynthesis within plant cells?
Chlorophyll
What is carotenoid?
Any of a class of mainly yellow, orange, or red fat-soluble pigments, including carotene, which give color to plant parts such as ripe tomatoes and autumn leaves
What is xanthophyll?
a yellow or brown carotenoid plant pigment that causes the autumn colors of leaves
What is anthocyanin?
a blue, violet, or red flavonoid pigment found in plants
What is chlorophyll?
a green pigment, present in all green plants and in cyanobacteria, responsible for the absorption of light to provide energy for photosynthesis. Its molecule contains a magnesium atom held in a porphyrin ring
What is photosynthesis?
the process by which green plants and some other organisms use sunlight to synthesize foods from carbon dioxide and water, generally involves the green pigment chlorophyll and generates oxygen as a byproduct
Where do the light reactions occur? The Calvin Cycle?
Light reactions occur in the thylakoid membrane. The Calvin Cycle occurs in the stroma.
What is the overall reaction of photosynthesis?
6 CO2+6H20==>6O2+C6 H12 06
light
What are the two parts of photosynthesis?
Light dependent reactions and light independent reactions (Calvin Cycle)
What is the structure of a chloroplast?--thylakoids, grana, stroma, etc.
A chloroplast consists of an outer and inner membrane that serve as protection. Inside, stacks of thylakoids called grana are surrounded by the stoma.The stacks of thylakoid sacs are connected by stroma lamellae.
What happens in the light reactions?
Excited electrons move down electron transport chain to create ATP through chemiosmosis. NADPH is formed when hydrogen is added to NADP+. Water is split and oxygen is released as a waste product.
Why are the light reactions called the light reactions?
Light is the main energy source in the process.
Why are the light-independent reactions called the dark reactions?
They don't depend on light to carry out the process and can go on without it.
Why do the dark reactions need the light reactions in order to function?
The light reactions provide ATP and NADPH for the dark reactions which serve as energy sources.
How are ATP and NADPH involved in photosynthesis?
ATP is an electron carrier for the Calvin Cycle and NADPH is a hydrogen carrier.
What are the reactants of photosynthesis?
Water and Carbon Dioxide
What are the products of photosynthesis?
Oxygen and Glucose
What is an autotroph?
self feeding", organisms that are able to make energy-containing molecules from inorganic raw material by using basic energy sources-- MAKE FOOD FOR THEMSELVES
What does a photosystem do?
The 2 photosystems carry out the light-dependent portion of photosynthesis, providing the Calvin Cycle with the necessary ATP and NADPH.
What factors might affect the rate of photosynthesis?
light intensity, carbon dioxide concentration and temperature.
What is a photosystem made up of?
Pigment molecules, reaction center, and light harvesting complex
How do Photosystems I and II combine to carry out the light reactions?
Photosystem 2 supplies the electrons for PS I thus creating ATP. PS I utilizes those electrons to creates NADPH.
Describe non-cyclic electron flow during the light reactions (in detail)
In noncyclic electron flow, electron are transferred to photosystem I and then ultimately transfered to NADP+ to produce NADPH. Therefore the electrons are lost, only being replaced by the splitting of water
Describe the cyclic electron flow (in detail)
In cyclic electron flow, electrons from photosystem I are transferred back P700, the photochemical reaction center of photosystem I, supplying more ATP but no NADPH.
When will a plant shift from non-cyclic to cyclic photophosphorylation?
When the chloroplast runs low on ATP for the Calvin cycle, NADPH will accumulate and the plant may shift from noncyclic to cyclic electron flow (as shown):
NADP+ + 2H+ + 2e- ? NADPH + H+
How does an electron transport chain function?
Produces ATP and NADPH which are necessary to fix CO2 in the Calvin Cycle
What is chemiosmosis?
the movement of ions across a selectively permeable membrane, down their electrochemical gradient, ATP is generated
What is photophosphorylation?
refers to the use of light energy from photosynthesis to ultimately provide the energy to convert ADP to ATP, thus replenishing the universal energy currency in living things
What is the function of ATP Synthase?
enzyme that creates ATP
What are the 3 stages of the Calvin Cycle?
Fixation, Reduction, Regeneration
CO2 is combined with what to form the 3-carbon sugar that is the first stable product of the Calvin Cycle in C3 plants?
CO2 is combined with RuBP to make 3PG
This step in carbon fixation is catalyzed by what enzyme?
Rubisco
What sugar is released from the Carbon Cycle to be converted into glucose or other organic molecules?
G3P (times two)
The molecules of this sugar that aren't released are used for what purpose?
To recycle the molecules to make more G3P, it is more efficient this way
What coenzyme provides the reducing power to reduce BPG into G3P?
NADPH
Oxygen builds up when stomata are closed in C3 plants. How is this a problem?
Oxygen build-up in plants is bad! It is a waste material that leads to photorespiration
At the same time, plants lose water through open stomata in the process of transpiration
What do C4 plants do to combat this problem? (oxygen build-up) Include details like enzymes, oxaloacetate, etc.
C4 plants move the Calvin Cycle (and all of its rubisco) deeper inside the leaf to the bundle sheath cells where it is not exposed to oxygen build-up
How do CAM plants take things a "step further"? (in detail, malic acid)
C4 plants have 2 room chambers (mesophyll cell and bundle-sheath cell) while CAM plants have one--just the mesophyll cell. This allows the C4 pathway to proceed during the nighttime where there is less heat and wind (= less transpiration)
List examples of C3, C4, and CAM plants.
C3= Most plants (ex: pine trees, oak trees, etc.)
C4= Corn, summer annual plants
CAM= Succulents, agaves, orchids, bromeliads