Photosynthesis Test Flashcards
What are autotrophs?
Organisms that sustain themselves without eating anything derived from other organisms, the producers of the biosphere. They produce the biosphere, making organic molecules from
CO2 and other inorganic molecules.
What are photoautotrophs?
Organisms that use the energy of sunlight to make organic molecules. Almost all plants are photoautotrophs
What is photosynthesis?
The process that converts solar energy to chemical energy. This process nourishes almost the entire living world
What are heterotrophs?
Organisms that obtain most of their organic material from other organisms, the consumers of the biosphere. Almost all heterotrophs depend on photoautotrophs for food and CO2.
What is chlorophyll?
The pigment within chloroplasts, giving leaves their green color. Found inside the membranes of thylakoids
What is the mesophyll?
The interior tissue of the leaf, 30-40 chloroplasts are typically found in each mesophyll cell
What are stomata?
The microscopic pores of a lead where CO2 enter and O2 exits
What are thylakoids?
A third membrane system of connected sacs that are suspended in the stroma within the chloroplast that are sometimes stacked. The chlorophyll is inside the membranes of thylakoids
What are grana?
Stacked columns of thylakoids
What is stroma?
The dense, interior fluid of a chloroplast. The stroma is surrounded by 2 membranes
What is the thylakoid space?
The space inside the thylakoid sacs, separated from the Stroma by the thylakoids themselves
What are the reactants and products of photosynthesis?
Reactants: 6CO2 , 12H20 , light energy
Products: C6H12O6 , 6H2O , 6O2
How does electron flow in photosynthesis compare to cellular respiration?
The electron flow is reverse, photosynthesis is a redox process where H2O is oxidized and CO2 is reduced
Is photosynthesis endergonic or exergonic? where does the energy come from?
Endergonic, the energy boost needed is provided by light
What are the 2 parts of photosynthesis?
Light reactions(photo part) and he calvin cycle(synthesis part)
Where do light reactions occur?
Thylakoids
What occurs in light reactions?
- H2O is split
- O2 is released
- The electron acceptor NADP+ is reduced to NADPH
- ATP is generated from ADP by adding a phosphate group, called photophosphorylation
Where does the release of O2 come from in photosynthesis?
The splitting of water into just hydrogen and oxygen
Where does the Calvin cycle occur?
The stroma
What occurs in the Calvin cycle?
Sugar is formed from CO2 using ATP and NADPH
What is carbon fixation?
incorporating CO2 into organic molecules
What is light absorbed by the chlorophyll used for?
The drive the transfer of electrons and hydrogen ions from water to NADP+
How does photophosphorylation occur?
Light reactions generate ATP using chemiosmosis to power the addition of a phosphate group to ADP
What is the first step of the calvin cycle?
Carbon fixation
What are photons?
Light behaves as though it consists of discrete particles, these “particles” are called photons Each photon has a fixed amount of energy, and is not a tangible object. The amount of energy is inversely related to wavelength
What are the main functions of chloroplasts?
Chemical factories powered by the sun that have thylakoids that light energy into the chemical energy of ATP and NADPH
Which wavelength is the shortest, longest and has the most and least energy?
Shortest and most energy: purple
Longest and least energy: red
What is a spectrophotometer?
A device that measures a pigment’s ability to absorb various wavelengths by sending light through pigments and measuring the fraction of light transmitted at each wavelength
What is a pigment?
A substance that absorbs visible light and reflects the light it doesnt absorb
What is an absorption spectrum?
a graph plotting pigment’s light absorption vs wavelength
What is an action spectrum?
An action spectrum profiles the relative effectiveness of different wavelengths of radiation in driving a process