Photosynthesis and Respiration Flashcards
What is photosynthesis?
Process by which plants, some bacteria, and some protistans use the energy from sunlight to produce sugar
Overall reaction: 6H2O + 6CO2 + hv → C6H12O6 + 6O2
What does ‘oxygenic’ refer to in photosynthesis?
Uses water as electron donor and produces oxygen gas
What is the source of light for photosynthesis?
Sunlight
How does light provide energy for plants?
Energy produced by the sun reaches the earth as electromagnetic radiation
What does brightness depend on in terms of light?
Depends on the number of photons absorbed per unit time
What is the wavelength, and how is it measured?
Distance moved by a photon during one of its vibrations, measured in nanometers
What are the two ends of the electromagnetic radiation spectrum?
Gamma rays (shortest wavelength, highest energy) and radio waves (longest wavelength, lowest energy)
What is visible light?
Very small part of the spectrum that can be seen by the human eye (between 380 and 750 nm)
What is the role of visible light in photosynthesis?
Each photon contains just enough energy to excite the electrons of molecules without causing damage to the cell
Who devised an experiment to learn which wavelengths of light were most effective in photosynthesis?
Thomas Engelmann (1883)
What pigments are most important in plants for photosynthesis?
Chlorophyll a and Chlorophyll b
What are accessory pigments?
Absorb light and pass the energy to chlorophyll a in the reaction center, e.g., xanthophylls, carotenoids, phycobilins
Where does photosynthesis take place in plants?
Chloroplast
What are the parts of a chloroplast?
Outer membrane, inner membrane, intermembrane, thylakoids, grana, lumen, stroma
What is a photosystem?
Organizations of pigments, proteins, and enzymes bound in the membranes of the thylakoids
What are the two possible routes for electron flow in photosynthesis?
Noncyclic Electron Flow and Cyclic Electron Flow
What does noncyclic electron flow produce?
ATP and NADPH
What is the predominant route for electron flow in photosynthesis?
Noncyclic Electron Flow
What is the main function of chemiosmosis in chloroplasts?
To create a proton gradient that allows ATP synthesis
What is the Calvin cycle?
Utilizes energy from light reactions to fix and reduce carbon dioxide
What are the three phases of the Calvin cycle?
Carbon fixation, reduction, and regeneration of CO2 acceptor (RuBP)
What is the main product of glycolysis?
2 Pyruvate
What is fermentation?
Breaks down glucose into an acid or alcohol, doesn’t produce ATP but sustains glycolysis
What are the two types of fermentation?
Alcoholic Fermentation and Lactic Acid Fermentation
