Ch. 7 - Photosynthesis Flashcards
Photosynthesis (3)
- refers to the light dependent reactions and synthesis to the putting together of sugar (the 3C sugar G3P) during the Calvin Cycle
- all of our oil and gas originally from historic PS
- PS organisms trap solar energy into ATP and NADPH which they use to drive the production of carbohydrates (a way to convert solar into chemical energy)
Photoautotroph
Organism that obtains energy from sunlight and carbon from CO2 by photosynthesis
Heterotroph
Organism that cannot make its own organic food molecules and must obtain them from consuming other organisms or their organic products = a consumer or decomposer
Cellular respiration and photosynthesis
- Glucose oxidized to CO2; oxygen reduced to water
- CO2 reduced to glucose; H2O oxidized to O2
Mesophyll
Found in interior of leaf; each cell has ~30-40 chloroplasts
Stoma/stomata
Tiny pores used for gas exchange
Inner compartment
Filled with thick fluid - stoma (Calvin Cycle here)
Thylakoids membrane
Contains pigments (light reactions here)
Photosynthesis in 2 stages
- light dependent reactions (thylakoids membrane): some ATP is produced via photophosphorylation and NADP+ is reduced is NADPH
- Calvin Cycle
NADP+
Nicotinamide adenine dinucleotide phosphate - same function as NAD+ in CR
Electromagnetic spectrum (3)
- entire spectrum of radiation ranging in wavelengths form less than a nm to more than a km
- shorter wavelength > higher energy
- longer wavelength > lower energy
Carotenoid pigments
Last longer in the fall, after green chlorophyll molecules have been broken down = beautiful fall colours
Photon
Fixed quantity of light energy; the shorter the wavelength, the greater the energy
Excited state of a photon (2)
- When a molecule absorbs a photon of light, its electrons are boosted to a higher energy level
- energy is quickly lost in the form of heat and light (longer, lower energy wavelength)
Chlorophyll a (2)
- Absorbs mainly blue-violet light and red light
- looks blue-green because it reflects mainly green light
Chlorophyll b (2)
- absorbs mainly blue and orange light and reflects (and appears) yellow-green
- broadens the range of light that a plant can use by conveying absorbed energy to chlorophyll a, which then puts the energy to work in the light-dependent reactions
Photosystems (3)
- similar (but not identical to ETC in respiration)
- are sets of light absorbing pigments and their associated electron carriers
- consists of a number of light-harvesting complexes surrounding a reaction-centre complex
Example of photosystem (2)
- in the thylakoids membrane light energy transfer between different pigment molecules to reach chlorophyll a
- chlorophyll a passes on excited electron to a primary electron acceptor
light harvesting complex (2)
contains various pigment molecules bound to proteins
-function as a light-gathering antenna
