photosynthesis and nutrition Flashcards
reactants and products
reactants: CO2, water, and light
products: sugar
two stages
light reaction (take place in thylakoid membrane)
Calvin cycle (take place in stroma)
light reactions
convert light energy to chemical energy of ATP and NADPH
Split H2O into O2
Calvin Cycle
uses ATP and NADPH to convert CO2 to sugar G3P
returns ADP, inorganic phosphate, and NADP+ to light reactions
cycle goes around three times
function of chloroplast pigments
absorb light
types of photosynthetic pigments
essential pigment: chlorophyll a
accessory pigments: chlorophyll b, carotenoids, phycobillins
the pigments absorb different wavelengths of light
what contributes to yellowing and reddening of leaves
carotenoids
what creates green color of leaves
chlorophyll
C3 pathway
most typical photosynthetic pathway, produces three carbon molecule G3P, three phases: carbon fixation, reduction, regeneration of RuBP
starts with RuBP and ends with RuBP
CO2, ATP, and NADPH needed
catalyzed by rubsico
photorespiration
rubsico fixes O2 instead of CO2, causing CO2 to be released and using ATP
no sugar produced
occurs in hot and dry conditions when stomata is closed
C4 and CAM pathways
first carbon fixation involves PEP carboxylase instead of rubisco
CO2 is stores as malate or aspartate
4 C molecules of produced
2nd carbon fixation is the calvin cycle
how are carbon fixations separated in C4 and CAM
separated spatially in C4: mesophyll and bundle sheath cell
CAM: stomata opens at night and closes during the day
night: CO2 incorporated into organic acid
Day: Calvin cycle occurs
C4 advantages
higher opitmal temperature, more photosynthesis, conservation of water, used 1/3 to 1/6 less rubisco, less water loss due to nitrogen efficiency
C4 disadvantages
more ATP needed
CAM features
high water use efficiency, facultative use of CAM pathway (can be switched into), used by ferns, aquatic plants, succulents, and epiphytes
types of nutrients
micronutrients and macronutrients
macronutrients
sulfure, phosphate, magnesium, calcium, potassium, nitrogen
beneficial elements
other nutrients that are essential for only limited groups of plants
nutrient deficiency symptoms
necrosis (dying of cells), chlorosis (not enough chlorophylls)
magnesium property
it is phloem mobile, meaning it can move through the phloem
soil function
provides most nutrients, mixture of inorganic material and dead organism, some living organisms
where do plants grow into
the topsoil
layers of soil
O horizon (humus) at top, A horizon (topsoil), E, B, C, less organic matter found as you go down to R (bedrock)
grassland soil layers
has a lot of topsoil compared to forests
three main textures
clay, sand, silt
sand
many macropores, allowing for movement of water