C3 photosynthesis Flashcards
what type of reaction is photosynthesis
anabolic and endergonic
chloroplast structure
double layer membrane bound organelle containing the stroma, grana containg stacks of thylakoids, ribosomes and a single circular chromosome with no introns
in what organisms does photosynthesis occur
in plant cells containg chlorophyll and some photosynthetic bacetria and protista
purpose of photosynthesis
to make glucose for use in cellular respiration in plant cells
what is the thylakoid memebrane
internal system of interconnected membranes, carry out the light dependent reactions of photosynthesis
thylakoids
membranous sacks containg proteins complexes, chlorophyll, pigments and other accessory componenets - about 0;.25-0.08 microns in diameter
grana
sacks of 5-30 thylakoids, the phospholipid bilayer of the thylakoid is folded repeatedly into sacks to create grana, grana are connected by channels to form a single functional compartment seperate from the stroma
stroma
liquid filled interior of the chloroplast, the internal space enclosed by the chloroplast membrane excluding the thylakoid space, filled with colourless hydrophilic matrix, contains DNA, ribosomes and some temporary products of photosynthesis
endosymbiotic theory
chloroplasts were once believed to have free-living photosynthetic prokaryotic cellsk, one of these photosynthetic microbes was engulfed by another microbial cell, but not digested by it, the 2 cells lived in symbiotic relationship, being replicated together when the prokayotic cell replicated itself
how is the structure of chloroplasts evidence of endosymbiotic theory
enclosed by a double-membrane envelope (similar to the outer and inner membranes present in the cell wall of some bacteria), posses circular double stranded DNA not enclosed by a nuclear membrane, have there own ribosomes, produce their own RNA and proteins, size in the range of bacterial cells
simplified equation of photosynthesis
6CO2 + 6H2O → C6H12O6 + 6O2, with light above the arrow and chlorophyll below it
full equation of photosynthesis
6CO2 + 12H2O → C6H12O6 + 6O2 + 6H2O, with light above the arrow and chlorophyll below it
how is water obtained for photosynthesis
enters through the rooots via osmosis ammd the transpiration stream
how is water lost in a plant
roughly 90% of the wwater that enters the plants is lost via transpiration - evaporation of water vapour through the stomatal pores in the leaf
what factors increase transpiration
higher the heat and wind
what other uses does the plant have for water
needed for turgor pressure, most cellular activities need waater
how does transpiration occur
water travels from the rootts to the leaves against gravity using the xylem, water is polar so adheres to the walls of the xylem and coheres to other water molecules, creating enough tension to form ‘columns’ of water in the plant, as water enters the roots from the soil via osmosis, these water columns are pushed upward, allowing water to reach the stomata to evaporate
xylem
the tiisue that carries water up from tthe root to tthe leaf, contain strong cell walls made of lignin
how does carbon dioxide enter the plant
via dissusion through the stomata
where are stomata found
on the underside of the leaves to prevent excess evaporation of water vapour
chlorophyll
traps light (photoreceptor), needed for carbon fixation
how does light enter the leaf
absorbed by chlorphyll
two stages of photosynthesis
light dependant stage, light independent stage
where does the light dependent stage occur
grana/thylakoid of the chloroplast
what occurs in the light dependent stage
chlorophyll absorbs sunlight and coverts the light energy to chemical energy, this causes electrons to become energized, causing the water molcules to split into hydrogens and oxygens, oxygen is realesed as a waste product, half the hydrogens are joined onto thee NADP+ to forms NADPH, the other half pass through atp synthase which allows ADP + P to be converted to ATP
how is ATP formed
adding phosphate to ADP
ATP synthase and photosytem I and II
enzymes embedded in the thylakoid membrane
photosystem I and II
breaks h2o into hydrogens and O2
how are the hydrogens transported to the light independent stage
12 pass through ATP synthase, following the concentartion gradient, other 12 are transported using NADPH
light independent stage is aka
calvin cycle
where does the light independent stage occur
stroma
what occurs in the light independent stage
RuBisCo captures CO2, using energy provided by NADPH and ATP, carbons are broken off the CO2 and attach together, half the oxygens attach to the carbons, half the hydogens attach to the carbon-oxygen molecule to form glucose,, the other half of hydrogens attach to the remains oxygens to form h20
inputs of the light dependent stage
water, light ADP + Pi, NADP+
outputs of the light dependent stage
oxygen, NADPH, ATP
inputs of the light independent stage
NADPH, ATP form light dependent stage and more, carbon dioxide
outputs of the light indepedent stage
NADP+, glucose, ADP + Pi
