Week 8/9 (Photosynthesis) Flashcards
what is photosynthesis?
coverts light energy into chemical energy ( food )
where is the site of photosynthesis?
chloroplasts
where are chloroplasts found and what’s unique about them
-mainly in mesophyll cells
-they have a double membrane
stomata
-microscopic pores
-how O2 exits and CO2 enters the leaf
photosynthesis reaction
6CO2 + 12H20 + light + pigments -> C6H12O6 + 6O2 +6H2O
what do chloroplasts do ?
split water molecules
what type of reaction is photosynthesis?
redox reaction
polar to nonpolar covalent bonds
the light reactions are in where and what do they do
-in thylakoids
-convert solar energy to chemical energy
light independent reaction what is and where
calvin cycle in stroma
role of pigments
absorb photons in the thylakoid membrane
what colors do plants absorb vs what is transmitted?
absorb red,blue,indigo and transmit green
carotenoids
yellow/orange/ red accessory pigments which gives color to plants ex ripe tomatoes or autumn leaves
photophosphorylation
conversion of ADP to ATP using the energy of sunlight by activation of PSII
photolysis
splitting of water molecule into H protons and O in PSII
antenna complex in photosystems
hands energy from photon of light down to reaction center
Photosystem 1
actually comes second in line
-P700
-reaction center (chlorophyll a)
-generates NADPH
Photosystem II
-occurs first
-P680
-reaction centre (chlorophyll a)
-generates ATP
what do the photosystems do
use light energy to generate ATP and NADPH
linear electron flow
involves PS1 and PSII
produces ATP and NADPH
cyclic electron flow
involves PS1 and only produces ATP
ATP molecules are generated by what
-chemiosmosis
H+ moves from thylakoid lumen to stroma
inputs and outputs of light reactions
inputs:
light (sun)
water
NADP+
ADP and Pi
outputs:
ATP
NADPH
O2
purpose of calvin cycle ?
to produce 1G3P
3x turns for 1 G3P
6x turns for one glucose
what is needed for one CO2 molecule
3ATP and 2NADPH
what is needed to make 1G3P
3CO2
9ATP
6NADPH
on hot dry days what do plants do?
close their stomata to conserve water
photorespiration
-metabolizes a wasteful by product of photosynthesis
-no ATP is produced
-photorespiration decreases photosynthesis output
C4 plants
light reactions occurs in mesophyll cells and calvin cycle in bundle sheath cells to find a way around photorespiration
CAM plants
succulents
-open stomata during the night and close it during the day
-less risk of dehydration
-make oxygen at night
