unit 5 Flashcards
im crying so hard im sobbing i cant do it
Location of light
dependent
reaction
Thylakoid membranes of
chloroplast
Location of light
independent
reaction
Stroma of chloroplast
Chloroplast
structure
outer membrane
inter membrane space
inner membrane
stroma
granum(the stack)
thylakoid (individual)
lamella (connects thylakoid)
starch grain
circular DNA
70s ribosomes
Thylakoid
membranes
Folded membranes containing
photosynthetic proteins
(chlorophyll)
embedded with transmembrane
electron carrier proteins
involved in the LDRs
Products of
photolysis
H+
Picked up by NADP to form
reduced NADP for LIR
e-
passed along chain of
electron carrier proteins
oxygen
used in respiration or
diffuses out leaf via stomata
Chlorophyll
Located in proteins on thylakoid
membranes
mix of coloured proteins that
absorb light
different proportions of each
pigment lead to different
colours on leaves
Advantage of
many pigments
Each pigment absorbs a
different wavelength of visible
light
many pigments maximises
spectrum of visible light
absorbed
maximum light energy taken in
so more photoionisation and
higher rate of photosynthesis
Photolysis
Light energy absorbed by
chlorophyll splits water into
oxygen, H+ and e
H2O > 1/2 O2 + 2e- + 2H+
Photoionisation
of chlorophyll
Light energy absorbed by
chlorophyll excites electrons so
they move to a higher energy
level and leave chlorophyll
some of the energy released is
used to make ATP and reduced
NADP
Light-dependent
reaction (LDR)
First stage of photosynthesis
occurs in thylakoid membranes
uses light energy and water to
create ATP and reduced NADP
for LIR
involves photoionisation of
chlorophyll, photolysis and
chemiosmosis
What happens to
protons after
chemiosmosis
Combine with co-enzyme NADP
to become reduced NADP
reduced NADP used in LIR
Chemiosmosis
Electrons that gained energy
move along a series of electron
carriers in thylakoid membrane
release energy as they go along
which pumps proteins across
thylakoid membrane
electrochemical gradient made
protons pass back across via
ATP synthase enzyme producing
ATP down their conc. gradient
Products of
LDR
ATP (used in LIR)
reduced NADP (used in LIR)
oxygen (used in respiration /
diffuses out stomata)
Light
independent
reaction (LIR)
Calvin cycle
uses CO2, reduced NADP and
ATP to form hexose sugar
occurs in stroma which
contains the enzyme Rubisco
temperature-sensitive
Calvin cycle
CO2 (with rubisco)> 2 X GP (with ATP and reduced NADP) > 2 X TP (with ATP) > RUBP
RuBP
Ribulose Bisphosphate
5-carbon molecule
GP
Glycerate-3-phosphate
3-carbon molecule
TP
Triose phosphate
3-carbon molecule
Producing
hexose sugar
in LIR
Takes 6 cycles
glucose can join to form
disaccharides (sucrose) or
polysaccharides (cellulose)
can be converted to glycerol to
combine with fatty acids to
make lipids
Limiting factor
A factor which, if increased, the
rate of the overall reaction also
increases
Limiting
factors of
photosynthesis
Light intensity
CO2 concentration
temperature
How light
intensity limits
photosynthesis
If reduced, levels of ATP and reduced
NADP would fall
LDR limited - less photolysis and
photoionisation
GP cannot be reduced to triose
phosphate in LIR
How temperature
limits
photosynthesis
LIR inhibited - enzyme
controlled (Rubisco)
up to optimum, more collisions
and E-S complexes
above optimum, H-bonds in
tertiary structure break, active
site changes shape - denatured
How CO2
concentration limits
photosynthesis
f reduced, LIR inhibited
less CO2 to combine with RuBP
to form GP
less GP reduced to TP
less TP converted to hexose and
RuBP regenerated
Agricultural
practices to
maximise plant
growth
Growing plants under artificial
lighting to maximise light
intensity
heating in greenhouse to
increase temperature
burning fuel to release CO2
Benefit of
agricultural
practices for plant
growth
Faster production of glucose ->
faster respiration
more ATP to provide energy for
growth e.g. cell division +
protein synthesis
higher yields so more profit
Products of LIR
Hexose sugar
NADP - used in LDR
Stages of
aerobic
respiration
1) Glycolysis
2) Link reaction
3) Krebs cycle
4) Oxidative phosphorylation
