Photosynthesis Flashcards
(45 cards)
Photosynthesis
Occurs in the … of plants - inside palisade mesophyll tissues
Chloroplasts contain photosynthetic … which absorb … energy at particular …
Examples of pigments include chlorophyll a & b, carotene & xanthophyll
Chloroplasts … themselves to maximise exposure to light
Chloroplasts
Pigments
Light
Wavelengths
Orientate
Chloroplast orientation
Low light conditions - distribute …
High light intensity - line up in … columns against cell wall, side on to light to prevent damage by …
Evenly
Vertical
Over-exposure
Chromatography
A … separates photosynthetic …
Rf value = distance moved by … over distance moved by … front (always less than 1)
Chromatogram
Pigments
Pigment over solvent
Absorptions spectrum
Shows … absorption by a … at different …
Light
Pigment
Wavelengths
Action spectrum
shows rate of … at different …
Photosynthesis
Wavelengths
Absorptions & action spectrum
Close correlation;
… used in light absorption are used in …
Wavelengths
Photosynthesis
Light harvesting
= when photosynthetic … absorb … energy
Achieved by … complexes within … membranes of the …
Antenna complex structure
- antenna contains other pigments to allow a range of … to be absorbed
- … centre contains … = primary pigment
Pigments
Light
Antenna
Thylakoid
Chloroplasts
Wavelengths
Reaction - chlorophyll a
Light dependant stage
- light hits top of … complex and is passed between … pigments to … centre (proteins stop light escaping)
- chlorophyll a molecules absorb … & emit high energy …
- 2 types of reaction centre: … & …
-photons of light … electrons - raising their energy level as they then pass through electron … where they are used to synthesise … by … or to reduce …
Antenna
Accessory
Reaction
Light
PSI & PSII
Excite
Acceptor
ATP - phosphorylation
NADP
Phosphorylation
Addition of … group to … to form …
Photo-phosphorylation - … is also needed
Phosphate
ADP
ATP
Light
Light dependant stage: Cyclic photo-phosphorylation
- involves … only
- high energy … pass from … to an electron … and then to the … - which generate proton … for …
- these now lower energy electrons pass back to …
Electrons originates from PSI & returns to PSI
PSI
Electrons - PSI - acceptor - ETC
Gradient - chemiosmosis
PSI
Light dependant stage: Non-cyclic photo-phosphorylation
- involves … & …
- higher energy electrons (from …) are passed to … to from … NADP (2 electrons needed)
- … now has an electron shortage - … charge, so are primed to steal electrons from …
- simultaneously, PSII has passed the electrons to the … to generate a proton … for …
- the electron is returned to … - non-cyclic
PSI & PSII
PSI
NADP
Reduced
PSI - positive
PSII
ETC
Gradient
Chemiosmosis
PSI
Photolysis
Splitting of … by … - water molecules found in … space
Produces:
- E… - replace those lost during … photo-phosphorylation so enter PSII
- P… - reduces … - each NADP needs 2 protons & 2 electrons to become reduced
- O… - waste product
Water
Light
Thylakoid
Electrons - non-cyclic
Protons - NADP
Oxygen
Light independent stage (Calvin Cycle)
Fixed … into …
1) CO2 is taken up by 5C … (RUBP) to form an unstable … compound - catalysed by … enzyme
2) 2 molecules of 3C …-3-… (GP) is then formed from this
3) … & reduced … (from dependent stage) reduces the GP to 3C … … (TP)
4) TP gets converted into … then starch - most is used to regenerate … (using ATP) to allow light dependant stage to continue
Carbon dioxide - carbohydrate
1) Ribulose Bisphosphate
6 carbon (6C)
2) Glycerate-3-phosphate
3) ATP & reduced NADP
Triose phosphate
4) Glucose
RUBP
Identifying ATP & reduced NADP (Calvin Cycle)
ATP is needed … - GP to TP & RuP to RUBP
Reduced NADP only … - GP to TP
Twice
Once
Where does (ADP & Pi) & (oxidised NADP) go during light independant stage?
Returns to light .. stage to reform ATP & reduced NADP
Dependant
Production of macronutrients
Carbohydrates - … phosphate is converted into … then … via … reaction
Fats
1) a… c… A can be synthesised from …-3…phosphate and converted into … acids
2) … phosphate can be converted into …
Fatty acids + glycerol = t…
Protein
…-3-… can be converted into … acids for protein synthesis with help from … ions from … in soil - these for the … group
Triose
Glucose
Starch
Condensation
acetyl coenzyme
Glycerate-3-phosphate
Fatty
Triose glycerol
Triglycerides
Glycerate-3-phosphate
Amino acids
Nitrogen - Nitrate
Ammonium
Amino group
Limiting factors
If factor:
- Is too low - limited the rate of physical process (e.g. …)
- increases - … rate of the process
E.g.
temperature - affects … energy therefore rate of transport & … activity
Light intensity - needed to excite the … during light …stage of photosynthesis
Photosynthesis
Increases
Enzyme
Electrons
Dependant
Mineral nutrition: Nitrogen
Absorbed by the … by … transport as … from … in soil
Aids synthesis of … acids - forms amino …
Nitrogen deficiency - reduced … of all organs
Root
Active
Nitrate
Ammonium
Amino - group
Growth
Mineral Nutrition: Magnesium
Absorbed as Mg2+
Aids … production (forms part of it) & activation of …
Deficiency = … - existing Mg2+ is mobilised & transported to newly formed leaves
Chlorophyll
ATPass
Chlorosis
Where does the light dependant stage occur?
…
Thylakoid
Where does the light independent stage occur?
…
Stroma
Explain how carbon dioxide is used to produce glycerate-3-phosphate
… catalyses reaction between carbon dioxide & …;
Forms unstable … compound that splits into 2 3C GP
Rubisco
RuBP - ribulose bisphosphate
6C
Describe how glycerate-3-phosphate is converted into Triose phosphate
Glycerate-3-phosphate gets …;
Using … NADP;
ATP also required to supply …;
Reduced NADP & ATP - from light … stage
Reduced
Reduced
Energy
Dependant
Why are only some TP used to product hexose phosphate?
Most are needed to regenerate …
RuBP - ribulose bisphosphate
