Photosynthesis Essay Plans

factors affecting rate

photosynthetic pigments

light harvesting

light dependent stage - cyclic and z-scheme

light independent stage

leaf structure and function

HideShow resource information
Preview of Photosynthesis Essay Plans

First 367 words of the document:

Light needed to provide energy for photophosphorylation of ADP and Pi to ATP in
light dependent stage
Photosynthetic pigments found in thylakoid membranes of chloroplasts in
mesophyll cells (mainly) and guard cells
Accessory pigments e.g chlorophyll b, carotenoid such as carotenes and
xanthophylls absorb photons of light energy
Photons of light energy passed to along antenna complex primary pigment,
chlorophyll a, in reaction centre (PSI or PSII)
Carotenoids red/yellow in colour and absorb mainly blue-violet wavelengths of
Chlorophylls green in colour and absorb red and blue-violet wavelengths of light
Wavelengths of light absorbed by different photosynthetic pigments shown by
absorption spectrum
Evidence for requirement of light in photosynthesis is the correlation between the
action and absorption spectra
Action spectrum is the rate of photosynthesis plotted at different wavelengths of
Different photosynthetic pigments absorb different wavelengths of light, so having
more than one type of photosynthetic pigment allows plants to absorb more light
than if they only had one type
Photosynthetic pigments a plant has available for it to use in light harvesting can be
found by paper chromatography, separating out the different pigments
o pigments extracted by grinding leaf using pestle and mortar and solvent
o origin line drawn 2cm from bottom of chromatography paper
o extract of pigments added to origin line
o chromatogram places in glass tank containing solvent with level of solvent
just below origin line
o solvent left to rise up chromatography paper, taking pigments with it at
different rates
o chromatography paper taken out and dried
o Rf used to identify pigment
o Rf = distance travelled by pigment/distance travelled by solvent front
Large surface area of leaf, thin and transparent cuticle and epidermis and
intracellular movement of chloroplasts by cyclosis allows more light to be
Chlorosis is magnesium deficiency resulting in low production of chlorophyll and
yellow colouring of plants; slows/prevents light harvesting

Other pages in this set

Page 2

Preview of page 2

Here's a taster:

Limiting factors are conditions that prevent the rate of photosynthesis from further
Compensation point is when the carbon dioxide produced during respiration is
completely used during photosynthesis
Photosynthometers used to calculate the rate of photosynthesis by measuring the
volume of oxygen produced over a specific period of time
Volume of water available affects the rate of reaction because photolysis of water
in the non-cyclic version of the light dependent stage produces the electrons
needed to replace those lost from…read more

Page 3

Preview of page 3

Here's a taster:

Temperature affects the rate of photosynthesis by limiting action of enzymes such
as RuBP carboxylase and ATP synthetase
o Too low and the molecules have less kinetic energy so the number of
substrate collisions with the active site decreases therefore fewer
enzyme-substrate complexes are formed and less product is formed
o Too high and the enzyme becomes denatured, so there is a lower
concentration of substrate-specific active sites therefore the number of
substrate collisions with the active site decreases so fewer
enzymes-substrate complexes are formed…read more

Page 4

Preview of page 4

Here's a taster:

In thylakoids of chloroplasts
Photophosphosylation of ADP and Pi to ATP
Photolysis of water to 2e-`s, 2H+'s and ½ O2
NADP is reduced by 2H+'s from photolysis of water and 2e-`s from light hitting PSI
Also known as Z-scheme
Light absorbed by PSII and passed on to chlorophyll a (P680)
Chlorophyll a emits 2 e-'s, which are raised to a higher energy level and picked up
by an electron acceptor
Electron's passed along a chain of carrier molecules until it is…read more

Page 5

Preview of page 5

Here's a taster:

Also known as Calvin Cycle
Uses ATP and reduced NADP made in the light dependent stage
Carbon dioxide combines with ribulose bisphosphate (RuBP) using enzyme RuBP
carboxylase as a catalyst
Product of unstable 6C compound formed, which decomposes into 2x 3C molecules
of glycerate 3-phosphate (GP)
ATP used to phosphorylate 2x 3C molecules of GP to 2x 3C molecules of glycerate
Reduced NADP acts as reducing agent to reduce glycerate bisphosphate to
glyceraldehyde 3-phosphate (GALP)
1/6 of GALP produced is converted…read more


No comments have yet been made

Similar Biology resources:

See all Biology resources »See all resources »