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A2 Biology

Photosynthesis ­ Unit 4 Section 1

Plants need energy for things like photosynthesis, active transport, DNA
replication, cell division and protein synthesis. Animals need energy for
things like muscle contraction, the maintenance of body temperature, active
transport, DNA replication, cell division and protein synthesis.

Photosynthesis is the process…

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Contained in the inner membrane of the chloroplast surrounding the
thylakoid is a gel substance called stroma. It contains enzymes, sugars,
inorganic ions and oil droplets.

There are two stages to photosynthesis, these are the Light Dependant and
light Independent reaction.

The light Dependant Reaction The Light Independent Reaction
It…

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2. Photolysis of water produces protons, electrons and 02 - Photolysis of
water produces protons, electrons and O2, so the electrons move along
the electron transport chain, they must be replaced. Light energy splits
water into proteins electrons and 02
3. Energy from the excited electrons makes ATP - Energy…

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This reduction reaction also requires H+ ions which come from
the reduced NADP.
Triose phosphate then converts into many useful organic
compounds.
3. Ribulose phosphate is then regenerated
Five out of every six molecules of TP produced in the cycle are not
used to make hexose sugars, but to regenerate…

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Net production: the amount of energy available that is available to the next
trophic level.
Habitat: is the place where an organism lives, such as a stream, tropical
rainforest or a sand dune.
Population: is a group of organisms of the same species, living and breeding
together in a habitat.…

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Finding a mate: Reproduction is a powerful driving force and the likelihood of
finding a mate.
Territory: many species of animals show clear territorial behaviours.
Parasitism and Disease: they have a devastating effect on individuals.

Every species occupies a different niche. A niche is the role of a species within…

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there; this soil contains seeds, roots and soil organisms. There number of
plants and animals in the beginning is much higher.

Happens in the same way but there is already a soil layer so succession
happens at a higher level, so the pioneer plant will be a bigger plant.
At…

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Can be used to find temperature over thousands of years.
The pollen is preserved in the peat bogs.
Layers accumulate over a long time, so the pollen age increases in
depth.
They can take cores from the peat bogs and extract the pollen grains
and identify the plant species in…

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Rising temperature

An increase in temperature will affect the metabolism of all organisms.

Normally and increase in the temperature will create the enzyme
reaction to increase, speeding up reactions.
Enzymes have very specific optimum temperatures.
When it increases above this temperature then they decrease the
metabolic reactions.

This means that…

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There are different ways to reduce the increasing CO2 concentrations which
is one cause of global warming. Is to move carbon between organisms and the
atmosphere it called the carbon cycle. The carbon is absorbed by the plants
when they carry out photosynthesis. The carbon is passed to the animals…

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