Biomass can
provide energy by
burning fast
growing trees.
Biomass can
provide energy
via fermentation.
Biofuels are alternatives to fossil fuels, which
do not produce particulates or add to
greenhouse gas levels.
Biogas contains mainly methane, some
carbon dioxide, and traces of hydrogen,
nitrogen and hydrogen sulphide.
Biogas containing more than 50%
methane is burnable, but below
10% methane it is explosive.
Biogas is a ‘cleaner’
fuel than petrol and
diesel but contains
less energy than
natural gas.
Biogas can be used
to provide
electricity, hot
water and steam
for heating or to
fuel cars.
Gasahol is a mixture of petrol and alcohol
used in cars in countries like Brazil.
e
Loam is a soil with a mixture of sand and clay.
Humus is mostly
decomposed dead
material in soil.
When humus decomposes it
releases minerals into the soil,
and aerates the soil.
Most life in soil needs a supply of air and water.
Earthworms bury organic material, which is decomposed
by bacteria and fungi.
Earthworms aerate and drain soil with their burrows.
Earthworms mix up layers
of soil.
Earthworms neutralise
acidic soil.
Charles Darwin recognised the importance of earthworms in
agriculture.
f
There are four major advantages
of living in water: No shortage
of water/risk of dehydration.
Less temperature variation.
Support of the body. Easy to
dispose of waste.
There are two disadvantages to living in water: Regulating
water content and resistance to movement.
Light, temperature and mineral content of water all
vary with seasons and depth of the water.
Some food chains in oceans start with
bacteria, not plants, and some rely on
‘marine snow’
Phytoplankton
are microscopic
plants.
Zooplankton are
microscopic
animals.
Sewage and fertiliser run off
can cause eutrophication
Biological indicators are
species which are only able to
survive in particular levels of
oxygen or at particular pHs.
g
Biological washing
powders contain
carbohydrases to
digest carbohydrate
stains, proteases to
digest protein stains,
and lipases to digest
fatty stains.
Biological washing powders work best at about 40ºC.
Sucrose sugar can be
broken down by the enzyme
sucrose into the smaller,
sweeter, sugars glucose and
galactose.
Using sweeter sugars than sucrose, means less sugar
has to be added to foods.
Immobilising enzymes means fixing them into an insoluble
material so they are easier to handle and use.
Immobilised enzymes do not contaminate the
substance they are added to.
Immobilised enzymes can be used in
a continuous process
Lactose intolerant people do not produce the
enzyme lactase, so are unable to digest
lactose sugar from milk.
Bacteria in the gut of lactose intolerant people ferment
the lactose, causing wind and diarrhoea
h
New organisms produced
by genetic engineering are
called transgenic
Genes do the produce the
same proteins, no matter
which organism they are
put in to.
Restriction
enzymes cut DNA
to leave ‘sticky
ends’.
Ligase enzymes are used to
stick other genes to the ‘sticky
ends’ of cut DNA.
Bacteria can be
genetically
engineered to
produce human
insulin for
diabetics
Transgenic
organisms can be
cloned to produce
identical copies,
and large
quantities of the
useful product
Bacteria contain loops of
DNA called plasmids.
Assaying techniques are
techniques used to identify if
the new gene has been
successfully transferred.
Assaying
techniques are
techniques used to
identify if the new
gene has been
successfully
transferred.
Electrophoresis is a
technique used to
separate pieces of
DNA.
Radioactive
probes are used to
show up the DNA
during DNA
‘fingerprinting’.