B1C1P1 Revision

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B1C1P1 Revision
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B1 - Genes
Nucleus contains Chromosomes (23 from each
parent, made of DNA). Each Chromosome contains
Genes. Pairs of Genes, one from each parent
control your bodys characteristics like Eye
Colour, Height, etc. Each type of Gene
controlling one characteristic is called an
Allele. There are dominant and Recessive Alleles.
This diagram is for Eye Colour.
Diseases such as Huntingtons and Cystic Fibrosis
are Inherited genetic diseases you cannot catch
them! Sex is also inherited.
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B1 continued
Ethics have to make decisions on issues such as
abortions if you find out that the fetus has
cystic fibrosis. How reliable are these
tests? Gene Therapy being developed viruses
carry genes around the body which replace faulty
alleles with normal alleles. Cloning Asexual
reproduction in some plants and bacteria already
happens. Humans have now made clones (easy to do
with plant cuttings, hard to do with animals but
Dolly The Sheep was cloned in the nineties. Stem
cells could be taken from an embryo and cloned to
help treat patients with some diseases as stem
cells have the ability to turn into any part of
the human body.
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C1 The Atmosphere
Only 15km thick! Made of Nitrogen (78), Oxygen
(21), Argon (1), Carbon Dioxide (0.04) and
water vapour. Where is the driest place on Earth?
Scientists and politicians worried about link
between Carbon Dioxide concentration and Global
Warming (CO2 is a greenhouse gas)
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C1 continued
Main Air Pollutants Sulfur Dioxide, SO2 (causes
Acid Rain), Carbon Monoxide, CO (Poisonous Gas,
can kill you), Nitrogen Dioxide, NO2 (acid rain,
breathing problems), Particulates (breathing
problems)
Air Quality does it matter where you live?
Concentration of gases and particulates measured
in parts per billion, ppb. Poor air can affect
health.
All measure temperature of lab. Accuracy,
reliability, outlier, range, mean.
Combustion (demo bunsen and beaker) fuel reacts
with oxygen to produce carbon dioxide and water.
Some fuels contain Sulphur and Nitrogen so
produce nitrogen dioxide and sulphur dioxide too.
Fire Triangle HEAT, FUEL, OXYGEN take one
away to stop the fire.
Atoms are never lost in a reaction!
Catalytic convertors, power station filters and
cleaner fuels can all improve air quality.
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P1 Earth and Universe
The Universe is about 14 billion years
old. Scientists use evidence such as that found
in rocks to try to work out how the Earth was
formed and how old it is. Scientists produce
Theories which other scientists can then discuss
and try to prove if they are right or
wrong. James Hutton proposed the Rock
Cycle. Alfred Wegner proposed Continental Drift
the idea of Tectonic Plates - only 100 years ago
and everyone thought he was mad. We now have
evidence for this theory magnetic stripes on
the seafloor and similar creatures found on
separate continents. Movement of tectonic plates
can cause earthquakes, volcanoes and tsunamis
when pressure built up in the rock is released
suddenly. What killed the dinosaurs? We dont
yet know were still collecting evidence but
the most popular theory is an asteroid collision.
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P1 - cont
Stars go through life cycles gravity pulls them
together then nuclear fusion starts and fuels the
star until the Hydrogen runs out when they swell
up and eventually die. The Universe was probably
formed from the Big Bang - there is evidence for
this although there are religious theories too.