MITOCHONDRIA
in the cytoplasm of
a cell depends on
the activity of the
cell.
this is because
of RESPIRATION
occurs in
mitochondria
RIBOSOME
are smaller and
found in the
cytoplasm
DNA
NUCLEUS
contains genes.
DNA make up
a code and
form bases in
chromosomes
double helix
MESSENGER RNA
carries DNA to the
ribosome to make
protein
Discovering the structure
Watson and Crick discovered
it by -photographers showing
double helix -data indicating
bases occured in pairs
Proteins and mutations
grouping organisms
proteins:
made up of
amino acids
they have different jobs e.g: structural
proteins (collagen). Hormones carry
message to control reaction (insulin
control blood sugar levels). Carrier
(haemoglobin carriers oxygen).
Enzymes
Enzymes
speed up reaction:
Biological catalysts
work best at a
terticular temp
and pH
Mutations
can occur
spontaneously, by
radiation, or
chemicals
Respiration
respiration releases
energy from food to be
used for many different
processes in living
organisims
AERobic respiraion
it involves the
use of oxygen.
C6H12O6 + 6O2 -> 6CO2 + 6H2O
ANAERobic respiration
Anaerobic respiration is a type of
respiration that does not use oxygen. It
is used when there is not enough
oxygen for aerobic respiration.
glucose -> lactic acid (+energy)
Cell division
multicellular
it means a living
organism that has
different cells e.g
humans
it allows organisms to become
more complex and allows cells to
take up different jobs. this is
called CELL DIFFERENTIATION
needs to allows communication
between cells, supply cells with
nutrients, control changes within
the environment
Mitosis
produces new
cells for growth
two genetically
identical cells are
made
Meiosis
produces gametes(sex cells)
gametes are HAPLOID
cells because they only
contain one chromosone
The circulatory system
Blood
plasma is liquid bit of
blood. it transports
important substances
around your body
dissolved food (glucose).
carbon dioxide. hormones.
plasma protein
(antibodies). waste (urea).
water. red blood cells.
vessels
ARTERIES - these carry
blood AWAY from the
heart
CAPILLARIES - these are
involved in the exchange of
materials at the tissue
VEINS - these carry blood TO
the heart
The heart
DOUBLE
CIRCULATORY
SYSTEM :
blood pumped
to the lungs
and returns to
the heart to be
pumped round
body. blood is
at a higher
pressure and
flows to tissue
faster
Growth and
development
measuring growth
two main
phrases of
rapid growth:
just after birth,
adolescene
(puberty)
3 ways of
measuring
length: easy
but only
measures
growth in
one
direction
Dry mass:
best way,
but organism
dies
because no
water
Wet mass:
easy to
measure
but not
accurate
differentiation
stem cells stay
undifferentiated.
they can
develop into
anything
process by which a cell
changes to become
specialised for its job
some scientists use
embryonic stem cells.
But they can be found
in adults
some people argue against
this becuase they believe
human embryos shouldnt be
used for experiments science
they are potential life.
New genes for old
Selective breeding
is where human artifically
select the plants/animals that
are going to breed and have
their genes remain in the
population. Its usual to develop
best features
e.g. maximum yeild
of meat, milk etc.
good health and
disease resistance.
speed, attractiveness
etc
can reduce ALLELES in
population (gene pool)
increasing risk of harmful
recessive characteristics in
offspring. or reduction in
variation, population cant
adapt
genetic engineering
basic idea is to move genes
(sections of DNA) from one
organism to another so that it
produces useful biological
produces
the desired characteristics are selected
the genes responsible are identified
and removed (isolated)
the genes are inserted into other organism
the organisms are allowed to reproduce (replicate)
Cloning
cloning animals
it is done by
transferring a cell
nucleus
dolly the sheep
ethical issue
cloning plants
plants keep there
ability to differentiate
making them easier
to clone
tissue culture
a plant is selected that has certain characteristics
a large number of small pieces of tissue are
cut from plant
the small pieces are grown in test tubes containing
a growth mineral
Aseptic technique is used at all stages to stop any
microbes infecting the plant
it is making an
exact cope of
another
organism.
clones are
genetically
identical